[Coupling anaerobic baffled reactor and membrane-aerated biofilm reactor].

Based on the consistent anaerobic status of outer layer of membrane-aerated biofilm reactor (MABR) and internal anaerobic baffled reactor (ABR), MABR and ABR were started up separately. The aerating membrane module was installed into a compartment of anaerobic baffled bioreactor to form the Hybrid MAB-ABR (HMABR). After the installation of membrane module, total COD and VFA concentrations in the HMABR effluent were deceased by 59.5% and 68.1% respectively, with increased nitrogenous pollutant remove efficiency by 83.5%, at influent COD concentration of 1600 mg/L and NH4+ -N concentration of 80 mg/L. When organic loading rate was increased by 50%, the effluent COD concentration was still below the level of 60 mg/L, indicating its good capability of counteracting influent organic loading fluctuation. Due to the decreased COD concentration and increased nitrate concentration in the third compartment after installing the membrane module, the biogas volume and methane contents in the third compartment were decreased, resulting in the steady and excellent effluent quality. In this hybrid process, the improved simultaneous removal of carbon and nitrogen for high-strength nitrogenous organic pollutants was realized in a single reactor.

[Simultaneous nitrification and denitrification of membrane-aerated biofilm reactor].

A carbon membrane-aerated biofilm reactor was developed to treat municipal wastewater, in which the carbon and nitrogen were removed simultaneously. The results showed that COD removal, NH4+-N removal and TN removal efficiency could reach 82.5%, 95.1% and 84.2%, respectively, under the conditions of intra-membrane pressure of 13.6 kPa, HRT of 14 h, influent COD and NH4+-N concentrations of 338 mg/L and 75 mg/L. However, in the last period during the operation of the reactor, the TN removal efficiency dramatically decreased because of the excessive growth of biomass on the nonwoven fiber, which also had serious negative effect on nitrification course. The microbiological community and spatial profiles were observed by fluorescence in situ hybridization and scanning electron microscopy. The anaerobic and anoxic bacteria were mainly located in the outer anaerobic region of the biofilm, while the aerobic ammonium oxidizing bacteria were mainly located in the inner aerobic region of the biofilm. The co-existing and coupling effect of aerobic nitrifying bacteria and anaerobic denitrifying bacteria provided the large biological potential for the simultaneous nitrification and denitrification in the carbon membrane-aerated biofilm reactor.

[Influence of controlling factors on partial nitrification performance in membrane bioreactor].

A membrane bioreactor (MBR) was developed successfully to carry out partial nitrification process. Temperature, and dissolved oxygen (DO) were investigated as the factors which may affect the results. It has been proved that the optimal operational parameters were at 35 degrees C, ammonia loading 0.45 kg x (m3 x d)(-1) and < 0.5 mg/L, respectively, with the effluent NO3(-) -N concentration below 20 mg x L(-1) and rho(NO2(-) -N)/rho(NH4(+) -N) ratio being close to 1.0. It is not observed severe membrane fouling during all the experiment. Fluorescence in situ hybridization analysis indicated that aerobic ammonium oxidizers were the dominant population, and nitrite-oxidizing bacteria were inhibited. The microbiological community analysis further provided the necessary biological information for the realization of partial nitrification.