Impact of carbon/nitrogen ratio on the performance and microbial community of sequencing batch biofilm reactor treating synthetic mariculture wastewater.

The differences of cultured organism species, aquaculture model and supervisor mode lead to different carbon/nitrogen ratios in mariculture wastewater. Therefore, the performance, microbial community and enzymatic activity of sequencing batch biofilm reactor were compared in treating synthetic mariculture wastewater at different chemical oxygen demand/nitrogen (COD/N) ratios. Compared with COD/N ratio of 6, the ammonia-oxidizing rate and nitrite-oxidizing rate at COD/N ratio of 5, 4 and 3 increased by 3.

Effect of aerobic/anoxic duration on the performance, microbial activity and microbial community of sequencing batch biofilm reactor treating synthetic mariculture wastewater.

The effect of aerobic/anoxic duration on the performance, microbial community and enzymatic activity of sequencing batch biofilm reactor (SBBR) were investigated in treating mariculture wastewater. The microbial oxygen uptake rate and nitrifying rate gradually decreased with the aerobic/anoxic duration from 120/210 to 30/300 min, whereas the nitrite reducing rate and nitrate reducing rate had the opposite results. The activities of dehydrogenase, ammonia monooxygenase and nitrite oxidoreductase gradually decreased with the aerobic/anoxic duration from 120/210 to 30/300 min, but the activities of nitrate reductase and nitrite reductase had a gradual increment.

Single and combined impacts of nickel and cadmium on the performance, microbial community and enzymatic activity of sequencing batch reactors.

The performance, microbial enzymatic activities and the microbial community of sequencing batch reactors (SBRs) were evaluated under the single and combined nickel (Ni) at 20 mg/L and cadmium (Cd) at 10 mg/L. The single and combined Ni and Cd had no adverse impacts on the COD removal, whereas the NH-N removal efficiency declined sharply from about 99% to 34.42% and 42.

Effects of transient 3-chloroaniline shock loading on the performance, microbial community and enzymatic activity of sequencing batch reactor.

Chloroanilines from industrial wastewater can produce adverse effects on biological wastewater treatment systems due to their potential biotoxicity. The performance, nitrogen removal rate, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated under transient 3-chloroaniline shock loading. After 40 mg/L 3-chloroaniline shock loading of 24 h on day 9, the chemical oxygen demand (COD) removal efficiency decreased from 90.

Long-term effect of different Cu(II) concentrations on the performance, microbial enzymatic activity and microbial community of sequencing batch reactor.

The performance, microbial community and enzymatic activity of sequencing batch reactors (SBRs) were investigated under 75-day exposure of different Cu(II) concentrations. Cu(II) at 0-5 mg/L had no distinct impact on the chemical oxygen demand (COD) and nitrogen removal, oxygen-uptake rate (OUR), nitrification and denitrification rate, and microbial enzymatic activity. The inhibitory effects of Cu(II) at 10 and 30 mg/L on the nitrogen removal rate, OUR, and microbial enzymatic activity of SBR increased with an increment in operation time due to the Cu(II) biotoxicity and the Cu(II) accumulation in activated sludge.

Insights into long-term effects of amino-functionalized multi-walled carbon nanotubes (MWCNTs-NH) on the performance, enzymatic activity and microbial community of sequencing batch reactor.

Carbon nanotubes (CNTs) inevitably enter domestic sewage and industrial wastewater with the continuous increase of their production and application field. The potential effect of CNTs on biological wastewater treatment processes has raised wide concerns due to their biotoxicity. In the present study, the performance, microbial community and enzymatic activity of sequencing batch reactors (SBRs) were evaluated under 148-day exposure of amino-functionalized multi-walled CNTs (MWCNTs-NH) at 10 and 30 mg/L.

Effects of aluminum oxide nanoparticles on the performance, extracellular polymeric substances, microbial community and enzymatic activity of sequencing batch reactor.

The performance, pollutant removal rate, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were investigated under oxide nanoparticles (AlO NPs) stress. AlO NPs at 0-50 mg/L showed no evident impact on the COD and NH removals of SBR. The oxygen-uptake rate, nitrifying rate and nitrite-reducing rate slightly diminished with the increase of AlO NPs concentration.

Insights into the effect of nickel (Ni(II)) on the performance, microbial enzymatic activity and extracellular polymeric substances of activated sludge.

The performance, nitrogen removal rate, microbial enzymatic activity and extracellular polymeric substances (EPS) of activated sludge were assessed under nickel (Ni(II)) stress. The organic matter and NH-N removal efficiencies were stable at less than 10 mg/L Ni(II) and subsequently decreased with the increment of Ni(II) concentration from 10 to 30 mg/L. The specific oxygen uptake rate and dehydrogenase activity kept stable at less than 5 mg/L Ni(II) and then declined at 5-30 mg/L Ni(II).

Long-term impacts of carboxyl functionalized multi-walled carbon nanotubes on the performance, microbial enzymatic activity and microbial community of sequencing batch reactor.

The performance, microbial community and enzymatic activity of sequencing batch reactors (SBRs) were evaluated under long-term exposure of 0, 10 and 30 mg/L carboxyl functionalized multi-walled carbon nanotubes (MWCNTs-COOH). The presence of 10 mg/L MWCNTs-COOH displayed no adverse impacts on the COD and NH-N removal of SBR, whereas 30 mg/L MWCNTs-COOH declined the COD and NH-N removal. MWCNTs-COOH inhibited the denitrifying process and led to the accumulation of effluent NO-N concentration.

Impact of ampicillin on the nitrogen removal, microbial community and enzymatic activity of activated sludge.

The performance, nitrogen removal rate, extracellular polymeric substances (EPS), microbial community and enzymatic activity of activated sludge have been assessed in a sequencing batch reactor under ampicillin stress. The chemical oxygen demand and ammonia removal kept relatively stable at 0-30 mg/L ampicillin. No obvious nitrite and nitrate accumulation was found in the effluent.