Research On The Technology Retrofit Of A Chemical Industry Park Wastewater Treatment Station In Beijing

Beijing Chemical Industry Group had a wastewater treatment station which was originally built in 2005 and located in Beijing Huateng Chemical Industry Park. The design process water quantity was 2000 m3/d, aimed to deal with the different sources of wastewater in the park. However, the current industrial park sewage water was about 300 m3/d, which was far lower than the design capacity; and the effluent quality of original process and operation treatment was poor. In addition, the upcoming Beijing "Integrated Water Pollutantion Discharge Standard" (DB11/307-2013) put forward new requirements on waste water discharge, and part of the effluent quality using the original process couldn’t meet the prescribed limit. Therefore, the upgrade scheme of the original technology was proposed.The industry park sewage had five kinds of sources, so the composition was complex, the effluent quantity was large, and there were lots of biodegradable compounds. Through the analysis of the need of dealing with the amount of effluent and water quality, by a multi-angle scheme comparison, we finally identified the "hydrolysis+two levels of A/O+deep processing" as the process route, and the characteristics and advantage of this process were compared. Different removing effects of processing units in the process were investigated; we continuous monitored COD, BOD5, ammonia nitrogen, total nitrogen and total phosphorus removal efficiency, and compared the effluent standard limits with the result. We found that the removal efficiency remained at above 90%, and concentration of all the pollutants was low. Thus, the result further confirmed the feasibility and stability of the process.In addition, the detailed analysis of each operation unit was made. A specific retrofit measurement, including the structures of the specifications of the components and equipment cost, was put up. The construction scheme, based on the principle of energy conservation, environmental protection, and economic efficiency, was designed. The necessary updates were carried on for the structures, and the maximum engineering benefits were fully considered. After the retrofit, compared with the source, COD can be decreased by about 125t and ammonia nitrogen can be decreased by 12.7t; compared with the original effluent, COD showed a decrease of 6.6t and ammonia nitrogen showed a decrease of 1.8t. Thus, the annual payment on sewage charge was declined by 175 thousand yuan at least.