Case Studies

Case Studies

Nanostone Water’s installed reference cases and multiple pilot studies throughout the world have helped to validate and optimize the performance of our ceramic membranes in a variety of applications highlighted below.


Chemical Refinery Waste Water Reuse Case Study

A chemical refinery located in Qinghai China operated a non-biological waste water treatment plant with chemical precipitation followed by clarification, conventional media filtration, and finally with reverse osmosis (RO).

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The RO membranes failed after a short period of time due to high turbidity, high silt density index (SDI), and biological fouling. The more robust and longer lasting Nanostone Ceramic UF membranes were chosen over polymeric UF membranes to improve the system performance. After the Nanostone Ceramic UF membranes were installed, the water quality to the RO membranes was dramatically improved with SDI levels < 3 and turbidity < 0.1 NTU. The Nanostone Ceramic UF membranes operate very stable in dead end mode of operation at a flux rate of 170 LMH (100 GFD).

View the full case study with supportive charts by downloading the PDF.

Coal to Chemical Waste Water Reuse Case Study

Refining coal to other materials is known as CTX, and is a large industry in China. Waste water from the CTX process is difficult to treat industrial waste water. Regular biological treatment is not enough to meet discharge requirements and so the facilities must find ways to reuse this water prior a zero liquid discharge system. Ultrafiltration and RO are the technologies of choice in this application to enable water reuse. A ceramic UF membrane is a promising upgrade for those looking for a more robust UF choice for this type of waste water treatment.

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Refining coal to other materials, such as gas and liquids and gases, is known as CTX, and is a large industry in China. Waste water from the CTX process is difficult to treat industrial waste water. Regular biological treatment is not enough to meet discharge requirements and so the facilities must find ways to reuse this water prior a zero liquid discharge system. Ultrafiltration and RO are the technologies of choice in this environment. Some projects running with polymeric UF membranes are suffering the pain of constant membrane fouling and fiber breakage because of the complicated organic pollutants and high level of variation in water quality. Frequent cleaning of the membranes results in fiber breakage and shortened lifecycle. A ceramic UF membrane is a promising upgrade for those looking for a more robust UF choice for this type of waste water treatment.

View the full case study with supportive charts by downloading the PDF.

Cold Source Water for Industrial Makeup Case Study

Industrial companies require clean water for cooling, boiler makeup, and a variety of manufacturing processes. It is common to use ultrafiltration or microfiltration (UF/MF) membranes to treat the incoming water supply to reduce turbidity and suspended solids of industrial process water directly, or in use as pretreatment to protect the performance of Reverse Osmosis (RO) membranes.

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In many parts of the world, a surface water source will see low temperature periods during the 3-6 months of winter ranging from extremes of 0.3 to 5.0°C (32.5-41°F). For a polymeric MF/UF membrane plant operating in such cold conditions, the typical response is to reduce the flux during the cold periods. Where a plant would be designed for a flux rate of up to 45 GFD (76 LMH) at a temperature of 20°C (68°F), the same design would be reduced to just 28 GFD (48 LMH) if the temperature is reduced to 4°C (39°F), according to the design programs
of most manufacturers. This leaves the designer with two choices: 1) design the plant to reach a design flow rate at the cold condition by adding more membrane area and reducing the flux; or 2) reducing the output of the plant during cold conditions. In most industrial plants, the water demand is constant and so the flux of the polymeric membrane plant must be reduced to be able to keep up during the winter months. Polymeric membrane fibers constrict in extreme cold conditions, reducing the permeability beyond what the water viscosity change alone would predict. In some studies it is shown that there is a permanent permeability reduction from exposure to cold water conditions that never returns even when the water temperature rises. Other changes noted by polymeric membranes in cold conditions include: 1) increased fiber breakage, 2) increased backwash durations, and 3) less effective chemical cleanings.

With ceramic membranes, however, there is a much lower coefficient of expansion due to temperature, and so there is no observed change in permeability beyond the change in water viscosity. This means that a plant can simply size the feed pump to run at a higher pressure during the cold periods without needing to reduce the plant output.

View the full case study with supportive charts by downloading the PDF.