Due to the concern of environmental, social and governance issues, water management in the global mining industry is becoming more and more strict, and responsible practices must be taken to ensure water quality and environmental friendliness. In remote and water shortage areas, it is difficult to achieve good water management during mining. Miners operating in these environments need better solutions to deal with water shortages, logistical problems and comply with strict water management and discharge regulations.
Challenges of mining in arid and remote areas
Many important areas in the world with Exploitable mineral resources are often the most water deficient areas. Since there is no direct water source, operators tend to consume more resources when supplying water to the mining process and meeting the on-site non potable water demand.
Reverse osmosis system with high pressure pump and energy recovery
In order to better treat intractable mining process wastewater and acid mine drainage, reverse osmosis (RO) provides an alternative to conventional treatment. Reverse osmosis membranes use pressure to force water through tight polymer structures that are not easily permeable to dissolved salts. The salt removed by the membrane is concentrated into waste liquid. In addition to salt, RO also provides treatment methods to remove common metals, sulfate and suspended solids in mineral water, so as to produce stable and high-quality water, which can be used for a variety of purposes, including non potable water applications, thus reducing the burden of dragging the water to the site.
The use of membranes allows operators to better control the treatment process without worrying about changing pretreatment concentrations or chemical properties. Moreover, as a treatment process with almost no chemical substances, RO will not produce oil sludge or chemical waste.
Operators using reverse osmosis to treat mining wastewater will tend to recover as much water as possible. However, doing so will encounter a key limitation: the inherent high osmotic pressure of mining wastewater (the result of high salt and high metal concentration). To overcome this limitation, operators can use high-pressure pumps and energy recovery systems, which can provide the necessary pressure rise to drive water through the reverse osmosis membrane to concentrate salt and metals to the greatest extent.
Since the reverse osmosis membrane system operates at high pressure in high salinity applications, the waste liquid flow (although the flow is significantly reduced) is still at high pressure after the membrane array. Therefore, the energy recovery system can be used to transfer the pumped energy from the waste stream back to the high-pressure pump, provide additional boost to the inlet pressure, and allow the design engineer to use smaller high-pressure pump motors.
The use of energy recovery system can also reduce the energy demand of reverse osmosis membrane system. Any reduction in energy demand is beneficial because the site often generates high electricity bills.
