Mining Water Treatment: How to Meet Stricter Standards
Every industry needs certain supplies to operate. In the mining industry, one of those supplies is essential for human life, but it is in short supply: water.
Coal mining companies utilize water to cool equipment and control dust, as well as extract, wash, and, in some cases, transport coal. Other mining companies use water to process minerals and reclaim precious metals from ore.
The bad part is that these water uses lead to mineral impurities and cause other solids to build up in companies' process water. The end result? The wastewater becomes so toxic that mining companies can't use it without prioritizing water treatment.
The Necessity of Mining Water Treatment
Mining water treatment is critical because environmental regulations have made it impossible for companies to reuse toxic mining effluent (or even return tainted water to the environment). Those regulations are for a good reason. For example, if there's significant rainfall in an area, that rainfall can lead to acid runoff from surface mines, mine drainage, and tailing piles, polluting rivers and streams. In drier areas, the consequences are equally devastating—mining and processing ores can toxify aquifers.
Overall, mining wastewater usually has high levels of suspended solids and is incredibly acidic. It's easy to find metals, heavy metals, organic compounds, and metalloids like iron, arsenic, and manganese in mining companies' wastewater. In some instances, especially for coal mining firms, the wastewater is even highly saline.
Consequently, it's no wonder environmental regulations don't allow mining operators to reuse their water and build a healthy supply of process water. However, in response to this parameter, many mining companies continuously rely on freshwater supply, even though it's an ineffective solution.
Water scarcity is an ever-growing problem, and mining companies in water-stressed areas degrade what's still available when they only turn to freshwater sources. They also face increasing environmental, societal, and financial pressures when relying solely on freshwater. That's why the most profitable, sustainable solution is for mining companies to treat their wastewater so they can safely reuse it if it is technically and financially feasible.
Water Quality Standards for Treating Mining Wastewater
Successfully treating mining wastewater can be challenging. Mineral, ore, and coal mining companies must follow several water quality standards and rules. If you consider the U.S. alone, the Environmental Protection Agency (EPA) requires any U.S. mine generating wastewater to have a National Pollutant Discharge Elimination System (NPDES) permit. This document covers various wastewater and water treatment situations, including the following:
- Surface water runoff treatment
- Wastewater treatment resulting from coal and ore processing
- Wastewater treatment that will be injected into groundwater or released to surface water
- Wastewater treatment for permanent or temporary worker encampments
- Wastewater treatment that will be reused in dust control and landscaping on roads
- Mitigation and remediation of wastewater when closing a mine
Specific guidelines for mining companies are available on various pages of the EPA's website. For insight on where to find the list of regulations, here's some guidance:
- For effluent guidelines on mineral mining and processing, the regulations are in 40 CFR Part 436 in the Code of Federal Regulations. In 1975, the original guidelines were created but amended in 1976, 1977, 1978, and 1979.
- For ore mining companies, the effluent guidelines are available in 40 CFR Part 440. The guidelines were developed in 1975 but amended in 1978, 1979, 1982, and 1988. Some of the regulations cover extraction processes like picking, dressing, washing, sorting, milling, crushing, and grinding.
- For coal companies, regulations are available in the "Coal Mining Effluent Guidelines and Standards" included in 40 CFR Part 434. While the guidelines were published in 1975, they were amended in the late 70s, mid-80s, and early 2000s. The guidelines include wastewater discharges from mine drainage, coal preparation plants, and coal storage facilities.
While the US EPA makes its guidelines for mining water treatment accessible, adhering to the regulations is no easy feat. Fortunately, there are ways to treat mining wastewater effectively to meet water quality standards.
How Mining Wastewater Treatment Works
For mining companies that want process water, relying on a combination of chemicals and filtration is essential. Specifically, four things make mining water treatment possible.
1. pH adjusters
When treating wastewater, the first step is to restore optimal pH levels using pH adjustment chemicals. This step will not only increase the water quality but also help dissolved metals precipitate. When using the right amounts, pH adjusters can help increase/decrease the acidity in mining wastewater, reverting the water to a more balanced pH level.
2. Flocculants and Coagulants
Once mining wastewater has the right pH level, the next step is to use coagulants and flocculants. These treatment chemicals will combine the suspended solids and small metal particles in the water into large clumps, making it easier to eliminate with clarification and post filtration.
3. Added Chemicals
Even though coagulants, flocculants, and pH adjustment chemicals are the primary chemicals for treating mining wastewater, it's sometimes necessary to use additional chemicals to prepare the water for filtration and protect wastewater systems. Those additional chemicals include corrosion inhibitors, ion exchangers,, biocides, and algaecides.
4. Filtration
After using chemicals to optimize the quality of the mining water, filtration methods will remove specific types of organic matter and eliminate suspended particles. Different filtration machines achieve this, with popular ones being backwash filtration systems containing specific medias such as Natzeo media and centrifugal systems.
Innovative Technologies to Use
Even though there are only four critical elements in mining wastewater treatment, it's best to work with a partner who not only has the expertise and equipment to effectively treat mining wastewater but also an understanding of water quality standards. A partner that checks off these boxes will ensure mining companies meet environmental regulations to have an ample supply of process water.
But if your company is unsure of who to partner with, they should look no further than Genesis Water Technologies. Our team has many cost-effective mining water treatment technologies, including the following:
Centrifugal Filtration Systems: These technologies are mechanical methods that use a centrifuge to remove suspended solids. These solutions also reduce operating costs.
Electrocoagulation: Advanced modular electrocoagulation assists companies meet or exceed regulatory water quality standards. With this, companies can separate large quantities of contaminants in a single operation.
Advanced Oxidation Process: This tertiary treatment process brings an innovative solution to treat mining wastewater to meet stringent regulations on micropollutants, including COD.
GWT Zeoturb™ Bio-Organic Liquid Flocculant: A non-toxic, sustainable, and scalable solution, this eco-friendly treatment is perfect for the flocculation and clarification of process water and wastewater applications.
Sea water Reverse Osmosis Desalination Systems: An advanced treatment solutions for source water containing high chloride levels. These systems can be utilized for demineralization of seawater to be used for process water. These systems can also be used for demineralization of process wastewater in certain cases based on the water quality profile and feasibility.
To learn more about these mining water treatment solutions, our team is one call or email away. Contact our GWT team of water & wastewater treatment experts at +1 877 267 3699 or email us at customersupport@genesiswatertech.com.