Composting of selected organic wastes from peri-urban areas of Harare, Zimbabwe

سال انتشار: 1392
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 327

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شناسه ملی سند علمی:

JR_ROWA-2-1_014

تاریخ نمایه سازی: 4 خرداد 1395

چکیده مقاله:

Background: The composting process of peri-urban household wastes, changes that occur during composting,and the properties of the composting products that are of importance for use as soil amendments were studied.Seven different composting mixtures were made in large piles consisting of fallen tree leaves and fresh vegetableleaves mixed with grass or maize straw (0%, 10%, 30% and 50% w/w), wastes common in peri-urban areasof Harare.Results: The highest temperature peaks of the mixtures with 0% and 10% straw were in the range of 68°C to72°C. Mixtures with 30% straw had temperature peaks of 50°C (maize) and 52°C (grass). The mixture with 50% grassstraw reached a peak of 50°C, while the corresponding mixture with maize straw did not reach thermophilictemperatures. pH ranged from between 6.2 and 6.8 before composting to between 7.4 and 7.8 after composting.The ammonium concentration peaked at various times but declined to negligible concentrations at day 140. Theconcentration of nitrates increased with composting up to day 97 and decreased gradually thereafter. There was ageneral increase in nitrogen concentration from 0.9% to 2.3% as composting progressed. Decreases in organic C%and C/N ratio with composting were also observed, signifying mass loss.Conclusion: The results of this study indicated that household wastes with 50% straw or less can be compostedbut with measures being taken to achieve temperatures greater than 55°C for at least 3 days to destroy weedseeds and pathogens. The composts with 30% straw mixture had the greatest potential as a soil amendment inperi-urban areas of Harare as they effectively reduced nitrogen losses.

نویسندگان

Menas Wuta

Marondera College of Agricultural Science and Technology, University of Zimbabwe, P.O. Box 35, Marondera, Zimbabwe- Department of Soil Science and Agricultural Engineering, P.O. Box MP167,Mount Pleasant, Harare, Zimbabwe