a mechanical filtering system to treat pig slurry is proposed the filter was made from the aerobic decomposition product of the organic fraction of municipal wastes and wheat straw was used as the support. using a pilot plant to treat 2100 liters of swine slurry, an adequate reduction in bod//5; cod, and other parameters was obtained the organic matter content of the material trapped in the filter was similar to that of compost and farmyard manure, but the nitrogen and phosphorous levels and the c/n ratio were more similar to farmyard manure. after passing through a filtering system, the treated liquid can be used for fertirrigation and as a feed for algae in fish ponds after a period of stabilization, the solid material can be mixed to produce manure. other agricultural wastes such as rice straw, corn stalks, millet stems, banana, cotton, and coconut trash can also be used as support. rather than municipal solid waste compost, other kinds of compost obtained from agricultural wastes such as leaves, bark, husks, etc., can be used as the filter. (edited author abstract) 10 refs