Solving overflow pollution of sewage plant in Flood season: A sewage treatment plant in Naxi District, Luzhou, Sichuan Province

  Application background:  

A sewage treatment plant in Naxi District of Luzhou, Sichuan Province has a total design scale of 20,000 m³/d, and the water volume exceeds 30,000 m³/d in rainy season, resulting in overflow pollution.

  Solution:  

The original sewage treatment process remains unchanged. According to the current situation of low influent concentration in rainy season, the load redundancy of biochemical system and NFSSS flocculant are used to accelerate the sludge settling speed to realize the overflow sewage control of sewage interception pipe network in sewage plant. When the water quantity increases in rainy season, an appropriate amount of NFSSS nano-flocculant is added to the inlet end of secondary sedimentation tank to realize the rapid separation of mud and water in secondary sedimentation tank and ensure the clarification of effluent. At the same time, the sludge is intercepted to the biochemical system to ensure the treatment effect of the biochemical system and achieve the overflow sewage discharge standard in the rainy season.

  Effect display:  

Through the above scheme, the water treated in rainy season can reach 28,000 to 30,000 m³/d, and the highest instantaneous water can reach 32,000 m³/d, increasing the treatment capacity by 1.6 times. The effluent from the secondary sedimentation tank is clarified, and the effluent continues to reach the standard. The performance of sludge settling was improved by the addition of reagent, and the effluent indexes were improved significantly.

Change map of sediment level and water intake in settling tank

                                                Before dosing                                                               After dosing