Simulation and engineering demonstration of the advanced treatment of rainy overflow wastewater using a combined system of storage tank‐wastewater treatment plant‐wetland

Abstract

We propose a new technology to advanced treat overflow wastewater from a combined sewer system using a storage tank‐wastewater treatment plant (STP)‐constructed wetland (CW) system. The engineering demonstration (a 7,500 m3 storage tank and a 3,436 m2 CW) has been built to treat the combined sewer overflows (CSOs) at the largest combined rainwater/wastewater overflow outlet in the middle reaches of the Xinbaoxiang River, which is the second largest river in the Dianchi Lake Basin. During the rainfall period, CSOs enter the storage tank. After sedimentation purification, the higher concentration CSOs at the bottom enter the STP, and the upper low‐concentration CSOs enter CWs, thereby linking the multiple means of treating CSOs and minimizing the impact of CSOs on the STP. During the dry season, CWs can also assist in purification of polluted river water. The supernatant (COD <80 mg/L) and the bottom part water (COD >200 mg/L) of the storage tank were sent to CWs and STP, respectively, for treatment. The project was stably operated over 6 months. The final effluent qualities were 12, 1.79, and 0.18 mg/L for COD, TN, and TP, respectively, which achieved the surface water class V standard.Practitioner points A combined system of storage tank‐wastewater treatment plant‐wetland was proposed to advanced treat overflow wastewater of rainy season. The SWMM could calculate the water quality and volume of overflow under different rainfall conditions in the runoff area. The effluent of the engineering demonstration reached the standard of surface water class V.

Impact of sewer overflow on public health: A comprehensive scientometric analysis and systematic review

“…To mitigate biodegradation caused by sewer overflow, a recent study suggests combined application of sedimentation tank and multi-stage treatment with plants (Jin et al, 2020). Based on this combined set-up, the authors achieved TP (total phosphorus) and COD (chemical oxygen demand) removal of 23.9% and 45.9%, respectively during SO event.…”

“…ANN and SWMM can accurately predict water quality in sewers and stormwater systems. (Even et al, 2007;Jin et al, 2020;Khwairakpam et al, 2020;Riechel et al, 2016;Tiwari and Sihag, 2020;Xu et al, 2017;Yang et al, 2021a) Physico-chemical & microbiological Organic loading and sediment resuspension from SO cause serious chemical and biological degradation of river and beach water quality, thus reducing aquatic biodiversity. Major contaminants include COD, BOD5 and E. coli.…”

The global progress on the non-point source pollution research from 2012 to 2021: a bibliometric analysis

“…Wastewater is usually discussed as PS pollution and easily controlled. It is worth mentioning that the overflow of wastewater during rainstorms is a research focus of NPS pollution [35].…”