Effect of the sewage as a cool and heat source on wastewater biological treatment in cold area

It's important to exploit and utilize the sewage as cool and heat source for energy saving and environmental protection, but we need to think of how great the effect on wastewater biological treatment is in cold area. Based on two typical engineerings which were operating in practice, the article analysed the temperature distribution of sewage system and demonstrated the adjustable characteristic of the ground in nearby sewage trench to water temperature. Furthermore, the study discussed the effect of the sewage as cool and heat source on wastewater biological treatment. The investigation reveals that the ground has the adjustable effect on the waster-water temperature in sewage trench. If the temperature of the used wastewater is not below 8°C, the sewage as cool and heat source has no effect on the inflow temperature of wastewater treatment plant. The water temperature of aeration tank is about 5-7°C, the efficiency of active sludge biological sewage treatment is born by cold-adapted microorganisms, utilizating 2-3°C wasterwater heat energy has no effect on wasterwater biological treatment, all the water temperature is within activity temperaturescope.