Organic Waste Recycling

124 Organic waste recycling: technology and management

General description Raw sewage sludge (22% solids) is mixed with wood chips, and then transferred to a composting pad consisting of wood chips spread over perforated piping. Air is drawn through the pipe into a compost filter. The pile is maintained for 21 days followed by The nightsoil is mixed with paper and wood chips on a concrete pad and then transferred to the composting pad, which is a bed ofwood chips covering a perforated pipe. Air is drawn through the pipe into a compost filter. The pile is maintained for 21 days at Experiment. Nightsoil, water hyacinth, and (in some cases) rice straw were mixed and composted in piles for 2-3 months. Aeration through perforated bamboo poles. Temperatures of 43- 64

°C were maintained for at least 8 da

ys in the coolest

parts of the

Trench in ground, 2-3 ft deep. Material placed in alternate layers of refuse, nightsoil, earth, straw, etc. No grinding. Turned by hand as often as possible. Detention time of 120-180 days. Used extensively in India The sludge (30% solids) and sawdust are mixed at weight ratios 4:1. The windrows are turned for 3 months and then sold as a product “Grow Rich”. The maximum temperature achieved is 74

°C

Raw material Sewage sludge and wood chips Nightsoil, paper, wood chips Water hyacinth, nightsoil, rice straw Refuse, nightsoil, earth, straw, etc. Sewage sludge and sawdust

Table 3.3 Non-reactor composting systems Composting system Aerated static pile Bangalore (Indore) Windrow