Sustainable wastewater technologies minimize mining’s environmental footprint
Mining for some minerals, including coal, has been diminishing due to increased financial, social, and environmental pressures, both in the United States and abroad. At the same time, mining for lithium and other metals — used in energy storage for electric cars, and wind and solar generation — is revving up with the rush to tap into renewable energy. For example, a Silver, Nevada, lithium mine recently signed an agreement with Tesla to support the company’s manufacture of car batteries.
U.S. mining plays are on the increase. But, water and energy challenges for mining, both in the U.S. and globally, will require innovative solutions to protect water resources and lower carbon dioxide emissions.
Water is critical for all types of mining. In some locations, significant rainfall can lead to acid runoff from mine drainage, tailings piles, and surface mines, polluting streams and rivers. In drier locations, the mining and processing of ores uses up large volumes of scarce water supplies, and can also pollute groundwater with toxic chemicals.
In the U.S., operators are required to acquire a National Pollutant Discharge Elimination System (NPDES) permit for any effluent generated at a mine. Meeting permit requirements can involve a number of water and wastewater treatment scenarios, including:
- Domestic wastewater treatment for temporary or permanent mining camps
- Surface water runoff treatment
- Treatment of toxic wastewater generated during coal and ore processing
- Wastewater treatment for reuse in landscaping or dust control on the roads
- Wastewater treatment for release to surface water or injection into groundwater
- Remediation and mitigation of wastewater when closing a mine
Wastewater Treatment for Reuse
Not only are many productive mines around the world located in areas with stressed water supplies, but also, mining activity has contributed to the degradation of what little fresh water is available. In order to prevent further environmental contamination, mining companies can turn to advanced wastewater treatment solutions that produce water suitable for reuse.
With new technologies, such as the ECOBOX™ containerized system from Fluence, companies can protect local freshwater sources by treating and reusing mining wastewater for landscaping, irrigation, dust control, and even drinking water. This protects local water sources while meeting increasingly stringent environmental regulations and reducing the cost of wastewater disposal.
Decentralized Water Treatment
Constructing a water-delivery infrastructure from remote mining areas to a central treatment plant would be expensive, time-consuming, and require navigating difficult right-of-way issues. For these reasons, mine operations typically require some form of decentralized treatment of water and wastewater.
Benefits of decentralized treatment for mining operations include:
- Lower capital costs
- Reduced energy requirements, energy costs, and carbon dioxide emissions
- Faster startup with containerized treatment
- Lower maintenance requirements
A packaged plant from Fluence can provide a mining company with a reliable extended aeration treatment system that can be designed and sized for specific types and concentrations of pollutants. These plants can be shipped anywhere, require minimal installation and startup costs, and are simple to operate.
Energy-Efficient Wastewater Treatment
Wastewater treatment systems for mining operations run on electrical energy. Conventional treatment with activated sludge requires a lot of power to operate aeration pumps. New technologies that reduce this requirement can make mining a more sustainable industry.
Fluence’s innovative aerobic wastewater treatment technology, the membrane aerated biofilm reactor (MABR), cuts power requirements by 90% from conventional activated sludge aeration systems, which can provide environmentally responsible decentralized treatment for domestic wastewater at mining camps. MABR’s passive aeration design allows oxygen to diffuse through the membrane with minimal energy input. MABR plants offer simple, low-maintenance operation, low operating costs, and produces water suitable for discharge or use in irrigation.