Organic Waste Recycling

Composting 127

General description Reactor is of the complete-mix, rotating drum type. The sludge and recycled compost are added to a slowly rotating drum (which is stopped at night). The retention time is 24 h followed by a 2-week maturation period in a windrow. Tem

peratures of 60-75

°C are attained

Reactor consists of cylindrical tower with no interior floors or other mechanisms. Feed is introduced at the top and flows downward as product is removed by mechanical scraper from the bottom. Oxygen is supplied by forced aeration from the bottom. Residence times of 3-14 days. Temperatures of 60-85

°C are achieved. Then the raw compost is

matured for 6-8 weeks in a windrow Rectangular tanks, 20 ft wide, 10 ft deep, 200-400 ft long. Refuse is ground. Residence time of about 7 days. “Agiloader” moves on rails mounted on bin walls and provides periodic agitation by turning Five 9-ft wide steel conveyor belts are arranged to pass material from belt to belt. Each belt is an insulated cell. Air passes upward through digester. Detention time of 6-8 days. Dewatered digested sewage sludge was mixed with bark (1:3) and composted in large baskets that could be easily stacked. Temperatures o

f

up to 75

°C were attained. The retention time in the baskets was 9-12

weeks followed by 3-4 weeks maturation in piles

Raw material Sewage sludge and recycled compost Sludge, mushroom wastes, poultry wastes, organic bulking agents Municipal refuse, animal manure, sludge Municipal refuse Digested sewage sludge and bark

Table 3.4 Reactor composting systems (continued) Composting system HKS Kneer (Later version known as BAV) Metrowaste Naturizer (International) Open baskets