Wastewater Recycling Project to Conserve Groundwater, Mongolia
Tetra Tech supported the Millennium Challenge Corporation’s (MCC) wastewater recycling and groundwater conservation project in Mongolia by evaluating large combined heat and power plants (CHPs) and preparing impact assessments and feasibility studies in Mongolia.
Faced with declining river flow and diminishing wellfield production, Ulaanbaatar, Mongolia’s capital, must confront water shortages and the need for substantial investments in water supply and wastewater treatment. The city’s declining water supply is exacerbated by high groundwater demand from the city’s CHPs and an outdated central wastewater treatment plant that is over capacity, resulting in municipal and industrial pollution contaminating downstream wells along the Tuul River.
To provide a more sustainable water supply and increase economic development, the MCC is developing a Compact with the Government of Mongolia that includes increasing groundwater supply through new aquifer development in downstream wells, and a water recycling project that will use treated wastewater for combined heat and power plants, thereby conserving groundwater. MCC selected Tetra Tech to prepare the feasibility study, environmental and social baseline study, resettlement policy framework, and bid documents for the wastewater recycling project; and develop bid documents for the new Central Wastewater Treatment Plant (CWWTP) in Ulaanbaatar.
CHPs 3 and 4 supply most of the city’s power and central heat needs and use more than 50,000 cubic meters of potable groundwater per day. Tetra Tech conducted a detailed, on-site assessment of the large CHP’s metallurgy, equipment, operations, and water quality requirements. Based on this study, our team developed water quality requirements for recycled wastewater use in the cooling towers and other processes.
We also conducted a site assessment of the city’s existing CWWTP that was built in 1964 and has exceeded capacity due to the high volume and strength of wastewater from industrial uses, including tanneries and wool processing plants. Tetra Tech prepared design-build bidding documents to construct a new USD$400 million CWWTP.
Tetra Tech developed the process and design of a tertiary treatment wastewater recycling plant and connecting infrastructure to use recycled wastewater at the CHPs. Our team prepared bidding documents for the USD$100 million water recycling project, including the recycling treatment plant, pipelines, and work required at the existing CHPs.
Tetra Tech also completed an environmental and social baseline study to meet both U.S. and Mongolian requirements. The study included an assessment of potential environmental impacts and mitigation measures needed throughout the project area. We assessed and provided recommendations for the CWWTP biosolids management plan. Through our planning, we worked to minimize impacts to businesses and residents. We prepared a resettlement policy framework to outline the procedures for equitable compensation prior to construction for the small number of residents and business estimated to be impacted.
The recycling project will save 50,000 cubic meters of fresh groundwater per day, thereby directly increasing potable water supply. In addition to supporting the recycling project, the new CWWTP will enable sustainable use of the new downstream wells for additional water supply.