83 results on '"Pay Drechsel"'
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2. A spatio-temporal dataset on food flows for four West African cities
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Hanna Karg, Edmund K. Akoto-Danso, Louis Amprako, Pay Drechsel, George Nyarko, Désiré Jean-Pascal Lompo, Stephen Ndzerem, Seydou Sidibé, Mark Hoschek, and Andreas Buerkert
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Science - Abstract
Abstract Gaining insight into the food sourcing practices of cities is important to understand their resilience to climate change, economic crisis, as well as pandemics affecting food supply and security. To fill existing knowledge gaps in this area food flow data were collected in four West African cities - Bamako (Mali), Bamenda (Cameroon), Ouagadougou (Burkina Faso), and Tamale (Ghana). The data cover, depending on the city, road, rail, boat, and air traffic. Surveys were conducted for one week on average during the peak harvest, lean, and rainy seasons, resulting in a dataset of over 100,000 entries for 46 unprocessed food commodities. The data collected includes information on the key types of transportation used, quantity, source, and destination of the food flows. The data were used to delineate urban foodsheds and to identify city-specific factors constraining rural-urban linkages. The data can also be employed to inform academic and policy discussions on urban food system sustainability, to validate other datasets, and to plan humanitarian aid and food security interventions. more...
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- 2023
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Catalog
3. Investment priorities for research and innovation in urban agri-food systems: Toward more resilient cities in the Global South
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Gordon Prain, David Simon, Jess Halliday, and Pay Drechsel
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urban agriculture ,food systems ,controlled environment agriculture ,informal markets ,circular bioeconomy ,resource recovery ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Urban and peri-urban agriculture (UPA) is widely distributed throughout the Global South. Despite urban population growth and diversifying food habits, UPA delivers an important part of urban food supply, as well as other types of services to cities, such as employment and waste reuse. Nevertheless, the extent and importance of UPA varies between different urban areas, while challenges like limited recognition, land conversion, and water pollution and competition threaten the potential of UPA to contribute to urban resilience. Key investment priorities for research and innovation for overcoming current challenges include incentivized peri-urban zoning, urban allocation of productive lands, and increasing capacities for controlled environment agriculture (CEA). Innovative repositioning of food marketing can help to strengthen supply of healthy food from UPA production, increase decent employment, and turn food markets into nutrition hubs. Priority innovations for contributing to the circular bioeconomy of cities include scaling the safe use of wastewater for irrigation through investments in the adoption of multiple risk-barrier approaches and scaling UPA-based ecosystem services for valorising solid waste and environmental management. Innovations in urban governance are required to support these processes by bringing food systems into urban planning through food mapping and the multisectoral platforms for dialogue and policy formulation across city regions and with vertical levels of government. more...
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- 2022
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4. The cultural economy of human waste reuse: perspectives from peri-urban Karnataka, India
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Zachary Burt, C. S. Sharada Prasad, Pay Drechsel, and Isha Ray
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caste ,fecal sludge ,human waste management ,preference model ,resource recovery and reuse ,Environmental technology. Sanitary engineering ,TD1-1066 - Abstract
Safely managed waste reuse may be a sustainable way to protect human health and livelihoods in agrarian-based countries without adequate sewerage. The safe recovery and reuse of fecal sludge-derived fertilizer (FSF) has become an important policy discussion in low-income economies as a way to manage urban sanitation to benefit peri-urban agriculture. But what drives the user acceptance of composted fecal sludge? We develop a preference-ranking model to understand the attributes of FSF that contribute to its acceptance in Karnataka, India. We use this traditionally economic modeling method to uncover cultural practices and power disparities underlying the waste economy. We model farmowners and farmworkers separately, as the choice to use FSF as an employer versus as an employee is fundamentally different. We find that farmers who are willing to use FSF prefer to conceal its origins from their workers and from their own caste group. This is particularly the case for caste-adhering, vegetarian farmowners. We find that workers are open to using FSF if its attributes resemble cow manure, which they are comfortable handling. The waste economy in rural India remains shaped by caste hierarchies and practices, but these remain unacknowledged in policies promoting sustainable ‘business’ models for safe reuse. Current efforts under consideration toward formalizing the reuse sector should explicitly acknowledge caste practices in the waste economy, or they may perpetuate the size and scope of the caste-based informal sector. HIGHLIGHTS A discrete choice method is used to uncover preferences and power disparities in the Indian human waste economy.; Caste-adhering, vegetarian farmowners prefer to conceal the origins of fecal sludge-derived fertilizer (FSF).; Most workers are open to using FSF if it is dry and not malodorous.; The formalization of fecal sludge reuse could inadvertently perpetuate caste-based disparities and unsafe waste handling.; more...
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- 2021
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5. Food Flows and the Roles of Cities in West African Food Distribution Networks
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Hanna Karg, Jill Bouscarat, Edmund Kyei Akoto-Danso, Philipp Heinrigs, Pay Drechsel, Louis Amprako, and Andreas Buerkert
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foodshed ,food supply chain ,urban food system ,urbanization ,central places ,GIS ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
In West Africa, rampant urbanization is changing food systems, including the magnitude and composition of food flows and the length of supply chains. An increasing body of literature discusses pathways to sustainable transformation of urban food systems taking into account links between urban and rural spaces. Research and policy have focused on the role of cities as consumption centers receiving food from local, regional, and global hinterlands. This study aims at widening the perspective on the role of cities in food distribution, by bringing into focus a city's function as a consumption, aggregation, and disaggregation center. The analysis is based on a comprehensive set of primary data on food flows collected in four West African cities across different seasons. The analysis shows that the investigated cities are integrated into multi-scale urban and market networks. Their position within these networks interacts with their reliance on other territories for food supply and with their functions, such as the aggregation of goods. The capital cities of Ouagadougou (Burkina Faso) and Bamako (Mali) relied more on lower-rank urban settlements further away, while Tamale, a secondary city in Ghana, acted as an assembly market for local rural producers and in turn supplied larger urban centers. Bamenda, a secondary city in Cameroon, acted as a consumption center sourcing mainly from its hinterland. Beyond that, city functions were context-specific and varied according to type of product and season. Extending the perspective on the role of cities has implications for policy, including bringing into focus and strengthening midstream segments, such as market and transport links. more...
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- 2022
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6. Resource recovery and reuse as an incentive for a more viable sanitation service chain
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Krishna C. Rao, Miriam Otoo, Pay Drechsel, and Munir A. Hanjra
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Faecal sludge ,resource recovery ,business models ,cost recovery ,waste treatment ,Hydraulic engineering ,TC1-978 - Abstract
Recovering nutrients, water and energy from domestic waste streams, including wastewater and faecal sludge, is slowly gaining momentum in low-income countries. Resource recovery and reuse (RRR) offers value beyond environmental benefits through cost recovery. An expected game changer in sanitation service provision is a business model where benefits accrued via RRR can support upstream sanitation services despite the multitude of private and public stakeholders involved from waste collection to treatment. This paper shows options of how resource recovery and reuse can be an incentive for the sustainable sanitation service chain, by recovering costs where revenue can feed back internally or using generated revenues from reuse to fill financial gaps across the service chain to complement other supporting mechanisms for making waste management more attractive. more...
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- 2017
7. Heavy metal accumulation and health risk assessment in wastewater-irrigated urban vegetable farming sites of Addis Ababa, Ethiopia
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Desta Woldetsadik, Pay Drechsel, Bernard Keraita, Fisseha Itanna, and Heluf Gebrekidan
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Vegetable farming ,Wastewater irrigation ,Heavy metal ,Health risk ,Target hazard quotient ,Addis Ababa ,Food processing and manufacture ,TP368-456 - Abstract
Abstract Background Wastewater irrigation for vegetable production is a highly prevalent practice in Addis Ababa and a number of articles have been published on wastewater-irrigated soils and vegetables contaminated with heavy metals. However, to the best of our knowledge, an insight into assessment of human health risks associated with the consumption of vegetable crops grown on wastewater-irrigated soils is non-existent in the city. Long-term effect of wastewater irrigation on the build-up of heavy metals in soils and selected vegetable crops in Addis Ababa urban vegetable farming sites (10) was evaluated. By calculating estimated daily intakes (EDIs) and target hazard quotients (THQs) of metals, health risk associated with the consumption of the analyzed vegetables was also evaluated. Results The heavy metal concentrations in irrigation water and soils did not exceed the recommended maximum limits (RMLs). Moreover, Cd, Co, Cr, Cu, Ni and Zn concentrations in all analyzed vegetables were lower than the RML standards. In contrast, Pb concentrations were 1.4–3.9 times higher. Results of two way ANOVA test showed that variation in metals concentrations were significant (p more...
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- 2017
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8. Safe Re-use Practices in Wastewater-Irrigated Urban Vegetable Farming in Ghana
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Bernard Keraita, Robert C. Abaidoo, Ines Beernaerts, Sasha Koo-Oshima, Philip Amoah, Pay Drechsel, and Flemming Konradsen
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Ghana ,Health Risks ,Irrigated Urban Agriculture ,Safe Re-Use Practices ,Wastewater ,Agriculture ,Human settlements. Communities ,HT51-65 - Abstract
Irrigation using untreated wastewater poses health risks to farmers and consumers of crop products, especially vegetables. With hardly any wastewater treatment in Ghana, a multiple-barrier approach was adopted and safe re-use practices were developed through action research involving a number of stakeholders at different levels along the food chain. This paper presents an overview of safe re-use practices including farm-based water treatment methods, water application techniques, post-harvest handling practices, and washing methods. The overview is based on a comprehensive analysis of the literature and our own specific studies, which used data from a broad range of research methods and approaches. Identifying, testing, and assessment of safe practices were done with the active participation of key actors using observations, extensive microbiological laboratory assessments, and field-based measurements. The results of our work and the work of others show that the practices developed had a great potential to reduce health risks, especially when used to complement each other at different levels of the food chain. Future challenges are the development of a comprehensive framework that best combines tested risk-reduction strategies for wide application by national stakeholders as well as their potential implementation into legally enforceable national standards. more...
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- 2016
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9. Impact of Fecal Sludge and Municipal Solid Waste Co-Compost on Crop Growth of Raphanus Sativus L. and Capsicum Anuum L. under Stress Conditions
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Felix Grau, Nikita Drechsel, Volker Haering, Dieter Trautz, Weerakkodige Jayantha Sisira Kumara Weerakkody, Pay Drechsel, Bernd Marschner, Dissanayake Mudiyanselage Priyanga Sashikanjali Dissanayake, and Vijayapala Sinnathamby more...
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compost ,agriculture ,resource recovery and reuse ,Science - Abstract
Co-composted dewatered faecal sludge (FS) with organic fractions of municipal solid waste (MSW) has a high potential to be used as an agricultural resource in Sri Lanka. In addition to options for cost recovery in waste management, closing the nutrient and carbon cycles between urban and rural areas, substitution of mineral fertilizers, reduced pollution. and the restoration of degraded arable land are possible with important benefits. Up to now little is known about the usage of FS-MSW as fertilizer and it needs to be studied in order to achieve a better understanding and generate application recommendations. The aim of these experiments has been to evaluate the possibility of substituting mineral fertilization. Two field experiments were conducted on sandy loam to assess the effects of MSW compost and FS-MSW co-compost, its pelletized forms, and mineral-enriched FS-MSW on crop growth. As a short-term crop Raphanus sativus “Beeralu rabu” (radish) was studied for 50 days in a randomized complete block design (RCDB). Results show that, under drought conditions, FS-MSW co-compost increased the yield significantly, while MSW and FS-MSW compost enabled the highest survival rate of the plants. Similarly, the second field trial with a long-term crop, Capsicum anuum “CA-8” (capsicum), was planted as RCBD, using the same treatments, for a cultivation period of 120 days. Results display that during a drought followed by water saturated soil conditions co-compost treatments achieved comparable yields and increased the survival rate significantly compared to the control, fertilized with urea, triple super phosphate, and muriate of potash. Cost-benefit analysis (CBA) revealed that pelletizing decreased the monetary benefits if only fertilizer value is considered. It can be concluded that, under drought and water stress, co-compost ensures comparable yields and enables more resistance, but might not be economical viable as a one-crop fertilizer. These findings need to be validated with further trials under different climate regimes and soils. more...
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- 2017
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10. Food Waste to Livestock Feed: Prospects and Challenges for Swine Farming in Peri-urban Sri Lanka
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Nilanthi Jayathilake, Mohamed Aheeyar, and Pay Drechsel
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General Engineering - Abstract
Using farm animals for their natural capability of “recycling” food waste (FW) that is unfit for direct human consumption can support a circular economy as shown in the case of Sri Lanka’s Western Province. The reuse of organic residues including FW as animal feed is a traditional agricultural practice in Sri Lanka but is less studied within an urban FW context. A survey of piggeries using FW in and around the rapidly urbanizing city of Colombo showed that FW is a major feed source in the farms accounting for on average 82% of total feed. About 40% of the farms collected the FW mainly from hotels, restaurants, and institutional canteens. Urban FW is supplied to farmers free of charge when collected directly from the sources, although 26% of the farmers collected FW via intermediaries against a fee. As FW is collected daily, the restaurants appreciate the reliable service, the farmers the low-cost feed, and the municipality the reduced FW volumes to be collected. However, this triple-win situation encounters challenges such as (tourist related) seasonal low supply, which was exacerbated under the Covid-19 lockdown of food services. Another area of concern refers to biosafety. Although the large majority of interviewed farmers boil FW which contains raw meat or fish, there is a paucity of related guidelines and control. Given the benefits of FW use, it is worthwhile to explore how far these informal partnerships could be scaled without increasing transport costs for farmers, while introducing biosafety monitoring. For now, the regulatory environment is highly siloed and does not support material transitions across sector boundaries towards a circular economy. more...
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- 2022
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11. Water reuse to free up freshwater for higher‐value use and increase climate resilience and water productivity
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Pay Drechsel, Manzoor Qadir, and Jurgen Baumann
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Soil Science ,Agronomy and Crop Science - Published
- 2022
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12. Global and regional potential of wastewater as a water, nutrient and energy source
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Blanca Jiménez Cisneros, Manzoor Qadir, Younggy Kim, Praem Mehta, Amit Pramanik, Pay Drechsel, and Oluwabusola Olaniyan
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Energy recovery ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Green economy ,Waste-to-energy ,Wastewater ,Environmental protection ,Environmental science ,Sewage treatment ,021108 energy ,Eutrophication ,Energy source ,0105 earth and related environmental sciences ,General Environmental Science ,Resource recovery - Abstract
There is a proactive interest in recovering water, nutrients and energy from waste streams with the increase in municipal wastewater volumes and innovations in resource recovery. Based on the synthesis of wastewater data, this study provides insights into the global and regional “potential” of wastewater as water, nutrient and energy sources while acknowledging the limitations of current resource recovery opportunities and promoting efforts to fast‐track high‐efficiency returns. The study estimates suggest that, currently, 380 billion m3 (m3 = 1,000 L) of wastewater are produced annually across the world which is a volume five‐fold the volume of water passing through Niagara Falls annually. Wastewater production globally is expected to increase by 24% by 2030 and 51% by 2050 over the current level. Among major nutrients, 16.6 Tg (Tg = million metric ton) of nitrogen are embedded in wastewater produced worldwide annually; phosphorus stands at 3.0 Tg and potassium at 6.3 Tg. The full nutrient recovery from wastewater would offset 13.4% of the global demand for these nutrients in agriculture. Beyond nutrient recovery and economic gains, there are critical environmental benefits, such as minimizing eutrophication. At the energy front, the energy embedded in wastewater would be enough to provide electricity to 158 million households. These estimates and projections are based on the maximum theoretical amounts of water, nutrients and energy that exist in the reported municipal wastewater produced worldwide annually. Supporting resource recovery from wastewater will need a step‐wise approach to address a range of constraints to deliver a high rate of return in direct support of Sustainable Development Goals (SDG) 6, 7 and 12, but also other Goals, including adaptation to climate change and efforts in advancing “net‐zero” energy processes towards a green economy. more...
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- 2020
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13. Business models for urban food waste prevention, redistribution, recovery and recycling
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Pay Drechsel, Maren Reitemeier, Dehaja Senanayake, and Felix Thiel
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Energy recovery ,Food waste ,Natural resource economics ,Environmental impact assessment ,Waste collection ,Redistribution (cultural anthropology) ,Business ,Reuse ,Business model ,Resource recovery - Published
- 2021
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14. Gender dimensions of solid and liquid waste management for reuse in agriculture in Asia and Africa
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Pay Drechsel, Solomie A. Gebrezgabher, and Avinandan Taron
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Sanitation ,Natural resource economics ,Agriculture ,business.industry ,Circular economy ,Resource management ,Waste collection ,Business ,Reuse ,Social equality ,Resource recovery - Published
- 2021
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15. The WHO Guidelines for Safe Wastewater Use in Agriculture: A Review of Implementation Challenges and Possible Solutions in the Global South
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Pay Drechsel, Manzoor Qadir, and David Galibourg
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Geography, Planning and Development ,Aquatic Science ,Biochemistry ,Water Science and Technology - Abstract
Globally, the use of untreated, often diluted, or partly treated wastewater in agriculture covers about 30 million ha, far exceeding the area under the planned use of well-treated (reclaimed) wastewater which has been estimated in this paper at around 1.0 million ha. This gap has likely increased over the last decade despite significant investments in treatment capacities, due to the even larger increases in population, water consumption, and wastewater generation. To minimize the human health risks from unsafe wastewater irrigation, the WHO’s related 2006 guidelines suggest a broader concept than the previous (1989) edition by emphasizing, especially for low-income countries, the importance of risk-reducing practices from ‘farm to fork’. This shift from relying on technical solutions to facilitating and monitoring human behaviour change is, however, challenging. Another challenge concerns local capacities for quantitative risk assessment and the determination of a risk reduction target. Being aware of these challenges, the WHO has invested in a sanitation safety planning manual which has helped to operationalize the rather academic 2006 guidelines, but without addressing key questions, e.g., on how to trigger, support, and sustain the expected behaviour change, as training alone is unlikely to increase the adoption of health-related practices. This review summarizes the perceived challenges and suggests several considerations for further editions or national adaptations of the WHO guidelines. more...
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- 2022
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16. Farmers’ perceptions on irrigation water contamination, health risks and risk management measures in prominent wastewater-irrigated vegetable farming sites of Addis Ababa, Ethiopia
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Desta Woldetsadik, Bernard Keraita, Fisseha Itanna, Pay Drechsel, and Heluf Gebrekidan
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Irrigation ,010504 meteorology & atmospheric sciences ,business.industry ,010501 environmental sciences ,01 natural sciences ,Focus group ,Incentive ,Health promotion ,Geography ,Agriculture ,Environmental health ,Vegetable farming ,Water quality ,business ,Water resource management ,Risk management ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
The use of wastewater to produce food crops particularly vegetables is very prevalent in Addis Ababa, Ethiopia. This practice may pose health risks to farm workers and consumers. Hence, the study was designed to evaluate farmers’ perceptions on irrigation water quality, health risks and health risk mitigation measures in four wastewater-irrigated urban vegetable farming sites in Addis Ababa. Data were collected on farm through 263 individual interviews and 12 focus group discussions. The findings showed that despite differences in levels of knowledge and awareness on health risks, farmers appear informed about the contamination of their irrigation water. The difference in perception to quality consideration of Akaki River/irrigation water is highlighted by the result of Kruskal–Wallis H test analysis which shows significant mean value (1.33) of positive perception toward the water quality by male than female farmers. Interestingly, significant difference (p more...
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- 2017
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17. Urbanisation and emerging economies: Issues and potential solutions for water and food security
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Pay Drechsel, Rai S. Kookana, Priyanka Jamwal, and Joanne Vanderzalm
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Environmental Engineering ,010504 meteorology & atmospheric sciences ,Sanitation ,Natural resource economics ,Population ,Water supply ,010501 environmental sciences ,01 natural sciences ,Water scarcity ,Food Supply ,Water Supply ,Urbanization ,Environmental Chemistry ,Humans ,Cities ,education ,Emerging markets ,Waste Management and Disposal ,0105 earth and related environmental sciences ,education.field_of_study ,Food security ,business.industry ,Water ,Pollution ,Water security ,Business - Abstract
Urbanisation will be one of the 21st century's most transformative trends. By 2050, it will increase from 55% to 68%, more than doubling the urban population in South Asia and Sub-Saharan Africa. Urbanisation has multifarious (positive as well as negative) impacts on the wellbeing of humans and the environment. The 17 UN Sustainable Development Goals (SDGs) form the blueprint to achieve a sustainable future for all. Clean Water and Sanitation is a specific goal (SDG 6) within the suite of 17 interconnected goals. Here we provide an overview of some of the challenges that urbanisation poses in relation to SDG 6, especially in developing economies. Worldwide, several cities are on the verge of water crisis. Water distribution to informal settlements or slums in megacities (e.g. >50% population in the megacities of India) is essentially non-existent and limits access to adequate safe water supply. Besides due to poor sewer connectivity in the emerging economies, there is a heavy reliance on septic tanks, and other on-site sanitation (OSS) system and by 2030, 4.9 billion people are expected to rely on OSS. About 62-93% of the urban population in Vietnam, Sri Lanka, the Philippines and Indonesia rely on septic tanks, where septage treatment is rare. Globally, over 80% of wastewater is released to the environment without adequate treatment. About 11% of all irrigated croplands is irrigated with such untreated or poorly treated wastewater. In addition to acute and chronic health effects, this also results in significant pollution of often-limited surface and groundwater resources in Sub-Saharan Africa and Asia. Direct and indirect water reuse plays a key role in global water and food security. Here we offer several suggestions to mitigate water and food insecurity in emerging economies. more...
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- 2020
18. Training manual for fecal sludge-based compost production and application
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Nilanthi Jayathilake, Olufunke O. Cofie, Eric Nartey, Josiane Nikiema, Robert Impraim, Pay Drechsel, and Felix Thiel
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Waste treatment ,Sludge dewatering ,Compost ,engineering ,Environmental science ,Training manual ,engineering.material ,Pulp and paper industry ,Feces ,Resource recovery - Published
- 2020
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19. Spatial and temporal dynamics of croplands in expanding West African cities
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Nicole Dittrich, Angèle Cauchois, Hanna Karg, and Pay Drechsel
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West african ,education.field_of_study ,Geography ,business.industry ,Environmental resource management ,Population ,Satellite imagery ,Land use, land-use change and forestry ,business ,Urban agriculture ,education ,Land tenure - Published
- 2020
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20. Business models for fecal sludge management in India
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S. Velidandla, Krishna C. Rao, C. L. Scott, and Pay Drechsel
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Agricultural science ,Sanitation ,Business ,Business model ,Cost recovery ,Waste disposal ,Fecal sludge management - Published
- 2020
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21. A livelihood in a risky environment: Farmers’ preferences for irrigation with wastewater in Hyderabad, India
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Pay Drechsel, Stijn Speelman, Cecilia Saldías, and Guido Van Huylenbroeck
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Adult ,Male ,Risk ,Agricultural Irrigation ,Natural resource economics ,0208 environmental biotechnology ,Geography, Planning and Development ,India ,Water supply ,02 engineering and technology ,Wastewater ,010501 environmental sciences ,Standard of living ,01 natural sciences ,Willingness to pay ,Report ,Humans ,Environmental Chemistry ,Recycling ,Cities ,0105 earth and related environmental sciences ,Valuation (finance) ,Farmers ,Ecology ,business.industry ,Water Pollution ,General Medicine ,Middle Aged ,Livelihood ,020801 environmental engineering ,Agriculture ,Female ,business ,Models, Econometric ,Water use - Abstract
Most cities in developing countries fail to treat their wastewater comprehensively. Consequently, farmers downstream use poor-quality water for irrigation. This practice implies risks for farmers, consumers and the environment. Conversely, this water supply supports the livelihood of these farmers and other stakeholders along the value chains. Linking safer options for wastewater management with irrigation could therefore be a win-win solution: removing the risks for society and maintaining the benefits for farmers. However, in developing countries, the high investment costs for the required treatment are problematic and the willingness of farmers to pay for the water (cost recovery) is often questionable. Using a choice experiment, this paper gives insight into farmers' preferences for wastewater use scenarios, quantifying their willingness to pay. The case study is Hyderabad, India. Farmers there prefer water treatment and are prepared to pay a surplus for this. Considering the cost-recovery challenge, this information could be valuable for planning small on site wastewater treatment systems. more...
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- 2016
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22. Total Value of Phosphorus Recovery
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Lawrence A. Baker, Prathap Parameswaran, Bruce E. Rittmann, Pay Drechsel, Brooke K. Mayer, Paul Westerhoff, Munir A. Hanjra, Jared Stoltzfus, Mac Gifford, and Treavor H. Boyer
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Food security ,Waste management ,Nitrogen ,business.industry ,Natural resource economics ,Equity (finance) ,Phosphorus ,02 engineering and technology ,General Chemistry ,Eutrophication ,Wastewater ,010501 environmental sciences ,Reuse ,021001 nanoscience & nanotechnology ,01 natural sciences ,Waste treatment ,Metals ,Food processing ,Environmental Chemistry ,0210 nano-technology ,business ,Environmental quality ,Non-renewable resource ,0105 earth and related environmental sciences ,Resource recovery - Abstract
Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies. more...
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- 2016
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23. Perceptions of Food Waste Reduction in Sri Lanka’s Commercial Capital, Colombo
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Maren Reitemeier, M.M.M. Aheeyar, and Pay Drechsel
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animal feed ,landfill collapse ,020209 energy ,Geography, Planning and Development ,TJ807-830 ,Waste collection ,Context (language use) ,02 engineering and technology ,South Asia ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,TD194-195 ,01 natural sciences ,Renewable energy sources ,food waste management ,0202 electrical engineering, electronic engineering, information engineering ,GE1-350 ,Marketing ,0105 earth and related environmental sciences ,surplus food redistribution ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,business.industry ,stakeholder perceptions ,Public sector ,Private sector ,Food safety ,Environmental sciences ,Food waste ,Waste treatment ,Incentive ,Business - Abstract
In 2019, Sri Lanka introduced two policies that referred to food waste and the need to reduce it. To understand key stakeholders&rsquo, readiness in this context, this study analyzed the food waste perceptions of private and public sectors in Colombo (open markets, supermarkets, hotels, restaurants, canteens, food caterers and key authorities). Interviews were carried out with operational managers and public officials, as well as other stakeholders who have roles in food waste redistribution and reuse, such as NGOs and the livestock sector. So far, the food-waste-related policy recommendations lack an operational inter-institutional home which can build on measures, like standards, regulations and incentives. Thus, most food waste reduction initiatives are initiated by NGOs or by the private sector, e.g., by larger hotels and supermarket chains. These entities were ready to lead by example, based on the understanding that urban food waste is an internal (financial) management challenge. Among smaller local entities, food waste was perceived more as an external issue to be handled by the city&rsquo, s waste collection services. Although perceptions varied between entities generating smaller or larger quantities of food waste, there was general agreement that suboptimal capacities and mechanisms to quantify, monitor and cost food waste generation appeared to be obstacles for in-depth awareness creation and action. There was significant interest in communication platforms for cross-sectoral learning, win/win collaborations with reliable collection (reuse) services that are currently operational, such as those provided by piggeries, as well as surplus redistribution initiatives if food safety and related liabilities can be addressed effectively. more...
- Published
- 2021
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24. Fecal sludge-derived pellet fertilizer in maize cultivation
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Josiane Nikiema, Pay Drechsel, Olufunke O. Cofie, Surendra K. Pradhan, and Helvi Heinonen-Tanski
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Pellets ,010501 environmental sciences ,Development ,engineering.material ,complex mixtures ,01 natural sciences ,Nutrient ,Lixisol ,Fertilizer ,Pellet ,Organic matter ,Sanitation ,Waste Management and Disposal ,ta218 ,0105 earth and related environmental sciences ,Water Science and Technology ,chemistry.chemical_classification ,Cambisol ,Fecal sludge ,Compost ,fungi ,Public Health, Environmental and Occupational Health ,04 agricultural and veterinary sciences ,Pollution ,Maize ,chemistry ,Agronomy ,visual_art ,040103 agronomy & agriculture ,engineering ,visual_art.visual_art_medium ,0401 agriculture, forestry, and fisheries ,Sawdust - Abstract
Fecal sludge (FS) contains significant amounts of plant nutrients and organic matter although it also contains pathogens. Therefore, FS can be used as fertilizer after proper sanitization. This study was designed to test dried fecal sludge (DFS)-based pellet fertilizers on maize cultivation. The DFS fertilizers were produced by composting, co-composting with sawdust, or irradiated by gamma-irradiation, and then nitrogen-enriched and pelletized using gelatinized or gamma-irradiated cassava starch. These DFS pellet fertilizers were compared to each other and to no-fertilization, mineral fertilizer, and agro-industrial waste compost. The fertilizer applications were 150 or 210 kgN/ha. Maize was cultivated in pots containing Cambisol and Ferric Lixisol growth media. The EC-SDFS-PG pellet (DFS + sawdust co-composted, enriched with nitrogen and pelletized) at a rate of 210 kgN/ha produced the highest maize yield (4.4 ton/ha) among all other treatments, while mineral fertilizer produced 3.9 ton/ha. It is concluded that the EC-SDFS-PG pellet produces similar or higher maize yields than mineral fertilizer and more than the agro-industrial compost in both growth media types. more...
- Published
- 2016
25. Atlas of West African urban food systems: examples from Ghana and Burkina Faso
- Author
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Pay Drechsel and Hanna Karg
- Subjects
West african ,Geography ,Land use ,Urban planning ,business.industry ,Food marketing ,Food supply ,Food systems ,Socioeconomics ,Food safety ,business ,Urban agriculture - Published
- 2018
- Full Text
- View/download PDF
26. Financing resource recovery and reuse in developing and emerging economies: enabling environment, financing sources and cost recovery
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Anita Lazurko, Pay Drechsel, and Munir A. Hanjra
- Subjects
Finance ,Incentive ,Cost–benefit analysis ,business.industry ,Equity (finance) ,Reuse ,business ,Emerging markets ,Private sector ,Payment for ecosystem services ,Risk management - Abstract
Resource recovery and reuse (RRR) of domestic and agro-industrial waste has the potential to contribute to a number of financial, socioeconomic and environmental benefits. However, despite these benefits and an increasing political will, there remain significant barriers to build the required up-front capital which is discouraging private sector engagement. A systematic analysis and understanding of the enabling environment, public and private funding sources, risk-sharing mechanisms and pathways for cost recovery can help to identify opportunities to improve the viability of RRR solutions. This report looks at regulations and policies that remove disincentives for RRR, public and private funding sources for capital and operational costs, risk mitigation options through blending and structuring finance, and options for operational cost recovery. more...
- Published
- 2018
- Full Text
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27. Social Perspectives on the Effective Management of Wastewater
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Dalia Saad, Pay Drechsel, and Deirdre Byrne
- Subjects
Wastewater ,business.industry ,0208 environmental biotechnology ,Environmental resource management ,Effective management ,02 engineering and technology ,Business ,010501 environmental sciences ,01 natural sciences ,020801 environmental engineering ,0105 earth and related environmental sciences - Published
- 2017
28. On-farm treatment of wastewater used for vegetable irrigation: bacteria and virus removal in small ponds in Accra, Ghana
- Author
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Andrea I. Silverman, M. O. Akrong, Kara L. Nelson, and Pay Drechsel
- Subjects
Irrigation ,biology ,Sedimentation (water treatment) ,fungi ,Environmental engineering ,Indicator bacteria ,Filtration and Separation ,STREAMS ,Contamination ,biology.organism_classification ,Wastewater ,Environmental science ,Coliphage ,Bacteria ,Water Science and Technology - Abstract
Many urban farmers in Accra collect irrigation water from streams and open drains, which they store in small, on-farm ponds before use. Given that this water can be highly contaminated with wastewater, another potential role of the ponds is to disinfect irrigation water prior to use. To better understand the factors influencing bacteria and virus removal in these small ponds, we investigated the removal of culturable fecal indicator bacteria (Escherichia coli and enterococci) and coliphage (F+ and somatic coliphage) in a single batch of water stored for 3 days. Sunlight exposure was found to be important for removal. Bacteria and coliphage removal rates were faster in shallow sun-exposed water than in deeper water, due to sunlight attenuation with depth. Bacteria removal rates varied depending on solar irradiation, and correlations between total daily UVB fluence and bacteria removal rates were observed. Coliphage removal was observed in sun-exposed water but not in dark controls that allowed for sedimentation, further highlighting the importance of sunlight-mediated processes. These small ponds appear to have similar disinfection processes to larger-scale waste stabilization ponds, but can have more efficient inactivation due to their shallow depth and operation as batch reactors. Design and management recommendations for on-farm ponds are discussed. more...
- Published
- 2014
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29. Nutrient flows and balances in intensively managed vegetable production of two West African cities
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Andreas Buerkert, Christoph Steiner, Delphine Manka’abusi, Edmund K. Akoto-Danso, Bernd Marschner, Steffen Werner, George Nyarko, Volker Haering, Pay Drechsel, and Désiré Jean-Pascal Lompo
- Subjects
Irrigation ,Soil Science ,04 agricultural and veterinary sciences ,Plant Science ,West african ,Nutrient ,Wastewater ,Agronomy ,Biochar ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Environmental science ,Soil fertility ,Leaching (agriculture) ,Eutrophication - Abstract
This study reports and analyzes nutrient balances in experimental vegetable production systems of the two West African cities of Tamale (Ghana) and Ouagadougou (Burkina Faso) over a two‐year period comprising thirteen and eleven crops, respectively. Nutrient‐use efficiency was also calculated. In Tamale and Ouagadougou, up to 2% (8 and 80 kg N ha⁻¹) of annually applied fertilizer nitrogen were leached. While biochar application or wastewater irrigation on fertilized plots did not influence N leaching in both cities, P and K leaching, as determined with ion‐absorbing resin cartridges, were reduced on biochar‐amended plots in Tamale. Annual nutrient balances amounted to +362 kg N ha⁻¹, +217 kg P ha⁻¹, and –125 kg K ha⁻¹ in Tamale, while Ouagadougou had balances of up to +692 kg N ha⁻¹, +166 kg P ha⁻¹, and –175 kg K ha⁻¹ y⁻¹. Under farmers' practice of fertilization, agronomic nutrient‐use efficiencies were generally higher in Tamale than in Ouagadougou, but declined in both cities during the last season. This was the result of the higher nutrient inputs in Ouagadougou compared to Tamale and relatively lower outputs. The high N and P surpluses and K deficits call for adjustments in local fertilization practices to enhance nutrient‐use efficiency and prevent risks of eutrophication. more...
- Published
- 2019
- Full Text
- View/download PDF
30. Quantification of human norovirus GII, human adenovirus, and fecal indicator organisms in wastewater used for irrigation in Accra, Ghana
- Author
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Andrea I. Silverman, M. O. Akrong, Kara L. Nelson, Pay Drechsel, and Philip Amoah
- Subjects
Microbiology (medical) ,Veterinary medicine ,Agricultural Irrigation ,Stabilization pond ,Colony Count, Microbial ,Indicator bacteria ,Guidelines as Topic ,Wastewater ,Real-Time Polymerase Chain Reaction ,World Health Organization ,medicine.disease_cause ,Ghana ,Risk Assessment ,Microbiology ,Feces ,medicine ,Humans ,Waste Management and Disposal ,Water Science and Technology ,Indicator organism ,Bacteria ,biology ,Adenoviruses, Human ,Norovirus ,Public Health, Environmental and Occupational Health ,biology.organism_classification ,Bacteroidales ,Fecal coliform ,Infectious Diseases ,Sewage treatment ,Water Microbiology ,Environmental Monitoring - Abstract
Quantitative microbial risk assessment (QMRA) is frequently used to estimate health risks associated with wastewater irrigation and requires pathogen concentration estimates as inputs. However, human pathogens, such as viruses, are rarely quantified in water samples, and simple relationships between fecal indicator bacteria and pathogen concentrations are used instead. To provide data that can be used to refine QMRA models of wastewater-fed agriculture in Accra, stream, drain, and waste stabilization pond waters used for irrigation were sampled and analyzed for concentrations of fecal indicator microorganisms (human-specific Bacteroidales, Escherichia coli, enterococci, thermotolerant coliform, and somatic and F+ coliphages) and two human viruses (adenovirus and norovirus genogroup II). E. coli concentrations in all samples exceeded limits suggested by the World Health Organization, and human-specific Bacteroidales was found in all but one sample, suggesting human fecal contamination. Human viruses were detected in 16 out of 20 samples, were quantified in 12, and contained 2–3 orders of magnitude more norovirus than predicted by norovirus to E. coli concentration ratios assumed in recent publications employing indicator-based QMRA. As wastewater irrigation can be beneficial for farmers and municipalities, these results should not discourage water reuse in agriculture, but provide motivation and targets for wastewater treatment before use on farms. more...
- Published
- 2013
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31. Risk factor analysis of diarrhoeal disease incidence in faecal sludge-applying farmers’ households in Tamale, Ghana
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Thor Axel Stenström, Pay Drechsel, Razak Seidu, and Owe Löfman
- Subjects
Risk analysis ,education.field_of_study ,Veterinary medicine ,business.industry ,Transmission (medicine) ,Incidence (epidemiology) ,Population ,Public Health, Environmental and Occupational Health ,Development ,Pollution ,Environmental health ,Attributable risk ,Defecation ,Medicine ,Risk factor ,business ,education ,Waste Management and Disposal ,Risk management ,Water Science and Technology - Abstract
This study assesses the effect of risk factors and their inter-related mediation on diarrhoeal disease incidence in households applying faecal sludge in agricultural fields in Tamale, Ghana. Risk factors were assigned to three inter-related blocks: distal socio-economic, proximal public and domestic domains. The study involved 1,431 individuals living in 165 faecal sludge-applying households followed bi-weekly for 12 months. The incidence rate of diarrhoeal disease in the sludge-applying households was 1.09 (95% CI: 0.78–1.23) diarrhoeal episodes per person year at risk. Risk factors for diarrhoeal disease transmission in the public domain included sludge drying time (population attributable fraction (PAF) of 6%) and distance covered to collect water (PAF = 18%). The main distal socio-economic risk factor was wealth status (PAF = 15%). In the domestic domain, the risk factor significantly associated with diarrhoeal disease transmission was, not washing hands with soap after defecation (PAF = 18%). About 17% of the effect of sludge drying time (including distance to water facilities) was mediated by the domestic domain risk factors. The study recommends risk management strategies in sludge-applying households that address public and domestic domain risk factors in addition to specific farm level interventions. more...
- Published
- 2013
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32. Effect of biochar derived from faecal matter on yield and nutrient content of lettuce (Lactuca sativa) in two contrasting soils
- Author
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Bernd Marschner, Pay Drechsel, Fisseha Itanna, Desta Woldetsadik, and Heluf Gebrekidan
- Subjects
biology ,Chemistry ,Amendment ,Lactuca ,04 agricultural and veterinary sciences ,010501 environmental sciences ,engineering.material ,biology.organism_classification ,01 natural sciences ,Soil conditioner ,Nutrient ,Agronomy ,Loam ,Biochar ,040103 agronomy & agriculture ,engineering ,0401 agriculture, forestry, and fisheries ,Fertilizer ,Soil fertility ,0105 earth and related environmental sciences - Abstract
Faecal matter biochar offers an interesting value proposition where the pyrolysis process guaranties a 100% pathogen elimination, as well as significant reduction in transport and storage weight and volume. Therefore, to evaluate the effect of (1) biochar produced from dried faecal matter from household based septic tanks, and (2) N fertilizer, as well as their interaction on yield and nutrient status of lettuce (Lactuca sativa), lettuce was grown over two growing cycles under glasshouse on two contrasting soils amended once at the start with factorial combination of faecal matter biochar at four rates (0, 10, 20 and 30 t ha−1) with 0, 25 and 50 kg N ha−1 in randomized complete block design. For both soils, maximum fresh yields were recorded with biochar and combined application of biochar with N treatments. However, the greatest biochar addition effects (with or without N) with regard to relative yield were seen in less fertile sandy loam soil. We have also observed that faecal matter biochar application resulted in noticeable positive residual effects on lettuce yield and tissue nutrient concentrations in the 2nd growing cycle. For both soils, most nutrients analyzed (N, P, K, Mg, Cu and Zn) were within or marginally above optimum ranges for lettuce under biochar amendment. The application of faecal matter biochar enhances yield and tissue nutrient concentrations of lettuce in two contrasting soils, suggesting that faecal matter biochar could be used as an effective fertilizer for lettuce production at least for two growing cycles. Moreover, the conversion of the faecal matter feedstock into charred product may offer additional waste management benefit as it offers an additional (microbiologically safe) product compared to the more common co-composting. more...
- Published
- 2017
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33. MOESM1 of Effect of biochar derived from faecal matter on yield and nutrient content of lettuce (Lactuca sativa) in two contrasting soils
- Author
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Desta Woldetsadik, Pay Drechsel, Marschner, Bernd, Fisseha Itanna, and Heluf Gebrekidan
- Abstract
Additional file 1. Surface and chemical properties of faecal matter biochar.
- Published
- 2017
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34. Foodsheds and City Region Food Systems in Two West African Cities
- Author
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Edmund K. Akoto-Danso, Hanna Karg, Andreas Buerkert, Pay Drechsel, Rüdiger Glaser, and George Nyarko
- Subjects
spatial analysis ,Supply chain ,lcsh:TJ807-830 ,Geography, Planning and Development ,Population ,urban food systems ,foodsheds ,city region food systems ,food flows ,urban food supply ,GIS mapping ,climate change ,lcsh:Renewable energy sources ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Agricultural economics ,Food chain ,education ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,lcsh:GE1-350 ,education.field_of_study ,Food security ,Renewable Energy, Sustainability and the Environment ,business.industry ,lcsh:Environmental effects of industries and plants ,Environmental engineering ,04 agricultural and veterinary sciences ,City region ,lcsh:TD194-195 ,Geography ,040103 agronomy & agriculture ,Food processing ,0401 agriculture, forestry, and fisheries ,Food systems ,Livestock ,business - Abstract
In response to changing urban food systems, short supply chains have been advocated to meet urban food needs while building more sustainable urban food systems. Despite an increasing interest in urban food supply and the flows of food from production to consumption, there is a lack of empirical studies and methodologies which systematically analyse the actual proportion and nutritional significance of local and regional food supplied to urban markets. The aim of this empirical study therefore was to compare the geographical sources supplying food to the urban population (“foodsheds”) in Tamale, Ghana and Ouagadougou, Burkina Faso, to record the supplied quantities and to assess the level of interaction between the sources and the respective city. The study was conducted over two years, covering the seasons of abundant and short supply, via traffic surveys on the access roads to the two cities, and in the Tamale markets, resulting altogether in more than 40,000 records of food flow. Results indicated that food sources were highly crop- and season-specific, ranging from one-dimensional to multi-dimensional foodsheds with diverse sources across seasons. Across the commodity-specific foodsheds, city region boundaries were established. Within the proposed city region a relatively large proportion of smallholders contributed to urban food supply, taking advantage of the proximity to urban markets. While food provided from within the city region offers certain place-based benefits, like the provision of fresh perishable crops, a larger geographical diversity of foodsheds appeared to enhance the resilience of urban food systems, such as against climate related production failures. more...
- Published
- 2016
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35. Safe Re-use Practices in Wastewater-Irrigated Urban Vegetable Farming in Ghana
- Author
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Flemming Konradsen, Philip Amoah, Ines Beernaerts, Robert C. Abaidoo, Bernard Keraita, Pay Drechsel, and Sasha Koo-Oshima
- Subjects
Untreated wastewater ,lcsh:Recreation. Leisure ,lcsh:TX341-641 ,lcsh:GV1-1860 ,Wastewater ,lcsh:Home economics ,lcsh:Regional planning ,Ghana ,Safe Re-Use Practices ,lcsh:Technology ,lcsh:Urban groups. The city. Urban sociology ,lcsh:Agriculture ,lcsh:Social Sciences ,Food chain ,lcsh:HT51-1595 ,Vegetable farming ,lcsh:HT101-395 ,Action research ,lcsh:Human ecology. Anthropogeography ,Environmental planning ,lcsh:Environmental sciences ,Health Risks ,lcsh:GE1-350 ,lcsh:T ,lcsh:S ,lcsh:Geography. Anthropology. Recreation ,lcsh:HT390-395 ,Active participation ,lcsh:H ,Work (electrical) ,lcsh:G ,lcsh:Communities. Classes. Races ,Sewage treatment ,Business ,lcsh:GF1-900 ,Water resource management ,Irrigated Urban Agriculture ,lcsh:Nutrition. Foods and food supply ,lcsh:TX1-1110 - Abstract
Irrigation using untreated wastewater poses health risks to farmers and consumers of crop products, especially vegetables. With hardly any wastewater treatment in Ghana, a multiple-barrier approach was adopted and safe re-use practices were developed through action research involving a number of stakeholders at different levels along the food chain. This paper presents an overview of safe re-use practices including farm-based water treatment methods, water application techniques, post-harvest handling practices, and washing methods. The overview is based on a comprehensive analysis of the literature and our own specific studies, which used data from a broad range of research methods and approaches. Identifying, testing, and assessment of safe practices were done with the active participation of key actors using observations, extensive microbiological laboratory assessments, and field-based measurements. The results of our work and the work of others show that the practices developed had a great potential to reduce health risks, especially when used to complement each other at different levels of the food chain. Future challenges are the development of a comprehensive framework that best combines tested risk-reduction strategies for wide application by national stakeholders as well as their potential implementation into legally enforceable national standards. more...
- Published
- 2016
36. Effects of biochar and alkaline amendments on cadmium immobilization, selected nutrient and cadmium concentrations of lettuce (Lactuca sativa) in two contrasting soils
- Author
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Bernd Marschner, Desta Woldetsadik, Bernard Keraita, Fisseha Itanna, Pay Drechsel, and Heluf Gebrekidan
- Subjects
chemistry.chemical_element ,Lactuca ,010501 environmental sciences ,engineering.material ,01 natural sciences ,Faecal matter ,Immobilization ,Animal science ,Phytoavailability ,Biochar ,Poultry litter ,0105 earth and related environmental sciences ,Lime ,Cadmium ,Multidisciplinary ,biology ,Chemistry ,Research ,04 agricultural and veterinary sciences ,Lettuce ,biology.organism_classification ,Manure ,Agronomy ,Loam ,040103 agronomy & agriculture ,engineering ,0401 agriculture, forestry, and fisheries ,Cow dung - Abstract
To assess the efficiency of seven treatments including biochars produced from dried faecal matter and manures as stabilizing agents of cadmium (Cd)-spiked soils, lettuce was grown in glasshouse on two contrasting soils. The soils used were moderately fertile silty loam and less fertile sandy loam and the applied treatments were 7 % w/w. The reduction of bioavailable Cd (ammonium nitrate extractable) and its phytoavailability for lettuce were used as assessment criteria in the evaluation of stabilization performance of each treatment. Moreover, the agronomic values of the treatments were also investigated. Ammonium nitrate extraction results indicated that faecal matter biochar, cow manure biochar and lime significantly reduced bioavailable Cd by 84–87, 65–68 and 82–91 %, respectively, as compared to the spiked controls. Unpredictably, coffee husk biochar induced significant increment of Cd in NH4NO3 extracts. The immobilization potential of faecal matter biochar and lime were superior than the other treatments. However, lime and egg shell promoted statistically lower yield and P, K and Zn concentrations response of lettuce plants compared to the biochar treatments. The lowest Cd and highest P tissue concentrations of lettuce plants were induced by faecal matter and cow manure biochar treatments in both soils. Additionally, the greatest Cd phytoavailability reduction for lettuce was induced by poultry litter and cow manure biochars in the silty loam soil. Our results indicate that faecal matter and animal manure biochars have shown great potential to promote Cd immobilization and lettuce growth response in heavily contaminated agricultural fields. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-2019-6) contains supplementary material, which is available to authorized users. more...
- Published
- 2016
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37. The challenges of wastewater irrigation in developing countries
- Author
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Liqa Raschid-Sally, Manzoor Qadir, Peter G. McCornick, Pay Drechsel, Akissa Bahri, Dennis Wichelns, and Paramjit Singh Minhas
- Subjects
education.field_of_study ,Sanitation ,Natural resource economics ,Cash crop ,Population ,Soil Science ,Wastewater ,Urbanization ,Sewage treatment ,Business ,education ,Irrigation management ,Water resource management ,Agronomy and Crop Science ,Environmental quality ,Earth-Surface Processes ,Water Science and Technology - Abstract
The volume of wastewater generated by domestic, industrial and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse reasons, many developing countries are still unable to implement comprehensive wastewater treatment programs. Therefore in the near term, risk management and interim solutions are needed to prevent adverse impacts from wastewater irrigation. A combination of source control, and farm-level and post-harvest measures can be used to protect farm workers and consumers. The WHO guidelines revised in 2006 for wastewater use suggest measures beyond the traditional recommendations of producing only industrial or non-edible crops, as in many situations it is impossible to enforce a change in the current cash crop pattern, or provide alternative vegetable supply to urban markets. There are several opportunities for improving wastewater management via improved policies, institutional dialogues and financial mechanisms, which would reduce the risks in agriculture. Effluent standards combined with incentives or enforcement can motivate improvements in water management by household and industrial sectors discharging wastewater from point sources. Segregation of chemical pollutants from urban wastewater facilitates treatment and reduces risk. Strengthening institutional capacity and establishing links between water delivery and sanitation sectors through inter-institutional coordination leads to more efficient management of wastewater and risk reduction. more...
- Published
- 2010
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38. From world cafés to road shows: using a mix of knowledge sharing approaches to improve wastewater use in urban agriculture
- Author
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Nadia Manning-Thomas, Tonya Schuetz, Pay Drechsel, Gordana Kranjac-Berisavjevic, and Philip Amoah
- Subjects
Knowledge management ,business.industry ,Impact pathway ,Key (cryptography) ,Stakeholder ,Food safety ,business ,Urban agriculture ,Field (computer science) ,Knowledge sharing - Abstract
This paper documents the application of several innovative knowledge sharing approaches and some of the lessons learnt in a project addressing food safety concerns deriving from wastewater irrigated vegetables in Ghana. Knowledge sharing activities received particular attention in the project to facilitate its impact pathway, in particular to (i) verify preliminary research messages on good practices, (ii) raise awareness and build capacity, and (iii) equip various stakeholder groups with knowledge, skills and materials. Key approaches and tools applied were the world cafe approach for the verification of research messages. The approach brought together farmers, traders and street food vendors to openly discuss proposed improvements in current practices and their potential for wider uptake. For target-oriented message dissemination multi-media training materials were prepared following recommendations from the intended users, like extension agents, catering and farmer field schools. The materials made use... more...
- Published
- 2009
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39. Urban growth, wastewater production and use in irrigated agriculture: a comparative study of Accra, Addis Ababa and Hyderabad
- Author
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Daniel J. Van Rooijen, Pay Drechsel, Trent W. Biggs, and Ian K. Smout
- Subjects
Food security ,business.industry ,Geography, Planning and Development ,Agricultural economics ,Water scarcity ,Water resources ,Wastewater ,Urban planning ,Agriculture ,Management of Technology and Innovation ,Business ,Water resource management ,Urban agriculture ,Environmental degradation ,Water Science and Technology ,Food Science - Abstract
The relationships between urban development, water resources management and wastewater use for irrigation have been studied in the cities of Accra in Ghana, Addis Ababa in Ethiopia and Hyderabad in India. Large volumes of water are extracted from water sources often increasingly far away from the city, while investments in wastewater management are often lagging behind. The resulting environmental degradation within and downstream of cities has multiple consequences for public health, in particular through the use of untreated wastewater in irrigated agriculture. Despite significant efforts to increase wastewater treatment, options for safeguarding public health via conventional wastewater treatment alone remain limited to smaller inner-urban watersheds. The new WHO guidelines for wastewater irrigation recognize this situation and emphasize the potential of post- or non-treatment options. Controlling potential health risks will allow urban water managers in all three cities to build on the benefits from the already existing (but largely informal) wastewater reuse, those being the contribution to food security and reduction of fresh water demands. more...
- Published
- 2009
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40. Occupational Exposure to Pesticides: Blood Cholinesterase Activity in a Farming Community in Ghana
- Author
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Huub J. Gijzen, Elvis Nyarko, Laud Mike Tagoe, William J. Ntow, Pay Drechsel, and Peter Kelderman
- Subjects
Adult ,Male ,medicine.medical_specialty ,Sprayer ,Health, Toxicology and Mutagenesis ,Toxicology ,Occupational medicine ,Occupational Exposure ,Environmental health ,medicine ,Cholinesterases ,Humans ,Pesticides ,Cholinesterase ,biology ,Pesticide residue ,business.industry ,General Medicine ,Pesticide ,Pollution ,Agricultural Workers' Diseases ,Agriculture ,Linear Models ,biology.protein ,Female ,Occupational exposure ,Risk assessment ,business - Abstract
A survey was undertaken to establish the extent of pesticide exposure in a farming community. Cholinesterase (ChE) activity in whole blood was used as a marker for assessing exposure to pesticides. Complete data were gathered for 63 farmers at Akumadan (exposed) and 58 control subjects at Tono, both prominent vegetable-farming communities in Ghana, by means of a questionnaire and blood cholinesterase analyses (acetylcholine assay). Although whole-blood ChE was significantly lower in the exposed than the control participants, it was not significantly correlated with either confounders of age, sex, body weight, and height or high-risks practices. The high-risks practices revealed during the survey included lack of use of personal protective clothing, short reentry intervals, and wrong direction of spraying of pesticides by hand or knapsack sprayer. About 97% of exposed participants had experienced symptoms attributable to pesticide exposure. The frequent symptoms were reported as weakness and headache. There is the need to review safety precautions in the use and application of pesticides in Ghana. more...
- Published
- 2008
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41. Business models for fecal sludge management
- Author
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L. di Mario, E. Kvarnstrom, Krishna C. Rao, and Pay Drechsel
- Subjects
Waste treatment ,Waste management ,Biogas ,Sewage treatment ,Business ,Business model ,Cost recovery ,Business management ,Fecal sludge management ,Waste disposal - Published
- 2016
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42. Testing the implementation potential of resource recovery and reuse business models: from baseline surveys to feasibility studies and business plans
- Author
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Pay Drechsel, Miriam Otoo, George K. Danso, Ganesha Madurangi, Solomie A. Gebrezgabher, and Krishna C. Rao
- Subjects
Process management ,Sanitation ,business.industry ,Risk analysis (business) ,Environmental resource management ,Public sector ,Resource management ,Environmental impact assessment ,Business ,Reuse ,Business model ,Baseline (configuration management) - Published
- 2016
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43. Effect of low-cost irrigation methods on microbial contamination of lettuce irrigated with untreated wastewater
- Author
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Flemming Konradsen, Bernard Keraita, Robert C. Abaidoo, and Pay Drechsel
- Subjects
Irrigation ,business.industry ,Public Health, Environmental and Occupational Health ,food and beverages ,Drip irrigation ,Contamination ,Crop ,Toxicology ,Infectious Diseases ,Wastewater ,Environmental protection ,Agriculture ,Environmental science ,Vegetable farming ,Parasitology ,business ,Surface irrigation - Abstract
OBJECTIVE To assess the effectiveness of simple irrigation methods such as drip irrigation kits, furrow irrigation and use of watering cans in reducing contamination of lettuce irrigated with polluted water in urban farming in Ghana. METHODS Trials on drip kits, furrow irrigation and watering cans were conducted with urban vegetable farmers. Trials were arranged in a completely randomised block design with each plot having all three irrigation methods tested. This was conducted in both dry and wet seasons. Three hundred and ninety-six lettuce, 72 soil, 15 poultry manure and 32 water samples were analysed for thermotolerant coliforms and helminth eggs. RESULTS Lettuce irrigated with drip kits had the lowest levels of contamination, with, on average, 4 log units per 100 g, fewer thermotolerant coliforms than that irrigated with watering cans. However, drip kits often got clogged, required lower crop densities and restricted other routine farm activities. Watering cans were the most popular method. Using watering cans with caps on outlets from a height 1 m. CONCLUSION Simple, cheap and easily adoptable irrigation methods have great potential to reduce crop contamination in low-income areas. When used in combination with other on-farm and post-harvest risk reduction measures, these will help to comprehensively reduce public health risks from using polluted water in vegetable farming. more...
- Published
- 2007
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44. Effectiveness of common and improved sanitary washing methods in selected cities of West Africa for the reduction of coliform bacteria and helminth eggs on vegetables
- Author
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Robert C. Abaidoo, Philip Amoah, A. Klutse, and Pay Drechsel
- Subjects
medicine.medical_specialty ,Irrigation ,Public health ,Public Health, Environmental and Occupational Health ,Spring onion ,Contamination ,food.food ,Coliform bacteria ,Risk perception ,Toxicology ,Fecal coliform ,Infectious Diseases ,Geography ,food ,Environmental protection ,medicine ,Parasitology ,Risk assessment - Abstract
OBJECTIVE To analyse and improve the effectiveness of common indigenous washing methods for the reduction of faecal coliform (FC) populations on the surface of wastewater-irrigated vegetables and to determine simple factors affecting their efficacy. METHODS Questionnaire interviews were used to gather information on common methods used for washing vegetables in seven West African countries. The efficacy of the most common decontamination methods was measured in terms of log reductions in FC populations on homogenised contaminated lettuce, cabbage and spring onion samples. RESULTS The large majority of urban households and restaurants in the subregion are aware of vegetable-related health risks and wash vegetables before consumption. Methods used vary widely within and between Ghana and neighbouring francophone West African countries. However, several of the most common methods do not reduce the contamination to any desirable level. Significantly, different log reductions are achieved depending on the washing method, contact time and water temperature. Tests to improve the apparent ineffective methods were especially promising in view of the relatively expensive vinegar. However, up to 3 log units reduction is also possible at a much lower price with 'Eau de Javel' (household bleach), which is commonly used in francophone West Africa. CONCLUSION Washing vegetables before consumption is an important component of a multiple barrier approach for health risk reduction. The high risk perception among consumers demands that more information be made available on the appropriate use of these washing methods. Any washing method will need complementary efforts to reduce contamination before the vegetables enter the kitchen, such as safer irrigation practices. more...
- Published
- 2007
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45. Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting
- Author
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Bernard Keraita, Robert C. Abaidoo, Flemming Konradsen, and Pay Drechsel
- Subjects
Wet season ,Toxicology ,Irrigation ,Infectious Diseases ,Wastewater ,Dry season ,Public Health, Environmental and Occupational Health ,Randomized block design ,Vegetable farming ,Environmental science ,Parasitology ,Water quality ,Contamination - Abstract
Summary Objective To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. Methods Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. Results On average, 0.65 log units for indicator thermotolerant coliforms and 0.4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes / ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0.66 / day for the wet season and 1.49 / day for the dry season. Conclusion In combination with other measures for improving water quality, the measure can significantly reduce faecal contamination of lettuce during the dry season. However, it is not suitable for the wet season due to unfavourable conditions for pathogen die-off and re-contamination by splashes from contaminated soils. The results provide a good basis for risk assessments and for devising more appropriate measures for risk reduction, especially in sub-Saharan Africa. more...
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- 2007
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46. Influence of urban wastewater on stream water quality and agriculture in and around Kumasi, Ghana
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Philip Amoah, Pay Drechsel, and Bernard Keraita
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Urban Studies ,Wastewater ,Sanitation ,Agriculture ,business.industry ,Environmental pollution ,Water quality ,Environmental Science (miscellaneous) ,business ,Water resource management ,Urban agriculture ,Peri-urban agriculture ,Waste disposal - Abstract
This paper presents some findings from an ongoing International Water Management Institute research project in Ghana on urban wastewater use in agriculture. The paper focuses on the influence of urban wastewater on stream water quality and peri urban agriculture in Kumasi, and aims to develop strategies to reduce environmental pollution and risks from agricultural use of wastewater. It drew on interviews with local authorities, sanitation services providers, vegetable producers, traders and consumers, and on an assessment of the existing sanitation infrastructure and water quality. With few industries in Kumasi, urban wastewater is generated mostly from domestic sources. Population increase and lack of investment have overstretched the few available sanitation facilities, and large volumes of untreated or partially treated wastewater end up in nearby streams. High levels of faecal coliform were recorded in the city and downstream, as well as on vegetables in Kumasi’s markets, as contaminated wastewater streams are used for irrigation. Although urban and peri urban agriculture has a positive impact on food supply and livelihoods, it poses health risks for farmers and consumers. The paper discusses the constraints on addressing these problems and makes some recommendations regarding low-cost strategies for safer use of available water, better urban decentralized wastewater management and increased public awareness. more...
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- 2003
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47. Consumer perceptions of fruit and vegetable quality: certification and other options for safeguarding public health in West Africa
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B. Keraita and Pay Drechsel
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- 2015
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48. A global, spatially-explicit assessment of irrigated croplands influenced by urban wastewater flows
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Kara L. Nelson, Pay Drechsel, Anne Thebo, Eric F. Lambin, and UCL - SST/ELI/ELIC - Earth & Climate
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Irrigation ,010504 meteorology & atmospheric sciences ,Sanitation ,Renewable Energy, Sustainability and the Environment ,Public Health, Environmental and Occupational Health ,010501 environmental sciences ,01 natural sciences ,Downstream (manufacturing) ,Wastewater ,Environmental science ,Sewage treatment ,Water quality ,Water resource management ,Surface water ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
When urban areas expand without concomitant increases in wastewater treatment capacity, vast quantities of wastewater are released to surface waters with little or no treatment. Downstream of many urban areas are large areas of irrigated croplands reliant on these same surface water sources. Case studies document the widespread use of untreated wastewater in irrigated agriculture, but due to the practical and political challenges of conducting a true census of this practice, its global extent is not well known except where reuse has been planned. This study used GIS-based modeling methods to develop the first spatially-explicit estimate of the global extent of irrigated croplands influenced by urban wastewater flows, including indirect wastewater use. These croplands were further classified by their likelihood of using poor quality water based on the spatial proximity of croplands to urban areas, urban wastewater return flow ratios, and proportion of wastewater treated. This study found that 65% (35.9 Mha) of downstream irrigated croplands were located in catchments with high levels of dependence on urban wastewater flows. These same catchments were home to 1.37 billion urban residents. Of these croplands, 29.3 Mha were located in countries with low levels of wastewater treatment and home to 885 million urban residents. These figures provide insight into the key role that water reuse plays in meeting the water and food needs of people around the world, and the need to invest in wastewater treatment to protect public health. more...
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- 2017
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49. [Untitled]
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Frits Penning de Vries, Dagmar Kunze, and Pay Drechsel
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education.field_of_study ,Agroforestry ,business.industry ,Population ,Malthusianism ,Environmental Science (miscellaneous) ,Deforestation ,Environmental protection ,Agriculture ,Soil retrogression and degradation ,Economics ,Population growth ,education ,business ,Environmental degradation ,Nexus (standard) ,Demography - Abstract
Soil nutrient mining and other forms of soil degradation threaten future soil productivity, especially in sub-Saharan Africa (SSA). Data from 36 countries in SSA show a significant relationship at the supra-national level between soil nutrient depletion (including erosion), reduced fallow periods, and population pressure and thus illustrate the unsustainable population-agriculture-environment nexus on the continent which so far has been described in case studies only. It appears that Malthusian mechanisms are at work, despite encouraging indications of farmers' concerns and adaptation to changing conditions. It is agreed that a re-examination of the common land degradation assessments and farmers' response to changing conditions would be useful, however, this should not delay other recommended interventions. more...
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- 2001
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50. Wastewater use in irrigated agriculture
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Alexandra E.V. Evans and Pay Drechsel
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education.field_of_study ,Sanitation ,business.industry ,Geography, Planning and Development ,Population ,Sewage ,Agricultural economics ,Water scarcity ,Wastewater ,Agriculture ,Management of Technology and Innovation ,Environmental science ,Sewage treatment ,Water pollution ,business ,education ,Water resource management ,Water Science and Technology ,Food Science - Abstract
Wastewater irrigation is a widespread phenomenon. Although its main drivers differ between regions and along the sanitation ladder, they clearly indicate that the practice will continue to increase. This is especially the case in low-income countries where farmers in the economically interesting peri-urban interface are hardly able to find unpolluted surface water sources, as a result of inadequate wastewater collection and treatment. In other countries, reuse of (usually treated) wastewater is an important strategy to cope with fresh water scarcity. Both water scarcity and the gap between population growth and investments in sanitation will without question continue to challenge us in years to come. At present, more than 80% of the sewage generated in developing countries is discharged untreated into the environment, and about 50% of the population depends on polluted water sources for various uses, including irrigation (UNESCO 2003). Global estimates of the total irrigated area under raw and diluted wastewater are still fragmentary, but are likely to range between 5 and 20 million hectares, with the largest share probably in China due to its severe water pollution problems. Poor wastewater treatment and resulting large scale water pollution also suggest that the share of area irrigated with unsafe wastewater is probably ten times larger than the area using treated wastewater (Scott et al. 2010). However, estimates are still rudimentary and much more work is required to fully understand the extent of this problem and its implications. The same applies to the affected population. Nearly two decades ago, Paul Lunven estimated that at least 10% of the world’s population consumes food irrigated with wastewater (WHO 2006). Current estimates point at roughly one billion consumers of agricultural products initially grown with wastewater. A part of this group consumes raw produce, such as salad greens. In developing countries, these consumers face the most severe health risks, as only a small percentage of the wastewater undergoes sufficient treatment. more...
- Published
- 2010
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