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To evaluate the effect of brown-rot fungi Oligoporus placenta and earthworm Eisenia fetida on decomposition of paper mill sludge, the paper mill sludge was mixed with cow dung in 0, 25, 50, 75, and 100% proportions and changes in physicochemical quality of waste mixtures was carried out for 28 days. All waste mixtures were treated with: Setup-I (E. fetida), Setup-II (O. placenta) and, Setup-III (E. fetida + O. placenta). A decrease in total organic carbon, C/N ratio and cellulose but an increase in total kjeldhal nitrogen, total phosphorus, total potassium and pH was recorded. The paper mill sludge in 50–75% proportion in feedstock showed the better results and rate of mineralisation were in order: Setup-III > Setup-I > Setup-II. The proportion of CD has direct role in waste mineralisation. The microbial population (bacterial, fungal and actinomycetes) and earthworm biomass were also high in Setup-III, suggesting the influence of brown-rot fungi on paper mill sludge humification. Results indicate that fungal inoculate in vermicomposting was effective in decomposing cellulose-rich industrial sludge.

Building bricks were produced by utilizing deinking paper mill sludge (DPMS) and alluvial soil by varying percentage of sludge at different firing temperatures. Different mix proportions were prepared with 0%, 5%, 10%, 15%, 20%, 25% and 30% of DPMS incorporation in alluvial soil by weight. Three firing temperatures of 900 °C, 950 °C and 1000 °C were investigated to simulate the typical condition of kiln. The density, firing shrinkage, water absorption, efflorescence, apparent porosity, compressive strength and thermal conductivity of the bricks were determined. The XRD and microstructural analysis of brick specimens were also studied. The optimum firing temperature was 950 °C. The thermal conductivity decreases with increase in percentage of deinking paper mill sludge. It was found that 15% deinking paper mill sludge gives optimum strength at firing temperature of 950 °C. Developed bricks satisfy the requirements of class 10 of Bureau of Indian Standards (BIS), in terms of efflorescence, compressive strength and water absorption. Thermal conductivity results show that the developed brick was thermally more insulated than the conventional bricks and can be used as alternative to conventional bricks. This will address the issue of waste management through cleaner production and show the ways towards sustainable, economical and energy efficient construction.

The need to view innovation policy through the lens of policy mixes has gained momentum given the growing complexity, the dynamics of real-world policy and the wide array of difficulties to address the current great societal challenges, notably the increasing pressure on the ecosystems that support our society. One of the main challenges concerning the transition towards bioeconomy, is to gain a more in-depth understanding on the policy mix to stimulate innovation in sustainability transitions. Our paper aims at enriching the portfolio of empirical case studies on policy mixes for innovation and sustainable transitions, by investigating the development of the policy mix underpinning the sustainability transition of the pulp and paper industry in Sweden. We apply a case study approach which draws on event history analysis, semi-structured interviews with industry and policy makers, literature reviews, a participative workshop with stakeholders from the pulp and paper industry, as well as on the IEA databases on climate change and energy efficiency policies and measures. Our analysis emphasises coordination, timing and scale in policy mixes as important elements to understand how instruments interact to accelerate sustainability transitions. The mapping of the policy mix shows that destabilising policies were crucial for accelerating the transition process of the industry. Prior to novelty creation policies, destabilising policies (e.g. environmental policies) were needed for 'innovation policy instruments' to be effective. More specific instruments (e.g. carbon tax), targeting particular functions of the innovation systems, require 'on-the-ground' policy intelligence and benefit from close interaction with industry.

Aeration, as a process in pulp and paper wastewater treatment, uses the greatest share of the energy. Therefore, if the energy efficiency of the treatment has to be improved, the focus must be on aeration. A key finding from the trials conducted for this paper, with effluent from a paper and pulp mill, was that the oxygen transfer coefficient could be doubled and the chemical oxygen demand could be decreased by 25%, if the effluent was pre-treated with 30 mg/l of aluminium coagulant (equivalent to 9.4 tonnes per day of AVR to 20000 cubic metres of effluent). Decrease in oxygen requirement implies decreases in aeration energy use. Pulp and paper mill effluents are not as biodegradable as municipal sewage, and the improvement in oxygen transfer properties of the effluent will have a positive influence over a longer period of time in the biological treatment. If the sludge is digested anaerobically, pre-treatment will also result in doubling the potential for methane generation. A holistic analysis of modifications to processes entails a study of the economic and environmental consequences as well. While the economic aspect is beyond the scope of this paper, only the net global warming as an environmental impact category has been studied, by taking recourse to specific emission coefficients. Of the four dosages of ferric aluminium sulphate considered in this analysis, the net greenhouse gas emissions are the least – 426 kg carbon dioxide equivalent per day when the daily consumption is 9.4 tonnes.

Reducing waste materials through reuse has in the recent past contributed to sustainable manufacturing in many industries. With the development of large-scale poultry farming, the treatment of large amounts of chicken feathers has become a problem and threatened its use as a renewable resource. This paper examines the use of chicken feathers in the paper making process; a process which would traditionally use wood as the raw material. The effects of combining feather fibre and wood pulp on paper performance were studied and compared to the properties of handsheets made with 100% wood pulp. With the increase of feather content, properties such as tightness, tensile index and bursting index decreased, whilst air permeability improved. There was no significant difference in water absorbency between various chicken feather/wood pulp handsheet samples however, the water absorbency started to decrease above 80% of chicken feather content. This could potentially open up a new avenue for the use of chicken feathers in applications that are meant to tolerate high humidity conditions, e.g., packaging products.

Guiding industries to produce in an effective and environmentally sustainable manner has become a key issue for governments around the world. Over the past 15 years, series of regional and industrial development policies have been introduced by the Chinese government. This has influenced the geographical distribution and energy efficiency performance of China’s industries. This paper quantifies the influence of enterprises geographical distribution on energy efficiency improvement in the paper industry and aims at providing some helpful suggestions on industrial development to policy makers. The main results show that, firstly, the paper industry in eastern China shows obvious characteristic of agglomeration. The average location quotient is 1.2278. However, following the industrial and regional development policies, the characteristic of agglomeration is weakening. Secondly, only when agglomeration reaches a certain level (location quotient is above 0.5447) will industrial agglomeration positively impact on industrial energy efficiency improvement (a 1% increase in agglomeration will increase dynamic energy efficiency by at least 0.23%). Thirdly, the regional development policies carried out by the government slow the pace of energy efficiency improvement in China’s paper industry. The empirical results indicate that the government needs to consider regional characteristics and consciously guide industrial enterprises to concentrate in the dominant area.

Different heating processes were applied to pretreat the pulp and paper mill sludge to enhance the hydrolysis stage. Hot air oven, autoclave, microwave and water bath were used for comparison. Chemical analyses exposed that all the pretreatment methods have shown improvement in solubilisation of organic matter. Among the pretreatments studied, heat transfer through hot air (80 °C for 90 min) mode had the highest impact on sludge solubilisation. There was an increase in cellulose (P = 0.0096), acid soluble (P = 0.0053) and insoluble lignin (P = 0.0012), but decrease in hemicellulose (P = 0.0009) content after pretreatment. The XRD and FT-IR spectroscopic characterisation shows the development of aliphatic, unsaturated and carbonyl carbon functionalities in the pretreated samples at higher severities. FESEM picture also confirms the change in structure after pretreatment. Thus, pretreatments contribute to disruption of the lignocellulosic structure making the cellulose easily accessible to acidogenic microorganisms.

China’s paper industry consumes a lot of energy and emits huge amounts of pollutions. The Chinese government over the past decades has done a lot to promote energy efficiency of the industry. This paper studies the impact of industrial polices to improve energy efficiency. The energy efficiency change is firstly studied under a framework of total factor efficiency. On this basis, different econometric models are built to discuss the detailed energy efficiency characteristics of the paper industry. The main results are as follow: (i) ownership structure did influence the energy efficiency, but the influence is different in different conditions; (ii) energy efficiency of the paper industry can be improved by economies of scale; (iii) market competition can to some extent overcome the motivation and supervision problem that often occur in state-owned companies; (iv) energy price cannot play the role of resource allocation well in China. Finally, based on our findings, some suggestions are provided.

This work assesses six different agricultural residues with the aim of finding alternative raw materials for a soda semichemical pulping process: stems of bell and chili pepper ( Capsicum annuum ), broad bean ( Vicia faba ), asparagus ( Asparagus officinalis ), pea ( Pisum sativum ), and okra ( Abelmoschus esculentus ). Pulping yields higher than 60% (m/m) were obtained, except for pea stems (43%). The drainability of all the pulps, expressed as the Schopper-Riegler index (oSR), had values of over 70 oSR. The Kajaani analyses of the fibers showed acceptable fiber lengths in all cases (0.64–0.92 mm), but on average shorter than the lengths of pulps from a commercial fluting paper (Old corrugated Container, OCC), that was found to be 1.27 mm. Handsheets of paper were produced both with the pulps under study and with mixtures of these pulps with OCC pulp. Several properties were measured to assess the use of the new fibers in a paper for cardboard production. The property showing the greatest differences was the Gurley porosity, ranging from 25 mL/min (asparagus) to 1300 mL/min (broad bean). Of the six residues tested, the okra residue fiber showed better properties than the commercial paper fiber (Concora Medium Test indexes: 1.5 N m 2 /g and 1.1 N m 2 /g respectively, Burst Indexes: 2.3 kPa m 2 /g and 1.7 kPa m 2 /g, respectively), yielding similar mechanical properties to those of high quality fibers obtained from miscanthus ( Miscanthus giganteus ). Broad bean residue could also be a promising raw material, though its properties are not as good as okra’s.

China has become the world largest paper and paperboard producer. However, pulp and paper industry has involved high resource consumption and severe pollution especially for water. This research has assessed the eco-efficiency of China's pulp and paper industry at the national level and provincial level. An overview regarding the cleaner production of China's pulp and paper industry was presented to reveal the measures for reducing environmental impact in the last two decades. Slacks-based measure was used to analyze the efficiency levels of 16 provinces' pulp and paper industries. To uncover the underlying causes of eco-efficiency performance, Malmquist–Luenberger index was calculated to discover the drivers of productivity growth of pulp and paper industries. Our results showed that the pollution treatment of China's pulp and paper industry has made progress in terms of water consumption and water pollution, although the absolute amount of pollution discharge is still large. Chemical oxygen demand emissions are still the first critical influencing factor of pulp and paper industry's inefficiency. Furthermore, efficiency progress was the dominating contribution of the industry's productivity growth between 2010 and 2013. The policies for adjusting the industrial structure of pulp and paper industry have resulted in the scale effects through eliminating backward production capacity and accelerating merger and acquisitions. Moreover, the productivity of pulp and paper industry was underestimated when the undesirable outputs were ignored. It indicates that the stricter environmental regulations have positive effects on paper companies to internalize environmental pressures in the production activities through environmental management. In the future, pulp and paper companies should further internalize the cost of pollution treatment through scale effects and technology improvement.

International audience; An energy audit is a primary step toward improving energy efficiency at the facility level and ensuring a clean production. The pulp and paper sector is one of the most energy-intensive industries in Morocco. This article aimed at identifying energy conservation opportunities at a Small and Medium-sized paper industry. The audit results together with their financial viability are presented regarding the analysis of energy consumption and electrical quality issues. The paper introduces an action plan for a more efficient energy use of some specific applications such as furnaces and compressed-air installations as well. The recommended energy efficiency measures have the potential of saving about 347.85 MWh of electrical energy and 101.78 MWh of thermal energy corresponding to reductions of 11.48% and 2.22%, respectively. The total investments related to the application of the action plan is approximately 290.53 kMAD and the global payback period does not exceed one year. It was also shown that a total quantity of 283.39 t of CO2 emissions can be saved annually.

China's paper industry accounts for a larger proportion of the global paper industry and consumes large amounts of energy. Energy conservation and pollution reduction of the industry have become the focus of China's national development strategy. Energy efficiency is an important index which directly determines the amounts of energy consumption and pollution emissions. To understand the energy efficiency evolution of China's paper industry, this paper establishes an input-output data of the paper industry for 29 provinces in China and applies DEA method and econometric models to estimate and comprehensively discuss the energy efficiency issues based on the framework of total factor efficiency. Our results indicate that China's paper industry has a large energy saving potential even though its energy efficiency has improved during the period 1990–2013. The saving potential is about 65% under the meta-frontier and 44% under the group-frontier. Moreover, there are significant differences between different regions in production technology and energy efficiency. The performance of eastern China is better than other regions. But the technology gaps between the different regions are shrinking and converging over time. Finally, some policy recommendations are proposed to improve the energy efficiency of the industry.

Worldwide pulp and paper industry is recognized as a serious threat due to the discharge of various toxic contents present in its effluent to the surrounding environment. To combat this challenge, the role of oleaginous yeast to utilize the pulp and paper industry effluent for the integrated toxic contents removal and sustainable biodiesel production were undertaken. Oleaginous yeast Rhodosporidium kratochvilovae HIMPA1 was used as a model organism for its unique ability to utilize pulp and paper industry effluent as a culture medium and accumulate high quantity of triacylglycerol or neutral lipids as large size lipid droplets of 4.56 ± 0.24 μm within its cellular compartment. The maximum cell dry weight (13.87 g/L) with total lipid yield of 8.56 g/L was obtained after 144 h of cultivation. Data showed significant reduction in effluent toxic components i.e. color, 89%; lignin, 94.27%; phenol, 99.60%; biochemical oxygen demand, 77.36%; total dissolved solids, 84.59%; and chemical oxygen demand, 94.22%. Fatty acid methyl esters profile revealed high quantity of long chain monounsaturated fatty acids (45.43%) and polyunsaturated fatty acids (15.91%) that improves biodiesel quality under low temperature condition in terms of low cold filter plugging point along with good oxidative stability and cetane number as per American Society for Testing and Materials D6751-02 and European Committee for Standardization - EN14214 guidelines.

Recycling of waste paper was investigated with the aim of boosting the use of recycled materials and reducing the impact of waste paper on environment. Commercially important cyanoethyl cellulose product from waste paper was synthesized successfully through a cycle of chemical treatments. Waste paper was functionalized to cyanoethyl cellulose in an alkaline heterogeneous reaction environment with acrylonitrile under different reaction conditions with respect to degree of substitution. The variables studied were: Sodium Hydroxide and acrylonitrile concentration, reaction time and temperature for alkalization and cyanoethylation. All the cyanoethyl cellulose products were assessed for solubility, degree of polymerization and degree of crystallinity. The optimum conditions for cyanoethyl cellulose synthesis comprised of 8.34 M/anhydro glucose unit aqueous sodium hydroxide concentration, 30 °C alkalization temperature, 60 min alkalization time, 70 M/anhydro glucose unit acrylonitrile concentration, 60 min reaction time for cyanoethylation and 50 °C cyanoethylation reaction temperature. The optimized cyanoethyl cellulose product was characterized with fourier transform infrared spectroscopy, proton magnetic resonance spectroscopy, X-ray diffraction and scanning electron microscopy. This investigation helped to find the proper cleaner production approach towards sustainable environment management by synthesizing valuable cyanoethyl cellulose product and demonstrated that waste paper have the capacity to produce upgraded and high quality cyanoethyl cellulose for variety of applications.

The pulp and paper industry accounts for approximately 5% of total industrial energy consumption and contributes 2% of direct carbon dioxide (CO2) emissions from industries. World paper and paperboard demand and production are increasing significantly, leading to an increase in this sector's energy use and CO2 emissions. Although current studies identify a wide range of energy-efficiency technologies that have already been commercialized for the pulp and paper industry, information is limited or scattered regarding new energy-efficiency technologies that are not yet fully commercialized. Development of emerging or advanced energy-efficiency technologies and their deployment in the market will be crucial for this industry's mid- and long-term energy saving and climate change mitigation strategies. This paper compiles available information on energy savings, environmental and other benefits, costs, and commercialization status for 25 emerging technologies to reduce the energy use and CO2 emissions. The purpose is to provide a well-structured comprehensive review on these emerging energy-efficiency technologies for engineers, researchers, investors, policy makers, pulp and/or paper companies, and other interested parties.

The handmade paper industry utilizes quantum of dyes for making bright colored handmade paper used for wedding cards, fancy and decorative paper, etc. A study has been conducted on adsorption of direct black dye (used extensively in handmade paper industry to make black colored handmade paper) on fly ash obtained from thermal power plant of Yamuna Nagar. The effluent has been characterized for pH, suspended solids, total solids and chemical oxygen demand. The batch and column studies have been conducted on the adsorption of direct black dye solution of different concentrations on fly ash at varying pH, dosage of fly ash, temperature, contact time, particle size fractions of fly ash and initial concentration of dye solution. In batch studies, it was observed that the experimental data fit well with Langmuir adsorption isotherm in comparison to Freundlich and Temkin isotherms. The maximum adsorption capacity of 76.33 mg/g was achieved at 318 K in batch studies. The column experimental data fitted well to Yoon–Nelson model and Thomas model in comparison to Bohart–Adams model. The maximum adsorption capacity of 45.54 mg/g in column study was obtained for 2.4 cm bed height, 150 ppm inlet concentration and 1.6 mL/min flow rate of dye solution. The calculations of thermodynamic parameters indicate that the adsorption of black dye on fly ash is spontaneous and endothermic in nature and follows first order kinetics with rate constant of 0.201 min−1. It has been found that fly ash is a potential low cost adsorbent to treat effluent of handmade paper industry. The exhausted fly ash can be further reused as filler in paper making and hence can offer a viable closed loop solution in curbing pollution from this predominantly small sector industry.

Developing separation materials for rapidly oil absorption and emulsions separation is urgently needed and remains a great challenge. Here, a biomass-derived banana peel/waste paper (BPWP) hybrid aerogel with hierarchical porous structure has been successfully fabricated via combination of freezing-cast, freeze-drying and pyrolysis approach, for application in oil adsorption and water-in-oil emulsions separation. In this hybrid system, the microsheets that derived from banana peel immobilize were immobilized on surface of the waste paper fibers, forming a hierarchical structure. The resulting BPWP aerogels exhibit a compression strain of 75%, high-hydrophobicity (WCA of 149.3°)/underair superoleophilicity (OCA of 0°), and high porosity, which can absorb of free oils in water with high oil sorption capacity of 35–115 times its own weight. Moreover, these aerogels effectively separate various surfactant-stabilized water-in-oil emulsions driven solely by gravity, with high separation efficiency above 99.6% and higher fluxes of up to 8550 L m−2 h−1 than traditional filtration membranes with pressure driven, even the sizes of emulsified droplets are smaller than the pore size of the BPWP aerogels. More importantly, the BPWP aerogels exhibit a superior antifouling property and regenerability for emulsion separation, which match well with the requirements for treating the real emulsions. Due to the advantages of banana peel/waste paper aerogels in rich source and high oil separation efficiency, the obtained banana peel/waste paper aerogel can be a potential candidate in industrial applications and environmental protection. This work opens up a new avenue for design new hierarchical biomass-derived aerogels for a variety of applications including energy storage, sensors and pressure-sensitive electronics.

The design and testing of a novel vermicomposting system, acronymed FLUVTS ─ FLippable Units Vermireactor Train System ─ is presented. It enables rapid vermicomposting of paper waste without the need of pre-composting and requires animal manure supplementation to the extent of only 10:1 paper: manure mass ratio in contrast to reported systems which must have 50% or more of the feed mass as animal manure. Moreover, the system enables the vermicomposting to be accomplished at a high rate, achieving near-total convertion of feed to vermicast at solid retention times of just 30 days in comparison to conventional systems which take 90–120 days for the same process. Uninterrupted vermireactor operation for 6 months, during which the feed was put in and its vermicompost harvested once in 30 days, demonstrates the robustness and the consistency of the system. The suitability of the paper-waste vermicompost as an organic fertilizer was then tested in terms of it's effect on seed germination and early growth of four food plants chilly (Capsicum annuum), ladies finger, (Abelmoschus esculentus), cucumber (Cucumis sativus), and tomato (Lycopersicon esculentum). In general, the paper waste vermicompost when applied at levels

High pressure laminate has a key role at the protection of wood-based panels. Borax and recycled papers can be used for production of high pressure laminate which may impart the multitude effects. The readily availability of waste papers and borax may be a useful alternative to expensive papers with high quality, and also can compensate the strength losses of recycled papers. The recycled paper and borax are relatively inexpensive and environmentally friendly, and this results the production of not only a cleaner product but also provides an excellent performance against applied load, humidity and high temperature. In this study, three types of waste papers including newsprint, writing and paperboard were first recycled to be used for production of high pressure laminate. Phenol formaldehyde and borax were utilized to improve the strength and fire retardancy of high pressure laminate. Bending resistance, flame resistance and water absorption of high pressure laminate samples were tested. The results of the experiments showed that high pressure laminate made of recycled newspaper and borax had a superior performance when compared to samples that made from writing paper and paperboard. For example, an increase up to 1.4 times was observed in the bending resistance. The mixing of borax with resin increased the strength of high pressure laminate at 95 percent confidence level. The amount of water absorption after 2 h, bending resistance, glowing time and char length of high pressure laminate with recycled newspaper and borax were equal to 14%, 41 mNm, 37 s and 0.7 cm, respectively. The bending strength of coated particleboard with this overlay increased up to 1.5 times. High pressure laminate produced from recycled paper and borax was introduced as an environmentally acceptable product.

The global cement industry produces over four billion tonnes annually. In recent years, the quest for increasing energy efficiency has led this industry to test and use “waste” materials as alternative fuels (AF). The objective of this study was to examine the use, as alternative fuel, of the shredded non-recycled plastics and paper residue (NRPP) of a materials recovery facility at the Balcones plant in San Antonio, Texas; this material has a Lower Heating Value (LHV) of about 17 MJ/kg and is called “engineered fuel” (EF). The results showed that EF consists of mostly paper fiber, a biogenic material, so its use helps to decrease CO2 emissions from cement production. In the US, on an average about 4.3 MJ of thermal energy are used to dry, decompose, and sinter the carbonate minerals to produce one kg of “clinker” that is then ground to cement powder and mixed with other compounds. If the maximum amount of EF that can be used by the U.S. cement industry (83 million tonnes of cement per year) were to be separated at Material Recovery Facilities and used as alternative fuel in cement kilns, the diversion of non-recycled paper and plastics from landfills would amount to 17.7 million tonnes of EF. The general methodology used for the Life Cycle Assessment (LCA) is Eco-indicators 99 that uses the SimaPro database and four scenarios were assessed. The corresponding chemical structure of the EF was calculated and the associated emissions during combustion were determined. The laboratory analyses determined the average makeup of the sampled fuels consisted of 20% fossil based carbon and 80% biogenic. The use of EF in the cement industry reduces greenhouse gas emission by up to 3 tonnes of CO2 per tonne of EF used in place of a high-quality coal. The study also found that use of EF in cement production has no adverse effect on the stack emissions of cement plants, nor on the quality of cement produced. The mercury concentration in the stack gas of U.S. cement kilns is well below the U.S. standard and the total dioxin emissions of all cement plants amount to only 0.05% of the dioxins emitted by all U.S. sources. Furthermore, the cement process incorporates the residual ash in the EF into the final clinker, thus resulting in both energy and materials recovery.

Sustainability measurement in economics includes assessment of environmental and economic effects in an integrated manner. In this study, system level economic data are integrated with environmental impacts determined from a life cycle assessment (LCA) of a common product. We adopt a costing methodology that captures conventional costs, but additionally incorporates externality costs to present a convenient, easily interpretable metric. Green Net Value Added (GNVA) is a type of full cost accounting that incorporates total revenue, the cost of production, depreciation, and environmental externalities. We present externality costs disaggregated by upstream sectors, full cost of production, and GNVA to evaluate the relative sustainability of Bounty® paper towels manufactured at two production facilities. We found that the longer running, more established line had a higher GNVA. The predominant components contributing to externality costs come from the stationary sources in the supply chain: electricity generation (27–35%), refineries (20–21%), pulp and paper making (15–23%). Health-related externalities from Particulate Matter (PM2.5) and Carbon Dioxide equivalent (CO2e) emissions are to a great extent driven by electricity usage and emissions by the facilities, followed by pulp processing and transport. Supply chains for other facility purchases, product distribution, and end-of-life management contribute the least to the environmental health-related costs.

The aim of this study is to enhance the use of agro-industrial byproducts and to address the environmental concerns by a novel method of co-production of thermoplastic composites with a solid residue constituting biorefinery. Accordingly, the reuse of 10–30 wt. % solid residues (SRH) from the enzymatic hydrolysis of recycled paper sludge (PS) in the production of thermoplastic composites with polypropylene (PP) was investigated. Thermal properties, water absorption, tensile strength and morphology of the prepared composites were evaluated. Higher thermal stability, rougher and wetter surface, and characteristics of a brittle material were observed in PP-SRH composites in comparison to the pristine PS-PP composites and the neat PP. The water absorption increased with increasing amount of SRH, but in lower proportion compared to other common raw materials used in the preparation of composites. Use of SRH resulted in similar or better properties compared to the composites made with the unhydrolyzed paper sludge, suggesting that SRH has potential for recycling and utilization as filler in the development of thermoplastic composites.

The papermaking industry has developed rapidly in recent years in China. Papermaking is a high-energy-consuming process. Consequently, large-scale paper mills usually have cogeneration systems that supply both electricity and steam for the papermaking process. In China, almost all these cogeneration systems in paper mills are powered by coal combustion, which consumes a large amount of energy and emits large amounts of greenhouse gas. The Integrated Gasification Combined Cycle (IGCC) technology is regarded as a clean and efficient method of coal utilization. In this work, an IGCC process for application in paper mills was designed and modeled. An IGCC coupled with a cascade refrigeration process (CRP) was further proposed in order to reuse the waste heat from the dryer section and improve the energy efficiency of the papermaking process. A paper with a conventional cogeneration system, one with an IGCC cogeneration system, and one with an IGCC coupled with a CRP cogeneration system were analyzed and compared in terms of energy efficiency, capital investment, operational cost, and dynamic payback period. The results showed that the integration of IGCC technology allows paper mills to be more competitive than those featuring conventional cogeneration systems in terms of energy efficiency and operational cost.

Recycling and recovery of materials from used products is one of the major avenues to reduce material throughput. Ideally, all materials are anticipated for being reused by the economy an infinite number of times. In reality, recovery of secondary materials may be difficult because of high costs, or because of degraded quality compared with virgin materials. The search for potential reduction of throughput in material cycles should be based on a knowledge of the limits to repeated cycles. To gain understanding of recycling limits, we developed a method to estimate the actual reduction potential for each throughput in a material's multi-cycle life. First, we investigated the material flow system of paper in Taiwan, and developed a supply chain network of paper flows. Systematic elaboration of the flows revealed where paper can be recycled and where paper can be lost. Second, we estimated the reduction potential with a material input–output Markov chain model, which maps the distribution and loss of materials on the supply chain processes. The model estimated the quantities and the life pathways of recycled materials across continuous life-cycles. An indicator was used to quantify the total performance of the material across repeated life-cycles. This method offers an opportunity to examine practices that approach the limit of reduction. This case study shows that the use and separation of paper waste after discarding may need to be reformed to extend the life-cycles of the material.

Life Cycle Assessment (LCA) is a well-established and informative method of understanding the environmental impacts of consumer products across the entire value chain. However, companies committed to sustainability are interested in more methods that examine their products and activities' impacts. Methods that build on LCA strengths and illuminate other connected but less understood facets, related to social and economic impacts, would provide greater value to decision-makers. This study is a LCA that calculates the potential impacts associated with Bounty® paper towels from two facilities with different production lines, an older one (Albany, Georgia) representing established technology and the other (Box Elder, Utah), a newer state-of-the-art platform. This is unique in that it includes use of Industrial Process Systems Assessment (IPSA), new electricity and pulp data, modeled in open source software, and is the basis for the development of new integrated sustainability metrics (published separately). The new metrics can guide supply chain and manufacturing enhancements, and product design related to environmental protection and resource sustainability. Results of the LCA indicate Box Elder had improvements on environmental impact scores related to air emission indicators, except for particulate matter. Albany had lower water use impacts. After normalization of the results, fossil fuel depletion is the most critical environmental indicator. Pulp production, electricity, and fuels for product production drive fossil fuel depletion. Climate change, land occupation, and particulate matter are also relevant. Greenhouse gas (GHG) emissions by pulp, electricity, papermaking, and landfill methane from the disposed product, drive climate change impacts. Pulp provides significant offsets to balance climate change impacts due to sequestration of atmospheric carbon dioxide. Ninety-nine percent of land occupation is for the growth of the trees for pulp production. Papermaking, electricity, and pulp production cause the most potential particular matter formation.

Industrial productivity is often judged solely by the primary product's marketability, while opportunities for secondary products derived from process by-products are often overlooked. In paper mills, large volumes of moisture-rich paper mill residuals (cellulose sludge) are produced, for which commercial use is currently difficult. Port Hawkesbury Paper LP, Port Hawkesbury, Nova Scotia, produces over 7 t/hr of waste sludge with a seasonally-dependent dryness ranging from 25 to 38% (w/w). Various chemical or mechanical dewatering options exist; however, knowledge of the unique sludge composition and properties is essential to predicting how the product will react under each method. Sonication, Fournier rotary press technology, freeze/thaw cycling, and gravity drying were among the dewatering opportunities briefly explored outside of the chosen method, acidification. Notably, many industries utilizing dewatering technologies may not be producing value-added by-products, while geographic and climatic placement may limit processes which are possible for others. In the present study examining enhanced end-use value, further dewatering occurred through a comparative in situ experiment contrasting sulfuric acid and ferric sulfate acidification (direct acid injection into sludge). While both proton donors acidified the sludge and decreased moisture content, sulfuric acid was the more cost-effective option, yielding an ∼4% increase in dryness, with commensurate economic and environmental benefits.

This paper investigates the feasibility of dyeing cotton fibers with solution extracted from date pits which are abundant vegetal material. The extraction step and its optimization were conducted in the first part of this paper. This second part studies the influence of the main dyeing conditions on the color yield K/S and the CIELab coordinates. The studied parameters are pH of the dye bath, temperature and duration of dyeing. Experiments were carried out using Box-Behnken experimental design to be able to analyze the main effects of each parameter, to detect interactions between these parameters and to deduce optimum conditions for dyeing process. The fastness properties of dyed samples were also evaluated. Obtained results indicate interesting sweat, washing and rubbing fastness in the range of 4–5. Three metallic mordants (Alun, ZnSO4 and CuSO4) and three biological mordants (gall nuts, chlorophyll (a) and green almond shell) were used to improve the degree of absorption as well as the color fastness of cotton fabrics dyed with aqueous extract from date pits. The obtained results showed high improvement of fastness (sweat, friction, washing and light fastness) for biological mordants than the metallic ones.

This work presents the results in the field of materials engineering, and they are related to recycling of paper production waste sludge particles at amounts of 10 wt% and 20 wt% in tall oil polyol-based rigid polyurethane foam with and without tris (1-chloro 2-propyl) phosphate flame retardant. The impact of both systems on physical and mechanical properties, thermal stability, fire resistance and ignitability is studied. Paper production waste sludge particles filled rigid polyurethane foams display better fire performance thus resulting into reduction of the emission of CO2 and CO as well as reduction in average heat release rate. Scanning electron microscopy has shown that paper waste sludge particles and tris (1-chloro 2-propyl) phosphate together act systematically, and synergism between two materials may be observed. It is as well determined that paper production waste sludge particles reduce thermal conductivity by approx. 15% for polyurethane foam with paper production waste sludge particles and by approx. 13% for polyurethane foam with paper production waste sludge particles and conventional flame retardant. Moreover, the substitution of tris (1-chloro 2-propyl) phosphate, petroleum based polyol and hydroflurocarbons with 10 wt% and 20 wt% of PPWS particles, tall oil polyol and water reduces carbon dioxide emission by 60.8% and 39.6%, respectively, contributing to cleaner production of rigid polyurethane foam.

Although the environmental performance of the paper industry has drastically improved since the nineties, Western manufacturers still refuse to reuse agricultural waste. Moreover, papermakers make extensive use of poorly biodegradable polyelectrolytes which are toxic to fish. With this in mind, we suggest pulping lignocellulosic residues by sulfur-free processes, decrystallizing cellulose, and introducing positively charged functional groups with the goal of partially replacing conventional cationic polymers. Functionalization of pulps from orange tree trimmings, rapeseed stalks and wheat straw was carried out with different concentrations of (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC). When the mole ratio of CHPTAC to anhydroglucose units was 4, cationic fibers reached charge density values over 0.2 meq/g after 40 or 60 min of reaction. Then, we tested the performance of these fibers in papermaking, using titanium dioxide, whose zeta potential is negative, as filler. Opacity of lightweight paper was raised to 90%, surpassing a conventional cationic polyacrylamide (CPAM), while the increase in brightness (from 37.8% to 41.9%) was not as good as that achieved with CPAM. Even if residues cannot replace wood, chemical modifications of them can result in valuable cationic fibers, making synthetic polyelectrolytes less necessary.

Recycling is becoming one of the main activities of the papermaking industry to palliate the consumption of natural resources. However, with the recycling process, the fibers experience structural damages due to the hornification phenomena and the mechanical refining. The present work aims to compare the effect of mechanical refining during recycling cycles, to recover the original mechanical properties of paper with the incorporation of lignocellulosic micro/nanofibers (LCMNF) from banana leaf residue. For that, industrial fluting paper was submitted to a recycling cycle and the effect of the increasing intensity of PFI-refining was compared versus the incorporation of LCMNF additions ranging from 1.5 to 4.5 wt%. In addition, with the objective of demonstrating that the proposed process could be plausible at a large scale, process water with high conductivity and charge density was used for comparison with tap water, usually used at laboratory scale. Results showed that the incorporation of 1.5 wt% of LCMNF was enough to recover the original properties of fluting paper (a breaking length value greater than 3443 m) with a low impact in pulp drainability (54 oSR). At the same time, no structural damages were caused to the fibrous compounds, implying that the life span of paper products can be successfully increased. Higher dosages lead to papers with significantly improved mechanical properties, opening the opportunity to adopt environmental friendly strategies such as decreasing basis weight or, on the other hand, to reach new market niches by maintaining the basis weight.

Cascading use of biomass is a recognized strategy contributing to an efficient development of the bioeconomy and for mitigating climate change. This study aims at assessing the potential of cascading use of woody biomass for reducing GHG (greenhouse gas) emissions and increasing the overall wood flow efficiency in the European Union's forest and bioeconomy sectors. A scenario and life cycle approach was followed to quantify the potential benefits of cascading use of woody biomass. We started from a reference scenario in which (post-consumer) waste wood and paper are re-utilized for energy only (S0). Then we compared the reference scenario with two alternative scenarios, the current waste wood and paper recycling practices (S1) and the maximum technical potential to increase recycling of waste wood and paper flows (S2). Following a supply chain perspective, different stages of production were analysed, including forgone fossil-fuels substitution, optimization at manufacturing level and forest regrowth. Through cascading use, the wood use efficiency ratio (cascade factor) in the European wood sector would be increased by 23% (S0 vs S1) and 31% (S0 vs S2) and GHG emissions (cradle-to-gate energy use) would be reduced by 42% (28 MtCO2-eq/year) and 52% (35 MtCO2-eq/year) in scenarios S1 and S2. However, increased wood product cascading is counter effected in the short term by reduced savings in the energy sector by 49% and 48% (−43 and −42 MtCO2-eq/year) in scenarios S1 and S2 due to delayed availability of waste wood and waste paper fibers. This explorative study highlights the potential of cascading use of woody biomass in the wood production chains to contribute to a reduction of environmental impacts related to wood resource and energy use, but it also reveals trade-offs in terms of GHG emissions reduction, relevant especially in meeting short-term (2020–2030) renewable energy targets.

Environmental issues, legal requirements, and economic benefits of recycling activities lead to the development of reverse logistics operations and waste management. The current research considers a closed-loop supply chain for a cardboard recycling network including multiple suppliers and production stages. A mixed integer linear programming model is proposed to optimize the paper and cardboard recycling network, and a robust optimization approach is utilized to deal with demand uncertainty in this network. The model maximizes the total profit. It considers the operation, transportation, purchasing and holding inventory costs as well. Moreover, to illustrate the application of the proposed model, a real-world cardboard closed-loop supply chain design is investigated. The proposed model considers the option to open a new recycling center in the current network. The proposed model determines the optimal quantities of the waste paper, paper, sheet and cardboard that flow in this network. Finally, the computational analysis indicated that the proposed model provides efficient solutions for the studied cardboard closed-loop network.

This study presents a novel decentralized sanitary separation system as a zero-discharge solution for blackwater (BW) (faeces, urine and toilet paper) treatment for remote tourist facilities located in sensitive areas. The system operates with low water and energy consumption, enables safe operation and requires low maintenance. The BW was collected from two vacuum toilets (VTs) (0.8 L flush water) and separated in peat filters (PFs) to obtain a liquid fraction (LF) and a solid fraction (SF) of the BW. The LF from the PFs was thereafter treated in a biofilter (BF) and finally evaporated in the evaporation module (EM) powered by solar vacuum collectors (SVC). In the PFs, particles larger than 1 mm were reduced from the BW by 96.5%. Furthermore, the total suspended solids (TSS) mass removal efficiency of the PFs averaged 51.5%. Reduction of ammonia through nitrification was noticeably enhanced after 100 days of the system operation (max. 55.8%). 21.2% or 0.54 kg of total phosphorus (TP) was retained in the PFs, to be further composted and reused for agricultural purposes. An additional 5% or 0.10 kg of TP was retained in the BF. The final step of the LF treatment was in the EM at a sanitizing temperature of >60 °C to prevent the release of human pathogens into environment. With a total electricity consumption of 9.1 kWh/day and a heat consumption of approximately 5.1 kWh/day gained by the SVC, the system successfully integrated different approaches to treating the BW, recycling nutrients, and removing pathogens.

This article is a reply to “Comment on the paper: Ben Ali S, Jaouali I, Souissi-Najar S, Ouederni A, Characterization and adsorption capacity of raw pomegranate peel biosorbent for copper removal, Journal of Cleaner Production (2016)”. Our paper does not contain scientific errors, interpretations, calculations or conclusions in different study parts (Characterization, adsorption, optimization, kinetic, isotherm and thermodynamic study) as Tran Nguyen Hai claimed. We take advantage of this opportunity to correct if there are any typing errors and to improve the FTIR wave number table. That, many objections raised by Tran Nguyen Hai come from (1) comparison of figures with different x-axis scale; (2) calculation and verification based on inappropriate units; (3) comparing to self nonexistent results in cited paper; (4) comparing and evaluating our results dealing with pomegranate peel to orange peel substrate; (5) proposing basic analytical analysis whereas more sophisticated analysis were used; (6) basing on the uncorrected proof version of our paper. Thereafter a reply to any objection raised by Tran Nguyen Hai in Tran, (2017) .

In the current paper, a suggested process of coupled ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) to produce isotonic solution (IS) and drinking water from coastal well water was investigated. Due to its high fouling potential, the feed water was pretreated using UF. Results showed that UF eliminates almost the totality of natural organic matter (NOM), and a relatively high portion of calcium (calcium rejection ∼75%) due to the complex Ca-NOM formed. To understand the fouling mechanism, previously developed mathematical models and equations were adopted. It was shown that the fouling mechanism for UF fits the blocking pores model. For NF, the extended model using cross-flow mode showed a slight difference compared to UF (No compression cake phase). It was concluded that, with some experimental precautions, fouling mechanism of the NF membrane used is internal pore blocking mechanism. Due to its attractive quality, the brine of NF was used to produce drinking water by RO treatment. The energy consumption of the UF-NF-RO system was investigated for different operating conditions. Finally, the permeate of the UF-NF process was compared to a commercialized IS. It was found that the two solutions revealed a remarkable similarity. However, a specific post-treatment should be added to the process to accomplish the pharmaceutical exigencies of IS.

Many food manufacturers in the U.S. are attempting to reduce the environmental footprint of their high biological oxygen demand (BOD) effluents due to increased risk of financial surcharges from publically owned treatment works, water scarcity issues and changes in societal opinions about large scale biodegradable waste releases. Managers at these firms are often reluctant to consider on-site processing due to their fear of committing to unfamiliar and complex wastewater treatment processes with excessive capital expenditures. While an abundance of research has been performed on the use of biochar (i.e. charcoal intended to be used for agricultural purposes produced from organic waste feedstocks via pyrolysis) to mitigate the problem of heavy metal ions from traditional manufacturing effluents by filtration, little is known on biochar's potential to treat high BOD industrial aqueous food wastes. This paper attempts to fill this gap by gauging the environmental and financial sustainability of a vertically integrated biochar filtration system, wherein maple wood biochar is used to treat high BOD tofu whey effluent and subsequently re-utilize that material as an enriched value-added soil amendment to improve crop quality and yields in basil and lettuce. Results show whey filtered biochar significantly increased fresh weight in basil and lettuce above the no biochar and unfiltered biochar controls. This novel approach could potentially help food and beverage manufacturers sustainably reduce their carbon and water footprints by harvesting and monetizing the nutrients found in their wastewaters, while allowing farmers to close regional nutrient cycles by returning nutrient rich carbon to the soil and reduce the use of synthetic fertilizers or costly peat moss or perlite soil amendments in greenhouses.

The Eastman process discharges a wastewater stream with high organic contents. Its chemical oxygen demand (COD) and flowrate are up to 60,000 mg/L and 1011 kg/h, respectively. The ecological environment will be polluted severely in case of an inappropriate disposal of this wastewater. This paper proposes a novel “waste control by waste” strategy to dispose of such a wastewater with a combination of modeling and experiment methods. First, several possible schemes are simulated and evaluated with Aspen Plus software. One scheme that employs internally synthesized 2,2,4-trimethyl-1,3-pentanediol di-isobutyrate (TXIB) to extract organics is chosen because it can alleviate the recovery problems of solvent. The simulation of this scheme shows a mass fraction increase of water in disposed wastewater from 96.941% to 98.572%. Second, experiments concerning extraction and reaction are performed to obtain the requisite parameters for simulation. The optimum operating conditions for extraction column are obtained: room temperature and pressure, the number of trays is 8, the flowrate of extractant is 350 kg/h. The optimum operating conditions for esterification reaction are obtained: reaction time is 3.5 h, catalyst concentration is 8% and reaction temperature is 130 °C. Finally, the importance of each variable in the wastewater treatment process is evaluated based on complex network theory, and two variables comprised of recycle extractant flow and reactor temperature are selected accordingly. One control scheme is proposed based on selected key variables after its anti-disturbance ability is verified with Aspen Dynamics software.

Aerobic Granulation Technology for treatment of wastewater is developed in last two decades. Aerobic Granules are special type of self-immobilization of microorganisms, without any surface medium for growth of microbial film. They have compact cores and have high diffusional confrontations to external particles and, hence have high acceptance of the toxic compounds to their integral cells. Most aerobic granules are large and have a compact core, and so are recommended for use in the biological treatment of high-strength industrial wastewaters. This technology requires small foot print, 25% of the area of conventional activated sludge setup and this process can reduce up to 50% on energy-costs. This paper reviews on start-ups, advances in aerobic granulation technology from laboratory studies to pilot scale and to its full-scale application for treatment of different types of domestic and industrial wastewater. Gaps in knowledge and new ideas for future work of aerobic granulation technology are also being discussed.

The clarification of tailings slurry using polymer flocculants has been widely used in the mining industry to promote the cleaner production of mineral resources. In this paper, a data-driven prediction model was proposed using gradient boosting machine (GBM) for the non-linear relationship modelling and firefly algorithm (FA) for GBM hyper-parameters tuning. Two studies were performed, among which the main study omitted the influence of chemical characteristics of mineral processing tailings (MPT) while the supplementary study considered. For the main study, 27 types of MPT and 4 types of anionic flocculants were used to prepare the dataset. The flocculation performance was represented by the initial settling rate (ISR) and its influencing variables were selected to be the particle size distribution (PSD) of MPT, the solids content of tailings slurry, the flocculants type, and the flocculants dosage. For the supplementary study, the chemical characteristics of 7 types of MPT were also considered as influencing variables and its influence on the predictive performance of GBM was investigated. The main study shows that the optimum GBM model achieved a correlation coefficient of 0.841 between the predicted and experimental ISR values on the testing set, denoting it was robust in predicting the ISR of the flocculation. Compared with the solids content, the flocculants dosage and the flocculants type, the PSD of MPT was found to be the most significant influencing variable for the flocculation with an importance score of 0.420 out of 1. The supplementary study shows that the predictive performance of GBM could be improved considering chemical compositions of MPT, which were also important influencing variables for the flocculation process.

The use of biomass for energy production is one way to ensure energy security and address the environmental issues related to the use of fossil fuels in developing countries. Small and medium-sized enterprises (SMEs) need electric power and thermal energy for their activities. In Burkina Faso, this type of thermal energy is generally produced by SMEs from firewood. However, cashew companies produce a large amount of waste (shell, press cake, nut shell liquid) which can be converted into fuel. Separating the cashew nut from the shell requires two energy-intensive steps: roasting and drying. The energy is provided by cashew shells which are usually burned in boilers, but this method results in the production of anacardic acid and smoke both of which are irritating and which may be carcinogenic due to the presence of cashew nuts shell liquid (CNSL). This paper describes the production of energy from cashew waste by making briquettes out of the press cake, which is left over after the removal of CNSL from the nut shell. The process consists in carbonizing the press cake at a temperature of 350 °C and grinding to a grain size of 0.5 mm. The resulting charcoal powder is then mixed with water and a binding agent (cassava starch), in this case cassava starch selected for its physical-chemical properties, availability in the local market, and its low price. The resulting mixture is then densified in a screw press to obtain briquettes 5.5 cm in diameter and 10 cm in length. Several proportions of water and cassava starch were tested and the best briquettes were obtained with a mixture of 35% of water, 10% of cassava starch and 55% of press cake charcoal. The mechanical and physicochemical analysis of briquettes gave a net calorific value of 25.7 MJ/kg, a density of 0.91, a compressive strength index of 382.89 kPa and an impact resistance index of 61.10. A water boiling test performed afterwards showed that the combustion performance of the briquettes was the same as that of wood charcoal.

Straw pulping plays a vital role in virgin pulp supply and regional agricultural residue utilization. However, a significant decrease in its production has been observed. From an environmental perspective, why has there been a sharp decrease in straw pulping? Are there any innovations in straw pulp production that alleviate the heavy environmental burdens of straw pulping? In this study, factors contributing to the decrease in straw pulp are examined. An innovative technique to produce straw pulp is introduced and its environmental performance is analyzed and compared with conventional pulping. The results show that the main reasons contributing to the environmental burdens of straw pulping lie in the difficulties in black liquor extraction and alkaline recovery for the black liquor. Technical processes are changed in the innovative technique of straw pulping through using a rapid displacement cooking process, converting black liquor into fertilizers, utilizing total chlorine-free bleaching, etc. The new technique (Case B) achieves superior environmental performance than that of the conventional technique (Case A) from a carbon metabolism perspective. Specifically, 1022.90 kg and 857.80 kg of biogenic-carbon (bio-carbon), and 594.32 kg and 628.13 kg of fossil-carbon are needed to make 1 ton of bleached straw pulp for Case A and Case B, respectively. The carbon efficiencies for Case A, Case B (when pulp is the only desired product) and Case B (when including other products) are 39.10%, 46.63% and 92.21%, respectively. The carbon factors for Case A, Case B (when pulp is the only desired product) and Case B (when including other products) are 3.66, 3.60 and 1.86 kg CO2-eq, respectively. In addition, the corresponding E factors, which reflect the waste generation level, are 3.20, 2.69, and 1.39 kg, respectively. The new technique for straw pulping, which follows the principle of a circular economy by fully utilizing resources and reducing the generation of waste, achieves both economic and environmental benefits. It is a promising technique for straw pulping.

This paper reports pollutant removal performances from mixed industrial wastewater employing subsurface flow constructed wetland systems in Bangladesh. Two parallel hybrid wetland trains were established; each train included a vertical flow (VF) followed by a horizontal flow (HF) wetland. One hybrid system was packed with construction materials (i.e. recycled bricks), whereas the other system included agricultural by-products (i.e. sugarcane bagasse). All wetland units were planted with Canna indica. The hybrid trains were operated under non recirculation and recirculation phases; input hydraulic loading across each VF system ranged between 219.3 and 438.0 mm/d. Mean nitrogen, organics, solids, phosphorus and color removals across the hybrid systems were 67.5–80.0, 74.0–85.0, 55.0–95.0, 64.0–89.0 and 46.0–83.0% respectively. Lower input biodegradation ratio influenced organics removal routes in wetland systems that employed recycled bricks. In contrast, organic contents of sugarcane bagasse material supported microbial routes in the other system. VF wetland with organic media achieved higher TN removal rates (1.82 g/m2 d), due to internal carbon (C) generation. Higher phosphorus removals (89.0%) were observed in hybrid system packed with recycled brick media, due to adsorption process. HF wetland packed with recycled brick was efficient in removing color compounds, whereas the other HF system (with organic media) showed high sulfate removals. Nitrogen and BOD removal improvement was observed in VF wetland (packed with recycled brick media) during recirculation period; in contrast, effluent recirculation reduced removal rates of such pollutants in VF system that employed organic media. In general, this study shows potential application of particular materials as the main media of wetland systems, to achieve pollutant removals from industrial wastewaters in Bangladesh.

In this paper, the enrichment of methane by membrane technology was studied by employing (i) a model as well as (ii) a real biogas mixture produced on a laboratory-scale. Thereafter, the endurance of the process was tested at an existing biogas plant. The commercial gas separation module under investigation contained hollow fiber membranes with a polyimide selective layer. During the measurements, the effect of critical factors (including the permeate-to-feed pressure ratio and the splitting factor) was sought in terms of the (i) CH4 content on the retentate-side and (ii) CH4 recovery, which are important measures of biogas upgrading efficiency. The results indicated that a retentate with 93.8 vol% of CH4 – almost biomethane (>95 vol% of CH4) quality – could be obtained using the model gas (consisting of 80 vol% of CH4 and 20 vol% of CO2) along with 77.4% CH4 recovery in the single-stage permeation system. However, in the case of the real biogas mixture, ascribed primarily to inappropriate N2/CH4 separation, the peak methane concentration noted was only 80.7 vol% with a corresponding 76% CH4 recovery. Besides, longer-term experiments revealed the adequate time-stability of membrane purification, suggesting such a process is feasible under industrial conditions for the improvement of biogas quality.

Sludge microbial fuel cell (SMFC) is capable of extracting biomass energy directly from the sludge while generating electricity. However, most of organic matters in the excess sludge are the cell substances that are difficult to be used by microorganism directly. In this paper, adding graphene oxide (GO) and reduced graphene oxide (rGO) in SMFC was proposed and their advantages were reflected by no requiring external energy, in-situ promoting the electricity production and reducing sludge effectively. The results showed that the contents of lactate dehydrogenase (LDH) for adding 0.4 g GO in SMFC (0.4-GO SMFC) and adding 0.4 g rGO in SMFC (0.4-rGO SMFC) were 2 and 1.81 times higher than that of adding nothing in SMFC (ordinary SMFC), respectively. The species and compositions of organic matter in 0.4-GO SMFC and 0.4-rGO SMFC decreased significantly and their sludge reduction rate were 3 and 2.2 times that of ordinary SMFC, respectively. Comparing with ordinary SMFC, the maximum power density of 0.4-GO SMFC and 0.4-rGO SMFC was up to 214.09 and 80.52 mW m−3 separately, and their internal resistance decreased by 71% and 48%, respectively. Thus, it can be concluded that GO and rGO had the function of breaking cell and accelerated electrons transporting, so they could greatly promote the sludge reduction and electricity production of SMFC.

High residual phosphorus in anaerobically digested source-diverted blackwater allows for increased phosphorus recovery through struvite (NH4MgPO4·6H2O) precipitation. Due to the complex matrix of blackwater, recovered products inevitably contain co-precipitates of other wastewater components that have not been well characterized. The potential hazards present include pathogens, antimicrobial resistance genes (ARGs), organic and inorganic compounds. In this study, several important struvite precipitation conditions (pH, Mg2+:PO43− molar ratio and MgCl2 dosing rate) were tested to determine their impact on phosphorus recovery, while taking into account the co-precipitation of enteric bacteria, ARGs and micro- and macronutrients. Results demonstrate that phosphorus recovery efficiency does not correlate to the degree of metal/microbial co-precipitation. Both PO43− recovery and co-precipitates were affected by the operation conditions examined, and the optimal condition for nutrient recovery from blackwater was at pH 9, a 1.5:1 Mg2+:PO43− molar ratio, and a dosing rate of 24 mM min−1. Although previous struvite recovery studies have identified optimal conditions for phosphorus recovery, limited information is available on the process optimization to minimize the potential risks. Downstream application of recovered struvite inevitably contains co-precipitated hazards that if not assessed can result in undesirable public health outcomes. It is necessary to evaluate struvite application and public health exposure to identify key steps that reduce public health impacts. Hence examination of struvite precipitation parameters on enhanced phosphorus recovery, along with co-precipitates, is necessary when considering the public health risk associated with efficiently recovering residual nutrients.

This paper verified the feasibility of water hyacinth for the treatment of formaldehyde in wastewater. In laboratory study, water hyacinth exhibited high removal efficiency for input 100–300 ppm formaldehyde. Formaldehyde consumed by water hyacinth root was lifted from the root to stem and then to leaf, and finally it was converted into some acidoid. Particularly, the removal activity was strengthened with enhanced root activity and chlorophyll in water hyacinth in the presence of 0.5 ppm Eupatorium odoratum L. extract. Meanwhile, the growth of water hyacinth was effectively controlled, exhibiting suppressed emergence of sprouts and low growth rate (≤0.032 g.day−1). In pilot study, water hyacinth also exhibited excellent removal ability to formaldehyde during the four recycle experiments and the growth rate was maintained to a low value about 0.023 g.day−1. In conclusion, water hyacinth managed with Eupatorium odoratum L. extract was proposed as a sustainable biotechnical treatment for formaldehyde.

Poly(lactic) acid as a biodegradable polymer has attracted a lot of attentions due to its environmental merits and availability in sufficient quantities for use in the packaging industry. Recycling of poly(lactic) acid and converting it to a new product, instead of a compost material or primary monomer, is an economical and environmental solution. In this paper, recycled poly(lactic) acid fibers melt-spun from disposable package flakes were dyed by using three disperse dyes having different molecular weights and their dyeing behavior and fastness properties have been studied. Dyeing temperature, time and concentration were fully investigated. The results showed that with an increase in the temperature from 80 °C to 120 °C, the amount of dyeing exhaustion rate increased for different disperse dyes. The recycled poly(lactic) acid fibers exhibited a good exhaustion rate in a short time (20 min), low concentrations (0.5% on weight of the fabric) and low temperature (80 °C). The good to excellent washing fastnesses between 4 and 5 were observed for the recycled poly(lactic) acid fibers which were dyed by the three selected disperse dyes under the optimized conditions. Accordingly, it could be considered that the recycled poly(lactic) acid fibers have a great capability to be dyed with low damage, energy consumption, costs and effluent with disperse dyes.

The aim of the present paper was to investigate the effect of solids (SRT) and hydraulic (HRT) retention time on Integrated Fixed Film Activated Sludge (IFAS) University of Cape Town (UCT) membrane Bioreactor (MBR). In particular, three different pairs of SRT and HRT values were analysed, namely, Phase I 56 d/30 h, Phase II 31 d/15 h and Phase III 7 d/13 h. The short-term effect of these three SRT/HRT conditions was assessed by analysing several system performance indicators: organic carbon and biological nutrient (nitrogen and phosphorus) removal, biomass respiratory activity, activated sludge filtration properties and membrane fouling. The results showed that the decrease of SRT/HRT had a positive influence on system performance. Specifically, the IFAS-UCT-MBR showed excellent removal of organic matter - highest value (99%) at the shortest SRT/HRT (7 d/13 h). Also, the increase in organic loading rate resulting from the decrease of SRT and HRT led to improved nitrogen removal due to higher N removal by sludge wasting requiring less N removal (as N2) by denitrification. Complete nitrification of influent ammonia was achieved at all three SRT/HRT phases, guaranteed by the presence of biofilm carriers in the aerobic reactor, which ensured a higher media SRT than suspended biomass SRT. The increase of the organic loading rate and decrease in SRT led also to a higher heterotrophic activity as demonstrated by the respirometric batch tests, which is due to the increasing active biomass fraction of the volatile suspended solids as SRT decreases. The SRT/HRT decrease over the three phases resulted in an overall increase of the Extracellular Polymeric Substance concentration, which caused an increase in membrane fouling.

Wood residues generated from orchard maintenance operations represent a serious disposal problem, as well as a valuable opportunity for the bioenergy sector. However, their widespread use as renewable fuel is hindered by uncertainty about crucial quality issues, such as: ash content, ash melting behavior and chemical composition. This paper investigates the main physical and chemical characteristics of pruning residues generated by five of the most common European orchard crops: vine, olive, apple, pear and hazelnut. The results of the analyses are contrasted with the quality specifications set by EU standard UNI EN 14961-1 2010 for forest residues, in the absence of a standard specifically designed for orchard pruning residues. All tested orchard residues biomasses fulfill set specifications, and they also present similar characteristics in terms of ash content, size distribution and heating value. However, the chemical composition of pear and vine residues may raise some concern, due to the high content of nitrogen of the former, and to the high ash, sulfur and chlorine content of the latter. Olive and hazelnut pruning residues seem the most suitable for direct combustion, probably because the origin crops are cultivated less intensively and receive smaller chemical inputs.

Supercritical carbon dioxide was utilized as a sustainable alternative to solvent extraction of waxes from the waste needles of two spruce species, namely Norwegian and Sitka spruce. These extracts were rich in nonacosan-10-ol, an organic compound with hydrophobic properties that lends its use in the preparation of superhydrophobic coatings. The highest crude yields were 1.7% w/w of needles obtained at 400 bar and 60 °C, while nonacosan-10-ol was selectively extracted at 200 bar and 60 °C (8070 ± 91.1 μg/g of needles). Purification of nonacosan-10-ol from the wax extracts was conducted using a simple rapid green recrystallization technique. This yielded a recovery of 44.6% ± 2% and 48.4% ± 2% of the total nonacosan-10-ol from the original crude Sitka (3600 μg/g of needles) and Norwegian wax (1920 μg/g of needles) respectively. Application of nonacosan-10-ol to a filter paper led to the formation of highly hydrophobic surfaces, with preliminary contact angles of up to 149°. This sustainable production method may develop opportunities to valorize forestry waste within a holistic biorefinery.