Properties of dewatered sludge thermal conditioning
脱水污泥热调质的特性

Thermal conditioning is one of the effective methods to improve the sludge deep dewaterability.Results show that compared to stirring speed,reaction temperature and time have more influences on sludge thermal conditioning.As the reaction temperature rose from 160 ℃ to 180 ℃,reaction time increased from 45 min to 60 min,the volatile suspended solids(VSS) dissolve quickly and release the cells’ bound moisture,showing that the main conditions of broking sludge cells’ wall are that reaction temperature is 160~180 ℃,reaction time is 45~60 min.The specific resistance of sludge has a great change after thermal conditioning.With the increasing of reaction temperature,specific resistance to pressure filtrate decreases continuously and the dewaterability of sludge becomes better and better.The experimental results show that the conditions of thermal conditioning which reaction temperature is 180 ℃,reaction time is 60 min,stirring speed is 30 r/min,are the best and the water content of filter cake is about 50% in this case after filter press.Under the best reaction conditions,there are more organic matters dissolving in the filtrate causing the COD concentration reaching 19 000 mg/L.Especially it is good for the anaerobic digestion for the sludge.