Many wastewater treatment plants have significant costs related to sludge transportation because of limitations in plant infrastructure, disposal options and treatment capabilities.
The Ovivo Membrane Thickening (MBT) process uses silicon carbide membranes to thicken waste activated sludge (WAS), typically up to 3 percent solids, which reduces the volume of sludge to be hauled.
Ovivo MBT produces WAS that is three times thicker than unthickened WAS, and typically two times thicker than that produced by conventional decanting operations. Operator time is minimised because thickening is performed on a continuous basis, rather than in batches. In addition, the equipment runs independently in a steady state mode.
Thickening with MBT requires no polymers or chemicals, minimal infrastructure and process footprint, and can be retrofitted into existing tankage.
Ovivo MBT provides reduced operating and maintenance costs for thickening and significant savings in hauling costs.
The MBT process consists of a membrane thickener tank and an aerobic sludge holding tank. All blowers, permeate pumps, recycle pumps, aeration equipment and instrumentation are included in the process package to ensure one source of responsibility.
WAS is fed directly from the liquid treatment process into the sludge holding tank (SHT). The flow is transferred at a rate of 4Q into the membrane thickener tank via a pump. Sludge is thickened typically up to 3 percent solids by the MBT by pulling clean water through the membrane, leaving solids behind. Because of the quality of filtration by the membrane, the permeate from the thickener may be combined with the treated effluent flow that is to be sent to disinfection instead of recycling back to the headworks of the treatment facility. The thickened sludge from the membrane thickener is transferred over a weir back into the sludge holding tank. In the SHT the sludge is actively mixed and digested with the aid of Ovivo’s TransMAX air diffusers.