Biodiversity Protection

Located adjacent to Cuihu National Urban Wetland Park, Beijing Daoxianghu Water Plant is situated in the northern Haidian District, a critical node of Beijing’s "Western Hills-Yongding River" ecological corridor. As the "Northern Eco-Tech Green Core" of Haidian, it serves as a pivotal zone driving the high-quality development of urban and ecological spaces in the northern region. The plant’s ecological water replenishment and landscape greening projects form an integrated "point-line-plane" ecological network with the nearby Cuihu Wetland Park and Wenquan Park. Simultaneously, the plant’s ecological practices provide environmental support for the construction of Haidian’s Northern Eco-Tech New Area, improving the regional investment and residential environment while indirectly promoting green industry clustering and urban quality enhancement, achieving synergistic unity of "ecological benefits, social benefits, and economic benefits."
The plant adopts a "fully underground treatment + above-ground park" model, with a 20,000-square-meter ecological park built on the surface, featuring a greening coverage rate of over 80%, significantly enhancing regional vegetation coverage compared to traditional plants. The project occupies a total of only 4.66 hectares, saving over 70% of land compared to conventional above-ground plants of similar scale, reducing the occupation of surrounding farmland and green spaces, and providing room for regional ecological reserves, indirectly alleviating the pressure of urban construction on natural ecosystems. Additionally, through technologies such as enclosed underground treatment, multi-stage biological deodorization, and noise control, the plant resolves the issues of "odor nuisance and noise pollution" associated with traditional plants. It features a 200-square-meter water technology exhibition hall and hosts educational activities such as "Ecology Open Days," receiving over 800 visitors annually for exchanges and tours, effectively promoting the concepts of water recycling and ecological protection while serving dual purposes as a recreational space and an educational platform.
The plant utilizes treated high-quality reclaimed water as the core source for ecological replenishment, establishing a complete water cycle chain of "wastewater collection-purification-reuse-ecological restoration" for the Nansha River Basin. In 2024, Daoxianghu Reclaimed Water Plant supplied over 20 million tonnes of replenishment water to the Nansha River. After receiving the plant’s effluent, the water quality of the Nansha River improved from Grade V (inferior) to a stable Grade IV¹², resolving the issues of "seasonal flow interruption and black, odorous water." This promoted water flow and exchange in the river channel, enhancing its self-purification capacity. Following replenishment and restoration, the Nansha River has become a "green corridor" connecting various ecological patches, facilitating gene exchange and population dispersal of flora and fauna, and improving the connectivity and integrity of the regional ecosystem.

12 Environmental Quality Standards for Surface Water (GB 3838-2002), Class IV Standards Requirements.

As a historically significant river in western Hangzhou, the Yuhangtang River suffered severe degradation in water quality and ecological function due to industrialization, urbanization, and human activities. To improve its water environment and restore ecosystem functions, BEWG implemented a comprehensive remediation project for the southern river network, integrating pollution control with ecological restoration to successfully reconstruct a synergistic land-water ecosystem and significantly enhance regional ecological resilience.
The project covers 22 river section with a watershed area of 24.76 km². Through the construction of large-scale storage pipelines, installation of intelligent diversion wells, and physical interception measures in river channels, a systematic solution of "terminal interception + intelligent diversion + large-scale storage" was established. This approach drastically reduced the total pollutant load entering water bodies from the source and addressed overflow pollution caused by combined sewer systems. Simultaneously, systematic aquatic ecological restoration was carried out: emergent plants (e.g., reeds and calamus) and submerged plants (e.g., Vallisneria and Hydrilla) were introduced to reconstruct healthy "underwater forests" and food chains. A "bacteria-algae-mussel" biochain assimilation system was built to purify water quality. Additionally, ecological rehabilitation of riparian zones was implemented using multi-layered, terracing combinations of trees, shrubs, and xeric/hygrophytic herbs, constructing life corridors in land-water ecotones. The complex plant community structure significantly enhanced biodiversity in riparian zones, providing habitats for insects, amphibians, birds, and other species. Current ecological monitoring records indicate:66 species of phytoplankton, 29 species of zooplankton, 5 species of benthic organisms, showing that a stable aquatic food chain has been established. The presence of indicator fish species such as Sarcocheilichthys sinensis and Plagiognathops microlepis confirms fundamental improvement in water quality. The restored area has attracted 51 bird species, demonstrating enhanced terrestrial biodiversity.

The Xiaotaihou River, located in the southeastern part of Beijing, serves as a critical aquatic corridor connecting the central urban area and the Beijing Sub-Center. The segment from Kouzi Village to Maying Village was listed as one of the 53 black and odorous river channels in Tongzhou District in 2017. Since July 2015, BEWG has implemented the Xiaotaihou River Landscape Enhancement and Ecological Restoration Project. Today, the aquatic ecological condition of the river has been fundamentally revitalized.
To address the challenges of poor water quality and fragile ecosystems under reclaimed water supplementation in the Xiaotaihou River,BEWG constructed a six-level self-stabilizing ecological structure¹³  and innovatively implemented mesh-shaped energy flow and material flow regulation technology¹⁴. This approach rapidly established a stable, self-sustaining ecosystem, successfully restoring the river’s healthy ecological functions. Current monitoring data indicate that indicator species such as Oryzias sinensis and Rhodeus spp have become dominant populations. Top predators including the Eastern Buzzard (Buteo japonicus), Falcon (Falconidae), and Short-eared Owl (Asio flammeus) have been observed inhabiting the area.
The restored river channel not only functions as a cultural and tourism gateway landscape for the Sub-Center but has also facilitated the natural dispersal of biological communities to the downstream sections of the Xiaotaihou River and the upstream areas of the Liangshui River, radiating and promoting the enhancement of biodiversity across the watershed.

13 It refers to the artificial design and guidance to restore or reconstruct six key trophic levels and functional biological communities within the river ecosystem, thereby forming a structurally complete, functionally sound, and self-sustaining stable ecosystem. These six interdependent and functionally distinct biological community layers include: Submerged macrophyte communities, Emergent and riparian plant communities, Plankton communities, Benthic organism communities, Freshwater fish communities, Riparian animal communities.
14 It refers to an active management technology based on food web and ecological dynamics principles. The core approach involves artificially constructing a "six-level ecological structure" to promote efficient energy flow (transmitted through food chains) and material cycling (such as carbon, nitrogen, and phosphorus), thereby rapidly stabilizing the ecosystem and maximizing its purification functions.

The Qingquan River Constructed Wetland Project in Liaocheng, Shandong Province, adopts a combined process of horizontal subsurface flow and surface flow wetlands. It is primarily used for the advanced purification of effluent from Guanxian Wastewater Treatment Plant, with the treated water discharged into the Qingquan River. The wetland is designed to treat 80,000 tonnes of reclaimed water daily, with effluent meeting the Class IV surface water quality standards, and achieving Class III standards for over 80% of the annual operational days. Annual pollutant reduction includes 84 tonnes of COD and 14.6 tonnes of ammonia nitrogen.
The construction and operation of the wetland have not only significantly improved the water quality of the Qingquan River but also created a dynamic wetland ecological landscape for Guanxian County. The wetland has become an indispensable near-natural waterfront recreational space for residents. The wetland covers a constructed area of 150,000 square meters, including 50,000 square meters of open water bodies and 100,000 square meters planted with various aquatic plants, trees, and shrubs. Wetland plants such as cattails (Typha), calamus (Acorus calamus), pickerelweed (Pontederia cordata), water rush (Scirpus validus), yellow iris (Iris pseudacorus), canna (Canna), purple loosestrife (Lythrum salicaria), and lotus (Nelumbo nucifera) bloom in succession, directly expanding the range of biologically available habitats.
Since the wetland’s completion, over 30 bird species have been cumulatively observed and recorded, representing an 80% increase compared to pre-construction records. Winter monitoring recorded a single maximum count of over 100 waterfowl (e.g., geese and ducks). Fish species have recovered from nearly zero to 8 species, and 3 species of amphibians and reptiles have been identified.

Daqing Longfeng Wetland, the largest urban wetland in China, plays a critical role in regulating regional climate, mitigating floods and waterlogging, managing stormwater runoff, degrading pollutants, and enhancing the urban environment. Due to its location in a water-scarce city, Longfeng Wetland is facing problems such as the decline of groundwater level and insufficient rainfall replenishment. The effluent quality of the Second Sewage Treatment Plant in Dongcheng District, Daqing City, located in Daqing Longfeng Wetland Nature Reserve, focuses on municipal wastewater treatment utilizing improved A2O (Anaerobic-Anoxic-Oxic) and advanced treatment processes. The effluent quality meets the National Grade 1A Standard, achieving an annual wastewater reduction of 36 million tonnes and providing approximately 102,000 cubic meters of ecological replenishment water daily. This has significantly improved the ecological environment around the wetland, with the bird population increasing year by year.

The Wuyi Canal is a key upstream channel in the Taihu Lake Basin, connecting the Beijing-Hangzhou Canal and the Yangtze River to the north, and Gehu Lake and Taihu Lake to the south. It serves multiple functions, including water supply, flood drainage, and navigation. The water quality of the Wuyi Canal directly impacts the quality of water flowing into Taihu Lake. Due to pollutant discharges along its banks, the water quality along the canal has consistently failed to meet the requirements of its functional zoning, making it a critical bottleneck hindering the improvement of water environmental quality in the Taihu Lake Basin.
The receiving water body for the effluent from Yixing City Urban Wastewater Treatment Plant is the Wuyi Canal. Through continuous refinement of operational management and process control, the plant has further optimized its effluent quality while consistently meeting discharge standards. Annual pollutant reductions include over 140 tonnes of total phosphorus  and over 1,300 tonnes of total nitrogen, providing significant support for ecological protection in the Taihu Lake Basin. Additionally, the plant actively promotes ecological civilization initiatives by regularly hosting educational tours for schools and community groups, strongly leveraging its role in ecological education. In 2023, Yixing City Urban Wastewater Treatment Plant was designated as a Wuxi City Second-Level Ecological Civilization Education Practice Base.

Jimo District of Qingdao City is a National Environmental Protection Model City, a China Excellent Tourism City, and a Provincial-Level Civilized City. With the rapid development of Jimo District and the continuous improvement of infrastructure, sludge treatment and disposal issues have become increasingly prominent, including: Growing volumes of sludge requiring disposal; Lack of environmentally friendly landfill facilities;
Inability to achieve harmless reuse; environmental and social problems caused by sludge odor.
Through comprehensive analysis and systematic planning from sludge generation to final disposal, starting with research on the utilization pathways of carbonized residues, BEWG formulated a sludge carbonization process route with a treatment capacity of 300 t/d (at 80% moisture content), adopting the sequence of "deep dehydration + drying + carbonization + flue gas purification +construction material utilization". The carbonization technology independently developed by BEWG features five key characteristics:

• Medium-high temperature pyrolysis carbonization process: No tar is produced during pyrolysis, and the combustion temperature of pyrolysis gas exceeds 850°C, ensuring thorough pollutant decomposition and contributing to stable and reliable system operation.
• Sludge volume reduction exceeding 85%: The final product has a moisture content of ≤1%, with heavy metals solidified in the sludge and nutrients such as nitrogen, phosphorus, and potassium retained in the sludge carbon, meeting requirements for land use and construction material utilization, thereby facilitating sludge resource recovery.
• Combustion and recycling of combustible gas generated during carbonization pyrolysis: Reduces energy consumption, sequesters a portion of organic carbon in the carbonized residues, reduces greenhouse gas emissions, and supports the achievement of "Dual Carbon" goals.
• Flue gas emissions compliant with the national Standard for Pollution Control on Municipal Solid Waste Incineration(GB18485-2014) and Shandong Provincial local standards: Emission levels are only 30-40% of those from sludge incineration.
• Oxygen-free pyrolysis process: Eliminates conditions for dioxin formation at the source. Sludge is fully enclosed within the workshop, and sludge odors are co-combusted and purified, effectively avoiding pollution and making it an environmentally friendly sludge treatment and disposal project.
 To prevent secondary pollution during transportation, the project adopts in-situ treatment of sludge generated from wastewater treatment plants. Given the highly limited on-site space, we leveraged our proprietary "sludge-water synergy" technical advantage by renovating the original sludge dewatering room of the wastewater plant and modularizing sludge disposal processes distributed across existing structures. This approach achieves efficient sludge treatment and disposal while compactly utilizing land and releasing urban environmental capacity.

In recent years, many schools have integrated the concept of ecological environment protection into school-based courses and internship practice courses. Based on this, Beijing Enterprises Water Group (Danyang) Co., Ltd. has become a "learning station" for primary and secondary school students in Danyang and surrounding cities to protect water resources and prevent water pollution. In 2024, schools such as Danyang New District Experimental Primary School, Danyang No.3 Middle School, and the School of Engineering of Zhongbei College of Nanjing Normal University have organized students to come to Beijing Enterprises Water Group (Danyang) Co., Ltd. and visited the water plant's science popularization exhibition hall and sewage treatment facilities to take a vivid and intuitive on-the-frontline environmental protection education course. The event effectively enhanced students' awareness of water resources and water ecological environment protection.