Quality Of Municipal Solid Waste Compost Research Articles

Factors influencing utilization of municipal solid waste compost among urban farmers in western Uganda

BackgroundEffective management of solid waste is one of the most serious environmental problems confronting urban governments in developing countries due to insufficient financial resources and institutional capacity to provide basic solid waste management infrastructure, impoverished urban populations, low rates and coverage of collection, and rising food consumption rates. Composting has been touted as the most economical solution for reducing organic fraction of urban waste volumes while releasing vital nutrients for the soils. However, there is a paucity of information on utilization and associated factors of urban wastes in Uganda. This study aims to assess the level of utilization of Municipal Solid Waste (MSW) compost produced from Clean Development Mechanism (CDM) plants and associated factors among farmers in Fort Portal and Mbarara Municipalities, western Uganda.MethodsData was collected using a cross-sectional survey from 359 and 361 randomly selected farmers in Mbarara and Fort Portal, respectively. A semi-structured questionnaire was employed to collect quantitative data and analyzed statistically using SPSS and STATA statistical programs. Probit model was used to determine factors that influence farmers’ decisions to utilize MSW compost as a soil conditioner.ResultsThe findings revealed a very low level of utilization in both municipalities, 1.7% in Fort Portal and 2.2% in Mbarara. The results indicated that annual farm income, access to other soil conditioners, experience with the use of fertilizers, membership to a farmers’ group and the cost of MSW compost significantly influenced farmers’ decision to use MSW compost.ConclusionsThe findings call for government investment in policies aimed at increasing the level of utilization of the MSW compost by improving accessibility to soil conditioners, creating opportunities for maximizing household incomes, farmer-to-farmer experience sharing, dissemination of information through extension programmes and other innovative communication approaches, operationalization of farmers’ groups and introduction of subsidy schemes on the price of compost through operational tax waivers in urban areas of Uganda. Finally, to guarantee quality and to improve the adoption of compost generated at the CDM plants, there is a need for research to assess the quality of MSW compost, undertake a supply chain analysis and cost–benefit study and set a price commensurate with the quality, and develop guidelines and rates of application of the MSW compost.

Aerobic Municipal Solid Waste Compost Quality According to Different Layers of Composting Bioreactor

Composting is one of the methods of solid waste management (SWM) where the organic component of solid waste stream is biologically decomposed under controlled conditions. A bioreactor tank was designed to contain 59.2 kg of mixed organic municipal solid waste, the organic matter was degraded under aerobic condition for 30 days. The tank was 45 cm in diameter, 130 cm total height and a 0.2 cm wall thickness. Three circular openings with screwed cover having diameter of 12 cm were leveled at (20, 40 and 80) cm respectively to withdraw samples. Temperature, moisture and pH were measured for three layers as process guideline indicators. Maximum temperature ranged between (34.79 to 46.91) ºC. Initial pH value was 6.53, ended within a range of (7.4 to 7.44). Chemical analysis for the composts in the three levels proved that the final C/N ratio ranged between (13.8 to16.1), TOC ended within a range of (17.33% to 25.24 %), final nitrification index (N-NH4/N-NO3) ranged between (0.22 to0.31), final of P% ranged between (0.89% to 1.23%), final of K% ranged between (1.69% to 1.81%) and results of germination index (GI %) ranged between (76.54%, to 88.35%) for three layers respectively. At the close of the experiment results proved that aerobic in-vessel composting could reduce the large amounts of wastes by 40% as a total mass. A satisfactory degree of decomposition was apparent in all levels, and the material was characterized by a pleasant earthy odor, and the obtained compost can be classified as mature compost. In conclusion, the three different layers do not have much effect on the quality indices of the final product.

An assessment of municipal solid waste compost quality produced in different cities of India in the perspective of developing quality control indices

A study was conducted to investigate physico-chemical properties, fertilizing potential and heavy metal polluting potentials of municipal solid waste composts produced in 29 cities of the country. Results indicated that except a very few samples, all other samples have normal pH and EC. Organic matter as well as major nutrients N and P contents in MSW composts are generally low as compared to the composts prepared from rural wastes. Heavy metal contents in composts from bigger cities (>1 million population) were higher by about 86% for Zn, 155% for Cu, 194% for Cd, 105% for Pb, 43% for Ni and 132% for Cr as compared to those from smaller cities (<1 million population). Composts prepared from source separated biogenos wastes contained, on average, higher organic matter (by 57%), total N (by 77%) and total P (by 78%), but lower concentrations of heavy metals Zn (by 63%), Cu (by 78%), Cd (by 64%), Pb (by 84%), Ni (by 50%), and Cr (by 63%) as compared to those prepared from mixed wastes. Partial segregation at the site of composting did not improve quality of compost significantly in terms of fertilizing parameters and heavy metal contents. Majority of MSW composts did not conform to the quality control guideline of ‘The Fertilizer (Control) Order 1985’ in respect of total organic C, total P, total K as well as heavy metals Cu, Pb and Cr. In order to enable the relevant stakeholders to judge overall quality, a scheme has been proposed for the categorization of composts into different marketable classes (A, B, C, and D) and restricted use classes (RU-1, RU-2, and RU-3) on the basis their fertilizing potential and as well as potential for contaminating soil and food chain. Under the scheme, ‘Fertilizing index’ was calculated from the values of total organic C, N, P, K, C/N ratio and stability parameter, and ‘Clean index’ was calculated from the contents of heavy metals, taking the relative importance of each of the parameters into consideration. As per the scheme, majority of the compost samples did not belong to any classes and hence, have been found unsuitable for any kind of use. As per the regulatory limits of different countries, very few compost samples (prepared from source separated biogenos wastes) were found in marketable classes (A, B, C and D) and some samples (11–14) were found suitable only for some restricted use.

Residues of organochlorine pesticides and PCBs in some Brazilian municipal solid waste compost

Persistent organic pollutants (POPs), organochlorine pesticides and polychlorinated biphenyls (PCBs), listed as per the Stockholm Convention (α -HCH, β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, p,p′-DDE, aldrin, endrin, dieldrin, PCBs 28, 52, 118, 138, 153, and 180), were analyzed in municipal solid waste (MSW) compost samples from three different Brazilian composting plants located in three São Paulo State cities: Araras, Araraquara and São Paulo (Vila Leopoldinha). Quantitative and qualitative analyses were carried out using gas chromatography electron capture detection (GC-ECD) and gas chromatography mass spectrometry (GC-MS) (Ion Trap, electron impact ionization), respectively. The samples were analyzed in triplicate and the target POPs were not detected by GC-ECD. Twelve pollutants were identified in two samples when qualitative analysis (GC-MS) was used (β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, and p,p′-DDE, PCBs 28, 118, 138, 153 and 180). The composting process has advantages such as urban solid waste reduction and landfill life-span increase, however the MSW compost quality, which can be utilized for agricultural purposes, should be evaluated and be controlled. This kind of study is the first step in making available information to answer questions regarding MSW compost for sustainable agricultural use, such as the pollutants accumulation in soil and in groundwater, and plants uptake.

Assessment of municipal solid waste compost quality using standardized methods before preparation of plant growth media

The quality of compost and its suitability for agricultural application depend upon physical and chemical parameters such as water-holding capacity, porosity, pH, electrical conductivity, C/N ratio, available nutrients and the absence of toxic substances. In the present study a complete characterization of an industrial municipal solid waste compost (MSWC) based on standardized European methods (CEN) for soil improvers and growing media was obtained, and compared with the quality of other Spanish composted biowaste and conventional substrates such as peat and pine bark. The MSWC was obtained from the main composting plant in Galicia (Spain), which processes organic waste that has been separated at origin and collected from more than 100 000 inhabitants. The MSWC presented a lower C/N ratio (15) than peat (84) and composted pine bark (CPB) (211), but had a similar ratio to other marketed MSWC. The nutrients and heavy metals were extracted using different recommended solvents (water, CaCl2 + diethylen triamin pentaacetic acid, and aqua regia). The nutrient concentrations of composted urban waste or manure were much higher than those of peat, CPB or pine bark. On the basis of the results of the plant tolerance test, the MSWC could be employed directly as a soil improver, but would need to be diluted with other low-salt components such as peat or CPB before being used as a growing media.