Co-composting faecal sludge and food waste (Nepal)

Co-composting is the controlled aerobic decomposition of organics utilizing multiple feedstock’s (faecal sludge and organic solid waste), which allow the recycling of nutrients into agriculture thereby closing the nutrient loop. This study was carried out with the purpose of analysing the quality of compost produced by co-composting faecal sludge and food waste with sawdust as an additive at the Kathmandu University. A total of 90 days of composting period was considered for maturation and temperature, moisture, pH, C:N ratio, nitrogen, phosphorus and potassium values were measured. Results indicated that for both the co-composts pH fluctuated in the range of 4.0–7.0 and stabilized to near neutral on the 90th day, the humidity was between 19 to 75%, the temperature of bed was in the range of 12–47°C. The final value of fertilizer from both composts was within the range of Soil Resource and Development Institute (SRDI) standard. However, the fertilizer from co-compost made Dewatered Faecal Sludge and Food Waste (DFSFW)+ Sawdust (SD) showed the higher quality because of N, P, K and C:N value of 1.7%, 0.7%, 0.6% and 12.6% respectively. Similarly, the final mass retained from co-compost Dewatered Faecal Sludge (DFS)+ Sawdust (SD) was 5.7 kg whereas mass retained from co-compost DFSFW+SD was 6.9 kg using the same mass of 15 kg raw materials indicate the higher efficiency of co-composting. Results indicated that co-composting is more effective in converting the mass of food waste and dewatered faecal sludge into quality compost than dewatered faecal sludge.