Optimization of a compact on-site stormwater runoff treatment system: Process performance and reactor design.

Stormwater runoff has become a major anthropogenic urban pollution source that threatens water quality. In this study, coagulation-sedimentation, and ammonium ion exchange and regeneration (AIR) modules were coupled as a CAIR system to efficiently treat stormwater runoff. In the coagulation module, 99.

Performance and microbial community of MBBRs under three maintenance strategies for intermittent stormwater treatment.

Maintaining microbial activities is a critical problem for biological treatment processes of stormwater runoff because of its intermittent nature. In this study, the suitability of the moving bed biofilm reactor (MBBR) was assessed for stormwater treatment by long-term dry - rainy alternation operation. Three strategies to maintain microbial activities during the dry period, including keeping idle (MBBR), introducing river water throughout the period (MBBR), and ahead of a rainy day (MBBR), were investigated.

Mainstream nitrogen separation and side-stream removal to reduce discharge and footprint of wastewater treatment plants.

The activated sludge process is efficient for pollutant removal, but was criticized for its large upfront investment and land area requirements. Improving nitrogen removal to levels sufficient to reduce eutrophication is a challenge to conventional nitrification and denitrification, which is limited by process configuration (with nitrate recirculation) and environmental inhibition. To satisfy stringent discharge standards within a compact plant footprint, a sustainable strategy by moving nitrogen removal from mainstream to side-stream is designed by a cycle of ammonium exchange, regeneration and nitrogen removal (AERN), combined with biological and physiochemical technologies.

Enhancing methane production of anaerobic sludge digestion by microaeration: Enzyme activity stimulation, semi-continuous reactor validation and microbial community analysis.

Effects of microaeration pretreatment on sludge hydrolysis, biogas production and microbial community structure in anaerobic digestion (AD) were investigated by bench-scale tests and semi-continuous experiments. Bench tests showed that microaeration led to the release of dissolved organic matters, generation of volatile fatty acids and stimulation of enzyme activity. Correlation analysis showed that methane production was significantly correlated with the activity of α-glucosidase at 0.

Sludge reduction and microbial structures of aerobic, micro-aerobic and anaerobic side-stream reactor coupled membrane bioreactors.

An anoxic/oxic membrane bioreactor (MBR) and three side-stream reactor (SSR) coupled membrane bioreactors were operated in parallel to investigate effects of dissolved oxygen (DO) level in SSR on sludge reduction and microbial community structure of SSR-MBRs. The four MBRs were equally efficient in COD and ammonium nitrogen removal. The anaerobic and micro-aerobic SSR favored nitrogen removal through denitrification, simultaneous nitrification and denitrification and autochthonous substrate release as carbon source.

Effects of hydraulic retention time on process performance of anaerobic side-stream reactor coupled membrane bioreactors: Kinetic model, sludge reduction mechanism and microbial community structures.

An anoxic/oxic membrane bioreactor (AO-MBR) and three anaerobic side-stream reactor (ASSR) coupled MBRs (ASSR-MBR) were operated to investigate the effects of hydraulic retention time of ASSR (HRT) and to elucidate sludge reduction mechanisms in ASSR-MBRs. Increasing HRT from 3.3 to 6.

Correlation of microbial community structure with pollutants removal, sludge reduction and sludge characteristics in micro-aerobic side-stream reactor coupled membrane bioreactors under different hydraulic retention times.

A micro-aerobic side-stream reactor (MSSR) was inserted in returned sludge line of a membrane bioreactor (MBR) for sludge reduction. Three MSSR coupled MBRs (M-MBRs) and an anoxic/oxic MBR (AO-MBR) were operated in parallel to investigate effects of micro-aerobic condition and hydraulic retention time (HRT) of MSSR (HRT) on process performance. M-MBRs and AO-MBR were equally effective in COD and NH-N removal.

Enhancement of sludge reduction by ultrasonic pretreatment and packing carriers in the anaerobic side-stream reactor: Performance, sludge characteristics and microbial community structure.

Effects of ultrasonic pretreatment and packing carriers on sludge reduction, settleability, dewaterability and microbial community structure in the anaerobic side-stream reactor (ASSR) were investigated with three anaerobic reactors operated in parallel. Ultrasonication from 3.65% in the ASSR to 5.