A Novel Model With Incremental Treatment Capacity Sewage Sludge Treated By Bioleaching And A Biotechnology Treating Food Waste By Maggot

At present,the dewatered sludge with moisture content of 80%or above generated annually exceeded 3.8×107 t in China.Moreover,sludge amount every year increase at the rate of of 10%?15%.Reduction,harmlessness,and recycling of sewage sludge are urgent for its treatment and disposal.For this sake,to achieve high dryness of dewatered sludge cake with moisture content 60%or below has become the key problem needed to be solved.Bioleaching has been developed as an attractive method to remove heavy metals,kill pathogens,and eliminate offensive odour derived from sludge.In addition,previous experiments had confirmed that sludge dewaterability could be drastically improved after bioleaching,and the moisture content of the bioleached sludge cake could be reduced to below 60%by chamber filter press.As a result,the bioleached sludge cake is easy to be crushed and composted.Since 2010,the traditional bioleaching process can treat 100 m³ of concentrated sludge a day in Wuxi Taihu Xincheng Wastewater Treatment Plant.However,limited information on how to increase sludge treatment capacity on the basis of the existing equipments is available.Therefore,we expected to increase sludge treatment capacity by bioleaching approaches coupled with physico-chemical methods to stmegthen dehydration of sludge.The results showed that the dewaterability of municipal sewage sludge could be markedly enhanced after bioleaching treatment.On the basis of the original process through the improvement of production process,filling 25 m³ bioleached sludge and nutritional enriching agents?0.45%of the raw sludge?into 45 m³ raw sludge,reaction time was 2-3h,then added activating agent?0.23%of the raw sludge?.The specific resistance to filtration?SRF?of bioleached sludge was decreased to 0.56×10¹² m/kg from initial 33.2×10¹² m/kg,indicating that sludge dewaterability was drastically increased facilitated by bioleaching.Consequently,the bioleached sludge was dewatered easily into bioleached sludge cake with lower moisture of 60%or below by diaphragm chamber pressure filter without adding any chemical flocculants.In addition,it was also noted that the filtrate of bioleached sludge from the diaphragm chamber pressure filter with COD?200 mg/L,Total N?80 mg/L,Total P?0.5 mg/L could be discharged directly into Sewage Treatment Plant without adverse effect.The new process can deal with about 300 m³ sewage sludge every day.On the other hands,the discharge of food waste is increasing in China with the improvement of people's living standard.At present,most of food waste are disposed illegeally.Conventional treatment methods of food waste is to collect and to separate into oil,liquid phase and solid residu.The oil phase is used to refine biodiesel.Wastewater would be treated through anaerobic digestion system.Solid residue of the food waste would be treated by sanitary landfill,incineration,compost and so on.To recyle solid residue of food waste with high economic benefit,we developed a novel biotechnology to treat it by housefly larvae?maggot?.Moreover,a pilot study with the complete set of equipments is performed and produce satisfactory effectiveness.The food waste can be reduced more then 75%with maggot and the residuum is odorless and fluffy texture.The Nutrients and harmful substances of residuum can meet the national standards of "organic fertilizer?NY525-2012?,so it can be translate into biological organic fertilizer,1 t food waste can generate about 0,2 t maggot,the maggot has a very high economic value.The food waste can be utilized fully by maggot and does not produce secondary pollution,which has good environmental benefits and high economic benefit.