The system is capable of simultaneously removing total phosphorus (TP), nitrate-nitrogen (NO3-N) and total suspended solids (TSS) to meet the stringent Level 1 A standard for effluent discharge. The TETRA Denite denitrification filter technology has more than 30 years of experience in secondary, tertiary and advanced wastewater treatment applications throughout the world. TETRA Denite acts as a bioreactor to achieve denitrification; the technology allows the growth of microorganisms on the gravel surface and filter layer. Such biological treatment processes can also achieve Level 1 A standard quality of effluent discharge through secondary wastewater treatment. Severn Trent Services adds that the TETRA Denite system is both a fixed-biofilm bioreactor and a deep bed filter, whose main function is to remove NO3-N and TSS. TP is reduced by adding flocculant to meet a high standard of effluent discharge. The Denite denitrification filter is capable of simultaneously removing NO3-N, TP and SS to meet the extremely stringent discharge requirements in a single step, which greatly reduces the floor space, capital investment costs and operating costs while ensuring space for future upgrade and transformation.The Yangtaizi Wastewater Treatment Plant is one of the first wastewater treatment plants to meet the Level 1 A standard of effluent discharge in China. The plant’s construction was undertaken as part of the State’s ‘three rivers and three lakes’ water pollution control project. The plant will account for nearly one-third of the total wastewater treatment in the surrounding urban areas. Phase II of the project is expected to reach a scale capable of treating 100,000 tons (24 million gallons) of wastewater per day.