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Lateritic soil, a prevalent geological material in tropical regions, often exhibits poor engineering properties, leading to road pavement failures. Meanwhile, the alarming rise in plastic waste poses environmental concerns. This innovative study explores the potential of utilizing waste plastics as a lateritic soil addictive for sustainable road construction. Varying percentages by weight of shredded waste plastic (2%, 4%, 6%, 8%, and 10%) were incorporated into lateritic soil samples, evaluating its effects on soil geotechnical properties. The results revealed that lateritized plastic (shredded plastic waste and lateritic soil) containing 2% shredded plastic waste gave the optimum maximum dry density of 1.985 g/cm3, and the lateritized plastic containing 10% shredded plastic waste gave the highest optimum moisture content of 18%. However, the lower California bearing ratio obtained on the addition of plastic waste showed that the lateritized plastic is relatively weak and can only be used for roads with low traffic. The incorporation of shredded plastic waste into lateritic soil for stabilization is a promising polymer science-based method. By reducing the need for conventional materials and diverting plastic waste from landfills, this approach contributes to a more environmentally friendly infrastructure supporting the achievement of United Nation Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

This experimental investigation involves adaptation of constrained simplex mixture design optimization technique for modeling of the mechanical behavior of soil–saw dust ash (SDA) which is a derivative from industrial byproducts to provide efficient waste management practices. The soil enhancement protocols deployed were to improve its engineering properties for pavement foundation purposes. The statistical analyses engaged in this research study were achieved using Design Expert software for the formulation and imposition of the components constraints, derivation of the mixture experimental runs and design proportions of ingredients. The experimental responses obtained from the laboratory works showed a maximum unconfined compressive strength (UCS) and California bearing ratio (CBR) results of 248 kN/m2 and 35% with mixture fraction of 0.875:0.125 for soil and SDA two component mixture respectively. For the investigation and development of the Extreme Vertex Design (EVD)-model, information from experimental exercises was used. The procedures included statistical assessment, ANOVA, diagnostic tests, and influence statistics, as well as numerical optimization utilizing the desirability function to examine the datasets. Desirability score of 1.0 was derived at a mix ratio of 0.8125: 0.1875 for the two components of soil–SDA to produce maximized CBR and UCS response of 35.053% and 257.152 kN/m2 respectively. Furthermore, the adequacy of the model generated was assessed by statistical validation and simulation exercises using student's t-test and F-test with P(T < = t) one-tail of 0.490 and 0.499 for F-test and P(F< = f) two-tail of 0.960 and 0.977 for t-test calculated for CBR and UCS responses, respectively. The calculated statistical results with P-value > 0.05 signified that there is no significant difference between the actual and EVD-model simulated results. [ABSTRACT FROM AUTHOR]

The development of effective and cost-efficient landfill liners is crucial to prevent groundwater contamination from leachate, safeguarding soil quality and the environment. Composite liners, particularly those combining bentonite with supplementary materials such as fly ash or marble dust, present a promising solution. This study delves into a comprehensive investigation of the physical properties of landfill liners composed of bentonite-fly ash and bentonite-marble dust mixtures through an extensive series of laboratory tests. The research systematically analyzes various proportions of bentonite with fly ash and marble dust, evaluating their impact on liner performance in comparison to Bentonite-sand mixtures. Physicochemical analyses are employed to understand the interactions and behaviors of these distinct substances within the amended bentonite. A wide array of physical properties, including Atterberg's limits, compaction characteristics, free swell index, modified free swell index, California bearing ratio, cohesion, and angle of internal friction, are meticulously examined. Collectively, these properties offer a comprehensive overview of the suitability and performance potential of bentonite-fly ash and bentonite-marble dust mixtures as landfill liners, presenting a viable alternative to traditional bentonite-sand mixtures. The study reveals synergistic effects between bentonite and both fly ash and marble dust, highlighting their significant contributions to enhancing the physical traits of landfill liners. This advancement in landfill liner design holds the promise of effectively mitigating detrimental environmental impacts associated with waste disposal. While this study provides a robust foundation, it is essential for future investigations to prioritize long-term performance assessments and real-world implementation. Validation and fine-tuning of these findings are crucial to ensuring practical applicability and efficacy within authentic landfill construction scenarios. This holistic approach will contribute to the continued evolution and optimization of landfill liner design, addressing the pressing challenges of sustainable waste management and environmental protection. [ABSTRACT FROM AUTHOR]

In recent years, a sudden upsurge in the quantity of municipal solid waste (MSW) has been observed, and the status quo demands a constructive and economically viable solution. The use of stabilized municipal solid waste (SMSW) in road construction can help in reducing the burden on landfills and waste management authorities. In the existing study, SMSW was accumulated from the Okhla landfill which is situated in New Delhi that is rich in an organic content. This SMSW was then blended with soil (5%, 10%, and 15%) and bottom ash with varying percentages (10%, 20%, 30%) individually and a mix of soil and bottom ash in the ratio of 1:1 to reduce the content of organic matter. The blended sample was then tested to check its compaction value, California bearing ratio (CBR), unconfined compressive strength (UCS), durability, and scanning electron microstructure (SEM). The results indicated that the addition of bottom ash to SMSW decreases the maximum dry unit weight that varies between 1.65 and 1.51 KN/m3 while this value reduces to 1.72 to 1.67 KN/m3 in the case of the bottom ash–soil blend. Also, CBR value reduces to 25.50 to 18.00% in case of bottom ash and 25.89 to 21.92% for bottom ash–soil samples and inverse in the case of SMSW samples blended with soil ranges between 19.95 and 22.59%. The California bearing ratio value of all samples under soaked condition meets the minimum criteria (> 10%) as specified in IRC SP-72 for low-volume roads, but at the same time failed to meet the durability specifications. Thus, it is recommended to use this soil subgrade material in arid regions. [ABSTRACT FROM AUTHOR]

Effective use of natural materials and industrial by products has a direct impact on economy, sustainable environment, and waste management. Poorly graded desert sand (SP) is widely observed in sand dunes and sand seas. Studies were performed to get beneficial use of cement kiln dust (CKD) in soil improvement. But there is a lack of information concerning using of CKD as an improving material for poorly graded sand with the aid of salt water. Salt water is widely available in Egypt from seas and some deep wells, using it will help in saving drink water which suffers from shortage in many countries. The aim of this research is to study the possibility of improving SP using CKD and salt water to be used in backfilling work and subbase layers of roads and pavements. Mixtures of poorly graded sand and various CKD ratios (10%, 20% and 30%) were classified and tested using grain size distribution, compaction, shear strength and California bearing tests. The results were compared with potable water. The results show that adding CKD improves the characteristic properties of SP even with salt water. The study enhances the using of 20% CKD with optimum water content of 9.12% of salt water to have noticeable improvement for SP and to be used efficiently in backfilling and subbase layers. [ABSTRACT FROM AUTHOR]

The present study investigates the potential of Municipal Solid Waste Incinerator Bottom Ash (MSWI-BA) collected from a waste-to-energy conversion plant in Delhi for geoenvironmental applications. The physicochemical and geotechnical properties of freshly quenched MSWI-BA were examined for cement-stabilized specimens with varying cement content ranging from 3% to 9%. The study aimed to assess the influence of pH and metal(loid)s concentrations during the standard curing period. The results demonstrated that adding cement formed C-S-H and C-A-H gel and Ca-hydrates within the matrix of 28-day cured samples. Specimens with 7% and 9% cement content exhibited the presence of quartz, calcite, belite, and other strength-enhancing compounds, leading to significant improvements in unconfined compressive strength and California bearing ratio values by up to 119.37% and 96.42%, respectively. Thermogravimetric analysis indicated moisture loss and breakdown of aluminates and silicates caused cracking at temperatures above 720 °C. The incorporation of cement resulted in the encapsulation of heavy metals, with the concentrations of Zn and Cu remaining within permissible limits. This study confirms the applicability of cement-stabilized MSWI-BA for flexible road pavements, earth fills, and various geoenvironmental applications. [ABSTRACT FROM AUTHOR]

The management of waste and its environmental impact remains an issue. Thus, various strategies are being explored to mitigate this problem. For this research case, the ash of plantain peel and coal was harnessed to enhance soil for usage in designing road pavements. The form of the soil, as regards its plasticity and grain assortment, positions it as a sandy lean clay material. Geotechnical parameters of the natural soil were established before being treated with coal ash (CA) and plantain peel ash (PPA), and subjected to tests for the Atterberg limits, California bearing ratio (CBR) and compaction, as well as investigations pertaining to its crystallinity and morphology. These assessments showed that strength parameters of soil increased on adding CA and PPA. However, the inclusion of these admixtures should be conducted until optimal strength is achieved as seen in 9% CA + 6% PPA. The use of soil stabilised with CA and PPA is suitable for general fillings and embankments. These findings revealed that integrating CA and PPA together would have the potential of stabilising soil as pavement layer material while also eliminating the pollution that emerges from the improper disposal of coal and plantain peels from the environment. [ABSTRACT FROM AUTHOR]

This study delves into the potential of using modified sabkha soil, a lowquality material, as a cost-effective solution for road construction in Kuwait, a country grappling with resource limitations. The research evaluates the effects of adding different percentages of bitumen (0%, 4%, 8%, and 10%) to sabkha soil samples, specifically looking at their load-bearing capacity under long-term soaking conditions. The findings indicate that adding up to 8% bitumen enhances the soil's geotechnical properties and its loadbearing capacity. However, any further addition leads to a decline in these properties. Importantly, the soil's load capacity shows significant improvement under soaked conditions. These encouraging laboratory results suggest that utilizing waste sabkha soil could pave the way for effective soil waste management techniques, thereby addressing environmental concerns related to sabkha soil disposal. [ABSTRACT FROM AUTHOR]

Along with the economic loss caused by the non-use of waste worldwide, uncontrolled storage also brings an additional cost. Today, the rapid increase in the population and the rapid depletion of natural resources in nature lead us to research the recycling possibilities of waste materials. In this context, using marble waste in road pavements is one of the best areas of use. This study investigated the suitability of substituting the marble waste obtained from a marble quarry in Bilecik, Turkey, in the road base layer instead of the aggregate, which was used all the time in the base layer in highway construction at different intervals. The physical tests carried out in this context have met the base material limit conditions of the Turkish Highways Technical Specification (THTS). Mixtures obtained in modified Proctor experiments, and optimum water contents (wopt) and maximum dry unit volume weight (rdmax) were determined for each mixture. California bearing ratio (CBR) values remained above the limit value of all mixtures for 0 days and 7 days of curing according to the specifications for THTS. In addition, CBR values were obtained after freezing-thawing at 4, 12, and 20 cycle numbers. According to the freezethaw test results, there was an increase in CBR values in the first 4 cycles and a decrease in the following cycles. Still, all the test results obtained remained above the limit value according to the specifications for THTS. Aggregate unit cost constitutes approximately twice the unit cost of marble waste. Besides, this difference has created an economic equality distance of 18.9 km. Therefore, a marble quarry, a road construction site within the calculated economic equality distance and marble waste material will provide a financial gain for our country. With the evaluation of quarry waste all over the world, we can leave a liveable world with rich raw material resources and a strong economy for future generations. [ABSTRACT FROM AUTHOR]

Industrial waste barrels were discarded from 1947 to 1961 at a DDT dumpsite in the San Pedro Basin (SPB) in southern California, USA at ~890 m. The barrels were studied for effects on sediment concentrations of DDX, PCBs, PAHs and sediment properties, and on benthic macrofaunal assemblages, including metazoan meiofaunal taxa >0.3 mm. DDX concentration was highest in the 2–6 cm fraction of the 10-cm deep cores studied but exhibited no correlation with macrofaunal density, composition or diversity. Macrofaunal diversity was lowest and distinct in sediments within discolored halos surrounding the barrels. Low macrobenthos density and diversity, high dominance by Entoprocta, and numerical prevalence of large nematodes may result from the very low oxygen concentrations in bottom waters (< 4.4 μM). There is potential for macrofauna to remobilize DDX into the water column and ultimately the food web in the SPB. • A first quantitative study on macrofauna (> 0.3 mm) in relation to proximity of DDT waste barrels in San Pedro Basin. • DDX and fauna exhibit high spatial variability, with low density of macrofauna but high density of nematodes. • Vertical distribution of the SPB macrofaunal is concentrated within the upper 2 cm, above peak DDX concentrations. • There is no clear influence of DDT-waste barrels on macrofaunal community structure and vertical distribution. • A first study of DDT waste disposal effects on deep-sea macrobenthos now includes macrofaunal-sized metazoan meiofauna. [ABSTRACT FROM AUTHOR]

AB2020 established a deposit‐refund system in California, where consumers are reimbursed the California Redemption Value (CRV) upon recycling eligible containers at a recycling center. We study recycling under this policy, focusing on consumer convenience, reported recycling and diversion behavior, and responses to changes in the CRV amount. We find that consumers prefer nearby centers with flexible operating hours and short waiting times. While the CRV induces recycling, an increase in CRV would not lead to major recycling increases, given the limited number of containers entering trash streams. Finally, most diverted containers are taken from trash streams, not curbside recycling bins. [ABSTRACT FROM AUTHOR]

Many governing bodies have launched efforts to shape the operations of manufacturers, administration of civic entities, and behavior of individuals to limit waste generation. Typically, such efforts commence with the enactment of targeted legislations that create operational changes (e.g., recycling fees, collection centers) to the waste collection and disposal processes. For example, over 25 states in the United States have enacted legislations that aim to properly dispose used electronic and electrical goods (i.e., e‐waste) and divert such waste away from landfills. We argue that such legislations can have an impact that extends beyond just reducing e‐waste. This is because such laws may not only motivate individuals to restrict e‐waste but also induce broader behavioral spillovers that can prompt individuals to reduce waste in general. To explore this idea, we exploit a quasi‐experimental setup that arises from California's enactment of the Electronic Waste Recycling Act (EWRA). Specifically, a difference‐in‐differences analysis reveals that the introduction and implementation of the EWRA resulted in at least 4.93% reduction in municipal solid waste (MSW). A plausibility analysis illustrates that these MSW reductions are much larger than what can be attributed purely to the decline of e‐waste. Furthermore, we show that the effect of e‐waste laws is stronger when consumers have increased market access through (i) online connectivity and (ii) offline proximity. Our study informs policy makers on the effects of e‐waste legislation and the critical role of market access in enhancing the impact of such legislation. [ABSTRACT FROM AUTHOR]

Requiring manufacturers to manage their products when they become waste is an innovative form of regulation, one that has been adopted by countries in Asia, Europe, and North America on a variety of products that range from vehicles to appliances to batteries. However, even in many unregulated industries, some manufacturers are voluntarily assuming more responsibility for their end-of-life products, driven by customer demand and cost efficiencies. This article explores various forms of take-back regulation and highlights some of the key features of the institutions that emerge in response. In addition, it presents seven strategic product recovery alternatives, followed by a discussion of some factors managers should consider in developing a take-back strategy. INSETS: Major Product Take-Back Bills introduced into U.S. State...;RosettaNet. [ABSTRACT FROM AUTHOR]

This essay excavates geographies of environmental injustice and racial violence in San Francisco, California using the artwork of Asian/American artists Weston Teruya, Michael Arcega, and Stephanie Syjuco made during their residencies at Recology (the city's privately-owned waste management facility). At Recology's Artist-In-Residence program, cultural workers salvage materials from the dump, transforming the city's waste into objects with educational and artistic value. Reading the visual lexicon deployed in, and the conditions of production and circulation of, these assemblages, I trace the wastelanding of communities of color across the Northern California region through processes of incarceration, toxic exposure, displacement, and labor exploitation. These artworks, I argue, assist in uncovering the terrain of slow violence in the region and across scales, or what Rob Nixon has called "landscapes of temporal overspill that elude rhetorical cleanup operations with their sanitary beginnings and endings" (2011, 8). [ABSTRACT FROM AUTHOR]

While electric vehicles (EVs) have been promoted for green consumption, improper or inadequate management of end-of-life (EOL) EV batteries, as the current practice, compromises the benefits of EV adoption. This study aims to contribute to both theoretical research of material flow analysis and timely management of EOL EV batteries at various geographic scales (i.e., national, state, and county). Theoretically, this study tests two battery lifespan scenarios (i.e., constantly at 3–8 years and dynamically increasing over time), three discard probability functions (i.e., uniform, truncated normal, and Weibull), and three EV sale projections (i.e., low, moderate, and high). Results show that the short-term EOL volume (by 2025) can be particularly sensitive to the lifespan parameter. The long-term estimates involve most uncertainties related to the EV market penetration. Various discard probability functions generally derive similar results. In practical terms, the results suggest that necessary infrastructure for proper EOL EV battery management is needed sooner than the public may have perceived. This study urges for regional planning that incorporates both temporal and spatial considerations. To illustrate an example of regional solutions, this study adopts empirical data in California to simulate and spatially match EOL EV battery clusters and the renewable energy facilities that can potentially reuse EV batteries as energy storage. Meanwhile, the spatial mis-match between the supply and demand, as can be the case in other regions, calls for region-wide coordination in terms of both infrastructure development and transportation planning. [ABSTRACT FROM AUTHOR]

Greenhouse gases (GHGs) are produced during the composting process, but few studies have measured emissions from a full-scale windrow of composting green-waste. This is important for evaluating composting as a waste management option and for understanding how changes to current composting management practices could help reduce emissions. This study uses micrometeorological mass balance (MMB) and open flow-through chamber techniques to measure emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from a windrow of composting green-waste in Northern California. The MMB technique yielded mean upwind–downwind concentration differences over the study period that showed sourcing of all three GHGs. CO2 showed a stronger signal than CH4 and N2O. A strong diel pattern was found in the concentration differences at lower levels and fluxes of CO2, with substantial noise likely obscuring any possible daily patterns for CH4 and N2O. Fluxes normalized by the time since the previous turn event revealed an initial rapid rise in CO2 concentration differences (at lower levels) and fluxes, peaking close to 13 h after the turn event followed by a gradual decline. The same pattern was not as clear for the other two gases but overall declines in concentration differences and fluxes were apparent with increasing time since the previous turn event. Substantial differences between MMB and chamber calculated fluxes were found, due to both differences in the techniques as well as sampling frequency. [ABSTRACT FROM AUTHOR]

Endangered San Joaquin kit foxes (Vulpes macrotis mutica; SJKF) and California ground squirrels (Otospermophilus beecheyi; CAGS) occur sympatrically in many locations. CAGS can constitute a nuisance species and control strategies have included lethal measures administered within CAGS burrows. These measures could harm or kill a SJKF if mistakenly applied to an occupied SJKF den. To identify attributes to distinguish between SJKF dens and CAGS burrow, we assessed dimensions, penetration depths by 9.7-cm and 7.5-cm spheres, ejecta patterns, and the presence of various types of sign at 65 dens to which radiocollared SJKF were tracked and at 80 burrows that CAGS were observed to enter. Mean entrance height, width, and circumference all were significantly larger for SJKF den entrances. However, the ranges of values for all dimensions for the CAGS burrows completely encompassed the ranges for the SJKF dens. Penetration depths with the 7.5-cm sphere were similar for SJKF dens and CAGS burrows. The 9.7-cm sphere could not be inserted in over half of CAGS burrows and exceeded 1 m in depth in over half of the SJKF dens. Most SJKF dens had dirt berms but so did over half of the CAGS burrows. SJKF scats, prey remains, CAGS scats, and trash were observed at both SJKF dens and CAGS burrows although at different frequencies. CAGS tracks were only observed at seven CAGS burrows. None of the attributes we assessed provided unequivocal criteria for distinguishing between SJKF dens and CAGS burrows. Also, SJKF occasionally usurp CAGS burrows and CAGS occasionally move into vacant SJKF dens. Therefore, administering lethal control measures within burrows should be avoided as it presents too great a risk to SJKF as well as the many other species that also use CAGS burrows. [ABSTRACT FROM AUTHOR]

Uses of science by environmental justice (EJ) activists reflect struggles to challenge professional scientific expertise, achieve fair outcomes, and effectively participate in decision-making processes. This qualitative research analyses the relationship betweencitizen scienceand EJ in a new waste facility siting conflict in urban Los Angeles, namely connections between citizen science and four dimensions of EJ:fair distribution,respect and recognition,participation in decision-making, andcommunity capabilities. Citizen science is one tactic in EJ, yet little research investigates its role in a new facility siting conflict, particularly in relation to multi-faceted EJ goals. The research reveals opportunities for individual empowerment and community capacity building using citizen science, and a small measure of improved respect and recognition for participants who brought their own knowledge, research, and voices to the table. At the same time, the work identifies limitations on citizen science to improve local participatory procedures and decision-making, which also constricted the achievement of outcomes most desired by the EJ group: to prevent approval and construction of the new waste facility. This paper argues that uses of citizen science contributed to partial achievement of EJ goals, while hindered by governance processes that call for public participation yet shield decision-makers from substantive engagement with the volume or content of that participation. [ABSTRACT FROM AUTHOR]

Background: Particulate matter (PM) has been documented to contribute to preterm delivery. However, few studies have investigated the relationships between individual constituents of fine PM (PM2.5 ) and preterm delivery, and factors that may modify their associations.Methods: In this study, we examined the associations between several prenatal exposure metrics to PM2.5 and 23 constituents of PM2.5 and preterm delivery in California from 2000 to 2006. In a retrospective cohort study including 231 637 births, we conducted logistic regression analyses adjusting for maternal, infant, temporal, geographic, and neighbourhood characteristics.Results: We observed increased risk for preterm delivery with full-gestational exposure for several PM2.5 constituents. Per interquartile range increase, ammonium (21.2%, 95% confidence interval (CI) 17.1, 25.4), nitrate (18.1%, 95% CI 14.9, 21.4) and bromine (16.7%, 95% CI 13.2, 20.3) had some of the largest increased risks. Alternatively, some PM2.5 constituents were inversely associated with preterm delivery, including chlorine (-8.2%, 95% CI -10.3, -6.0), sodium (-13.2%, 95% CI -15.2, -11.3), sodium ion (-11.9%, 95% CI -14.1, -9.6) and vanadium (-19.2%, 95% CI -25.3, -12.6). Greater associations between PM2.5 constituents and preterm delivery were observed for Blacks and Asians, older mothers, and those with some college education compared to their reference groups, as well as for births with gestational ages from 32 to 34 weeks.Conclusions: PM2.5 constituents ammonium, nitrate and bromine, often linked to traffic and biomass combustion, were most associated with increased risk of preterm delivery in California. Certain demographic subgroups may be particularly impacted. [ABSTRACT FROM AUTHOR]

Collection and recycling of household hazardous waste (HHW) can vary due to differences in household incomes, demographics, material recyclability, and HHW collection programs. We evaluate the role of household informedness , the degree to which households have the necessary information to make utility-maximizing decisions about the handling of their waste. Household informedness seems to be influenced by HHW public education and environmental quality information. We assess the effects of household informedness on HHW collection and recycling using panel data, community surveys, drinking water compliance reports, and census data in California from 2004 to 2012. The results enable the calculation of the responsiveness or elasticity of the output quantities of HHW collected and recycled for differences in household informedness at the county level. There are three main findings: (1) provision of HHW public education has a positive effect on the amount of HHW collected and recycled, but may have a negative effect on HHW collected in some circumstances; (2) environmental quality information about contaminant violations in drinking water has a negative association with the amount of HHW collected; and (3) when information is sent directly via mail to households, an increase in the number of contaminant level (MCL) violations is positively related to the amount of HHW collected. Understanding how these effects work in California can help waste management policy-makers and practitioners in other locations to plan appropriate information policies and programs to maximize household participation in HHW collection and recycling based on household informedness and demographic characteristics. [ABSTRACT FROM AUTHOR]

• Following a suitable Preferred Reporting Items (PRISMA) framework, Scopus, Web of Science (WoS), and Transport Research International Documentation (TRID) databases were systematically reviewed. • Qualitative analysis of sixty-seven articles published across the globe during 1988-2022 has been carried out to establish the potentiality of coal mining and processing wastes as sub-base and/or base material in pavements. • Physical, chemical, and mechanical properties of untreated coal wastes have been evaluated to establish the efficacy of these waste materials toward sustainable pavement construction. • Opportunities associated with the application of coal mining and processing wastes in the subbase and/or base layer(s) of pavement are extensively debated. With the rising trend in electricity usage, the amount of waste associated with the mining and processing of coal is also rising rapidly. Over the past few decades, improper utilization of these wastes has led to resource depletion, waste disposal, and environmental pollution issues. The key focus of the present study is to review the literature related to the utilization of untreated and treated coal mining and processing wastes in the construction of sustainable roads. Following a suitable Preferred Reporting Items (PRISMA) framework for systematic review, 67 records are considered for the qualitative analysis. The efficiency of these coal mining and processing wastes as secondary aggregate in the sub-base and/or base layer of pavement is reviewed based on their mechanical (California bearing ratio, Unconfined compressive strength, Flexural strength, and Indirect tensile strength) and durability (Freeze-thaw resistance and Resistance to shrinkage) properties. The effectiveness of chemical stabilization on strength gain criteria is also discussed on the basis of microstructural (Scanning electron microscopy and Energy dispersive X-ray spectroscopy) analysis. The findings of the present review suggest that utilization of coal wastes in the construction of bound sub-base and/or base not only addresses the waste disposal challenges but also assists the problems associated with raw material depletion. Additionally, based on the outcomes of past studies, this paper identifies the research gaps and presents future research directions that could open new avenues for the sustainable development of pavement. [ABSTRACT FROM AUTHOR]

Urban metabolism provides a framework to understand resource flows into cities and waste flows out. Its potential has been hampered by the lack of good disaggregated data. This article presents energy-use findings for the residential sector for the city of Los Angeles based on census-block-level aggregation of address-level electricity use obtained from the Los Angeles Department of Water and Power. City or county billing data by customer class over time can enable empirical tracking of energy conservation and efficiency programs by different customer classes, and matched to census information and county tax assessor data about building vintage, size, and type can provide information important for rate setting, for example, or energy conservation and efficiency program investments. We report on median electricity demand and corresponding greenhouse gas emissions and expenditures at three geographical aggregations: city council district (15 in total); neighborhood (114 in total); and census block group (2,538 in total). We find that the ratio of median annual demand between highest- and lowest-tier users is 26 at the census-block group level, but only 2.2 at the city council district level, demonstrating that spatial aggregation significantly masks the degree of variation that may be observed. We also show how such data can enable the description of energy to develop energy disclosure thresholds that reflect a city's morphology. In contrast to New York City's 50,000-square-foot reporting threshold, to capture half of Los Angeles' electricity consumption, the threshold for reporting would have to be 5,000 square feet. [ABSTRACT FROM AUTHOR]

This investigation was conducted to evaluate the influence of waste placement practices on the engineering response of municipal solid waste (MSW) landfills. Waste placement conditions were varied by moisture addition to the wastes at the time of disposal. Tests were conducted at a California landfill in test plots (residential component of incoming wastes) and full-scale active face (all incoming wastes including residential, commercial, and self-delivered components). The short-term effects of moisture addition were assessed by investigating compaction characteristics and moisture distribution and the long-term effects by estimating settlement characteristics of the variably placed wastes. In addition, effects on engineering properties including hydraulic conductivity and shear strength, as well as economic aspects were investigated. The unit weight of the wastes increased with moisture addition to a maximum value and then decreased with further moisture addition. At the optimum moisture conditions, 68% more waste could be placed in the same landfill volume compared to the baseline conditions. Moisture addition raised the volumetric moisture content of the wastes to the range 33–42%, consistent with values at and above field capacity. Moisture transfer occurred between consecutive layers of compacted wastes and a moisture addition schedule of 2 days of as-received conditions and 1 day of moisture addition was recommended. Settlement of wastes was estimated to increase with moisture addition, with a 34% increase at optimum moisture compared to as-received conditions. Overall, moisture addition during compaction increased unit weight, the amount of incoming wastes disposed in a given landfill volume, biological activity potential, and predicted settlement. The combined effects have significant environmental and economic implications for landfill operations. [ABSTRACT FROM AUTHOR]

Background: Sharps waste, especially medical sharps waste, can put those who come into contact with it at risk for injury and exposure to blood-borne pathogens. Options for self-injectors to dispose of their sharps while traveling vary greatly - from sharps containers in limited locations in some public restrooms to large kiosks centrally located to no containers at all. Currently, there is a lack of published data on sharps disposal bins in commercial airports. We surveyed commercial airports in California to assess the current state of sharps waste disposal. Many people with diabetes routinely use sharps every day for injecting medications or for self-monitoring glucose concentrations and these people, along with others who self-inject medications, must have a safe mechanism for sharps disposal when travelling by air., Methods: A five-question survey was sent to 30 commercial airports in California. Responses were collected and then analyzed based on the following three metrics: (1) the percentage of airports that responded and indicated that they had any sharps disposal bins, (2) the percentage of airports that responded and indicated that they had sharps disposal bins in over half their restrooms, and (3) the average percentage of bathrooms that have available sharps disposal bins in airports that responded to our survey., Results: Out of 30 commercial airports in California, we received survey responses from 13 airport representatives and direct email responses from 5 airport representatives. Out of 18 total responses, 11 airports (61.1%) reported that they had some form of available sharps disposal options. Out of the 13 survey responses, 6 airports (46.2%) reported that they had sharps disposal in over 50% of their restrooms., Conclusion: There is a lack of consistency in sharps waste disposal options among commercial airports in California. While many commercial airports in California offer sharps waste disposal options, not all commercial airports have sharps waste disposal options in all their public restrooms. There is room for improved availability of sharps disposal bins in California's commercial airports.

Abstract: How waste is managed – whether as a nuisance to be disposed of, or as a resource to be reused – directly affects local and global environmental quality. This analysis explores the GHG benefits of five treatment options for residual municipal solid waste (MSW) in California: Business As Usual (landfilling), Anaerobic Digestion, Incineration, 40% Reduction, and MaxEnergy (both incineration and anaerobic digestion). Because recycling efforts in California are already strong, this analysis focuses on non-recyclables and asks what else can be done with the material fractions that are currently reaching landfills. Using two different waste LCA models, EASEWASTE (a Danish model) and WARM (a U.S. model), we find that improved biogenic waste management through anaerobic digestion and waste reduction can lead to life-cycle GHG savings when compared to Business As Usual. The magnitude of the benefits depends strongly on a number of model assumptions: the type of electricity displaced by waste-derived energy, how biogenic carbon is counted as a contributor to atmospheric carbon stocks, and the landfill gas collection rate. Assuming that natural gas is displaced by waste-derived energy, that 64% of landfill gas is collected, and that our system boundary begins when waste is thrown away and ends with disposal or conversion to air emissions, reducing California''s residual waste by 40% can lead to a savings of 6Mt (million metric tonnes) of CO2-e per year, and digesting California''s biogenic waste could save 0.6Mt CO2-e per year. Source reduction is the most robust means to mitigate GHG emissions from waste, though either increasing landfill gas capture rates within the current management plan or digesting biogenic waste (and designing landfills to maximize carbon sequestration) provide two other important means for greenhouse gas mitigation from waste management. [Copyright &y& Elsevier]

Local governments like the City and County of San Francisco have shouldered the burden of toxic chemicals released into the environment through the substantial costs of health care, environmental cleanup, and infrastructure to purify drinking water, manage wastewater. and manage solid waste. Cities can no longer afford to wait for federal regulation to prevent toxic chemicals from appearing in products used locally. San Francisco's Precautionary Principle Policy calls on the City to act on early warning signs of harm and to use the best available science to identify safer alternatives. Under its umbrella, a wide array of policy tools have been utilized including financial incentives through procurement contracts, certification and promotion of safer business practices, requirements for information disclosure, and bans and restrictions on the sale of products when safer alternatives are readily available. These policies can often become the modek for regional. state, and national change. [ABSTRACT FROM AUTHOR]

Objectives Growing concern over the costs, environmental impact and safety of tobacco product litter (TPL) has prompted states and cities to undertake a variety of policy initiatives, of which litter abatement fees are part. The present work describes a framework and methodology for calculating TPL costs and abatement fees. Methods Abatement is associated with four categories of costs: (1) mechanical and manual abatement from streets, sidewalks and public places, (2) mechanical and manual abatement from storm water and sewer treatment systems, (3) the costs associated with harm to the ecosystem and harm to industries dependent on clean and healthy ecosystems, and (4) the costs associated with direct harm to human health. The experiences of the City of San Francisco's recently proposed tobacco litter abatement fee serve as a case study. Results City and municipal TPL costs are incurred through manual and mechanical clean-up of surfaces and catchment areas. According to some studies, public litter abatement costs to US cities range from US$3 million to US$16 million. TPL typically comprises between 22% and 36% of all visible litter, implying that total public TPL direct abatement costs range from about US$0.5 million to US$6 million for a city the size of San Francisco. The costs of mitigating the negative externalities of TPL in a city the size of San Francisco can be offset by implementing a fee of approximately US$0.20 per pack. Conclusions Tobacco litter abatement costs to cities can be substantial, even when the costs of potential environmental pollution and tourism effects are excluded. One public policy option to address tobacco litter is levying of fees on cigarettes sold. The methodology described here for calculating TPL costs and abatement fees may be useful to state and local authorities who are considering adoption of this policy initiative. [ABSTRACT FROM AUTHOR]

Objective To better estimate the burden of toxic cigarette butt waste and create awareness of the hazardous nature of cigarette butts on two large university campuses in San Diego by organizing and conducting student cigarette butt clean-up activities. Methods Two separate campus-wide clean-ups were conducted by student volunteers at San Diego State University (SDSU) and at University of California San Diego (UCSD) between April and July 2010. Results In 1 h, 63 volunteers at SDSU collected 23 885 butts; 6525 cigarette butts were collected in 1 h by 17 volunteers at UCSD. The average number of cigarette butts picked up per individual was 379.1 at SDSU and 383.8 at UCSD (range 25e1030 per volunteer). Conclusions The amount of cigarette waste on college campuses nationally may be quite substantial given the many thousands of cigarette butts gathered at each of the San Diego institutions. In just 10 s on average a volunteer could locate, walk to, pick up and put a cigarette butt in the collection bag and then begin looking for another discarded butt, indicating the saturation of cigarette butts on campus. Smoke-free policies on campus could have far-reaching effects not only in reducing smoking behaviour on campus and ground clean-up costs, but also on the environment. Campus cigarette waste clean-ups can be utilized to call attention to the issue of cigarette butt waste in the environment. [ABSTRACT FROM AUTHOR]

Purpose - The "environmental justice" movement has suggested that demographic inequities characterize the location of hazardous waste treatment, storage, and disposal facilities (TSDFs). While some researchers have found evidence that TSDFs are disproportionately located in minority areas, others attribute TSDF location to non-racial factors such as income and industrial employment. Design/methodology/approach - Both univariate and multivariate techniques were used to analyse the location of TSDFs in Los Angeles County, California; the focus on one county allowed this paper to overcome the problem of "fake" addresses for TSDF sites and to introduce specific land use/zoning variables that are not used in the other studies. Findings - Findings from the univariate results and the multivariate model reveal that: industrial land use and manufacturing employment do matter, as suggested by critics of environmental justice; income has first a positive, then a negative effect on TSDF location, a pattern that likely reflects the fact that the poorest communities have little economic activity, while wealthier communities have the economic and political power to resist negative environmental externalities; and race and ethnicity are still significantly associated with TSDF location, even when percentage African American and percentage Latino are evaluated as separate groupings. Research limitations/implications - All 82 Los Angeles County TSDFs currently listed by the California State Department of Toxic Substances Control (DTSC) are included in the study. Practical implications - Taken together, the results suggest that communities most affected by TSDFs in the Los Angeles area are working-class and ethnic minorities located near industrial areas. Originality/value - This paper represents the first work to analyse the siting of hazardous waste dump facilities and their correlation with status of surrounding residential neighbourhoods in Los Angeles county. [ABSTRACT FROM AUTHOR]

A comprehensive assessment was conducted of California's Used Oil Program, which was established in 1992 to reduce the illegal disposal, and promote the reuse, of used lubricating oil. This paper summarises selected key findings of the assessment and discusses them in the context of designing and implementing policy instruments for promoting environmentally responsible waste management. The approach known as 'community-based social marketing' is identified as a promising option. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are used in consumer products, including electronics, fabrics, and polyurethane foam. Exposures may occur during the products’ useful lifetime and also after the products’ disposal. A survey of California wastestreams (e-wastes, autoshredder waste and wastewater sewage sludge) attempted to assess the relative importance of these wastestreams as repositories of PBDEs. Based on measurements of PBDEs in samples of such wastestreams and on assumptions regarding use patterns, e-wastes appeared to be by far the predominant wastestream with 1200 metric tons (MT) of PBDEs year−1, followed by autoshredder waste (31MT of PBDEs year−1) and sewage sludge (2.3MT of PBDEs year−1). When these estimates were compared with the reported use of PBDEs in California, about half of the PBDEs could not be accounted for in the wastestreams examined. This suggests that additional wastestreams, such as household wastes should be evaluated for their PBDE content. Information on the presence and fate of PBDEs in all wastestreams needs to be included in decision making practices for waste management to avoid public health and ecologic catastrophes. [Copyright &y& Elsevier]

Concerns about rapid increases in the volume of electronic waste (e-waste) and its potential toxicity have sharpened policy makers' interest for extended producer responsibility to encourage manufacturers of consumer electronic devices (CEDs) to ‘design for the environment’. This paper examines consumer willingness to pay for ‘green’ electronics based on a 2004 mail survey of California households. Using ordered logit models, it was found that significant predictors of willingness to pay for ‘greener’ computers and cell phones include age, income, education, beliefs about the role of government for improving environmental quality, as well as environmental attitudes and behaviors, but neither gender nor political affiliation. Although most respondents are willing to pay only a 1% premium for ‘greener’ CEDs, innovation and EU directives may soon make them competitive with conventional CEDs. [ABSTRACT FROM AUTHOR]

As Class B biosolids land application has become less acceptable to many local jurisdictions, low-cost processes to achieve Class A standards have become more popular. Prominent among these low-cost processes is thermophilic anaerobic digestion. As a result, thermophilic anaerobic digestion is now a popular topic in wastewater treatment literature, but quantifiable methods for selecting a particular thermophilic process have not been offered. To provide for this need, an empirical model was developed from data collected in thermophilic anaerobic digestion studies conducted using East Bay Municipal Utility District's (Oakland, California) primary and waste activated sludge to feed both bench- and full-scale digesters. The model predicts at which thermophilic temperature and mean cell residence time (MCRT) one process will outperform or equal another, with respect to fecal coliform reduction. The different disinfection efficiencies in the different thermophilic processes might be explained by the presence or absence of high volatile acid and/or un-ionized ammonia levels in the processes' digested sludges. Data from these studies also show an apparent relationship between increased thermophilic temperatures and volatile solids destruction, and between increased temperatures and specific volatile acids production, for digesters operating at a 13-day MCRT and higher, but not for digesters operating at a 2-day MCRT. [ABSTRACT FROM AUTHOR]

Discusses a study that compared two test cells to evaluate the effects of leachate recirculation on refuse decomposition at Yolo County, California. Advantages of leachate recirculation; Methane production rate in the control and enhanced cells; Relationships among measures of solids composition.

Two collaborative studies have been conducted by the U.S. Environmental Protection Agency (EPA) National Exposure Research Laboratory (NERL) and National Health and Environmental Effects Research Laboratory to determine personal exposures and physiological responses to particulate matter (PM) of elderly persons living in a retirement facility in Fresno, CA. Measurements of PM and other criteria air pollutants were made inside selected individual residences within the retirement facility and at a central outdoor site on the premises. In addition, personal PM exposure monitoring was conducted for a subset of the participants, and ambient PM monitoring data were available for comparison from the NERL PM research monitoring platform in central Fresno. Both a winter (February 1-28, 1999) and a spring (April 19-May 16, 1999) study were completed so that seasonal effects could be evaluated. During the spring study, a more robust personal exposure component was added, as well as a more detailed evaluation of physical factors, such as air-exchange rate, that are known to influence the penetration of particles into the indoor environment. In this paper, comparisons are made among measured personal PM exposures and PM mass concentrations measured at the NERL Fresno Platform site, outside on the premises of the retirement facility, and inside selected residential apartments at the facility during the two 28-day study periods. The arithmetic daily mean personal PM[sub2.5] exposure during the winter study period was 13.3 µg/m³, compared with 9.7, 20.5, and 21.7 µg/m³ for daily mean overall apartment, outdoor, and ambient (i.e., platform) concentrations, respectively. The daily mean personal PM[sub2.5] exposure during the spring study period was 11.1 µg/m³, compared with 8.0, 10.1, and 8.6 µg/m³ for the daily mean apartment, outdoor, and ambient concentrations, respectively. [ABSTRACT FROM AUTHOR]

The article discusses the pollution problem faced by California, particularly toxic industrial wastes. The state charges that an industry-backed proposal to deregulate the disposal of toxic waste would put the responsibility of pollution control to polluters. The environmental report card of 1999 shows that the state has been given a satisfactory rating for its past efforts to protect ground water. Moreover, corporations had contributed to the prevention and control of industrial wastes by investigating and proper maintenance of their control system.

• Fe-EC was field-tested for its arsenic removal suitability in rural California. • Arsenic in groundwater was reduced from 150 µg/L to below 10 µg/L in all experiments. • Adding H 2 O 2 externally in the Fe-EC process shortened electrolysis time by 28 fold. • Waste was characterized per California regulations for planning waste management. • Increasing current density to eliminate electrode cleaning, needs further research. Small, low-income, and rural communities across the United States are disproportionately exposed to arsenic contaminated drinking water because existing treatment solutions are too expensive and difficult to operate. This paper describes efforts to overcome some barriers and limitations of conventional iron electrocoagulation (Fe-EC) to enable its use in the rural Californian (U.S.) context. Barriers and limitations of Fe-EC's application in rural California considered in this work include: 1) Frequent labor intensive electrode cleaning is required to overcome rust accumulation, 2) Electrolysis durations are long, reducing throughput for a given system size, and 3) Waste needs compliance with California standards. We report results from an investigation for overcoming these limitations via a field trial on a farm in Allensworth, a small, low-income, rural community in California. Our strategies to overcome each of the above barriers and limitations are respectively, 1) operating the Fe-EC reactor at high current density to result in sustained Fe production, 2) operating at high charge dosage rate with external H 2 O 2 , and 3) characterization of the arsenic-laden waste, and are discussed further in the paper. Main findings are: (1) Fe-EC removed arsenic consistently below the federal (and state) standard of 10 µg/L, (2) high current density failed to sustain Fe production whereas low current density did not, (3) electrolysis time decreased from > 1 hour to < 2 min with H 2 O 2 dosing of 5 mg/L at higher charge dosage rates, (4) dilution of As-sludge is required to comply with State's non-hazardous waste status, and (5) discrepancies were observed between lab and field results in using current density to overcome labor-intensive electrode cleanings. Finally, implications of overcoming limitations to scale-up of Fe-EC in relevant California communities are discussed. [ABSTRACT FROM AUTHOR]