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Tropentag, September 17 - 19, 2018 in Ghent

"Global food security and food safety: The role of universities"

Soil Rehabilitation Potential of Co-Compost Pellets Made from Municipal Solid Waste and Dewatered Faecal Sludge as Feedstock

AWS Pushpa Kumara1, Felix Thiel2, Jayantha Weerakkody1, Bandula Ranaweera1

1Wayamba University of Sri Lanka, Fac. of Agriculture and Plantation Management, Sri Lanka
2Ruhr University Bochum / International Water Management Institute, Inst. of Geography / Rural Urban Linkages, Germany


Solid waste management challenges are felt most keenly in the developing countries as a major consequence of development and modernisation. Sri Lanka as a developing country faces severe issues in managing the daily generated liquid and solid waste. Organic fractions of these waste takes a higher percentage. The organic portions of municipal solid waste (MSW) and co-composting of dewatered faecal sludge (DFS) is a feasible low-cost technology which enhances sanitation and waste management. The aim of this research was to evaluate the effect of MSW and DFS co-compost pellets produced with the addition of mineral fertiliser and biochar on soil chemical and biological properties. Trapezoidal windrow type co-compost piles were prepared with 18m3 volume and 70% MSW and 30% DFS. Temperature measurements, watering and turning were done as necessary. Weekly samples were collected for chemical analysis. Resulted co-compost was mechanically pelletized using biochar and mineral fertiliser as additives and used in maize cultivation.
The experiment was arranged as randomised complete block design using 7 treatments. Soil samples were collected from 30cm and 60cm depths to evaluate chemical and biological properties. There was a significant increase in pH values between control treatment (mineral fertiliser) and MWS-DFS co-compost treatments. The treatment with DFS-MSW-Biochar had the highest EC and organic carbon value suggesting that biochar has the ability to increase EC in soil and act as a carbon sequester. MSW-DFS co-compost treatments had the highest phosphorous and potassium values. Soil microbial activity was not significantly changed with the application of co-compost. Further, temperature changes during the co-composting process, was different from normal composting process, which may be resulted in a variation in feedstock characters. These results conclude that co-compost help to improve soil pH, EC, organic carbon, phosphorous and potassium with compared to the mineral fertiliser application. Hence, co-compost produced from MSW and DFS can potentially be used in soil rehabilitation while co-compost enriched with biochar act as a soil amendment.

Keywords: Biochar, co-compost, dewatered faecal sludge, municipal solid waste

Contact Address: Felix Thiel, Ruhr University Bochum / International Water Management Institute, Inst. of Geography / Rural Urban Linkages, Universitäts str 150, 11222 Bochum, Germany, e-mail: leifgrau@gmail.com

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