In China, environmental protection has become an important part of the national policy and strategy throughout recent years. The HeXian HuaQi chemical industry sewage plant, which was built in September 2016, is a direct outcome of this increased environmental focus.
The sewage plant has the capacity of over five thousand tons of water per day, and has a rather complex task of treating the input water from the surrounding industrial area due to the dozens of chemical enterprises located here. The water has a very strong pH value, a deep color, high levels of NH3-N and toxicity, and a fluctuating input of water volumes.
Considering all those factors, the project owner adopted a composite technology including a tank for pH adjustment, traditional A20, an ozone oxidation tank and a BAF tank. After treatment, the water quality has been kept at COD ≤ 50mg/L and NH3-N ≤ 1mg/L for the past two years.
Expect solutions and quality products
According to the project owner, the reason for choosing AVK was due to the ability of providing a total system solution. To meet the different processing techniques, AVK provided a total of 156 valves including concentric butterfly valves of manual and electrical actuation in upstream process to meet the extreme pH water, double eccentric butterfly valves for the downstream process to meet the high capacity output, and a large quantity of ball check valves and gate valves throughout the system.
When choosing quality pays off…
Due to the very strict project deadline set by the local government, a few locally manufactured knife gate valves were used in the project, as they were on stock and easily accessible. Nevertheless, only half a year later these valves were facing very serious corrosion, and the product owner was forced to stop the production and have the knife gate valves replaced - an update directly causing a discharge of unqualified sewage water during the rehabilitation time, which was then followed by a fee supervised by the local environment bureau.