Portion Of Municipal Solid Waste Research Articles

Valorisation of food waste into bio-based polyurethane rigid foams: From experimental investigation to techno-economic analysis

Food waste (FW) constitutes a significant portion of municipal solid waste and thus requires proper treatment. A ‘waste-to-wealth’ concept, in this case, urges the valorisation of FW to produce value-added products, given that such waste contains significant quantities of diverse nutrients. While most of these efforts have been focused on the recovery of carbohydrates, this paper introduces an FW biorefinery scheme to valorise FW lipids (FWLs) into bio-based polyols for polyurethane rigid foams (PURF). Considering economic viability, cost-effective dosages of enzymes for FW hydrolysis were first investigated. Subsequently, the obtained FWLs were converted into bio-based polyols through stepwise epoxidation and oxirane ring-opening. Characterisation results showed that FW hydrolysis aided the development of FWL-derived polyols into PURF. Moreover, the obtained PURF exhibited excellent properties that are suitable for thermal insulation applications in the fields of civil engineering and appliances. A further techno-economic analysis demonstrated a promising profitability of valorising FW into PURF. Proven as material-intensive, critical cost drivers of the proposed valorisation scheme mainly included the price of the PURF and the chemicals required for the synthesis. The FW processing rate also significantly influenced the economic viability. By providing a successful valorisation pathway from FW to PURF and highlighting vital economic variables, this work aims to provide insights to promote the sustainable development of FW biorefineries and relevant bio-based polymer industries.

Co-production and enhancement of biogas and biohydrogen by optimizing NaOH-urera pretreatment conditions for kitchen waste

Kitchen waste (KW) constitutes a major portion of municipal solid waste, posing an imminent environmental challenge. Given its high water and organic content, KW is suitable for Anaerobic Digestion (AD) prior to its disposal, as it reduces Chemical Oxygen Demand (COD) and simultaneously generates biogas. The unique contribution of this study is the investigation of NaOH-urea pretreatment as a method to enhance AD of KW and sludge, ultimately leading to more efficient and environmentally friendly waste disposal. NaOH-urea pretreatment is selected for its ability to improve hydrolysis, increase organic matter solubilization, and enhance nutrient balance, ultimately boosting biogas yield during AD. Response surface methodology (RSM) was used for optimizing pretreatment conditions. AD experiments were performed batch-wise. For optimization, pretreatment time, temperature, and NaOH-urea concentration were selected as independent variables. RSM results indicated that optimum NaOH-urea concentration, time, and temperature conditions were 30 g/L, 30 min, and −5 °C, respectively. At optimum conditions, cumulative biogas was 316 ml, whereas biohydrogen % (v/v) was 36.21 %. Furthermore, the Modified Gompertz Model (MGM) and Logistic Function Model (LFM) were used to observe the efficacy of NaOH-urea pre-treatment of KW., The reaction kinetics were also discussed. Akaike's Information Criterion was employed to determine which model best fits the obtained experimental data. It was found that MGM is better than LFM for this study. Through experimental investigations and numerical modeling, this research provides insights into optimizing biogas and biohydrogen production from KW.

Automobile fuels (diesel and petrol) from plastic pyrolysis oil—Production and characterisation

Plastics like high-density polyethylene (HDPE), polystyrene (PS), and Polypropylene (PP) constitute a large portion of municipal solid waste. Plastics can be pyrolysed for reuse, but the end-product qualities are critical to industry refining processes. Pilot-scale pyrolysis and vacuum distillation were used to thermally degrade the plastics and convert it to petrol (gasoline) and diesel. Batch pyrolysis of HDPE, PS, and PP at 540 oC yielded plastic pyrolysis crude oils. The crude oil was separated into different fractions starting with distillation temperatures of less than 170 OC, 170 to 380 °C, and above 380 °C. The quality of the produced crude oil, gasoline, and diesel cuts was evaluated analytically according to the fuel specifications. This study demonstrated that pyrolysis of plastics can convert up to 80% of solids by weight) into liquid crude oil. HDPE pyrolysis produces lower quantities of oil due to the production of wax. A high calorific value (38.1 to 42.9 MJ/kg) similar to fossil fuels indicates that the liquid product of plastic pyrolysis could be a viable energy source. Plastic pyrolysis crude oil from PS mostly yielded gasoline at around 70% by weight, while HDPE and PP yield predominantly diesel at more than 50% by weight. The distilled oil characterisation results were outstanding, confirming that the quality of produced petrol and diesel from plastics pyrolysis oil suppress minimum specifications for automotive fuel standards. The cetane index of HDPE and PP diesel was found to be 60 and 55 respectively, significantly above the required value of 46 for automotive diesel. Higher heating values of most petrol cuts were in the range of 41.1 to 44.6 MJ/kg. These and other fuel qualities are within or near the approved range for automotive fuel. Thus, the findings can be used to build a foundation for the industrial manufacture of automotive quality fuels from plastic solid waste.

Biodegradation of Paper Wastes by Freshwater Snails: Implications for Management.

The different types of paper wastes constitute a major portion of municipal solid waste. The present study was aimed to justify the use of freshwater snails for the biological degradation of the paper waste and subsequent availability of cellulose from fecal matter. Three aquatic snails Racesina luteola, Indoplanorbis exustus, and Physella acuta were used to degrade newsprint, cardboard, and common writing paper as paper waste. The consumption of papers by the snail species was subjected to statistical analysis, and the results of Kruskal-Wallis test indicated a significant variation in the paper-specific consumption pattern (K = 181.762, df = 2, p <0.0001) and no variation in the species-specific pattern. Among the three types of paper used for the study, cardboard was consumed at the highest rate (4.655 ± 0.401 mg per day), and the per capita consumption remained highest for the snail I. exustus (2.253 ± 0.273 mg per day). The microscopic images and SEM micrographs of the consumed paper revealed prominent grazing and scraping marks by the snails. The disintegration and relaxation of the papers after consumption indicated that they were on the pathway to degradation. The traditional way of degrading paper waste includes physical, chemical, or microbial treatment of paper pulp. This study represents a novel approach considering the freshwater snails as model organisms for the biodegradation process. Considerable amount of cellulose was present in the fecal samples, which can be extracted and purified for utilization as potent raw material.

Analysis and Evaluation of a Three-Stage Anaerobic Digestion Plant for Management of Biodegradable Municipal Solid Waste

Sub-Sahara Africa countries are faced with the problem of solid waste management and access to sustainable energy. There is a need to develop a technology that can help to manage the generated solid waste and the same time produce green energy that is sustainable. Hence, this research work that focused on the development of a novel three-stage anaerobic digestion (AD) plant for management of biodegradable portion of municipal solid waste. An experimental design and preliminary tests using co-digestion of municipal solid waste was conducted with the operation and process parameters utilized in this research work. Conceptual design was generated based on results of experimental design. The developed AD plant was evaluated for performance and the results obtained compared to an existing single stage fixed dome AD pilot plant using 100 kg of substrates with an organic loading rate of 3 kg/m3day for an operating time of 163 days. The cumulative biogas yield, and behaviour of the operation and process parameters utilized in this research work were evaluated. The results obtained reveal that unlike the single stage fixed dome AD pilot plant, the three-stage AD plant enables continuous production of biogas. Besides, optimum conditions of neutral pH range of 6.99 m to 7.01 m, slurry mesophilic temperature range of 37.05 °C to 37.15 °C, and organic loading rate of 3kg/m3d that favoured optimum biogas yield were established.

GENERATION AND CHARACTERISTICS OF HOUSEHOLD SOLID WASTE IN KHULNA CITY, BANGLADESH

For growing cities, solid waste management is a serious concern, focusing on household waste because it accounts for a significant portion of municipal solid waste. An accurate estimation of the quantity and characteristics of solid waste mixtures from diverse income levels is required for effective city-wide solid waste management planning. The purpose of this study is to assess the production and characteristics of domestic solid waste produced by different socio-economic groups in three wards (no. 17, 23 and 24) of Khulna city. Moreover, various factors that influence the pace of waste production have been critically investigated. The finding suggests that, household waste generation rate ranges from 0.421 to 5.81 kg/day, average of 1.917 kg/day and 0.476 kg/capita/day. The waste composition analysis depicts that kitchen garbage is the most prevalent component. The waste generation rate has a positive relationship with income level and household size. Nonetheless, the findings and proposed essential steps of this study would be beneficial in assisting policymakers in refining plans for controlling the municipal waste effectively.

Comparative analysis of the quantity and quality of both synthetic and biodegradable films on kitchen waste

The huge demand for plastic use, inadequacy in waste management, and casual community behavior towards proper disposal creates a remarkable threat to life on Earth. The garbage waste, which consists of plastic bags upon exposure to rainwater and the moisture content present in the landfill, proceeds to leachate generation. This poses a major influence on the design and operation of the landfill. The present work emphasizes the effect of different types of polymeric films on kitchen waste, which is a major portion of municipal solid waste. The study has been conducted considering different polymeric films, including LDPE, starch, and LDPE blended starch film of different wt% (4 wt%, 8 wt% & 12 wt%). The objective of the present work is the keen observation of the bed height settlement of kitchen waste having different weight percent of polymeric films and the measurement of the leachate volume taken out from different containers before and after centrifugation. The quality and property of leachate have been checked by considering various parameters like COD, pH, conductivity, and salinity. It has been noticed that there is an encouraging effect on prolonged biodegradation on leachate formation and successive waste bed settlement due to the presence of plastics. It was observed that 4 wt% of LDPE blended starch film has an optimal effect on waste disposal. Hence the present work will assist in mollifying the alarming threat inflicted by plastic disposal on municipal organic solid waste.

Dilution rate of compost leachate from different biowaste for the fertigation of vegetables

Compost leachate (CL) is often treated as sewage. Limited studies have characterised the use of CL for agriculture application due to the variation of nutrient range, potential pollutants and need for pretreatment before use. This paper reviewed the characteristics of CL in terms of its nutrients and physical characteristics from three types of biowastes, i.e. the organic portion of municipal solid waste (OP-MSW), animal manure and green waste. The nutrient range characterised are used to develop the dilution rate of the CL as fertigation water for three types of vegetables. The dilution rate of CL developed is based on the fertigation standards set by the Food and Agriculture Organization of the United Nations and Malaysia Standards. The results show that all CL contain high organic content and micronutrients, which exceeded the upper limits. For the fertigation of vegetables using the CL, based on the requirement of COD and micronutrients (Fe, Mn, Zn, Cu, Pb, Ni, Cd, Cr) of the vegetables, the CL from green waste required the lowest dilution rate (8–45 fold), followed by animal waste (33–65 fold) and the OP-MSW (193–1770 fold). The novel dilution range developed is vital to balance the essential nutrients in the CL while avoiding phototoxicity on plant and soil pollution. The dilution strategy developed is essential to support the conversion of CL as an organic liquid fertiliser for agricultural application.

Quantification of Solid Waste Destined in Kigali City Nduba Dumpsite

Kigali is Rwanda’s capital located in geographic center of the country. Rwanda is a fastest developing country where the urbanization is extensive and accelerates the increase of waste generated from households. Biodegradable organic matter constitutes a great portion of Municipal solid waste from Kigali City. The research was focused on the composition and quantification of Solid Waste destined in Kigali City dumpsite. The survey was carried out in Nyarugenge Sector of Nyarugenge District, city of Kigali with three selected cells and in each cell, two villages were selected in each village. The survey was conducted every week for four weeks corresponding to a month, to estimate the quantity of municipal waste discharge over a day and 60 households sample were involved in the research. Moreover, this survey was conducted between 24/June and 21/July. The sorting-and-weighing methodology was used for assessing the waste composition from each of the sample households for each week. The sorting-and-weighing methodology was used in assessing the waste composition from each of the sample households for each week. In the survey, the amount of solid waste generated and disposed of in each of survey areas (villages) as quantified, was found to be 686.000 kg. The result showed variation of weight percentage of waste: plastics (4%), paper (3%), cartons (3%), glasses (2%), metal (1%), biodegradable organic wastes (75%), others (clothes, shoes, bones, hair, pampers) (14%). The organic waste was found to be more generated with 500.000 kg and 73% fractions of entire municipal solids waste in Kigali city.

Valorization of waste waxed corrugated cardboard via pyrolysis for recovering wax

AbstractCorrugated cardboard (CCB) comprises a substantial portion of municipal solid waste, of which ~5% is wax coated CCB (WCCB) to enhance its performance. WCCB cannot be recycled, making it a suitable resource to recover wax and produce char. The WCCB was characterized for its extractable wax, lignin, and carbohydrate contents and by thermogravimetric analysis to study its thermal degradation behavior. WCCB was preliminarily examined by pyrolysis‐gas chromatography–mass spectrometry to determine product composition. WCCB samples were then pyrolyzed in auger and tube reactors at 450, 500, and 550°C, and their pyrolysis wax‐oil and char products characterized. WCCB and char were subjected to proximate, ultimate, surface area, analyses. The highest char yield was 36% at 450°C, and the highest wax‐oil yield was 53% at 550°C in the tube reactor. The wax‐oil fraction contained mainly alkanes, alkenes, and dienes (C9–C36), and chain length decreased with pyrolysis temperature. This wax fraction could be recovered and used as bunker fuel (C12–C40) or further converted to diesel (C10–C20).

Fermentative Production of Lactic Acid as a Sustainable Approach to Valorize Household Bio-Waste

Source-sorted organic portion of municipal solid waste (bio-waste) can be fermented to lactic acid, a platform chemical widely used in the production of biodegradable polymers, green solvents and chemicals. In the present study, fermentation of bio-waste using lactic acid producing bacterium (LAB) Lactobacillus delbrueckii was investigated. Results showed that adding 10% (v/v) of L. delbrueckii as LAB inoculum along with pH adjustment to 6.2 had the highest lactic acid yield (0.65 g/g total sugars). Nevertheless, pH adjustment without bio-augmentation could also result in relatively high yield of lactic acid (0.57 g/g total sugars). Furthermore, enzymatic hydrolysis was applied to boost the lactic acid production slightly increasing the yield to 0.72 g/g total sugars. Thus, fermentative production of lactic acid can be achieved without the addition of enzymes to reduce production costs. Overall, the results indicate that bio-waste could be a suitable substrate for the production of lactic acid.

Boosting landfill gas production from lignin-containing wastes via termite hindgut microorganism

Lignocellulose comprises a significant portion of municipal solid waste (MSW) − 40–70% in developed countries, including paper, wood, and yard waste. Cellulose and hemicellulose are often shielded by lignin, posing a barrier to waste decomposition and landfill gas generation. Unfortunately, lignin is resistant to microbial degradation under low-oxygen conditions that normally occur in MSW landfills.The bacterium strain TAV5, microaerophilic and member of phylum Verrucomicrobia, isolated from the hindgut of the Reticulitermes flavipes termite, the most widely distributed subterranean termite in North America. Its genome contains genes associated with methylotrophic competency which code for enzymes that structurally modify lignin. The overall goal of this research was to use TAV5 to modify lignin and boost methane production from MSW.Batch-scale reactors (125 mL) were filled with paper, yard, or wood waste, and four ratios of mixed of waste. Reactors were seeded with different ratios of TAV5 to anaerobic digester (AD) microorganisms (representing landfill anaerobic microorganisms). Based on batch tests, optimal ratios of TAV5 to AD microorganisms were used to seed wastes (mixed, yard, and wood) in 6-gallon reactors.Addition of TAV5 increased methane production from mixed waste, yard waste, and wood, by 49%, 34%, and 297%, respectively. TAV5 decreased acid soluble lignin by 7–39%, depending on waste type. TAV5 grown under aerobic conditions and room temperature (not requiring a heated anaerobic chamber) was found to remain viable and increase methane production under low-level oxygen conditions (1–2%). This finding will potentially lessen costs for growing large volumes of it for seeding landfills.

Evaluating Anaerobic Digestion Technology in Reducing the Quantity of Solid Waste: Case of Kigali Dumpsite

Biodegradable organic matter constitutes a great portion of Municipal solid waste and comprises organic material which can be broken down by bacteria like paper, card, green waste, food waste, miscellaneous items with an organic element and fine materials. This paper mainly evaluated the potential of anaerobic digestion technology in reducing the quantity of solid waste destined to the dumpsite in Kigali city. The paper evaluates the viability of using biodegradable waste meant to the land where the biogas is produced and undertaking its cost & benefit analysis for chemical, physical and biological characteristics of municipal solids waste on anaerobic digestion technology. The quantity of municipal waste generated in Kigali city was used for designing the biodigester required. The paper indicates that the organic waste in Kigali city produces 457 L/kg DM of methane and the overall assessed value of methane was 51,384,375 L with the electricity derived from the methane of 180,873 KWh which is 54% of the daily demand in Kigali city. The volume of the biodigester was found to be 58,065 m3. Based on the energy recovered, revealed that cities will benefit this research for the population demand for the increased electricity.

Effect of dry-solid content level in feeding slurry of municipal solid waste consumed by FSIG/GT power generation process; a theoretical study

The theoretical studies on Fuel Slurry Integrated Gasification/Gas Turbine (FSIG/GT) power generation process have progressed. The present focuses on the influence of dry-solid content level (DSC) in the slurry consumed by FSIG/GT process. At the present, the portion of Municipal Solid Waste (MSW)—known as LWTR (letter, wood, textile, and rubber)—fuels the unit. In such a process, the solid fuel is mixed with water to form a slurry, which is pumped into a drier. The dried fuel is fed to a gasifier and the produced gas is cleaned until reaching adequate levels of particle content and sizes, as well alkaline concentrations for injection in commercial gas turbines. Energy recovering is provided by steam cycles. The highest 1st Law efficiency became close to 32% when DSC nears 50%. The results demonstrate that power generation efficiencies are very sensitive regarding the DSC of feeding slurry. Such information might be useful at the decision-taking phase of power generation unit design.

Decentralized composting of household wet biodegradable waste in plastic drums: Effect of waste turning, microbial inoculum and bulking agent on product quality

Household wet biodegradable waste (HWBW) forms a major portion of municipal solid waste (MSW) in developing nations. Its recycling at the source of generation can not only reduce waste transportation costs but also prevent harmful air emissions. Therefore, the present study was planned to investigate the performance of a decentralized household composting system for onsite recycling of source-segregated HWBW. The study was carried out in the recycled plastic drums (capacity = 100 L). The effect of waste turning and addition of microbial inoculum and bulking agent (garden waste) on the composting process was examined. The results showed that proper provisions for aeration and periodic waste turning are necessary to produce good quality compost. The addition of a suitable microbial inoculum can reduce duration of waste stabilization. During composting, the peak temperature was found greater than 55 °C for 3–6 days and the compost yield (<4 mm fraction) was 18%–20%. The phytotoxicity tests results showed that the growth of cress plants is not affected in the presence of 20% of compost mixed in soil. One-time addition of inoculum at the start of composting process was found sufficient for completion of the active decomposition period within 30 days. Based on the above results, two-drum systems can be suggested as feasible option to produce compost from HWBW.

Gravimetric composition of the rejects coming from the segregation process of the municipal recyclable wastes

Rejects from selective collection are municipal solid waste (MSW) not used for recycling and are, therefore, destined for the landfill in Brazil. Knowledge of the composition and generation of this waste is important for strategically planning public policies that minimize its generation and its negative environmental impacts. However, this portion of MSW is not very well known. Therefore, the aim of this study was to analyze the rejects from the sorting process of the selective waste collection in the municipality of Blumenau, in the State of Santa Catarina, southern Brazil. The studied rejects came from the largest cooperative in the city, and its composition was sorted into 17 categories of 101 samples over the course of one year, with a total of 3893 kg of analyzed rejects. The waste collected by the selective collection of the municipality was evaluated monthly to determine which part of this quantity became rejects and to determine the composition and seasonality of these rejects. The study found that 30.5% of the waste sorted by the cooperative was rejected. Among these rejects, the presence of materials that could be marketed by the cooperative was verified. Hazardous and/or legally prohibited waste were also identified, as were organics, construction and demolition waste, health care waste, electronics, textiles, footwear, batteries, and bulbs. Seasonal analysis indicated a concerning constant generation of health care waste. Aside from that, there was an increase in the generation of waste from electrical and electronic equipment (EEE) during the Christmas period, when a large part of the population discards their EEE. This information is important for the enforcement of the MSW management structure as well as for educational campaigns aimed at the correct separation of waste that should be sent for selective collection.

Efficiency of microbial inoculation for a cleaner composting technology

There are contrasting opinions on the utilisation of microbial inoculant (MI) as a bioremediation technology for composting. The effectiveness can be affected by a diversity of factors, and the reproducibility of results can be a great challenge. This study aims to review the effectiveness of MI, specified as isolated or cultured single and consortium micro-organisms, for composting, with the main component of lignocellulosic waste (LW) and the organic portion of municipal solid waste (OPMSW). The potential for the enhancing effect of each parameter, i.e. compost quality parameters: pH, germination index, nitrogen content, phosphorus content, potassium content, C/N ratio; composting parameters: temperature, odour, enzymatic activities, organic matter content, microbial population, volume reduction, humification, is discussed and evaluated. Based on 13 analysed parameters, the use of MI tends to exert a significant positive effect on the composting of LW compared to that of OPMSW. There has not been a full consensus on the efficiency of MI for composting as it varies on a case-by-case basis. A decision framework is required for the application of MI for different composting scenarios. This overview proposes MI technology, which has been generally less practical than optimising the physicochemical parameters of the composting due to the higher variation in the composting efficiency. Comprehensive comparison studies between the two approaches are needed for further verification which can contribute to the support of composting as a clean technology. The unnecessary uses of resources (e.g. MI, electric, fuel) can consequently be avoided for environmental footprint minimisation.

Organic fraction of municipal solid waste – a valuable source of green energy in India

Purpose The purpose of this paper is to evaluate the green energy generation potential of the organic fraction of municipal solid waste (OFMSW) through anaerobic digestion (AD) route in India and its benefits. Design/methodology/approach In this study, performances of some AD plants presently operating successfully in India have been studied in the field (Section 3.1). Primary data collected from this study has been used to evaluate the biogas generation potential of OFMSW in Indian condition (Section 4). To ensure the validity, this gas generation potential has been compared with the gas yield data observed by the other researchers and with the gas yields of AD plants of some technology providers at some parts of the world (Section 4.1). From the future population projection (year 2030) and the future per capita waste generation rate obtained from the literature survey, estimation has been made for future quantity of municipal solid waste (MSW) (year 2030) (Section 2.3). Based on these data, the green energy generation potential from the bio-degradable portion of MSW through AD route, in India, has been evaluated (Section 4.2), and its economic and environmental benefits have been analyzed (Section 5) . Findings This secondary research work reveals that from the bio-degradable portion of MSW, India can generate about 583 MW of green energy daily and produce about 5.1 mil MT of bio fertilizer per annum presently, and these may go up to 2,273 MW and 19.5 mil MT, respectively, in the year 2030. Generation of green energy from OFMSW, in India, may save coal consumption of about 3.04 mil MT and reduce 35.42 mil MT of CO2 emissions per annum presently. Moreover, utilization of the bio-degradable portion of the MSW stream may save about 550 acres (2.23 sq. km) of landfill area per year presently and in total may save about 8,182 hectare (82.5 sq. km) of landfill area during the period of 15 years time. Research limitations/implications The population growth and future per capita waste generation rate are based on census report of Govt of India and survey report of World Bank, respectively. Separate collection of bio-degradable portion of MSW has not yet been developed properly in India. Practical implications This study reveals that in India, the high-moisture-content, low-calorific-value bio-degradable waste in India can be used for the generation of substantial amount of green energy in India, which in addition to financial gains would reduce the waste quantity at landfill site, conserve natural resources, save land, reduce green house gas emission, generate employment and help to protect environment. Considering these benefits and advantages, evaluated in this study, policy makers and city managers may review their approaches toward solid waste management system of their cities to meet the challenges of huge increase of MSW in the years to come in India. More research works may be initiated to improve the AD system of organic waste, and more capital may be employed in waste management business in India. Originality/value Numbers of research works have been carried out by other researchers for estimation of energy generation potential through AD of OFMSW for different countries; but no such work could be found to identify such potential and its benefits in India. This research work demonstrates how MSW can be used as a wealth for green energy production in India. The originality of this paper is the analysis of green energy generation potential from the low calorific value MSW in India.

Modeling chemical compositions of municipal solid waste

The objective of the paper is to develop a mathematical model to compute the chemical compositions of the organic portion of municipal solid waste (MSW) using proximate analysis data. The validation of the developed models were done using test of hypothesis and field samples. In the study, MSW samples were collected from 23 different locations throughout the year and chemical compositions of the organic matter were determined such as carbon, hydrogen, oxygen, nitrogen and sulfur using elemental analyser. Proximate analysis such as combustible volatile matter (VM) and ash content were also measured for all the sites. The range of variation in the chemical compositions and proximate analysis were observed as 5·2% ≤ carbon ≤ 21·2%, 0·64% ≤ hydrogen ≤ 2·7%, 17·2% ≤ oxygen ≤ 67·6%, 0·3% ≤ nitrogen ≤ 1·1%, 0·1% ≤ sulfur ≤ 0·37%, 9·3% ≤ VM ≤ 35·5%, 18·6% ≤ ash ≤ 72·1% on dry basis. Various statistical analyses such as standard deviation, mean, P value and F value were also carried out in the study.

Characterisation of chemical composition and energy content of green waste and municipal solid waste from Greater Brisbane, Australia

The development and deployment of thermochemical waste-to-energy systems requires an understanding of the fundamental characteristics of waste streams. Despite Australia’s growing interest in gasification of waste streams, no data are available on their thermochemical properties. This work presents, for the first time, a characterisation of green waste and municipal solid waste in terms of chemistry and energy content. The study took place in Brisbane, the capital city of Queensland. The municipal solid waste was hand-sorted and classified into ten groups, including non-combustibles. The chemical properties of the combustible portion of municipal solid waste were measured directly and compared with calculations made based on their weight ratios in the overall municipal solid waste. The results obtained from both methods were in good agreement.The moisture content of green waste ranged from 29% to 46%. This variability – and the tendency for soil material to contaminate the samples – was the main contributor to the variation of samples’ energy content, which ranged between 7.8 and 10.7MJ/kg. The total moisture content of food wastes and garden wastes was as high as 70% and 60%, respectively, while the total moisture content of non-packaging plastics was as low as 2.2%. The overall energy content (lower heating value on a wet basis, LHVwb) of the municipal solid waste was 7.9MJ/kg, which is well above the World Bank-recommended value for utilisation in thermochemical conversion processes.