Organic Solid Waste Research Articles

Material flow analysis and characteristics of multiple-source organic solid wastes from a perspective of ecological network analysis: A case study in Hefei, China.

The numerous resources are consumed and a large number of multiple-source organic solid wastes are discharged during urban metabolic, which put pressures to environment. This study combined material flow analysis and ecological network analysis to comprehensively analyse the metabolism of multiple-source organic solid waste in Hefei. Analysing current metabolic characteristics of urban multiple-source organic solid waste and relationships between the components of metabolic system can help urban environmental management. The internal material flows of the system were analysed by a metabolic network containing 5 nodes and 18 pathways, which revealed metabolic characteristics of multiple-source organic solid waste in Hefei. The study showed that the metabolic system of multiple-source organic solid waste was relatively stable though distribution of internal flows changed in 8 years. The metabolic environment and agricultural sector covered a relatively large weight in this model. The control and exploitation relationships dominated the metabolic system. The urban metabolic mechanism reflected in this research can improve efficiency of urban metabolic resource, optimize waste management and provide data support for sustainable urban development. This study provided scientific guidance for metabolic research in Hefei and similar cities in China's rapid economic development.

Monitoring of the Physicochemical Parameters During the Co-Composting of Dehydrated Faecal Sludge and Organic Household Solid Waste: Composts Maturity Assessment

Monitoring of the Physicochemical Parameters During the Co-Composting of Dehydrated Faecal Sludge and Organic Household Solid Waste: Composts Maturity Assessment

Sequential Extraction and Characterization of Nitrogen Compounds after Hydrothermal Liquefaction of Sewage Sludge.

Organic solid wastes such as sewage sludge are potential feedstocks for the production of drop-in biofuels. Hydrothermal liquefaction (HTL) is a process that converts the wet sewage sludge into an organic biocrude. To fulfill industrial fuel standards, the considerable heteroatom content of the biocrude needs to be lowered by downstream processes. Nitrogen (N) contained in several compounds poses a challenge and yet, the complex chemical composition of HTL-biocrude samples has hindered detailed analysis and understanding. In particular, N-containing aromatic substances appear very persistent in biocrude. In the present work, two alkaline (NaHCO3 and NaOH) and one acidic (HCL) aqueous solutions were subsequently applied to extract and recover polar N-containing compounds from the biocrude matrix with an N-content of 3.8 wt %. Gas chromatography-mass spectrometry, atmospheric pressure chemical ionization in positive mode, and Fourier transform ion cyclotron resonance mass spectrometry were applied for their characterization and results show that a large share of N-compounds with an aromatic, pyridinic structure was found in the acidic extracted fraction with an N-content of 9.5 wt %. Aliphatic N-compounds were less affected by the separation and ended in the residual fraction. N-compounds with multiple oxygen functionalizations are enriched in the alkaline extracted fractions. This showed that N-compounds with an aromatic structure are strongly affected by polar groups and can potentially be extracted by downstream processes with appropriate solvents.

Anaerobic co-digestion of municipal organic solid waste: Achievements and perspective

One of the biggest problems that people confront in the 21st century is energy insecurity and global climate change. Carbon-neutral technologies are becoming more essential to fulfill global energy demands. The biochemical method used by anaerobic digestion (AD) process to produce biogas could transform complex municipal organic solid waste (MOSW) into a clean, sustainable energy source. In recent studies of AD, anaerobic co-digestion (AcoD) has gained widespread attention since it often produces a higher biogas yield than single-substrate digestion. This manuscript closes such gap by identifying the drawbacks of single substrate digestion associated with system optimization and feedstock properties as well as carefully analyzing the advantages of AcoD. Additionally, this article reviews the microbial population composition, synergistic impact of various co-feedstocks, and methane forecasting using several mathematical models. The limitations and potential outcomes of producing methane from MOSW are also addressed to enhance the effectiveness of the AcoD process.

Cascade upcycling polystyrene waste into ethylbenzene over Fe2N @ C

Thermochemical conversion is one of the most effective ways to upcycle organic solid wastes into fuels and/or value-added chemicals. In this study, the tandem hydropyrolysis/hydrocracking of polystyrene (PS) to produce ethylbenzene was studied using metal nitrides as catalysts. Fe, N co-doped carbon-based catalyst (Fe2N @ C) with core-shell structure was synthesized. The experimental results showed that carbon doping significantly improved the catalytic performance of iron nitride. The yield of ethylbenzene obtained from Fe2N @ C catalysis was 81 wt%, which is much higher than that of Fe2N (63.3 wt%) and commercial iron nitride (FeN, 4.9 wt%) under the hydropyrolysis temperature of 480 ℃, hydrocracking temperature of 280 ℃, and low H2 pressure of 0.2 MPa. The high catalytic activity of Fe2N @ C is ascribed to the synergy of metal-based selective hydrogenation and acid site-mediated C-C bond activation. This work provides a flexible and efficient catalytic technology for the high-value utilization of polystyrene waste.

The Kinetic Analysis and Adsorption Isotherm of Chicken Egg Shells and Membranes Against Synthetic Dyes

Textile industry waste at this time is enough to worry the community and the environment. The presence of synthetic dyes in water is hazardous, even in small concentrations. These synthetic dyes are derivatives of aromatic compounds such as benzene, toluene, and naphthalene, which are more resistant and stable than natural dyes. The adsorption method is used because it is easier to do, has no side effects, and does not require complicated and expensive equipment. In this study, the shells and membranes of discarded chicken eggs became useful as an absorbent of indigo carmine dye with an adsorption capacity of 6.399 mg/g. The adsorption reaction kinetics were analyzed from the optimal contact time data, and the reaction isotherm was analyzed from the adsorption optimal concentration data. The kinetic model that fits the research is the second pseudo-order with R2 = 0.9998. The adsorption mechanism demonstrates that the adsorption capacity is proportional to the adsorbent's active sites. The adsorption isotherm model, with R2 = 0.9748, is more closely related to the Freundlich isotherm model, indicating that adsorption occurs in several layers. From an economic point of view, chicken egg shells and membranes can be recommended as dye absorbers that are eco-friendly, efficient, and simple to obtain while lowering organic solid waste.

Finite Difference Modeling of the Temperature Profile during the Biodrying of Organic Solid Waste

Biodrying is a complex process that is very useful in the treatment of solid waste, where variables, such as temperature, thermal conductivity and the moisture content of organic matter, oxygen concentration in the pore space of the waste mass, microbial heat generation, microbial biomass, among others, are involved. Given this complexity, the development of mathematical models that help us to understand this bioprocess is fundamental. In the present work, a mathematical model, based on the finite difference method, was developed to predict the temperature profile at nine recording points, in an organic solid waste pile, during the biodrying process. The bioprocess was carried out under natural convection and solar radiation conditions, inside a greenhouse-type structure. A network of 53 nodes, distributed in the x, y and z directions, on a rectangular prism, was developed. From this network, 27 base nodes were taken and the energy balance was developed for each node, and with this, the equation was obtained, in explicit form, to calculate the temperature. In these base equations, the microbial heat generation was considered, at between 2 and 140 W/m3; the convective coefficient was between 1 and 5 W/m2 °C; and the daily records were taken inside the greenhouse for the solar radiation (0 to 450 W/m2), temperature (15 to 50 °C) and RH% (70 to 30). The modeled temperature profiles of the center (C) and the midpoints of the pile were, on average, 91% close to the experimental values, during the period from 0 to 20 days of biodrying; 70% close, during the period from day 21 to 35, the period when the modeled values were lower, due to the turning of the pile; and 94% close to the experimental values from day 36 to 50, when the modeled values were higher, also due to turning. The modeled temperature profiles of the left, right, upper and lower surfaces were, on average 92% close to the experimental profiles over the 0–35 day period, and the modeled and experimental values were practically identical from day 36 to 50 of the biodrying process.

Characterization of humic substances developed during the composting of class II A organic solid waste: a case study in a composting plant in Montenegro, Brazil

Abstract
 The abundance of organic waste generated by agro-industrial activities leads to the need to find alternatives for adequate destinations for these. Composting is the most viable alternative due to its low cost, ease of operation and generation of a product with the possibility of economic exploitation. The objective of this work was to present the dynamics of the composting process in an organic waste processing plant in the municipality of Montenegro, RS, Brazil, as well as to present the results of chemical analyzes for the quantification of humic substances contained in the leachate resulting from the composting process. The results of the leachate revealed that it has high levels of humic substances (humic acids between 12.2 and 30.7%, fulvic acids between 12.2 and 45.5%) significantly higher than those found in the literature (9%). Leachate has humic characteristics desired for the preparation of a commercial product for use in agriculture and can be configured as an interesting extra income alternative for the economic health of the enterprise.
 Keywords: organic waste; composting; humic substances; agriculture.

Efficient degradation of VOCs using semi-coke activated carbon loaded 2D Z-scheme g-C3N4-Bi2WO6 photocatalysts composites under visible light irradiation

The coal chemical industry generates large quantities of volatile organic compounds (VOCs) and solid wastes. Within this work, porous semi-coke activated carbon (SAC) was produced from solid waste semi-coke (SC) powder. Through loading high performance photocatalysts onto SAC to efficiently degrade VOCs using synergistic effects of adsorption and photocatalysis, acheiving the resourcefulness of solid waste. The specific surface area of the prepared SAC can reach 619.27 m2.g−1, which was effective against the adsorption of VOCs. An one-step hydrothermal method was used to load a 2D Z-scheme g-C3N4-Bi2WO6 (NB) photocatalyst on a semi-coke activated carbon. The 50 wt% NB/SAC material degraded formaldehyde, benzene and toluene up to 93.6%, 84.4% and 78.8% in 130 min under visible light irradiation, being 6.09, 4.55 and 4.75 times higher than that of a single photocatalyst, respectively. The capture experiments showed that hydroxyl radicals (⋅OH) and superoxide radicals (⋅O2–) were the active species in the degradation pathway. The material maintained a high degradation performance of 84.8%, 79.6% and 74.0% even after five cycles. In this study, the mechanism of using SAC as a substrate to enhance performance in photocatalytic degradation was described. The results of this study offered new insights into the resourcefulness of solid waste and the effective degradation of VOCs. It also offered a promising theoretical foundation for the exploitation and utilization of high-performance photocatalysts.

Managing the Organic Municipal Waste in Palestine: Linking Policy, Practice and Stakeholders’ Attitude Towards Composting

Local authorities in Palestine are the service providers for solid waste management. Given that the organic fraction is the largest in municipal solid waste, and with ineffective management policies, the study of attitudes and behavioral aspects of personnel involved are very-important parameters in developing an effective waste management system and assisting policymakers in rectifying these policies. This study aims to assess the attitude of local authorities (LAs) in the southern West Bank of Palestine towards organic municipal solid waste composting and the factors that affect their attitude. The data was gathered via a structured questionnaire from all local authorities in the study area. The results showed that the local authorities’ attitude towards organic solid waste composting is low and can be considered dissatisfactory since only 36.5% of the local authorities are planning for composting compared to 63.5% who are not. The results also showed that municipal solid waste composting is significantly affected by nine factors, including financial capacity, proper machinery, enough refuse collection vehicles to collect solid waste fractions separately, availability of area of land to be used for composting, familiarity with composting systems, staff previous-experience in compost production, acceptance of the rapid composting system, staff training in compost production, and believe that solid waste composting is within the LAs’ responsibility. Implications municipal solid waste is growing continuously due to the population growth, increase methane emissions, and add more pressure on the landfills, which faces political and social restrictions for expansion in Palestine. In addition, there is severe restrictions on the import of chemical fertilizers imposed by Israel. Therefore, composting the organic fractions of solid waste can, to a large extent, extend the life of the landfills and compensate the shortage of fertilizers in the market, encourage organic farming and reduce methane emissions as well. Moreover, it can contribute to achieve the objective of the national strategy on solid waste management.

Design of sustainable geopolymeric matrices for encapsulation of treated radioactive solid organic waste

Among radioactive by-products generated by nuclear technologies, solid organic waste is drawing attention because of difficult management and incompatibility with the disposal strategies traditionally adopted. Recently, geopolymers have been proposed as valid and green alternatives to cement-based matrices. In this work, novel geopolymeric formulations have been studied at laboratory scale to encapsulate ashes from incineration of surrogate solid organic waste and to further pursue sustainability and circular economy goals. Indeed, the most widely used precursor of literature geopolymers, calcined kaolin, has been totally replaced by natural raw materials and recycled industrial by-products. In addition, a highly zeolitized volcanic tuff has been chosen to further improve the intrinsic cation-exchange capacity of the geopolymer, hence enhancing waste-matrix interaction. The alkaline activation of the precursors, achieved without silicates of any metal, resulted in a promisingly durable geopolymeric matrix, whose chemical composition has been optimised to provide compressive strength above 10 MPa after 28 days of curing. A water-saturated sealed chamber provided the optimal curing condition to limit the efflorescence and improve the mechanical properties. At least 20 wt% loading of treated surrogate waste was achieved, without compromising workability, setting time, and compressive strength, the latter remaining within acceptable values. In order to demonstrate matrix durability, leaching behaviour and thermal stability were preliminarily assessed by immersion tests and thermogravimetric analyses, respectively. The leachability indices of constituent elements resulted far above 6, which is the generally agreed requirement for cement-based matrices. Moreover, the mechanical resistance was not worsened by the water immersion. The preliminarily obtained results confirm the promising properties of the new matrix for the immobilization of nuclear waste.

A Review of the Current State and Future Prospects in Resource Recovery of Chinese Cereal Vinegar Residue

Vinegar residue (VR) is a typical organic solid waste in Chinese cereal vinegar production. It is characterized by high yield, high moisture and low pH and is rich in lignocellulose and other organic matter. To avoid the environmental pollution caused by VR, it should be properly treated. The industry’s existing treatment processes, landfills and incineration, cause secondary pollution and waste of resources. Therefore, there is an urgent demand for environmentally friendly and cost-effective resource recovery technologies for VR. To date, a considerable amount of research has been performed in the area of resource recovery technologies for VR. This review summarizes the reported resource recovery technologies, mainly anaerobic digestion, feed production, fertilizer production, high-value product production and soil/water remediation. The principles, advantages and challenges of these technologies are highlighted. Finally, as a future perspective, a cascade and full utilization model for VR is proposed by considering the inherent drawbacks and economic-environmental feasibility of these technologies.

The effect of fermentation of organic solid waste with C:N ratios with phosphate rock reinforcement on its biorecycling

A solid waste of organic materials was collected from the residential neighborhoods of Ramadi during 2017. To convert these wastes into valuable organic fertilizers resources that reduces their negative impacts. The study included two mixtures of collected solid waste of organic materials. The first mixture, involved preparing sample has Carbone over nitrogen ration of 40:1 prepared from the collected organic materials. While the second mixture had C/N of 30:1 by supporting the mixture with urea. The prepared mixtures were inoculated as percentage of its weight w/w with 5%( (organic waste: soil) using agricultural soil taken from 60 cm depth and the fermentation was completed aerobically for 40 days. The second stage of fermentation included application of 0,10 and 20 % of phosphate rock to the products of the first stage of fermentation. The results show reducing the concentration of carbon and increasing the concentration of nitrogen in the components of the mixtures. Regarding the interaction treatment of 30:1(C/N) with 20% RP recorded the lowest carbon concentration and the highest amount of fulvic acid 342 and 13.3 g. kg-1 respectively, the same mixture with no phosphate application gave the highest rate of N and humic acid reached 29.9 and 24.2 g. kg-1, respectively. The interaction treatment of 30:1 with 20% gave the highest average density of phosphate-dissolving bacteria reached 6.25 Logcfu.g-1, while 40: 1 with 10% RP gave the highest number of BFN bacteria reached 6.75 Logcfu.g-1. However, 40: 1 with no phosphate application gave the highest rate of formation of phenolic acids reached 8.8 g.kg-1, while the highest average amount of dissolved phosphorous was 9.69 g. kg-1 obtained from the treatment of 30:1 treated with 20% RP.

Valorizing the organic fraction of municipal solid waste by producing black soldier fly larvae and biomethane in a biorefinery approach

The use of organic fraction municipal solid waste (OFMSW) was evaluated by rearing black soldier fly larvae (BSFL) and by producing biomethane from the derived residual larval waste (R-OFMSW). To do so, OFMSW was sampled from two full scale plants during the year (four seasons) and OFMSW textures were also studied by considering untreated and pulped waste.Residual larval waste was then used to produce biomethane, closing the biorefinery process, and complete mass and energy balances are provided. On average, the larvae production was 155 ± 58 (n = 16) g kg− 1 OFMSWDM and biogas from R-OFMSW was 138 NL kg− 1 OFMSWDM (n = 16). No differences were observed considering seasonality, waste plants and OFMSW texture. Energy balance indicated that 37% of OFMSW energy content (ECOFMSW) was recovered as the sum of BSFL and biomethane from R-OFMSW, which was much lower than the energy recovered by producing solely biomethane directly from OFMSW, i.e. 50% of ECOFMSW, because BSFL consumed a large part of the potential of OFMSW.

Co-hydrothermal carbonization of corn stover and food waste: Characterization of hydrochar, synergistic effects, and combustion characteristic analysis

Hydrochar was prepared via the co-hydrothermal carbonization (Co-HTC) method using corn stover (CS) and food waste (FW) as materials, and the influences of the synergistic effect of Co-HTC on fuel performances and combustion behavior were analyzed. Characterization of hydrochar was conducted using elemental analysis, industrial analysis, SEM, BET, XRD, and FTIR. The outcomes indicated that the higher heating values (HHVs) of hydrochar increased, the atomic ratios of H/C and O/C decreased, the fuel ratios ranged from 0.33 to 0.57, and the average pore diameter decreased when the FW ratio was increased. The synergistic effect of Co-HTC of CS and FW improved hydrochar yield, energy yield, organics retention, and C capture efficiency. Thermogravimetric and kinetic analysis showed that Co-HTC improves the combustion characteristics of hydrochar. Thus, production of hydrochar via Co-HTC of CS and FW provides some guidance for the resourcing and reducing solid organic waste, and offers a promising direction for renewable energy production.

Urban Organic Waste as a Source of Bioenergy for Electricity Generation in Bhopal, Madhya Pradesh

Municipal Solid Waste Management (MSWM) is essential as it impacts health, the environment, and aesthetic society if it is not managed correctly. Hence improving the quality and standard of living. There is an urgent requirement to neutralize the waste and the best possible solution for organic waste. It can be used to generate biofuels and utilized to generate electricity. The production of energy from waste depends on organic waste, so the energy potential of Bhopal city has been categorized into different sectors such as Urban Organic Solid Waste (UOSW), Pulp & Paper, Cattle, and Poultry, in which UOSW is 42% and, the Urban Organic Liquid Waste (UOLW) 25%, Cattle 23%, Poultry 2% and Pulp & Paper 8%. The UOSW has been analysed, and it has been categorized in Slaug (1%), Organic Solid waste (33%), Poultry (3%), and Cattle (63%), and the UOLW in Slaug (1%), UOLW (98.9%), and paper and pulp (0.10%). Total waste generated in Bhopal per day is 1123 TPD of which, 54.3% is organic waste that we can use to generate biofuel, i.e., 609 TPD, which can generate 165MW energy per day.

Biochar: its characteristics application and utilization of on environment

Abstract There are a variety of organic waste feedstocks that may be used to make biochar, such as agricultural byproducts and municipal solid waste. Biochar’s distinctive properties, such as its high carbon content and cation exchange capacity, large specific outer area, and stable structure, have attracted increased interest. The purpose of this study was to offer an overview of biochar with a focus on its environmental application by methodically analyzing and summarizing research on its production, characterization, modification, and the utilization in this review. Based on the kind of feedstocks used, the Biochar’s physiochemical characteristics might vary greatly. A variety of processes are used to create biochar, including pyrolysis, gasification, and hydrothermal carbonization. Acidic, alkaline, oxidizing agent, carbonaceous materials, steam and gas purging may be used to alter biochar. The environment field of application influences the adoption of modification methods. Soil remediation and improvement, carbon sequestration, composting of organic solid waste, water and wastewater purification, catalyst and activator, electrode materials and electrode modification are all examples of applications for biochar. In order to get consistent results, additional research into the use of biochar in carbon sequestration is needed. Soil microorganisms and biochar should be studied further to determine the primary cause of increased soil fertility in various soils and feedstocks. When biochar is utilized for environment remediation, further consideration must be given to the release of heavy metals and PAHs from biochar into the environment. To further understand how biochar works as an activator for per sulfate, more research into the link between biochar structure and activation capabilities is needed. There are several environmental remediation applications for biochar, and greater research is needed to understand its mode of action.

Composting from organic municipal solid waste: a sustainable tool for the environment and to improve grape quality

AbstractComposting from organic municipal solid waste (MSW), such as a separate waste collection, is a valid tool for eliminating a considerable amount of waste that would otherwise be destined for landfills and incinerators, thus representing an effective complement to traditional forms of recycling. It allows organic substance to be recovered and reintegrated into the soil, thus preventing erosion phenomena, increasing the biological fertility of the soil and contributing significantly to the restoration of impoverished sites. Modern winegrowing must address the issue of vineyard fertility in the sustainability context. The goal of this study was to assess the advantages of distributing a sustainable product to the vineyard that can achieve vine balance (vegetative and productive equilibrium). In a Vitis vinifera L. Sangiovese cv., vineyard, four soil treatments were applied (three compost rates and a control): municipal solid waste compost (40 tons per hectare – MSW40, 15 tons per hectare – MSW15, 2.5 tons per hectare – MSW2.5), and no compost (CTRL). The vine physiology (leaf gas exchange and water potential) and berry compositions (phenolic and technological maturity) were studied during the 2018–2019 growing seasons in the Sieci area, Italy. The results of this experiment provide some general insights showing that MSW compost options can be expected to reduce water stress, balanced vine performance and provide sustainable recirculation of organic matter. MSW compost is a true agronomic and environmental resource.

Process study and CO2 emission reduction analysis of coal liquefaction residue fluidized bed pyrolysis

The direct coal liquefaction process usually produces a liquefaction residue of about 30% of its coal feed. The effective utilization of the coal liquefaction residue (CLR), which contains about 80% organic matter, is of great significance for improving the oil yield of the direct liquefaction process and reducing the amount of pollution emitted from this oil-containing organic solid waste. In this study, the CLR fluidized bed pyrolysis process was studied through a fluidized bed reactor pyrolysis experiment and steady-state thermal analysis. The characteristics of CLR were first analyzed, and then the pyrolysis experiment was conducted in a fluidized bed reactor system. The experiment results show that the oil yield is 34.81% at 540°C for an ash-free feedstock using a fluidized bed pyrolysis reactor. Based on the pyrolysis experimental data and the Aspen Plus software platform, the fluidized bed pyrolysis reactor, fractionation column, coke burner, gasifier, and other equipment were modeled to compare four different process schemes. CLR pyrolysis is an endothermic reaction, and its heat is usually supplied by coke combustion, which produces significant CO2 emissions. Case studies of the pyrolysis process were performed in detail in order to reduce CO2 emissions. Thermal efficiency, carbon efficiency, solid waste discharge, and CO2 emissions of the different schemes were compared, and a flexible fluidized pyrolysis (FFP) process coupled with water electrolysis was proposed. The introduction of green hydrogen and green oxygen to the process can realize near-complete utilization of carbon and hydrogen elements in the CLR and produce high-quality liquid fuels and syngas (for further chemical synthesis), and this new process can achieve almost near-zero CO2 emission in the entire unit. This process principle can also be applied to the CO2 emission reduction of organic solid waste pyrolysis, catalytic fluid cracking, fluid coking, and so on.

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.