Organic Waste Recycling

126 Organic waste recycling: technology and management

General description Dispersed flow rotating drum, slightly inclined from the horizontal, 9-12 ft in diameter, up to 150 ft long. Drum kept about half full of reuse. Drum rotation of 0.1-1.0 rpm, 1-5 days digestion followed by windrowing. No grinding. Forced aer

ation into drum. Temperatures of

60

°C or over are reached

Reactor is of the tower type with a special extraction and agitation mechanism at the bo

ttom. The reactor

is batch-ope

rated. Once the

reactor is loaded with the mixture of the sludge and agitation and assureuniform exposure to temperature. Residence time is 4-6 days. Circular tank. Vertical screws, mounted on two rotating radial arms,keep ground material agitated. Forced aeration through tank bottom and holes in screws. Continuous flow type. Dewatered sewage sludge is mixed with shredded paper and fed in

to a reactor. The retention time is

5-7 da

ys and tem

perature is over 60

°C are reached

The sewage sludge and recycled compost are mixed and ground and fed into the fermenter, where the mixture is aerated and turned. The retention time is 10 days and temperatures of up to 75

°C are attained.

The compost is then graded and bagged Cells-in-series type. Unground refuse placed in rotating drum, 11 ft diameter, 110 ft long, slightly inclined from horizontal. Threecompartments in drum. Refuse transferred to next compartment every 1-2 days for total digestion time of 3-6 days. Screened output cured in piles

Raw material Municipal solid wastes, sludge Dewatered sludge and recycled compost Sewage sludge and shredded paper, municipal refuse Dewatered sewage sludge and recycled compost Municipal refuse, sludge

Table 3.4 Reactor composting systems Composting system Dano Euramca (Roediger, Fermen-technik) Fairfield digester reactor Forced aeration through fermenter Geochemical-Eweson