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Membrane Distillation for Industrial Wastewater Treatment
Water recycling from industrial wastewater helps to reduce disposal cost, improves water efficiency, and protect our environment. This technology relates to a membrane distillation (MD) technology that can reject 100% of nonvolatile compounds and is insensitive to change in solution concentration which can be operated in both direct contact and vacuum mode. It is a good candidate to treat industrial wastewater containing high inorganic contents and dissolved solids. Through achieving zero liquid discharge, partners can rip off other benefits which include recovering of resources such as precious metals, reducing wastewater which in turns reduces onsite storage capacity and increases space utilization. Compared to other commercially membranes in the market, this technology has an unique structure, which renders the membrane superior performance in terms of vapor flux, anti-wetting properties as well as mechanical integrity.
We are looking for keen partners to develop the technology further, users who want to resolve issues with their wastewater disposal, or users who need an evaluation technology for inhouse wastewater treatment.
Technology Features, Specifications and Advantages
Membrane distillation is thermally driven membrane separation process, where a hydrophobic membrane provides a physical barrier for water vapor and liquid water feed stream. Low grade heat around 50 – 80oC is required to drive the process. Alternatively, for vacuum membrane distillation, 20 -80kPa can be applied to generate water vapor across the membrane.
It has advantages of mild operation conditions, 100% theoretical rejection to nonvolatile compounds, and insensitive to change in solution concentration. Thus, membrane distillation is a good candidate to treat industrial wastewater containing high inorganic contents and dissolved solids.
Membrane is the key for a successful membrane distillation process. An ideal membrane should have a high wetting resistance, good mechanical strength, and stable permeation flux. We have developed a novel hydrophobic membrane with unique morphology and structure that results in excellent anti-wetting properties, where the liquid entry pressure is larger than 5 bar. The membrane also has a good tensile strength and stable performance in treating metal containing wastewater. The stability can be further extended to solutions containing organic solvents. The membrane can maintain a solute rejection of >99% even when organic solvents, such as acetone or dimethyl formamide are present.
This membrane technology can be used to treat industrial wastewater that contains dissolved solids such as ions or heavy metals. It is also suitable when some organics are present in the wastewater streams. This property is especially relevant to wastewater from chemical, pharmaceutical and electronic sectors, where there are always organic solvents.
There are several benefits to customers:
- It will reduce the disposal cost of wastewater.
- The treated water can be recycled and reused, or it can be discharged directly.
- Resources in the wastewater, such as precious metals can be concentrated and recovered.
- It will reduce the amount of wastewater, which reduces onsite storage capacity and increases space utilization.