Waste water treatment in CSG and other mining operations – Miners have historically had many different reasons to treat waste water, but a new technology called Creative Water offers the newest and perhaps most powerful reason yet – to increase operating profits.
Company and technology
Creative Water Technology (CWT) Ltd is a Melbourne based company incorporated in 2006 providing Prescribed Waste solutions to industries worldwide. From a small R&D facility in Melbourne a new technology based on a number of patented processes has emerged that creates new and significantly more profitable opportunities for the mining industry.
CWT has already shipped appliances within Australia and is currently taking orders for 2012. GEA Process Engineering has recently licensed the technology and will in the near future be manufacturing and distributing CWT Appliances in most countries around the world, while in Australia CWT and GEA Process Engineering will both be selling the CWT Appliances.
CWT evaporators use as little as 50% of the energy of alternative evaporators, recover up to 97% of the water content and extract up to 100% of the commodities contained in the waste water. These units enable waste water treatment to become a profit centre rather than a cost centre.
Evaporation technology breakthrough
The energy efficiency of the new technology is a result of a paradigm shift. Instead of boiling off water, either at 100°C or in a vacuum, CWT technology performs industrial scale evaporation at low temperatures and atmospheric pressures by creating a weather system within the CWT Appliance so water is removed and distilled within a CWT Appliance in the same way that water is removed from the ocean and distilled as rain in the natural hydrological cycle.
The result is remarkably low energy consumption, typically less than 120kwh/ kL for moderate size Appliances and as little as 60kwh/kL for the largest Appliances in favourable conditions. The CWT Appliances offer continuous operation with minimal maintenance, chemical pre-treatment or disposables.
CWT is capable of handling extremely high contaminant levels and has already processed feed water with over 650,000 mg/l in commercial application. All CWT Appliances are capable of Zero Liquid Discharge meaning there is no brine or concentrate to dispose of and no environmental issues.
What about reverse osmosis?
The short answer is that Reverse Osmosis (RO) can only ever solve part of the water treatment problem – RO always creates a reject or brine stream and never achieves Zero Liquid Discharge. Commodities can never be recovered and waste water is still a problem – a more concentrated problem – than before.
Reverse Osmosis can process contaminant levels from 1,000 mg/L up to 70,000 mg/L, but only in cases where the water does not contain a range of contaminants such as oils/greases, certain bacteria, pigments, low micron metals, certain proteins or fibres. CWT can process much higher contaminant levels – up to 650,000 mg/L – and CWT can process water that contains all of the problematic contaminants that Reverse Osmosis cannot handle, and CWT can process these waste waters right down to Zero Liquid Discharge.
CWT uses more energy than RO, so if energy consumption is the primary issue then RO might be used to produce a brine concentrate which is then passed to a CWT Appliance. In this manner RO can be combined with CWT to achieve Zero Liquid Discharge with the lowest possible total energy consumption.
RO plants have expensive consumables such as membranes, filters and chemicals whereas CWT does not. Besides this RO plants typically require full-time operator(s) whereas CWT appliances are equipped with advanced PLCs and are designed to run autonomously. These other operating costs may overshadow energy consumption costs so sometimes the most economical way to achieve Zero Liquid Discharge is to use CWT Appliances without an RO front end.
1) The GEA Process Engineering Australia organization is a member of the GEA Group Aktiengesellschaft in Germany. GEA Process Engineering Australia objective is to deliver to the Australian Industry GEA’s trusted processes and designs regarding liquid handling, membrane technology, evaporation, drying, homogenization and other related processes.