The Study On Residual Sludge Treatment Of Hydrothermal Sequence Batch/EGSB/Magnesium Ammonium Phosphate Process

The treating rate of wastewater is high and sludge production is high but the harmless dispose rate is low and secondary pollution is serious around Taihu Lake. To realize harmless of residual sludge disposal, the combination of Hydrothermal sequence batch process (HSBP)+EGSB+ammonia phosphate magnesium (MAP) was studied. And resources was recycled in sludge to reduce the cost and it offered an example for the sludge treatment. This paper studied residual sludge of sewage treatment plant in a city, the combination of Hydrothermal sequence batch process (HSBP)+EGSB+ammonia phosphate magnesium (MAP) was used to dispose the residual sludge. The operation condition of the combination process and was studied in this paper.The results show that:1,Moisture content of residual sludge was more than 80% after dewatering by belt type filter press. And the dewatering performance was improved obviously and moisture content was less than 50%.And the total residual sludge reduced more than 60%.2,Sludge feeding and hydrothermal sludge heat were the key problems and braising technology was used in hydrothermal system and it saved energy more than 50%.3,EGSB was used to dispose hydrothermal mud leachate with high concentration of CODcr. Granular sludge was inoculated to the reactor and strains just needed 25 days to finish domestication under test conditions. When the system runs steadily, the flow rate was 3 m/h and organic load was 10kgCODcr/(m3.d),and CODcr remove rate reached 80% and methanogenic activity was 250L/h until 75days.4,MAP was used to remove NH3-N in order to recycle the sludge resources and reduce the cost. The remove rate of NH3-N in supernatant fluid of hydrothermal mud was 91% and the effluent NH3-N consistence was less than 180 mg/L and it has wide practicability because of its economy. 5,The total investment was 0.995 million and the operating cost was 133 yuan/m3 residual sludge without the equipment depreciation. Sludge was disposed effectively and it produced good environmental benefits too.