Utilization of municipal solid and liquid wastes for bioenergy and bioproducts production

Turning trash into treasure: Torrefaction of mixed waste for improved fuel properties. A case study of metropolitan city

Solid waste management is one of the biggest challenges of the current era. The combustible fractions in the waste stream turn out to be a good energy source if converted into refuse-derived fuel. Researchers worldwide are successfully converting it into fuel. However, certain challenges are associated with its application in gasifiers, boilers, etc. to co-fire it with coal. These include high moisture content, low calorific value, and difficulty to transport and store. The present study proposed torrefaction as a pretreatment of the waste by heating it in the range of 200 °C-300 °C in the absence of oxygen at atmospheric pressure. The combustible fraction from the waste stream consisting of wood, textile, paper, carton, and plastics termed as mixed waste was collected and torrefied at 225 °C, 250 °C, 275 °C, and 300 °C for 15 and 30 min each. It was observed that the mass yield and energy yield decreased to 45% and 62.96% respectively, but the energy yield tended to increase by the ratio of 1.39. Proximate analysis showed that the moisture content and volatile matter decreased for torrefied samples, whereas the ash content and fixed carbon content increased. Similarly, the elemental analysis revealed that the carbon content increased around 23% compared to raw samples with torrefaction contrary to hydrogen and oxygen, which decreased. Moreover, the higher heating value (HHV) of the torrefied samples increased around 1.3 times as compared to the raw sample. This pretreatment can serve as an effective solution to the current challenges and enhance refuse-derived fuel's fuel properties.

Hydrochar mediated anaerobic digestion of bio-wastes: Advances, mechanisms and perspectives

Bio-wastes treatment and disposal has become a challenge because of their increasing output. Given the abundant organic matter in bio-wastes, its related resource treatment methods have received more and more attention. As a promising strategy, anaerobic digestion (AD) has been widely used in the treatment of bio-wastes, during which not only methane as energy can be recovered but also their reduction can be achieved. However, AD process is generally disturbed by some internal factors (e.g., low hydrolysis efficiency and accumulated ammonia) and external factors (e.g., input pollutants), resulting in unstable AD operation performance. Recently, hydrochar was wildly found to improve AD performance when added to AD systems. This review comprehensively summarizes the research progress on the performance of hydrochar-mediated AD, such as increased methane yield, improved operation efficiency and digestate dewatering, and reduced heavy metals in digestate. Subsequently, the underlying mechanisms of hydrochar promoting AD were systematically elucidated and discussed, including regulation of electron transfer (ET) mode, microbial community structure, bio-processes involved in AD, and reaction conditions. Moreover, the effects of properties of hydrochar (e.g., feedstock, hydrothermal carbonization (HTC) temperature, HTC time, modification and dosage) on the improvement of AD performance are systematically concluded. Finally, the relevant knowledge gaps and opportunities to be studied are presented to improve the progress and application of the hydrochar-mediated AD technology. This review aims to offer some references and directions for the hydrochar-mediated AD technology in improving bio-wastes resource recovery.

A review of waste-to-hydrogen conversion technologies for solid oxide fuel cell (SOFC) applications: Aspect of gasification process and catalyst development

In the twenty-first century, there has been an increase in energy demand and waste production, due to the rising population of the world. One good approach for satisfying the energy demand and overcoming the waste management issues is to convert waste to energy. Additionally, using waste biomass as the feedstock of waste-to-energy (WtE) conversion methods makes them renewable and green and also helps the environmental challenges and reduces the emission of greenhouse gases (GHGs). Gasification is a thermochemical WtE route, which can produce hydrogen-rich gaseous biofuel called synthetic gas (syngas), from wastes. In this paper, different aspects of gasification process are reviewed with greater focus on catalyst usage. Syngas processing steps, which increase the quality and H₂ content of the syngas to form bio-hydrogen, are discussed. Solid oxide fuel cell (SOFC) technology is one of the most promising techniques of renewable energy production due to their environmental cleanness characteristics and high efficiencies. Thus, one of the best ways to exploit the energy content of the bio-hydrogen product of gasification is to employ it in a SOFC. Therefore, waste biomass gasification process can be integrated with SOFCs to build high efficiency systems for production of clean and renewable energy from waste, which are called integrated gasification fuel cell (IGFC) systems. These systems provide the opportunity of further upgrading of syngas inside the SOFC. In this paper, we are going to briefly discuss fuel cell technology (especially SOFCs) and review SOFC applications from the aspect of integration with gasification process (IGFC system). Finally, the impacts and issues of gasification process and SOFC technology are considered.

Process optimization and technoeconomic environmental assessment of biofuel produced by solar powered microwave pyrolysis

Microwave pyrolysis of corn stover has been optimized by Response surface methodology under different microwave power (500, 700, and 900 W) and three ratios of activated carbon additive (10, 15, and 20%) for obtaining maximum bio-oil yield followed by biochar. The optimal result has been evaluated and the environmental and techno-economic impacts of using solar-powered microwave heating have been tested. The optimal pyrolysis condition found to be 700 W microwave power and 10% of activated carbon. The yields of both bio-oil and biochar were about 74 wt% under optimal condition. The higher heat values of 26 MJ/kg and 16 MJ/kg were respectively achieved for biochar and bio-oil. The major components of bio-oil were hydrocarbons (36%) and phenols (28%) with low oxygen-containing compounds (2%) and acids (2%). Using the solar-powered system, 20,549 tonnes of CO₂ can be mitigated over the lifetime of the set-up, resulting in USD 51,373 in carbon credit earnings, compared to 16,875 tonnes of CO₂ mitigation and USD 42,167 in carbon credit earnings from a grid electricity system. The payback periods for solar-powered and grid-connected electrical systems are estimated to be 1.6 and 0.5 years, respectively, based on biochar and bio-oil income of USD 39,700 and USD 45,400.

Torrefaction of organic municipal solid waste to high calorific value solid fuel using batch reactor with helical screw induced rotation

The potential of producing high calorific value (CV) solid fuel was investigated in a helical screw rotation-induced (HSRI) fluidized bed reactor based on mechanical fluidization. The study revealed that the HSRI torrefaction improved the torrefied product properties. For the 40 and 0 rpm conditions, the CV, fixed carbon, and ash contents of torrefied solid fuel increased with an increase in temperature. In contrast, volatile matter, moisture content, mass and energy yields decreased. The CV of torrefied solid fuel increased by a factor of 1.43 and 1.58 at 280 °C for the 40 and 0 rpm conditions, respectively. HSRI torrefaction enhanced the removal of hydroxyl functional group. HSRI torrefaction improved the hydrophobicity of the torrefied solid fuel. Therefore, the HSRI fluidized bed reactor promotes uniform temperature distribution, a higher heat transfer rate within the sample particles in the reactor, and a homogenous torrefied solid product compared to the fixed bed reactor.

Effects of antibiotics on anaerobic digestion of sewage sludge: Performance of anaerobic digestion and structure of the microbial community

As a common biological engineering technology, anaerobic digestion can stabilize sewage sludge and convert the carbon compounds into renewable energy (i.e., methane). However, anaerobic digestion of sewage sludge is severely affected by antibiotics. This review summarizes the effects of different antibiotics on anaerobic digestion of sewage sludge, including production of methane and volatile fatty acids (VFAs), and discusses the impact of antibiotics on biotransformation processes (solubilization, hydrolysis, acidification, acetogenesis and methanogenesis). Moreover, the effects of different antibiotics on microbial community structure (bacteria and archaea) were determined. Most of the research results showed that antibiotics at environmentally relevant concentrations can reduce biogas production mainly by inhibiting methanogenic processes, that is, methanogenic archaea activity, while a few antibiotics can improve biogas production. Moreover, the combination of multiple environmental concentrations of antibiotics inhibited the efficiency of methane production from sludge anaerobic digestion. In addition, some lab-scale pretreatment methods (e.g., ozone, ultrasonic combined ozone, zero-valent iron, Fe³⁺ and magnetite) can promote the performance of anaerobic digestion of sewage sludge inhibited by antibiotics.

Techno-economic and environmental assessments for sustainable bio-methanol production as landfill gas valorization

With the regular increase in global solid waste, landfilling is intensively used for waste disposal. However, landfill gas (LFG) produced as a byproduct during waste decomposition in the landfills is a serious problem since it leads to damage to the eco-systems. Accordingly, it has been highlighted to convert LFG into other value-added chemicals. In this study, LFG utilization was studied in terms of conversion into methanol (MeOH) by considering different scenarios of LFG utilization. Techno-economic analysis and environmental assessment were performed to identify the economic feasibility and environmental impact of each case. From the economic analysis, bio-MeOH production costs of 879.16, 724.52, and 1,130.74 $ ton^-1 for case 1, 2, and 3 was estimated with the economic infeasibility, while substantial cost reduction through projected cost analysis can lead to economic competitiveness (449.52 $ ton^-1 for case 2 and 595.76 $ ton^-1 for case 3). In sequence, the quantitative environmental impacts in terms of climate change impact were 2.360, 0.835, and 0.605 kg CO₂-eq kg MeOH^-1 for cases 1, 2, and 3, respectively. Based on the results of two analyses, a multi-criteria decision analysis was conducted to investigate the acceptable case of bio-MeOH production in the economic and environmental aspects. It can be concluded that the most feasible case depends on decision-makers if only economic and environmental criteria were considered. Therefore, dry reforming and membrane separation of LFG have considerable potential for bio-MeOH production in terms of LFG utilization for high weighting of economic and environmental aspects, respectively.

Iron-based advanced oxidation processes for enhancing sludge dewaterability: State of the art, challenges, and sludge reuse

The increasing amount of sewage sludge produced in wastewater treatment plants (WWTPs) poses a great challenge to both environment and economy globally. As a requisite process during sludge treatment, sludge dewatering can significantly minimize the sludge volume and lower the operational cost for downstream transportation and disposal. Iron-based advanced oxidation process (AOP), a robust and cost-effective technique with relatively low technical barriers for high-level sludge dewatering, has been widely explored in the past 20 years. The development was mainly driven by the demands of efficient and sustainable sludge conditioning technology and the flexible sludge management approaches. The application of iron-based AOPs in sludge dewatering process attracts more and more attention. In this work, we discussed the current application of iron-based AOPs technology in the sludge dewatering processes in a holistic manner, summarized the factors affecting the sludge dewaterability in the treatment processes, and analyzed the mechanisms of iron-based AOPs to improve dewatering processes. Furthermore, we elaborated potential advantages, limitations, and challenges associated with implementing iron-based AOPs in the full-scale plants and shared the opportunities for sludge reutilization. This review aims to contribute to the development of highly efficient iron-based AOPs for sludge dewatering and offer perspectives and directions towards the new-generation of WWTPs with the sustainable and eco-friendly benefits.

Current Trends in Waste Plastics’ Liquefaction into Fuel Fraction: A Review

Polymers and plastics are crucial materials in many sectors of our economy, due to their numerous advantages. They also have some disadvantages, among the most important are problems with the recycling and disposal of used plastics. The recovery of waste plastics is increasing every year, but over 27% of plastics are landfilled. The rest is recycled, where, unfortunately, incineration is still the most common management method. From an economic perspective, waste management methods that lead to added-value products are most preferred—as in the case of material and chemical recycling. Since chemical recycling can be used for difficult wastes (poorly selected, contaminated), it seems to be the most effective way of managing these materials. Moreover, as a result this of kind of recycling, it is possible to obtain commercially valuable products, such as fractions for fuel composition and monomers for the reproduction of polymers. This review focuses on various liquefaction technologies as a prospective recycling method for three types of plastic waste: PE, PP and PS.

Integration of Waste to Bioenergy Conversion Systems: A Critical Review

Sustainable biofuel production is the most effective way to mitigate greenhouse gas emissions associated with fossil fuels while preserving food security and land use. In addition to producing bioenergy, waste biorefineries can be incorporated into the waste management system to solve the future challenges of waste disposal. Biomass waste, on the other hand, is regarded as a low-quality biorefinery feedstock with a wide range of compositions and seasonal variability. In light of these factors, biomass waste presents limitations on the conversion technologies available for value addition, and therefore more research is needed to enhance the profitability of waste biorefineries. Perhaps, to keep waste biorefineries economically and environmentally sustainable, bioprocesses need to be integrated to process a wide range of biomass resources and yield a diverse range of bioenergy products. To achieve optimal integration, the classification of biomass wastes to match the available bioprocesses is vital, as it minimizes unnecessary processes that may increase the production costs of the biorefinery. Based on biomass classification, this study discusses the suitability of the commonly used waste-to-energy conversion methods and the creation of integrated biorefineries. In this study, the integration of waste biorefineries is discussed through the integration of feedstocks, processes, platforms, and the symbiosis of wastes and byproducts. This review seeks to conceptualize a framework for identifying and integrating waste-to-energy technologies for the varioussets of biomass wastes.

Effects of incineration leachate on anaerobic digestion of excess sludge and the related mechanisms

Anaerobic digestion (AD) refers to a reliable channel for energy recovery from organics. However, the digestion efficiency of excess sludge (ES) has been unsatisfactory since there are defects relating to ES hydrolysis. Therefore, this study explored a method to improve the anaerobic digestion of ES, which could simultaneously treat ES and incineration leachate, and revealed the potential mechanism of AD process. As the investigation was conducted on the influences exerted by incineration leachate on the four phases (i.e., solubilization, methanogenesis, acidogenesis and hydrolysis) of ES anaerobic digestion, and the effect mechanism. According to obtained results, adding appropriate amounts of incineration leachate could facilitate the steps of solubilization, hydrolysis, acidogenesis and methanogenesis of ES. The hydrolysis and acidogenesis efficiency in the leachate added digesters were 5.7%-17.1% and 13%-45% higher than that of the control digester, respectively. Meanwhile, cumulative methane yields (CMY) were 27-86 mL/gVS higher than that in the control digester. Besides, the sludge floc stability was reduced by the leachate with the decrease in the median particle size (MPS) and apparent activation energy (AAE) of the sludge. According to microbial community and diversity analysis, adding incineration leachate increased the relative abundance of hydrolytic-acidification bacteria in the digesters and the relative abundance of Methanosaeta and Methanosarcina. Thus, the digestive performance exhibited by the leachate participated system was improved. These mentioned findings may provide an approach for treating ES and incineration leachate in practical engineering.

A review of microwave pyrolysis as a sustainable plastic waste management technique

The high demand for plastic has led to plastic waste accumulation, improper disposal and environmental pollution. Even though some of this waste is recycled, most ends up in landfills or flows down rivers into the oceans. Therefore, researchers are now exploring better ways to solve the plastic waste management problem. From a socio-economic perspective, there is also a concerted effort to enable energy recovery from plastic waste and convert it into useful products to generate income for targeted segments of the population. In fact, this concept of waste-to-wealth has been adopted by the United Nations as part of its Sustainable Development Goals strategies. The current article begins by reviewing the strengths and weaknesses of plastic recycling before focusing specifically on microwave pyrolysis as an alternative to conventional technologies in plastic waste management, due to its benefit in providing fast and energy-efficient heating. The key parameters that are reviewed in this paper include different types of plastic, types of absorbent, temperatures, microwave power, residence time, and catalysts. The yield of the final product (oil, gaseous and char) varies depending on the main process parameters. Key challenges and limitations of microwave pyrolysis are also discussed in this paper.

Simple microwave pyrolysis kinetics of lignocellulosic biomass (oil palm shell) with activated carbon and palm oil fuel ash catalysts

The important parameters characterizing microwave pyrolysis kinetics, namely the activation energy (E a) and the rate constant pre-exponential factor (A), were investigated for oil palm shell mixed with activated carbon and palm oil fuel ash as microwave absorbers, using simple lab-scale equipment. These parameters were estimated for the Kissinger model. The estimates for E a ranged within 31.55–58.04 kJ mol−1 and for A within 6.40E0–6.84E+1 s−1, in good agreement with prior studies that employed standard techniques: Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The E a and A were used with the Arrhenius reaction rate equation, solved by the 4th order Runge-Kutta method. The statistical parameters coefficient of determination (R 2) and root mean square error (RMSE) were used to verify the good fit of simulation to the experimental results. The best fit had R 2 = 0.900 and RMSE = 4.438, respectively, for MW pyrolysis at power 440 W for OPS with AC as MW absorber.

Resource recovery through bioremediation of wastewaters and waste carbon by microalgae: a circular bioeconomy approach

Microalgal biomass-based biofuels are a promising alternative to fossil fuels. Microalgal biofuels' major obstacles are the water and carbon sources for their cultivation and biomass harvest from the liquid medium. To date, an economically viable process is not available for algal based biofuels. The circular bioeconomy is an attractive concept for reuse, reduce, and recycle resources. The recovery of nutrients from waste and effluents by microalgae could significantly impact the escalating demands of energy and nutraceutical source to the growing population. Wastewaters from different sources are enriched with nutrients and carbon, and these resources can be recovered and utilized for the circular bioeconomy approach. However, the utilization of wastewaters and waste seems to be an essential strategy for mass cultivation of microalgae to minimizing freshwater consumption, carbon, nutrients cost, nitrogen, phosphorus removal, and other pollutants loads from wastewater and generating sustainable biomass for value addition for either biofuels or other chemicals. Hence, the amalgamation of wastewater treatment with the mass cultivation of microalgae improved the conventional treatment process and environmental impacts. This review provides complete information on the latest progress and developments of microalgae as potential biocatalyst for the remediation of wastewaters and waste carbon to recover resources through biomass with metabolites for various industrial applications and large-scale cultivation in wastewaters, and future perspectives are discussed.

Microbial valorization of underutilized and nonconventional waste streams

The growing burden of waste disposal coupled with natural resource scarcity has renewed interest in the remediation, valorization, and/or repurposing of waste. Traditional approaches such as composting, anaerobic digestion, use in fertilizers or animal feed, or incineration for energy production extract very little value out of these waste streams. In contrast, waste valorization into fuels and other biochemicals via microbial fermentation is an area of growing interest. In this review, we discuss microbial valorization of nonconventional, aqueous waste streams such as food processing effluents, wastewater streams, and other industrial wastes. We categorize these waste streams as carbohydrate-rich food wastes, lipid-rich wastes, and other industrial wastes. Recent advances in microbial valorization of these nonconventional waste streams are highlighted, along with a discussion of the specific challenges and opportunities associated with impurities, nitrogen content, toxicity, and low productivity.

A review of the microwave-assisted synthesis of carbon nanomaterials, metal oxides/hydroxides and their composites for energy storage applications

Currently, nanomaterials are considered to be the backbone of modern civilization. Especially in the energy sector, nanomaterials (mainly, carbon- and metal oxide/hydroxide-based nanomaterials) have contributed significantly. Among the various green approaches for the synthesis of these nanomaterials, the microwave-assisted approach has attracted significant research interest worldwide. In this context, it is noteworthy to mention that because of their enhanced surface area, high conducting nature, and excellent electrical and electrochemical properties, carbon nanomaterials are being extensively utilized as efficient electrode materials for both supercapacitors and secondary batteries. In this review article, we briefly demonstrate the characteristics of microwave-synthesized nanomaterials for next-generation energy storage devices. Starting with the basics of microwave heating, herein, we illustrate the past and present status of microwave chemistry for energy-related applications, and finally present a brief outlook and concluding remarks. We hope that this review article will positively convey new insights for the microwave synthesis of nanomaterials for energy storage applications.

Co-Management of Sewage Sludge and Other Organic Wastes: A Scandinavian Case Study

Wastewater and sewage sludge contain organic matter that can be valorized through conversion into energy and/or green chemicals. Moreover, resource recovery from these wastes has become the new focus of wastewater management, to develop more sustainable processes in a circular economy approach. The aim of this review was to analyze current sewage sludge management systems in Scandinavia with respect to resource recovery, in combination with other organic wastes. As anaerobic digestion (AD) was found to be the common sludge treatment approach in Scandinavia, different available organic municipal and industrial wastes were identified and compared, to evaluate the potential for expanding the resource recovery by anaerobic co-digestion. Additionally, a full-scale case study of co-digestion, as strategy for optimization of the anaerobic digestion treatment, was presented for each country, together with advanced biorefinery approaches to wastewater treatment and resource recovery.

Waste-Derived NPK Nanofertilizer Enhances Growth and Productivity of Capsicum annuum L

Waste generation is a global issue that necessitates effective management for both human and animal health as well as environment. There are several ways to reduce waste, but recycling appears to be the best choice. By recycling, not only will the problem of pollution be resolved, but valuable compounds could be generated to be used as nutrients for plants. In this study, eco-friendly methods were established to produce α- and β-chitosan (CS) (as a source of nitrogen) with different degrees of deacetylation from shrimp shells and squid pin waste, phosphorous through degreasing and calcination of bovine bone and potassium from evaporation of banana peels Kolakhar. The waste bulk products were physically characterized and dry-milled into nano-powders. Different concentrations of the produced nano-NPK fertilizer (10%, 25%, 50% and 100%) were foliar-applied to Capsicum annum L. cv. Cordoba plants and compared to commercial chemical fertilizer and untreated control plants. The obtained results revealed that the nano-composite NPK with 25% concentration significantly promoted growth, yield and harvest of C. annuum as compared with the control and chemical fertilizer-treated plants. This study demonstrated that the use of an eco-friendly preparation of waste NPK composites, with a low concentration, could be applied as foliar fertilizer over chemical fertilizer to enhance the growth and productivity of Capsicum.

Effects of Enzyme Volumes on Hydrolysis and Fermentation for Ethanol Production From Leftover Cooked Rice

This study aimed to utilize the enzymatic hydrolysis of leftover cooked rice (LCR) for fermentative ethanol production. Effect of glucoamylase volumes (V1: 5 U/g, V2: 25 U/g, and V3: 50 U/g) on the performance of LCR hydrolysis was also evaluated. It was found that the highest chemical oxygen demand (COD) of 77.5 g/L and reducing sugar (RS) of 34.6 g/L were achieved at V3. The LCR hydrolyzate obtained from enzymatic hydrolysis was then used as feedstock for ethanol fermentation. Higher ethanol production was obtained when RS increased from 18.7 g/L (V1) to 23.2 g/L (V2). However, lower ethanol production was found when RS further increased to 34.6 g/L (V3) probably because too high RS concentration led to the inhibition on the yeast. The maximum ethanol production and yield were 21.1 g/L and 0.3 g ethanol/g LCR, respectively. The LCR could be a promising substrate for fermentative ethanol production for industrial application.

Analyzing microalgal biofilm structures formed under different light conditions by evaluating cell-cell interactions

Biofilm structure plays an important role in microalgae biofilm-based culture. This work aims to understand microalgal biofilm structures formed under different light conditions. Here, Scenedesmus obliquus was biofilm cultured under the light spectra of white, blue, green, and red, and the photoperiods of 5:5 s, 30:30 min, and 12:12 h (light : dark period). Biofilms were observed with confocal laser scanning microscopes and profilometry, then the porosity and roughness of biofilm were determined. We found that cells under white light formed a heterogeneous biofilm with many voids, high porosity, and roughness. While under red and blue lights, cells formed homogeneous biofilms with low porosity. Biofilm structures formed under different photoperiods were different. The mechanism of forming different biofilm structures under different light conditions was interpreted from the aspect of cell-cell interactions. Moreover, the results revealed that biomass accumulation increased with the increasing biofilm porosity due to the high effective diffusion coefficient.

Bioconversion of municipal solid waste into bio-based products: A review on valorisation and sustainable approach for circular bioeconomy

Municipal solid waste management is one of the major issues throughout the world. Inappropriate management of municipal solid waste (MSW) can pose a major hazard. Anaerobic processing of MSW followed by methane and biogas generation is one of the numerous sustainable energy source options. Compared with other technologies applicable for the treatment of MSW, factors like economic aspects, energy savings, and ecological advantages make anaerobic processing an attractive choice. This review discusses the framework for evaluating conversion of municipal solid waste to energy and waste derived bioeconomy in order to address the sustainable development goals. Further, this review will provide an innovative work foundation to improve the accuracy of structuring, quality control, and pre-treatment for the ideal treatment of different segments of MSW to achieve a sustainable circular bioeconomy. The increasing advancements in three essential conversion pathways, in particular the thermochemical, biochemical, and physiochemical conversion methods, are assessed. Generation of wastes should be limited and resource utilization must be minimised to make total progress in a circular bioeconomy.

The effect of aqueous phase recirculation on hydrothermal liquefaction/carbonization of biomass: A review

Aqueous phase (AP) recirculation is attracting increasing interest in hydrothermal process field as it has the potential to increase the yield of bio-crude and/or hydrochar and decrease the cost of hydrothermal wastewater disposal. This work summarizes the effect of AP recirculation on hydrothermal processing biomass, including the discussions on the mechanisms account for the increased yield and the changing properties of the hydrochar and bio-crude. However, the application of AP recirculation in hydrothermal process is limited by the enrichment of nitrogen in bio-crude and the applicability of only specific biomass type. To alleviate these limitations, the feasibility of combining AP recirculation with other strategies (e.g., co-solvent and co-feed) has been discussed. The possibility of using AP as a resource (e.g., nutrient source, and material mediator) can be increased by AP recirculation due to the accumulation of substances.

Characterization of digestate microbial community structure following thermophilic anaerobic digestion with varying levels of green and food wastes

The properties of digestates generated through anaerobic digestion are influenced by interactions between the digester microbial communities, feedstock properties and digester operating conditions. This study investigated the effect of varying initial feedstock carbon to nitrogen (C/N) ratios on digestate microbiota and predicted abundance of genes encoding lignocellulolytic activity. The C/N ratio had a significant impact on the digestate microbiome. Feedstocks with intermediate C/N ratio (20–27) (where higher biomethane potential was observed) showed higher relative abundance of archaea compared to feedstocks with C/N ratios at 17 and 34. Within microbial networks, four microbial clusters and eight connector microorganisms changed significantly with the C/N ratio (P < 0.05). Feedstocks with C/N < 23 were richer in organisms from the family Thermotogaceae and genus Caldicoprobacter and enhanced potential for degradation of maltose, galactomannans, melobiose and lactose. This study provides new insights into how anaerobic digestion conditions relate to the structure and functional potential of digester microbial communities, which may be relevant to both digester performance and subsequent utilization of digestates for composting or amending soil.

Recycling of Organic Wastes through Composting: Process Performance and Compost Application in Agriculture

Composting has become a preferable option to treat organic wastes to obtain a final stable sanitized product that can be used as an organic amendment. From home composting to big municipal waste treatment plants, composting is one of the few technologies that can be practically implemented at any scale. This review explores some of the essential issues in the field of composting/compost research: on one hand, the main parameters related to composting performance are compiled, with especial emphasis on the maturity and stability of compost; on the other hand, the main rules of applying compost on crops and other applications are explored in detail, including all the effects that compost can have on agricultural land. Especial attention is paid to aspects such as the improvement of the fertility of soils once compost is applied, the suppressor effect of compost and some negative experiences of massive compost application.

Municipal solid waste generation, composition, and management: the global scenario

Purpose

Due to the increasing population and prosperity, the generation rate of municipal solid waste (MSW) has increased significantly, resulting in serious problems on public health and the environment. Every single person in the world is affected by the municipal solid waste management (MSWM) issue. MSWM is reaching a critical level in almost all areas of the world and seeking the development of MSW strategies for a sustainable environment. This paper aims to present the existing global status of MSW generation, composition, management and related problems.

Design/methodology/approach

A total of 59 developed and developing countries have been grouped based on their gross national income to compare the status of various MSWM technologies among them. A total of 19 selection criteria have been discussed to select appropriate MSWM technology(s) for a city/town, which affects their applicability, operational suitability and performance. All risks and challenges arising during the life cycle of the waste to energy (WtE) project have also been discussed. This paper also gives a comparative overview of different globally accepted MSWM technologies and the present market growth of all WtE technologies.

Findings

It was found that most developed countries have effectively implemented the solid waste management (SWM) hierarchy and are now focusing heavily on reducing, reusing and recycling of MSW. On the other hand, SWM has become very serious in low-income and low-middle-income countries because most of the MSW openly dumps and most countries are dependent on inadequate waste infrastructure and the informal sector. There are also some other major challenges related to effective waste policies, availability of funds, appropriate technology selection and adequacy of trained people. This study clears the picture of MSW generation, composition, management strategies and policies at the worldwide context. This manuscript could be valuable for all nations around the world where effective MSWM has not yet been implemented.

Originality/value

This study clears the picture of solid waste generation, composition, management strategies and policies at the worldwide context. This manuscript could be valuable for all nations around the world where effective MSWM has not yet been implemented. In this study, no data was generated. All supporting data were obtained from previously published papers in journals, the outcomes of the international conferences and published reports by government organizations.

Efficient biohydrogen and advanced biofuel coproduction from municipal solid waste through a clean process

The cleanest form of energy, i.e., biohydrogen, and advanced biofuel, i.e., biobutanol, were produced from the organic fraction of municipal solid waste (OFMSW). Ethanol as a byproduct of this process was used for the pretreatment of this substrate, and this pretreatment was improved by other process byproducts, i.e., acetic acid and butyric acid. The pretreatment was conducted with 85% ethanol and 0-1% (w/w) acetic/butyric acid at 120 and 160 °C for 30 min. The pretreatment catalyzed by 1% (w/w) acetic acid at 120 °C resulted in a hydrolysate with 49.8 g/L total fermentable sugars, which was fermented to the highest overall yield of acetone, butanol, and ethanol (ABE) and hydrogen. Through this process, 114.1 g butanol, 43.8 g acetone, 15.1 g ethanol, 97.5 L hydrogen were obtained from each kg of OFMSW, producing 270 g ABE and 151 L H₂ from each kg of substrate, corresponding to 6000 kJ energy production.

Changes in global trends in food waste composting: Research challenges and opportunities

Increasing food waste (FW) generation has put significant pressure on the environment and has increased the global financial costs of its appropriate management. Among the traditional organic waste recycling technologies (i.e., incineration, landfilling and anaerobic digestion), composting is an economically feasible and reliable technology for FW recycling regardless of its technical flaws and social issues. The global scenario of FW generation, technical advancement in FW composting and essential nutrient recovery from organic waste with waste recycling are discussed in this article. Recent research on various strategies to improve FW composting, including co-composting, the addition of organic/inorganic additives, the mitigation of gaseous emission, and microbiological variations are comprehensively explained. Subsequently, it is shown that the performing FW composting in an existing mechanical facility can improve organic waste degradation and produce value-added mature compost to save on costs and increase the technological feasibility and viability of FW composting to some extent.

Fast microwave-assisted pyrolysis of wastes for biofuels production - A review

Microwave-assisted pyrolysis of waste suffers from the problem that the waste generally has low microwave absorptivity thereby resulting in low heating rate and low pyrolysis temperature. In this case, fast microwave-assisted pyrolysis is proposed and developed to help the pyrolysis of waste. This study describes two methods that can be used to realize fast microwave-assisted pyrolysis of waste: (1) premixed method (wastes are mixed with microwave absorbent) and (2) non-premixed method (wastes are poured onto the heated microwave absorbent bed). Then, biofuels (bio-oil, bio-gas, and bio-char) produced from fast microwave-assisted pyrolysis of wastes are reviewed. The review results show that the yields of bio-oil, bio-gas, and bio-char obtained from fast microwave-assisted pyrolysis of wastes varied significantly in the ranges of 2-96 wt%, 2.4-86.8 wt%, and 0.3-83.2 wt%, respectively. Although the present research focused mainly on the premixed method, non-premixed/continuous fast microwave-assisted pyrolysis is still promising and challenging.

Gasification of sewage sludge within a circular economy perspective: a Polish case study

Sewage sludge (SS) is a by-product of wastewater treatment plant (WWTP) operation. Due to fast rates of urbanization and industrialization, and rapid population growth, the world community faces a serious challenge associated with its disposal. There is an urgent need to explore low cost, energy efficient, and sustainable solutions for the treatment, management, and future utilization of SS. Thermal conversion of SS is considered the most promising alternative for sustainable SS management. Among three main thermochemical processes, it seems that gasification (GAS) of SS has the most advantages. The aim of this paper is a presentation of the gasification process as a sustainable method of SS management that takes into account the idea of a circular economy (CE). Gaseous fuel production, phosphorus recovery potential, and solid adsorbent production during the gasification process are analyzed and discussed. Result of this study shows that the lower heating value (LHV) of the gas from SS GAS process is up to 5 MJ/m3n and it can be effectively utilize in an internal combustion engines. The analysis proved that solid fraction after the SS GAS process can be treated as a valuable phosphorus source and perspective adsorbent materials. The amount of P2O5 in this material was equal to 22.06%. It is similar to natural phosphate rocks (28.05%). The maximum of the adsorption capacity of the phenol was comparable with commercial activated carbon (CAC): 42.22 mg/g for solid fraction after SS GAS and 49.72 mg/g for CAC. Graphical abstract.

Microalgae-based wastewater treatment for nutrients recovery: A review

The water resource crisis and concerns with environmental pollution are pushing for upgrading of conventional wastewater treatment process. Microalgae-based wastewater treatment process has shown many advantages that can meet the new demand for improved wastewater treatment. However, considering the issues related to the complexity of wastewater characteristics and adaptability of microalgae species, and the challenges to the design and optimization of treatment processes in order to achieve higher removal efficiencies with lower costs, further exploration and research are still needed. This review provides an overview of microalgae strains commonly used for wastewater treatment, physical and chemical properties of various wastewaters and their suitability for algae cultivation, factors affecting algae growth, nutrient assimilation/removal and biomass productivity. The design and operation of microalgae-based wastewater treatment processes are also discussed. Moreover, the issues and limitations of microalgae-based wastewater treatment are also discussed and suggestions are proposed for the further research and development.

Removal of Ammonia from the Municipal Waste Treatment Effluents using Natural Minerals

Due to various ecological problems, it is required to remove the ammonia nitrogen from wastewater. Industrial wastewater that was not subjected to any purification was used in this study, while most processes described in the literature were carried out using synthetically prepared solutions. The study investigated the removal of ammonium ions using ion exchange on various commercial minerals, in 3 h long batch ion-exchange experiments. Furthermore, research on the sodium chloride activation of the selected mineral was conducted. The screening of the mineral with the highest removal potential was conducted taking into account the adsorption capacity (q) and maximal removal efficiency (E), based on the NH₄⁺ ions changes determined using the selective electrode and spectrophotometric cuvette tests. The highest adsorption capacity (q = 4.92 mg/g) of ammonium ions with the maximum removal efficiency (52.3%) was obtained for bentonite, with a 0–0.05 mm particle size. After pretreatment with a 1 mol/L NaCl solution, maximum efficiency increments were observed (55.7%). The Langmuir adsorption isotherm corresponds well with the equilibrium adsorption data (R² from 0.97 to 0.98), while the Freundlich model was found to be mismatched (R² = 0.77). Based on these results it was concluded that natural sorbents may be effectively applied in wastewater treatment. It can be observed that as the size of sorbent particles gets lower, the adsorption capacity, as well as the removal efficiency, gets higher. The bentonite pretreatment with the NaCl solution did not result in the expected efficiency improvement. The 2 mol/L solution affected about 3.5% of the removal efficiency yield.

Promoting circular economy in the surroundings of an organic fraction of municipal solid waste anaerobic digestion treatment plant: Biogas production impact and economic factors

The Anaerobic Digestion and Composting Plant of the Vallès Oriental Waste Treatment Centre processes source-selected organic fraction of municipal solid wastes generated in its surrounding area. To promote Circular Economy between Municipal Solid Waste and industrial waste management systems, the Treatment Centre is looking for complementary wastes to be valorised through co-digestion with its main substrate. The study includes waste characterization and a complete treatment cost analysis, that jointly with the biogas potential and the mass balance of the Plant allows to calculate the price of each waste to be treated in the Plant. Up to 13 industrial wastes have been characterised for its biogas potential and its treatment cost calculated. Treatment prices ranged between 83 and 51 € t^-1.

A theoretical study on municipal solid waste plasma gasification

Gasification is an innovative and effective process which reduces the amount of waste produced by society and affords a synthetic gas with diverse applicability. In this plasma gasification study at high temperatures, a previously developed Aspen Plus model was used for municipal solid waste (MSW). The study is focused on the behavior of the equivalence ratio (ER), steam to MSW (S/MSW) ratio and gasification temperature (T), as a function of three gasification agents (air, O₂ and steam), assessing the final syngas composition. The model was validated with results from literature. The highest hydrogen yield reached 64% (molar fraction), when steam was used as gasification agent, lower values corresponding to O₂ utilization. Instead, a CO-enriched syngas was achieved under O₂ atmosphere (58%). Enhanced lower heating value (LHV) was obtained for the syngas produced when ER = 1, under oxygen atmosphere at 1500 °C (13 MJ/Nm³). This is due to the formation of CO, promoted by O₂, which constitutes an important factor in enhancing syngas LHV. Tar presence in the gasification process normally implies significant complications, but in this study, no problems were noticed since gasification occurred at higher temperatures.

Simultaneous organosolv pretreatment and detoxification of municipal solid waste for efficient biobutanol production

Municipal solid waste (MSW) was used as a source for biobutanol production via acetone, butanol, and ethanol (ABE) fermentation. Organosolv pretreatment was used for simultaneous extraction of inhibitors, particularly tannins, and pretreatment of lignocellulosic fraction prior to hydrolysis. The hydrolysates of the pretreated MSW contained appreciable amounts of sugars and soluble starch together with a tolerable amount of inhibitors for Clostridium acetobutylicum. The hydrolysate obtained from MSW pretreated with 85% ethanol at 120 °C for 30 min fermented to the highest ABE concentration of 13.06 g/L with the yield of 0.33 g/g carbon source. Through this process, 102.4 mg butanol, 40.16 mg acetone, and 13.14 mg ethanol were produced from each g of organic fraction of MSW (OFMSW). The pretreatment at mild conditions with higher ethanol concentration accompanied with the lowest glucose yield (0.145 g/g) and the highest starch recovery resulted in the uppermost ABE yield of 0.16 g/g OFMSW.

Thermophilic Co-Digestion of the Organic Fraction of Municipal Solid Wastes-The Influence of Food Industry Wastes Addition on Biogas Production in Full-Scale Operation

Anaerobic digestion (AD) has been used widely as a form of energy recovery by biogas production from the organic fraction of municipal solid wastes (OFMSW). The aim of this study was to evaluate the effect of the introduction of co-substrates (restaurant wastes, corn whole stillage, effluents from the cleaning of chocolate transportation tanks) on the thermophilic anaerobic digestion process of the mechanically separated organic fraction of municipal solid wastes in a full-scale mechanical-biological treatment (MBT) plant. Based on the results, it can be seen that co-digestion might bring benefits and process efficiency improvement, compared to mono-substrate digestion. The 15% addition of effluents from the cleaning of chocolate transportation tanks resulted in an increase in biogas yield by 31.6%, followed by a 68.5 kWh electricity production possibility. The introduction of 10% corn stillage as the feedstock resulted in a biogas yield increase by 27.0%. The 5% addition of restaurant wastes contributed to a biogas yield increase by 21.8%. The introduction of additional raw materials, in fixed proportions in relation to the basic substrate, increases biogas yield compared to substrates with a lower content of organic matter. In regard to substrates with high organic loads, such as restaurant waste, it allows them to be digested. Therefore, determining the proportion of different feedstocks to achieve the highest efficiency with stability is necessary.

Comparison of thermophilic anaerobic and aerobic treatment processes for stabilization of green and food wastes and production of soil amendments

The management of organic wastes is an environmental and social priority. Aerobic digestion (AED) or composting and anaerobic digestion (AD) are two organic waste management practices that produce a value-added final product. Few side-by-side comparisons of both technologies and their digestate products have been performed. The objective of this study was to compare the impact of initial feedstock properties (moisture content and/or C/N ratio) on stabilization rate by AED and AD and soil amendment characteristics of the final products. Green and food wastes were considered as they are two of the main contributors to municipal organic waste. Stabilization rate was assessed by measurement of CH₄ and CO₂ evolution for AD and AED, respectively. For AD, CH₄ yield showed a second-order relationship with the C/N content (P < 0.05); the optimal C/N ratio indicated by the relationship was 25.5. For AED, cumulative CO₂ evolution values were significantly affected by the C/N ratio and moisture content of the initial feedstock (P < 0.05). A response surface model showed optimal AED stabilization for a C/N of 25.6 and moisture of 64.9% (wet basis). AD final products presented lower soluble chemical oxygen demand (COD) but lower humification degree and aromaticity than the products from AED. This lower stability may lead to further degradation when amended to soil. The results suggest that composting feedstocks with higher C/N produces an end-product with higher suitability for soil amendment. The instability of end products from AD could be leveraged in pest control techniques that rely on organic matter degradation to produce compounds with pesticidal properties.

Agronomic effectiveness of urban biochar aged through co-composting with food waste

Terra preta soils have been shown to develop after considerable modification of soil through char addition and over time natural ageing has led to increase in fertility of those soils. A co-composting experiment was conducted to accelerate the artificial ageing of urban biochar (UB) with the aim of achieving similar terra preta effect. UB was produced through the pyrolysis of 2:1 ratio of biosolids and green waste and then composted with food waste (10% v/v) until compost maturity at around 75 days. A portion of the UB was placed in litterbags within the composting biomass in order to examine the effects of co-composting more closely. Addition of 10% UB to food waste accelerated the composting process. As measured from the litter bags, co-composting UB with foodwaste increased CEC, pH, EC and nitrogen loading of composted UB relative to the un-composted UB. However, the composting process reduced BET surface area and porosity of UB most probably due to clogging of pores by the organics released during composting. The agronomic value of UB, UB co-composted with foodwaste and foodwaste compost was evaluated in a greenhouse pot experiment with sorghum plants on a sandy acidic topsoil. Results of the pot experiment showed higher plant growth, lower emissions of N₂O and higher nitrogen use efficiency in soil amended with UB than the soil amended with compost and co-composted UB.

Semi-continuous anaerobic digestion of extruded OFMSW: Process performance and energetics evaluation

Recently, extrusion press treatment shows some promising advantages for effectively separating of organic fraction of municipal solid waste (OFMSW) from the mixed MSW, which is critical for their following high-efficiency treatment. In this study, an extruded OFMSW obtained from a demonstrated MSW treatment plant was characterized, and submitted to a series of semi-continuous anaerobic experiments to examine its biodegradability and process stability. The results indicated that the extruded OFMSW was a desirable substrate with a high biochemical methane potential (BMP), balanced nutrients and reliable stability. For increasing organic loading rates (OLRs), feeding higher volatile solid (VS) contents in feedstock was much better than shortening the hydraulic retention times (HRTs), while excessively high contents caused a low biodegradability due to the mass transfer limitation. For energetics evaluation, a high electricity output of 129.19-156.37kWh/ton raw MSW was obtained, which was further improved by co-digestion with food waste.

Food loss and waste management in Turkey

Food waste can be an environmental and economic problem if not managed properly but it can meet various demands of a country if it is considered as a resource. The purpose of this report is to review the existing state of the field in Turkey and identify the potential of food waste as a resource. Food loss and waste (FLW) was examined throughout the food supply chain (FSC) and quantified using the FAO model. Edible FLW was estimated to be approximately 26milliontons/year. The amount of biodegradable waste was estimated based on waste statistics and research conducted on household food waste in Turkey. The total amount of biodegradable waste was found to be approximately 20milliontons/year, where more than 8.6milliontons/year of this waste is FLW from distribution and consumption in the FSC. Options for the end-of-life management of biodegradable wastes are also discussed in this review article.

An investigation of co-combustion municipal sewage sludge with biomass in a 20kW BFB combustor under air-fired and oxygen-enriched condition

The behavior of municipal sewage sludge (MSS) with biomass (Guar stalks (GS), Mustard Husk (MH), Prosopis Juliflora Wood (PJW)) has been investigated in a 20kW bubbling fluidized bed (BFB) combustor under both air-fired (A-F) and oxygen-enriched (O-E) conditions. The work presented is divided into three parts, first part cover the thermogravimetric analysis (TGA), second part cover the experimental investigation of BFB combustor, and third part covers the ash analysis. TGA was performed with a ratio of 50%MSS/50%biomass (GS, MH, PJW) and results show that 50%MSS/50%GS has highest combustion characteristic factor (CCF). The experimental investigation of BFB combustor was performed for two different ratios of MSS/biomass (50%/50% and 25%/75%) and the combustion characteristics of blends were distinctive under both A-F and O-E condition. Despite 50%MSS/50%GS showing the highest combustion performance in TGA analysis, it formed agglomerates during burning in BFB. Due to this formation of large amount of agglomerates, de-fluidization was observed in the combustor bed after 65-75min in A-F conditions. The rate of de-fluidization increased under O-E condition. The de-fluidization problem disappeared when the share of MSS was reduced to 25%, but small amounts of the agglomerate were still present in the bed. With oxygen enhancement, the combustion efficiency of BFB combustor was improved and flue gasses were found within permissible limit. The maximum conceivable combustion efficiency (97.1%) for BFB combustor was accomplished by using 50% MSS/50%PJW under O-E condition. Results show that a ratio of 25%MSS/75%biomass combusted successfully inside the BFB combustor and extensive work is required for efficient utilization of significant share of MSS with biomass. SEM/EDS analyses were performed for agglomerate produced and for the damaged heater to study the surface morphology and compositions. The elemental heterogeneity of fly ash generated during MSS/biomass combustion was analyzed using Microwave Plasma-Atomic Emission Spectroscopy (MP-AES).

Waste-to-methanol: Process and economics assessment

The waste-to-methanol (WtM) process and related economics are assessed to evidence that WtM is a valuable solution both from economic, strategic and environmental perspectives. Bio-methanol from Refuse-derived-fuels (RdF) has an estimated cost of production of about 110€/t for a new WtM 300t/d plant. With respect to waste-to-energy (WtE) approach, this solution allows various advantages. In considering the average market cost of methanol and the premium as biofuel, the WtM approach results in a ROI (Return of Investment) of about 29%, e.g. a payback time of about 4years. In a hybrid scheme of integration with an existing methanol plant from natural gas, the cost of production becomes a profit even without considering the cap for bio-methanol production. The WtM process allows to produce methanol with about 40% and 30-35% reduction in greenhouse gas emissions with respect to methanol production from fossil fuels and bio-resources, respectively.

Material flow and sustainability analyses of biorefining of municipal solid waste

This paper presents material flow and sustainability analyses of novel mechanical biological chemical treatment system for complete valorization of municipal solid waste (MSW). It integrates material recovery facility (MRF); pulping, chemical conversion; effluent treatment plant (ETP), anaerobic digestion (AD); and combined heat and power (CHP) systems producing end products: recyclables (24.9% by mass of MSW), metals (2.7%), fibre (1.5%); levulinic acid (7.4%); recyclable water (14.7%), fertiliser (8.3%); and electricity (0.126MWh/t MSW), respectively. Refuse derived fuel (RDF) and non-recyclable other waste, char and biogas from MRF, chemical conversion and AD systems, respectively, are energy recovered in the CHP system. Levulinic acid gives profitability independent of subsidies; MSW priced at 50Euro/t gives a margin of 204Euro/t. Global warming potential savings are 2.4 and 1.3kg CO₂ equivalent per kg of levulinic acid and fertiliser, and 0.17kg CO₂ equivalent per MJ of grid electricity offset, respectively.

Activation of peroxymonosulfate by nitrogen-functionalized sludge carbon for efficient degradation of organic pollutants in water

Nitrogen-functionalized sludge carbon (NSC) was prepared by urea-mediated pyrolysis of sewage sludge (SS) and was introduced, for the first time, as a potential metal-free catalyst to activate peroxymonosulfate (PMS) for oxidative removal of organic pollutants in water. The nitrogen functionalization of NSC catalysts significantly affected the chemical micro-environments as well as microstructures (morphology and porosity), improving the PMS activation activity towards removing various pollutants, e.g., acid orange 7, phenol and rhodamine B. On the basis of quenching studies and electron paramagnetic resonance, the formed dominant reactive oxidative species (ROS) in the NSC/PMS system was clarified to be nonradical singlet oxygen, in addition to the typical radical ROSs, sulfate and hydroxyl radicals. The incorporated pyridine N, graphite N and pristine CO in the NSC framework promoted the generation of ROS. This study provided new insights into environmentally friendly resourcing SS and exploiting novel cost-effective metal-free catalyst for PMS activation.

Dechlorination of organochloride waste mixture by microwave irradiation before forming solid recovered fuel

In order to form a modified solid recovered fuel (SRF) with low chlorine content, high calorific value and well combustion performance, low temperature microwave irradiation was applied to remove the chlorine of the organochloride waste mixture before they were mixed to form SRF. The optimizing conditions of final temperature, microwave absorbents and heating rate were also detected to obtain high dechlorination ratio and high ratio of hydrogen chloride (HCl) to volatiles. In the temperature range of 220-300°C, 280°C would be chose as the optimal low microwave modified temperature concerning at which the dechlorination ratio was high and ratio of HCl to volatiles was relatively high as well; The use of microwave absorbents of graphite and silicon carbide (SiC) had a pronounced effect on the dechlorination of organochloride waste mixture, and the dechlorination ratio was increased significantly which could be reached to 87%, almost 20% higher than absorbent absent sample; The heating rate should set be not too fast nor too slow, and there was no big difference between the heating rate of 13°C/min and 15°C/min; The content of Cl of modified SRF is dramatically decreased and reaches to a low level 0.328%. Hence, the modified SRF can be ascended from the third class to the second class according to the Finland chlorine Classes I-III. Moreover, the combustibility of modified SRF was substantial improved compared to the traditional SRF. The low heating value was almost 20.56MJ/kg which is close to the LHV of lignite coal and bituminous coal in China, and it increased by 60% over that of traditional SRF. Removing chlorine of organochloride waste mixture before they are mixed with other kinds of combustible waste to form a modified SRF which is expected to be an alternative fuel for combustion in the future.