Treatment of Coking Wastewater by a Submerged Membrane Bioreactor with Suspended Carriers

A renovated hybrid membrane bioreactor (HMBR) was investigated for its capability of coking wastewater treatment. The HMBR combined biofilm process and membrane filtration process. The system was efficient in degrading COD and phenol in coking wastewater and controlling membrane. It was found that the coking wastewater could be effectively treated with 88.6% of COD removal efficiency and 98.3% of phenol removal efficiency at hydraulic retention time (HRT) of 16 h. The removal efficiency of COD and phenol decreased gradually down to 83.2% and 97.7% when HRT decreased to 8 h. The long term experiments indicated that the degree of membrane fouling for HMBR was far lower than that for MBR. The scrubbing effect of suspended carrier in HMBR was observed to be capable of reducing the cake fouling of membrane. The operation time of HMBR was 8.4-fold longer than that with MBR.

Suspended Carrier Used in Municipal Wastewater Treatment

In this study, suspended carrier bed process was applied to treat the effluent from the chemical-biological flocculation plant. The bio-startup characteristics and the mechanisms of biofilm maturation were investigated. Results showed that the NH3-N removal efficiency was higher than 80% after a 10d run, and the NH3-N concentration of effluent was lower than 5.0mg/L, which satisfies the needs of The Pollutants Discharge Standard for Municipal Wastewater Treatment Plants (Class I-A). In other words, the suspended carrier used here did a good job. The bed finished its bio-startup process with stable nitrification efficiency. The biofilm formed on the carriers wing plates, which was helpful for its adhesion and ageing biofilm to fall off. It was found through electron microscope observation and PCR-DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis) that the biofilm which formed on the surface of the carrier contained plenty of microbes. The stability of the microbial system was efficient in stabilizing nitrification.

Research and Development of a New Nano-Attapulgite PVF Suspension Carrier in Wastewater Treatment

The optimum proportion and comprehensive performance as sewage treatment microbial carriers of a new type nanoattapulgite polyvinyl alcohol-formaldehyde suspended carrier (AT-PVF) was researched. The results show that when the polyvinyl alcohol (PVA) dosage is at the range of 10%-16%, H2SO4: PVA plays greatest impact on carrier performance, followed by CH2O: PVA and surfactant, PVA at last. Finally, a new formula of the AT-PVF carrier has been developed, which is showed as follows: PVA 13%, CH2O/PVA weight ratio=0.75, H2SO4/PVA weight ratio=1.0, surfactant 0.5%, AT 0.4%. Test results show that AT-PVF is superior to polyurethane carriers in physical, chemical and biochemical performance.