Method for enhanced phosphorus removal of membrane bioreactor

Abstract

The invention discloses a method for enhanced phosphorus removal of a membrane bioreactor. The method comprises the following steps: introducing sewage into an anaerobic pond for anaerobic treatment;introducing anaerobic purified water into an anoxic pond for anoxic treatment; introducing anoxic purified water into an aerobiotic pond for aerobiotic treatment; introducing aerobiotic purified waterinto a membrane pond and adding chemical phosphorus removal drugs for chemical phosphorus removal treatment; performing first-level reflux treatment on a part of phosphorus-removed purified water andreturning to the aerobiotic pond; performing second-level reflux treatment on a part of aerobiotic purified water and returning into the anoxic pond; performing third-level reflux treatment on a partof anoxic purified water and returning into the anaerobic pond. Total phosphorus concentration of phosphorus-removed purified water can be reduced by adjusting second-level reflux ratio, third-levelreflux ratio and / or dosage of chemical phosphorus removal drugs. The method provided by the invention is capable of flexibly and effectively coping with fluctuation of pollutant load of to-be-treatedsewage, realizing synchronous carbon removal and nitrogen and phosphorus removal, guaranteeing total phosphorus concentration of phosphorus-removed purified water not higher than 0.3 mg / L all the time and reaching level A standard of urban wastewater discharge.

Description

technical field [0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a method for strengthening phosphorus removal in a membrane bioreactor. Background technique [0002] Membrane bioreactor (MBR) is a new and efficient sewage treatment technology that combines membrane separation and biological treatment. Membrane bioreactor technology has many obvious advantages that other biological treatment processes cannot match, mainly for high volume load, strong load resistance, low sludge yield, good treatment effect, excellent effluent quality, small footprint, and process equipment Centralized, full automatic control can be realized. Among them, biological phosphorus removal mainly absorbs phosphorus from the external environment excessively through phosphorus accumulating bacteria, stores it in the body in the form of polyphosphate, forms phosphorus-rich sludge, and removes phosphorus from sewage by discharging excess sludge. Ef...

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Problems solved by technology

However, although MBR synergistic chemical phosphorus removal can remove most of the phosphorus, the phosphorus removal effect is not ideal. Due to the continuous aeration in the reactor, it is difficult to flocculate the phosphorus sediment, so the phosphorus chemical sludge contains micro Flocs, some of these micro flocs can pass through the membrane, which increases the concentration of phosphorus in the effluent; in addition, the increase in the concentration of chemical sludge in the MBR will increase the total concentration of sludge in the reactor, resulting in a decrease in membrane flux , leading to a decrease in the proportion of activated sludge in the reactor, thereby reducing the activity of the sludge; and because chemical sludge is more likely to cause serious membrane clogging than activated sludge, an increase in the proportion of chemical sludge has a negative effect on the membrane. There are also certain dangers

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