Recently, China Environment News made a special report on the initial rainwater storage project undertaken by Shanghai Taopu Sewage Treatment Plant. (For details, see the 07th edition of the China Environment News, September 11, 2024.) 

The following is the original report 

Guhong (Shanghai) Environmental Protection Engineering Equipment Co., Ltd. (hereinafter referred to as Guhong Environmental Protection) is a Sino-German joint venture established in Shanghai by the German clean technology group ABIONIK GROUP. It is an internationally renowned enterprise in the field of rainwater management and black and odorous water treatment. Guhong Environmental Protection aims to achieve the transfer and upgrading of German rainwater management technology in China through close cooperation between China and Germany, providing high-quality black and odorous water treatment and rainwater management solutions for domestic application customers. 

At present, the performance of GuHong Environmental Protection covers 22 provinces (autonomous regions and municipalities directly under the central government) such as Beijing, Shanghai, Jiangsu, Yunnan and Hunan, and has successfully implemented more than 200 projects. It has participated in the Shanghai World Expo venue rainwater collection and storage pool project, the Chizhou sponge city combined system overflow pollution control project, the Fuzhou sponge city construction water system comprehensive treatment interception well project, and the Shanghai Hongqiao sewage treatment plant front storage pool project, among other industry benchmark projects. 

Guhong Environmental Protection has a production and R&D base in Jiading District, Shanghai, with complete product solution capabilities and the ability to provide customers with comprehensive after-sales services. 

■ Project Background 

In recent years, with the rapid development of urbanization, the growth of impervious surfaces in cities has led to increasingly serious problems of initial rainwater pollution, posing a threat to urban water resources. 

In December 2018, the "Shanghai Sewage Treatment System and Sludge Treatment and Disposal Plan (2017-2035)" was introduced. The plan aims to gradually integrate and merge the existing small and medium-sized sewage treatment plants, adjust the functions of six sewage treatment plants in Tianshan, Taopu, Quyang, Longhua, Changqiao, and Sitang, and plan for the initial rainwater regulation and storage, as well as the upgrading of the rainwater system. Additionally, it reserves land for the upgrading of the surrounding rainwater system. 

The initial rainwater storage project of Shanghai Taopu Sewage Treatment Plant is a key project implemented in accordance with the requirements of the national "Ten Articles on Water" and the "Implementation Plan for Shanghai Water Pollution Prevention and Control Action Plan". It is crucial to improve the centralized sewage treatment capacity and improve the water environment of Taopu River and Xiqiu River. In 2018, the functional adjustment project of four sewage treatment plants including Taopu was included in the Overall Plan for the Fourth Phase of Comprehensive Environmental Renovation of Suzhou Creek by the Shanghai Water Affairs Bureau; In 2019, the project was approved by the Shanghai Municipal Development and Reform Commission and the Shanghai Municipal Commission of Housing and Urban-Rural Development, and construction was launched at the end of the year. 

■ Project Overview 

This project is the initial rainwater regulation and storage project of Taopu Sewage Treatment Plant, located in Putuo District, Shanghai. The service scope includes the initial rainwater regulation and storage of 8 diversion drainage systems, including Zhenbei, Zhenan, Jiaotongnan, Tongchuan, Zhenguang, Zhenru, Zhenjiang (partially), Caoyang, etc., with a service area of 21.56km2, including 0.54km2 in Baoshan District and 21.02km2 in Putuo District. 

The project will renovate some of the treatment structures (buildings) in the original Taopu Sewage Treatment Plant, and use them as initial rainwater storage tanks after renovation. There are a total of five storage tanks in the project, with a total storage capacity of 89,000 cubic meters. The emptying time of the storage tanks is 24 hours. When the storage tank is empty, the initial rainwater is lifted by the Qilianshan Road Pump Station and discharged to the main pipe of the West Main Line, and finally discharged into the Taihe Sewage Treatment Plant for treatment and discharge after meeting the standard. 

The layout plan is based on the current operation of the existing structures, combined with the distribution and capacity of the structures that can be used as storage tanks in this project. The catalytic reduction tank, the existing primary sedimentation tank, the additional aeration tank, and the SBR biological tank are transformed into storage tanks, and a new primary rainwater lift pump room is built in the existing sludge storage tank area. 

In 2021, Guhong Environmental Protection officially participated in the initial rainwater storage project of Taopu Sewage Treatment Plant, designing a flushing and venting drainage system for the original catalytic reduction tank, original primary sedimentation tank, additional aeration tank, and original SBR biological tank. 

■ Project advantages 

The red line of the project covers an area of 87,874.43 square meters. According to the overall transformation idea, the project is implemented within the existing red line of the plant. The specific general layout is as follows: 

Newly constructed buildings and structures (intake gate shaft, initial rainwater lifting pump room, power transformation and distribution room); New outdoor foundation (deodorization foundation, with deodorization equipment placed on it); Reconstruction of existing structures (reconstructing the existing catalytic reduction tank into a 1# storage tank; reconstructing the existing primary sedimentation tank and additional aeration tank into a 2# storage tank; reconstructing the existing three SBR tanks into 3#, 4#, and 5# storage tanks); Reconstruction of existing buildings (existing plant area 2# low-voltage distribution room, demolition of equipment, and reconstruction as a distribution room); The original buildings are retained and utilized (the current comprehensive building, laboratory building, canteen, bathroom, garage, mechanical workshop, and 1# low-voltage distribution room all retain their respective functions for use); Complete demolition of buildings and structures (including the current sludge pre-concentration tank, dehydration room, incineration workshop control room, sludge warehouse, oil depot, and other buildings, with the soil covering the land used for greening and landscape); Functional abolition of buildings and structures (the current intake pump room, blower room, fine grating and grit chamber, clean water tank and other buildings and structures will not be renovated in this renovation, but will be functionally abolished). 

■ Technical Features 

The main function of the storage tank is to store excessive initial rainwater during the rainy season and regulate the entire water supply and drainage system. 

The retention of mixed sewage in the initial stage can lead to serious deposition of pollutants in the storage tank, so the stored pollutants in the storage tank should be cleaned regularly. Manual cleaning is laborious, time-consuming and dangerous. An automatic flushing system can replace manual cleaning of the bottom of the pool after use: during the drainage process and after emptying, there are residual dirt and debris in the water body and at the bottom of the pool. This system can automatically clean the pool body through agitation, aeration, and flushing. The pollutants removed are discharged with the flushing water by the emptying pump, and the storage pool enters the preparation stage for the next use cycle. 

The systems in the storage tank can achieve remote monitoring, automatic control, and operation data recording and analysis of the entire system and equipment through an automatic control system. 

The automatic flushing system with a door-type design can generate a long-lasting, powerful flushing wave, with good flushing effect, high efficiency, mature and perfect technology, reliable and stable operation; The equipment is made of high-performance stainless steel material, which is corrosion-resistant and has a durable and sturdy structure; No noise during operation, driven by hydraulic pressure, no external water source required, energy saving; The system can be installed after simple modification of the existing storage tank, with minimal impact on the storage capacity of the tank and low requirements for civil engineering; In addition, it also has the advantages of high automation, convenient operation, and simple maintenance. 

The intelligent ejector can spray out gas-liquid mixture at regular intervals, aerate and degrade some organic matter in the water, and minimize the generation of odors in the storage tank. When the drainage of the storage tank reaches the set water level, the intelligent ejector starts to work, keeping the sediment at the bottom of the tank in a suspended state to avoid deposition at the bottom of the tank; When the storage tank is nearly empty, the intelligent ejector will flush the bottom of the storage tank from multiple angles and in full range. In addition, a high-definition camera can be configured to achieve fixed-point flushing; There is also a fixed injector system that is suitable for narrower corridors and culverts. 

■ Engineering Innovation 

The innovation of the project lies in providing a template for the adjustment and updating of urban drainage system functions, transforming small and medium-sized sewage treatment plants in the main urban area, adjusting their functions for the regulation and storage of initial rainwater, and using the original sewage transmission trunk line and the newly built initial rainwater treatment system at the end to treat and discharge the treated water; Secondly, in order to minimize the changes to the original civil engineering without altering it, the targeted design of flushing and emptying systems can be applied to other similar projects. The rotating and fixed injectors developed by Guhong Environmental Protection can be applied to irregularly shaped or circular storage tanks; The third is to adopt a combined flushing method of "rotating injector + fixed injector, gantry flushing + fixed injector" to reduce flushing dead ends and improve flushing efficiency. 

■ Benefit analysis 

At present, the project has completed the demolition of old equipment, the installation of the main civil engineering structure, and the installation of the main mechanical structure of the new equipment. Once the electrical installation and automatic control are online, the water supply can be accepted. 

The demonstration significance of this project lies in the fact that it has achieved functional adjustments and technological innovations without altering the original civil engineering. It not only responds to the requirements of relevant departments for functional adjustments of sewage treatment plants, but also provides innovative solutions for urban drainage systems; It is helpful to study the feasibility of transforming existing structures into primary rainwater lifting facilities, storage facilities, and treatment facilities, providing a reference for the study of anti-siltation and scouring technologies after transforming existing sewage treatment structures into storage facilities, and evaluating the improvement effect of environmental impact after transforming sewage treatment facilities into storage facilities. At the same time, it provides new ideas for the functional adjustment of the drainage system in mega cities, has high promotion value, provides strong technical support for the construction of the functional transformation of small and medium-sized sewage treatment plant facilities, and provides strong technical support for achieving the overall goal of eliminating urban black and odorous water bodies and improving water environment quality. 

The implementation of the project not only showcases Shanghai's environmental protection innovation in the process of urbanization, but also provides valuable experience for the renovation of drainage systems in the world's largest cities. With the comprehensive acceptance of the project, it will bring more inspiration to the treatment of urban black and odorous water bodies. 

(Ma Yujing)