Kaifeng Chanrong District Water System Plant-and-Network Project (fully underground WWTP, 40,000 m³/d, quasi-Class IV effluent)

The Chanrong District water system plant-and-network project in Kaifeng, Henan, stands at the northwest corner of Ronghe Avenue and Chunfeng Street in the city's industry-city integration demonstration zone, built by MCC Henan. It covers 62,000 m2 with 20,000 m2 of floor area and comprises an underground treatment box plus two three-storey buildings - the city's first plant with the entire treatment train hidden below grade. Scope The district has absorbed several universities and resettlement communities in recent years, pushing sewage volumes up while large-scale collection and treatment were missing and treated water had nowhere to go. The project plans plant and sewer network as one system, solving discharge from the campuses and housing estates and reserving interfaces for reclaimed-water reuse. It is now in operation; at full operation the plant will treat 40,000 m3/d on average. Concept Treatment structures are consolidated into an underground box, capped with soil and planted, giving a “plant below, park above” layout - well suited to land-scarce new districts, since noise and odour are contained and the surface returns to the public. Effluent meets the quasi-Class IV surface-water standard, the strictest in Kaifeng's wastewater sector, and can be reused nearby for landscape supplementation and municipal non-potable uses. Construction The box is an integrated complex structure built entirely below grade, with constrained working space, tight tolerances and high safety risk, where conventional staged construction is slow. The site team developed a single-side formwork support system for high and low spans with a synchronous pour method, letting structures at different elevations and spans be cast together and shortening the critical path. Dust was controlled with full soil coverage, site-wide spraying and enclosed hoardings; a smart environmental monitoring platform tracked dust, noise and construction water quality around the clock and fed adjustments to the works. Recognition The project won Henan Provincial Quality Structural Engineering (first half of 2025) and the second batch of provincial green construction demonstration projects for 2025. Once fully commissioned it will bring the surrounding universities and resettlement areas into centralised treatment and close gaps in the sewer network. Note Investment, ground-breaking and commissioning dates, and the specific biological process, are not disclosed and are left blank. The 40,000 m3/d figure is the full-operation average, not current throughput. Sources: CNR Henan, 6 June 2026, https://hn.cnr.cn/hnpdgb/shms/20260606/t20260606_527650491.html Image: Aerial view of the Kaifeng Chanrong plant, with the underground treatment box capped and planted as a park and two three-storey buildings with rooftop PV to the south (Source: CNR Henan, photo by MCC Henan)