破碎厨余垃圾对公共排水系统的影响

Influence of Crushed Kitchen Waste on Public Drainage System

为探究破碎厨余垃圾对公共排水系统的影响,对我国厨余垃圾排水水质、污水管道设计、化粪池设计及维护开展了调查研究。厨余垃圾的COD∶TN∶TP=174.2∶5.7∶1,具备缓解污水处理厂碳源紧张的基础。破碎厨余垃圾排放至下水道后,管道末端污水的COD、TN和TP浓度分别为413.0、64.55和8.13 mg/L,化粪池出口污水的COD、TN和TP浓度分别为300.4、54.53和4.33 mg/L。破碎后的厨余垃圾颗粒直径在1.5~6.4 mm之间,在管道内的起动临界流速为0.014~0.037 m/s,远小于0.6 m/s,故因厨余垃圾处理器造成下水道堵塞的可能性较小。厨余垃圾处理器的应用会使化粪池的设计容积增加20.9%,同时可使清掏周期最大缩短68 d。

The water quality, sewage sewer design, septic tank design and maintenance of kitchen waste drainage in China were investigated to explore the influences of crushed kitchen waste on public drainage system. The ratio of COD, TN and TP in kitchen waste was 174.2∶5.7∶1, which had the potential to alleviate the shortage of carbon source in sewage treatment plants. After the crushed kitchen waste was discharged into the sewer, the COD, TN and TP in the sewage at the end of the sewer were 413.0 mg/L,64.55 mg/L and 8.13 mg/L, respectively, and those in the sewage at the outlet of the septic tank were 300.4 mg/L, 54.53 mg/L and 4.33 mg/L, respectively. The diameter of crushed kitchen waste particles was between 1.5 mm and 6.4 mm, and the starting critical velocity in the sewer was between 0.014 m/s and 0.037 m/s, which was much less than 0.6 m/s. Therefore, the possibility of sewer blockage caused by kitchen waste disposal was small. The application of kitchen waste disposal increased the design volume of septic tank by 20.9%, and shortened the cleaning cycle by the maximum of 68 days.