NOVELTY - Polyacrylamide degradation and dehydration in sludge involves making backflow material by adding sawdust or straw exogenous additives. Aerobic fermentation is processed for 12-15 days, where last batch compost sludge is used as backflow material and the obtained backflow material is used as the additive for next compost. Water ratio of backflow material is 40-50%, where proportion of sludge and backflow material is regulated. The dehydrated sludge is mixed with the obtained backflow material, where initial water ratio of dehydrated sludge and backflow material is controlled to 50-65%.    USE - Method for degrading and dehydrating polyacrylamide in sludge (claimed).    ADVANTAGE - The polyacrylamide degrading and dehydrating method enables to reduce water ratio of compost product and can inoculate microorganism, which can degrade polyacrylamide for subsequent dehydrated sludge compost reaction as backflow material.    DETAILED DESCRIPTION - Polyacrylamide degradation and dehydration in sludge involves making backflow material by adding sawdust or straw exogenous additives. Aerobic fermentation is processed for 12-15 days, where last batch compost sludge is used as backflow material and the obtained backflow material is used as the additive for next compost. Water ratio of backflow material is 40-50%, where proportion of sludge and backflow material is regulated. The dehydrated sludge is mixed with the obtained backflow material, where initial water ratio of dehydrated sludge and backflow material is controlled to 50-65%. Aerobic fermentation is processed by placing the mixture in a sludge compost device under continuous ventilated condition with air volume of 0.05-0.10m3/(m3.minute), where carbon and nitrogen ratio is regulated. Variation condition of polyacrylamide in sludge is periodically detected in 12-15 days of composting period. Polyacrylamide is extracted and detected in dehydrated sludge, where obtained compost sample is dissolved in water and then oscillated for 1.8-2 hours with oscillating swing bed to disperse sludge uniformly in water. The mixture is stirred for 8-12 minutes with magnetic stirrer and then centrifuged for 10-20 minutes at 3500-4500 revolutions per minute. The liquid supernatant is tested, where polyacrylamide is extracted from sample with distilled water for multiple times. Content of sample is measured at wavelength of 580 nu m with starch-iodinated cadmium spectro-photometric method.