Membrane Wastewater Treatment of Combined Sewer Overflows and Sanitary Sewer Overflows

A non-biological wastewater treatment plant for treatment of overflow in a sewerage system or for treating first flush stormwater, comprising:

• a screen positioned to screen incoming wastewater,
• means for coagulating the screened wastewater downstream of the screen, and
• a membrane tank receiving the wastewater, the tank having submerged membranes through which the coagulated wastewater is directed, the membranes being of a pore size sufficiently small to separate out bacteria, as the sole means of reducing bacteria in the screened wastewater,
• whereby the non-biological wastewater treatment plant produces a physically/chemically treated permeate outflow to meet overflow discharge requirements.

A wastewater treatment system including biological treatment of sanitary sewage, the system including sewerage carrying wastewater to a biological treatment plant, and the system being subject to occasional overflows beyond capacity of the sewerage or the biological treatment plant, comprising:

• the biological treatment plant including a liquid side with biological treatment of an incoming stream of wastewater,
• upstream of and remote from the biological wastewater treatment plant, a diverter for overflow which may be beyond capacity of the sewerage or of the biological wastewater treatment plant,
• at least one non-biological overflow treatment plant, positioned to receive overflow from the diverter during a period of an overflow, the non-biological overflow treatment plant including a screen positioned to screen overflow wastewater from the diverter, means for coagulating the screened wastewater downstream of the screen, and a membrane tank receiving the wastewater, the tank having submerged membranes through which coagulated wastewater is directed, the membranes being of a pore size sufficiently small to separate out bacteria, and
• means for adding a disinfectant to the permeate outflow,
• whereby the non-biological overflow treatment plant produces a physically/chemically treated permeate outflow to meet discharge requirements for overflow wastewater.

A method for treating an overflow in a system of sewerage, comprising:

• providing at least one non-biological overflow treatment plant, positioned in the sewerage system remote from any biological treatment plant, to receive overflow during a period of an overflow,
• screening the overflow received in the non-biological overflow treatment plant,
• coagulating the screened wastewater in the non-biological overflow treatment plant, and
• treating the wastewater in a membrane tank having submerged membranes through which coagulated wastewater is directed, the membranes being of a pore size sufficiently small to separate out bacteria, as the sole means of reducing bacteria in the wastewater,
• whereby the non-biological overflow treatment plant produces a physically/chemically treated permeate outflow to meet discharge requirements for overflow wastewater.