About the technology

MBR is an advanced wastewater treatment technology which combines membrane separation with biological wastewater treatment. A typical MBR treatment system is made up of three parts, an anoxic zone (where there is no or a very low concentration of oxygen), aerobic zone (where oxygen is present) and membrane separation. Wastewater is pumped into the anoxic tank and is recirculated between the anoxic and aerobic tanks. Diff erent types of microbes grow under the anoxic and aerobic conditions which are responsible for breaking down various contaminants present in the wastewater.

Treated wastewater is drawn from the membrane module, which is made up of sheets of hollow fibre microfiltration PVDF membranes submerged in the aerobic tank. With the pore size of 0.1 micron, the PVDF membrane completely filters out the activated sludge, containing bacteria and other microbes from the treated water. The treated water is virtually free of bacteria, microbes and other suspended solids and can be directly reused or further purified using the reverse osmosis, without requiring further pre-treatment.

Schematic diagram of MBR process

The use of membrane technology allows the treatment system to operate at much higher concentration of bacteria and microbes in the reactor tank (MLSS can be as high as 15,000 mg/l as compared to conventional process which typically operate at MLSS of 3-4,000 mg/l) as the bacteria and microbes cannot pass through the membrane and are retained in the reactor tank.

A higher concentration of bacteria and microbes shortens the amount of time required to treat the wastewater. As a result of shortened reaction time and the elimination of further post treatment, we estimate that MBR occupies approximately 20% to 30% of the space required by a traditional biological treatment plant. Further more, there is more resilience to shock loading (which is a sudden increase in contaminant concentration during a wastewater treatment process) and variation in raw water quality, delivering reliable and good treatment performance.

We use PVDF membrane, which are more resistant to membrane fouling. It has higher flux and a longer life span compared to some other membrane materials.

Key advantages of MBR

• Good treated water quality, able to meet more stringent discharge limits, treated water is fit for direct reuse
• Small space, approximately 20-30% of the traditional treatment plant
• Generate much less sludge, saves sludge treatment and disposal cost
• Easy conversion for existing plant upgrading and expansion

Application of MBR

• Biological wastewater treatment
• Wastewater recycling
• Wastewater treatment plant upgrade: expand capacity, upgrade facilities within existing plant area to meet more stringent discharge limits