Method and apparatus for treating wastewater using membrane filters
First Claim
1. A method for removal of biological nutrients from a wastewater, comprising:
- providing wastewater to an inlet of a serial multizone activated sludge bioreactor containing activated sludge, the bioreactor having a downstream aerobic zone from which treated water is removed and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone;
filtering treated water from the activated sludge in the downstream aerobic zone through an immersed membrane filter;
purging solids from the immersed membrane filter with an oxygen containing purge gas; and
recycling return activated sludge charged with oxygen associated with the oxygen containing purge gas from the downstream aerobic zone to the upstream aerobic zone.
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Abstract
An apparatus using activated sludge for the removal of biological nutrients from a wastewater includes a bioreactor for containing a mixture of wastewater under treatment and activated sludge. The bioreactor is divided into a plurality of serially connected treatment zones and includes a wastewater inlet, a downstream aerobic zone and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone. A membrane filter is provided in the downstream aerobic zone so that it functions as an immersed membrane filter with a bioreactor containing an operative volume of wastewater and activated sludge. The immersed membrane filter filters treated water flowing from the bioreactor through a first outlet. An aerator is operative associated with the membrane filter for purging solids from the membrane filter. A second outlet in the downstream aerobic zone is connected to an inlet in the upstream aerobic zone for recycling activated sludge charged with oxygen from the downstream aerobic zone to the upstream aerobic zone.
A method for removal of nutrients from a wastewater includes providing a wastewater to an inlet of a serial, multi-zone, activated sludge bioreactor containing an activated sludge. The bioreactor has a downstream aerobic zone from which water is removed and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone. Treated water is filtered from the activated sludge in the downstream aerobic zone through an immersed membrane filter. Solids are purged from the immersed membrane filter with an oxygen containing gas and return activated sludge charged with oxygen is recycled from the downstream to the upstream aerobic zone or to an upstream deaeriation zone.
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Citations
16 Claims
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1. A method for removal of biological nutrients from a wastewater, comprising:
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providing wastewater to an inlet of a serial multizone activated sludge bioreactor containing activated sludge, the bioreactor having a downstream aerobic zone from which treated water is removed and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone;
filtering treated water from the activated sludge in the downstream aerobic zone through an immersed membrane filter;
purging solids from the immersed membrane filter with an oxygen containing purge gas; and
recycling return activated sludge charged with oxygen associated with the oxygen containing purge gas from the downstream aerobic zone to the upstream aerobic zone. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus utilizing activated sludge for the removal of biological nutrients from a wastewater, comprising:
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a bioreactor for containing a mixture of wastewater under treatment and activated sludge, the bioreactor being divided into a plurality of serially connected treatment zones, and having a wastewater inlet, a downstream aerobic zone and an upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone;
a membrane filter in the downstream aerobic zone, the membrane filter being situated in the downstream aerobic zone so that it functions as an immersed membrane filter with the bioreactor containing an operative volume of wastewater and activated sludge, the immersed membrane filter filtering treated water flowing from the bioreactor through a first outlet;
an aerator operatively associated with the membrane filter for purging solids from the membrane filter with an oxygen containing purge gas; and
a second outlet in the downstream aerobic zone connected to an inlet in the upstream aerobic zone for recycling return activated sludge charged with oxygen associated with the oxygen containing purge gas from the downstream aerobic zone to the upstream aerobic zone. - View Dependent Claims (8, 9, 10)
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11. A method for removal of biological nutrients from a wastewater, comprising:
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providing wastewater to an inlet of a serial multizone activated sludge bioreactor containing activated sludge, the bioreactor having a downstream aerobic zone from which treated water is removed and upstream aerobic zone between the wastewater inlet and the downstream aerobic zone, the upstream and downstream aerobic zones being separated by an anoxic zone;
filtering treated water from the activated sludge in the downstream aerobic zone through an immersed membrane filter;
purging solids from the immersed membrane filter with an oxygen containing purge gas; and
recycling return activated sludge charged with oxygen associated with the oxygen containing purge gas from the downstream aerobic zone to a deaeration zone upstream of the bioreactor inlet. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification