جستجوی مقالات مرتبط با کلیدواژه "composting" در نشریات گروه "پزشکی"

Life cycle assessment (LCA) is a vital tool for evaluating the environmental burden of solid waste. This study investigated the outcomes of selected studies that applied the LCA methodology in assessing the environmental consequences of solid waste management (SWM) systems in Africa. Thirteen process-based LCA studies on SWM were reviewed, drawing from established criteria in databases such as SCOPUS, Elsevier, and Google Scholar. These studies were distributed across various African countries, with three conducted in Mauritius and Nigeria each, two in Zimbabwe and South Africa each, and one in Tanzania, Ghana, and Uganda, respectively. The evaluated parameters included aspects such as goal and scope, functional unit, system boundary, impact assessment categories, and sensitivity analysis. The findings revealed that majority of the studies employed similar waste management scenarios to determine the most environment-friendly, yet they differed considerably in some parameters. Climate change and global warming were the most assessed impact categories. Municipal solid waste (MSW) and plastic waste were the leading waste categories. MSW typically comprises paper, bottles, metal, plastics, glass, organics, and mixed waste proportions. The study also stated that the lack of reliable data on solid waste was a significant challenge faced by African countries in LCA studies. The paper’s findings highlighted that a significant number of the studies, particularly in Nigeria, did not incorporate sensitivity analysis into their assessments, a crucial component for result interpretation. Consequently, the study emphasizes the importance of conducting more LCA research studies in African countries to produce pertinent data on SWM.

 Although vermicomposting is rich in nutrients, the virulent microbes and pathogens present in it may be a threat to human health and the environment. Therefore, the objective of this study is to investigate the microbial quality of produced vermicompost, including fecal coliform and parasitic eggs, at a pilot scale, and compare it to present standards. 

 Three various reactors containing decomposable domestic waste (T1), cow manure (T2), and dewatered sludge (T3) were used to produce vermicompost using Eisenia fetida. According to the standard methods, fecal coliforms, parasitic eggs, and some of the treatment characteristics including organic carbons, nitrogen, temperature, humidity, pH, electrical conductivity and metals were evaluated during the 56-day operation period. 

 According to the results, the number of fecal coliforms in treatments of T1, T2 and T3 reduced from 2.5 × 104, 6 × 105 and 15 × 106 to 1000, 1500 and 1500 MPN/g dw, respectively. All parasite eggs reached zero after the 3rd week. At the end of the study, the average of organic carbon in T1, T2, and T3 were 35.4 ± 6%, 50.7 ± 5%, and 58.4 ± 7%, respectively. This value for total nitrogen were 0.9 ± 0.2%, 1.8 ± 0.7%, and 4.2 ± 1.2%, respectively. 

 Results showed that the worm E. fetida has a great ability to reduce pathogens without the need for an increase in temperature. Furthermore, it can be concluded that vermicompost can improve the quality of compost in 8 weeks. The vermicomposting process can also greatly destroy the fecal coliforms and all parasite eggs.

 The present study was carried out to evaluate the production of eco-friendly and environmentally bio-fertilizer from a mixture of food waste (FW) and rice bran (RB). 

 The various mixtures of RB and FW (1:1, 1:2, 1:3, and 1:5) were prepared and spread in Diy beds for 20 days. After that, the raw compost was poured in four containers beds contains 100 adult earthworms Eisenia foetida for 30 days. Physical and chemical parameters including temperature, humidity, carbon to nitrogen (C/N) ratio, and pH were monitored. 

 The obtained results showed that at the first of composting process, the temperature was sharply increased and after that dropped and reached to the ambient temperature. The C/N ratio was decreased in studied Diy beds during preparing and vermicompost processes. The averages of C/N ratios in the raw FW and RB at mixing ratios of 1:1, 1:2, 1:3, and 1:5 were 45.35, 38.43, 35.3, and 32.11, respectively. The C/N ratios in the vermicompost were reduced to 20.85, 18.3, 16.86, and 15.16, respectively. 

 The results of this study showed that composting and vermicomposting process can be used as a potential tool for bio convert rice bran and food waste. However, it is suggested that the rice bran can be amended with food waste to ensure better quality of vermicompost.