Method for wastewater treatment with resource recovery and reduced residual solids generation

A process for treating wastewater comprising the steps of:

• wasting a volume fraction of organic cell mass from an aerobic membrane bioreactor to an anaerobic digester system;
• and
• maintaining a solids retention time (SRT) in the bioreactor that is (1) greater than a time needed to achieve growth of organisms suitable for converting carbonaceous biochemical oxygen demand (CBOD) into cell mass and (2) less than a time at which substantial decay of the organisms occurs;
• further comprising the step of filtering activated sludge from the aerobic membrane bioreactor in a membrane separator external to the membrane bioreactor.

A process for treating wastewater comprising the steps of:

• wasting a volume fraction of organic cell mas from an aerobic membrane bioreactor to an anaerobic digester system;
• and
• maintaining a solids retention time(SRT) in the bioreactor that is (1) greater than a time needed to achieve growth of organisms suitable for converting carbonaceous biochemical oxygen demand (CBOD) into cell mass and (2) less than a time a which substantial decay of the organisms occurs;
• further comprising the steps of removing and recovering phosphorus from the wastewater.

A process for treating wastewater comprising the steps of:

• wasting a volume fraction of organic cell mass from an aerobic membrane bioreactor to an anaerobic digester system;
• and
• maintaining a solids retention time (SRT) in the bioreactor that is (1) greater than a time needed to achieve growth of organisms suitable for converting carbonaceous biochemical oxygen demand (CBOD) into cell mass and (2) less than a time at which substantial decay of the organisms occurs;
• further comprising the steps of removing and recovering ammonia from the wastewater.

A process for treating wastewater comprising the steps of:

• wasting a volume fraction of organic cell mass from an aerobic membrane bioreactor to an anaerobic digester systems;
• and
• maintaining a solids retention time (SRT) in the bioreactor that is (1) greater than a time needed to achieve growth of organisms suitable for converting carbonaceous biochemical oxygen demand (CBOD) into cell mass and (2) less than a time at which substantial decay of the organisms occur;
• further comprising pretreating the wastewater prior to being introduced into the membrane bioreactor.