A membrane bioreactor for an innovative biological nitrogen removal process.
A hybrid system has been developed for biological nitrogen removal through nitrification-denitrification. The system includes an aerobic tank and an anoxic tank with an intermediate sludge settler connected to a membrane bioreactor (MBR) with a submerged 0.4 microm hollow-fiber membrane module. The laboratory system has a total working volume of 6.5 L treating a glucose-based synthetic wastewater. The experimental results demonstrate that the new process is highly effective for simultaneous organic and nitrogen removal. During the stationary operation, a sludge SS (suspended solids) concentration of 6 g/L or higher can be maintained in the reactors. The system has a COD (chemical oxygen demand) loading rate of up to 2,100 mg/L-d and a total nitrogen loading rate of up to 170 mg N/L-d. More than 95% COD can be degraded, and the total nitrogen removal efficiency can be 90% or higher as the nitrogen is reduced from 100 to around 7.5 mg/L. A high quality effluent is produced with a SS of less than 1 mg/L. With the MBR, organic degradation, nitrogen removal and sludge-liquid separation can be well achieved within a short HRT of about 10 hr.
Department of Civil Engineering, The University of Hong Kong, Hong Kong, China. chenwen@graduate.hku.hk
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D000332:Aerobiosis; D000693:Anaerobiosis; D019149:Bioreactors; D008567:Membranes, Artificial; D009566:Nitrates / Q000032:analysis / Q000302:isolation & purification; D009584:Nitrogen / Q000032:analysis* / Q000302:isolation & purification; D010100:Oxygen / Q000032:analysis; D012037:Refuse Disposal / Q000379:methods; D012722:Sewage / Q000032:analysis; D013053:Spectrophotometry; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods
D008567:Membranes, Artificial; D009566:Nitrates; D012722:Sewage; D009584:Nitrogen; D010100:Oxygen