Enhanced heterogeneous photo-Fenton-like degradation of tetracycline over CuFeO/biochar catalyst through accelerating electron transfer under visible light.

The visible-light induced heterogeneous photo-Fenton-like (HPF-like) process is regarded as a promising technique for organic pollutants degradation due to its efficient utilization of solar energy and high HO activation activity. This study prepared the CuFeO/biochar catalysts via hydrothermal technique at no extra reductant and systematically investigated their band structure and photoelectric properties. The dispersed distribution of CuFeO particles in CuFeO/biochar composites narrowed bandgap of CuFeO and promoted electron transport of CuFeO.

Photoelectrocatalytic degradation of p-chloronitrobenzene by g-CN/TiO nanotube arrays photoelectrodes under visible light irradiation.

As a typical refractory pollutant, p-chloronitrobenzene (p-CNB) from industrial wastewater poses a serious threat to the aquatic environment safety and human health. The photoelectrocatalytic (PEC) technology is regarded as a promising and cleaner approach for p-CNB removal. Therefore, the graphitic carbon nitride (g-CN) modified TiO nanotube arrays (g-CN/TNAs) were prepared as the photoelectrodes for p-CNB degradation.

Single and combined effects of divalent copper and hexavalent chromium on the performance, microbial community and enzymatic activity of sequencing batch reactor.

Divalent copper (Cu) and hexavalent chromium (Cr) are often encountered in industrial wastewater and municipal wastewater, the effect of combined Cu and Cr on biological wastewater treatment systems has cause wide concern. In the present research, the performance, microbial community and enzymatic activity of sequencing batch reactors (SBRs) were compared under the single and combined Cu at 20 mg/L and Cr at 10 mg/L. The chemical oxygen demand (COD) and ammonia nitrogen (NH-N) removal efficiencies under the combined Cu and Cr were less than those under the single Cu and Cr.

Insights into the effects of single and combined divalent copper and humic acid on the performance, microbial community and enzymatic activity of activated sludge from sequencing batch reactor.

The performance, microbial community and enzymatic activity of activated sludge from four identical sequencing batch reactors (SBRs) were compared by treating synthetic wastewater under the single and combined divalent copper (Cu) at 20 mg/L and humic acid (HA) at 20 mg/L. Compared with the absence of Cu and HA, the single HA slightly enhanced the oxygen uptake rate (OUR), the nitrification and denitrification rates and the activities of dehydrogenase, nitrifying enzymes and denitrifying enzymes, whereas the single Cu had the opposite results. The combined Cu and HA inhibited the OUR, nitrogen removal rate and enzymatic activity of activated sludge almost the same as the single Cu.

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.

Size-dependent effects of ZnO nanoparticles on performance, microbial enzymatic activity and extracellular polymeric substances in sequencing batch reactor.

ZnO nanoparticles (NPs) have been detected in various wastewater treatment plants. It is widely assumed that size has a crucial effect on the NPs toxicity. Concerns have been raised over probable size-dependent toxicity of ZnO NPs to activated sludge, which could eventually affect the treatment efficiencies of wastewater treatment facilities.

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.

Effect of magnesium oxide nanoparticles on microbial diversity and removal performance of sequencing batch reactor.

The performance, microbial enzymatic activity and microbial community of a sequencing batch reactor (SBR) have been explored under magnesium oxide nanoparticles (MgO NPs) stress. The NH-N removal efficiency kept relatively stable during the whole operational process. The MgO NPs at 30-60 mg/L slightly restrained the removal of chemical oxygen demand (COD), and the presence of MgO NPs also affected the denitrification and phosphorus removal.

Impacts of silver nanoparticles on performance and microbial community and enzymatic activity of a sequencing batch reactor.

The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated under silver nanoparticles (Ag NPs) stress. Over 5 mg/L Ag NPs inhibited the COD and phosphorus removals, whereas the NH removal kept stable during the whole operational period. The organic matter, nitrogen and phosphorus removal rates were obviously inhibited under Ag NPs stress, which showed similar varying trends with the corresponding microbial enzymatic activities.

Performance evaluation and microbial community shift of a sequencing batch reactor under silica nanoparticles stress.

The performance, microbial community and enzymatic activity of a sequencing batch reactor (SBR) were evaluated at different silica nanoparticles (SiO NPs) concentrations. SiO NPs concentration at 5-30mg/L had a slight inhibitory impact on the nitrogen and COD removals, whereas the phosphorus removal was obviously inhibited at 30mg/L SiO NPs. The rates of nitrification, nitrite reduction and phosphorus removal decreased with the increase of SiO NPs concentration.

Long-term impacts of titanium dioxide nanoparticles (TiO NPs) on performance and microbial community of activated sludge.

The long-term impacts of titanium dioxide nanoparticles (TiO NPs) on the performance and microbial community of activated sludge were evaluated in a sequencing batch reactor (SBR). TiO NPs impacted the COD and phosphorus removals of activated sludge, whereas the NH-N removal efficiency had no distinct change at 0-60mg/L TiO NPs. The presence of TiO NPs obviously inhibited the organic matter and nitrogen removal rates of activated sludge.

Magnetic FeO nanoparticles induced effects on performance and microbial community of activated sludge from a sequencing batch reactor under long-term exposure.

The performance and microbial community of activated sludge from a sequencing batch reactor (SBR) were investigated under long-term exposure of magnetic FeO nanoparticles (FeO NPs). The COD removal showed a slight decrease at 5-60mg/L FeO NPs compared to 0mg/L FeO NPs, whereas the NH-N removal had no obvious variation at 0-60mg/L FeO NPs. It was found that 10-60mg/L FeO NPs improved the denitrification process and phosphorus removal of activated sludge.

Long-term effects of cupric oxide nanoparticles (CuO NPs) on the performance, microbial community and enzymatic activity of activated sludge in a sequencing batch reactor.

The long-term effects of cupric oxide nanoparticles (CuO NPs) on the performance, microbial activity and microbial community of activated sludge were investigated in a sequencing batch reactor (SBR). The SBR performance had no evident change at 0-10 mg/L CuO NPs, whereas the CuO NPs concentration at 30-60 mg/L affected the COD, NH-N and soluble orthophosphate (SOP) removal, nitrogen and phosphorus removal rate and microbial enzymatic activity of activated sludge. Some CuO NPs might be absorbed on the surface of activated sludge or penetrate the microbial cytomembrane into the microbial cell interior of activated sludge.

Long-term effects of nickel oxide nanoparticles on performance, microbial enzymatic activity, and microbial community of a sequencing batch reactor.

The nitrogen and phosphorus removal, microbial enzymatic activity, and microbial community of a sequencing batch reactor (SBR) were evaluated under long-term exposure to nickel oxide nanoparticles (NiO NPs). High NiO NP concentration (over 5 mg L) affected the removal of chemical oxygen demand, nitrogen, and phosphorus. The presence of NiO NP inhibited the microbial enzymatic activities and reduced the nitrogen and phosphorus removal rates of activated sludge.