[Nitrogen Removal of Double-bacteria-layer System via PN/A Process].

Nitrification and anaerobic ammonia oxidation (ANAMMOX) sludge was acclimated via SBR and MBR reactors respectively, both of which were embedded with microbial immobilization technology and spliced together to construct a PN/A double-bacteria-layer system. A short-term experiment proved that ammonia-oxidizing bacteria (AOB) and ANAMMOX bacteria in the system played dominant roles separately in different stages, which maintained the acid-base balance and achieved efficient removal of NH4+-N (98.8%). A long-term experiment showed that the PN/A double-bacteria-layer system improved the utilization of dissolved oxygen (DO) and enhanced the stability and nitrogen removal efficiency, with limited dissolved oxygen. The nitrogen removal efficiency of the PN/A double-bacteria-layer system remained stable at~80% when the influent NH4+-N was 200 mg·L-1 or 400 mg·L-1 in the presence of 1.0 mg·L-1 DO, whereas those of the control group were only 58.1% and 61.4%, respectively. When influent NH4+-N and DO were 400 mg·L-1 and 3.0 mg·L-1, respectively, the PN/A double-bacteria-layer system achieved a nitrogen removal efficiency, nitrogen loading rate (NLR), and nitrogen removal rate (NRR) of 87.9%, 0.4 kg·(m3·d)-1, and 12.8 mg·(g·h)-1, respectively.

[Adhesion Force Analysis of Protein Fouling of PVDF Ultrafiltration Membrane Using Atomic Force Microscope].

To determine the fouling behavior of bovine serum albumin (BSA) on differet hydropniic PVDF ultrafiltration membrane over a range of pH, atomic force microscopy (AFM) and self-made colloidal probes were used to detect the microscopic adhesion forces of membrane-BSA and BSA-BSA, respectively. The results showed a positive correlation between the flux decline extent and the membrane-foulant adhesion force in the initial filtration stage, whereas the foulant-foulant interaction force was closely related to the membrane fouling in the later filtration stage. Moreover, the membrane-BSA adhesion interaction was stronger than the BSA-BSA adhesion interaction, which indicated that the fouling was mainly caused by the adhesion interaction between membrane and foulant. At the same pH, the adhesion force between PA membrane-BSA was smaller than that of PP membrane-BSA, illustrating the more hydrophilic the membrane was, the better the antifouling ability it had. The adhesion force between BSA-BSA fouled PA membrane was similar to that between BSA-BSA fouled PP membrane. These results confirmed that elimination of the membrane-BSA adhesion force is important to control the protein fouling of membranes.

[Efficacy of A2/O-MBR Combined Process in Wastewater Treatment and the Characteristics of Membrane Fouling].

The hydrophilic modification of PVA composite membrane was applied in the reversed A2/O-MBR process to treat wastewater, the removal efficacy of COD, NH4(+) -N, TN, TP, turbidity and performance of composite membrane were investigated. The results indicate that the average removal rates of COD, NH4(+) -N and TP were higher than 90%, 95% and 80% under different reflux ratio, respectively. The reflux ratio had large impact on TN removal rate: when the reflux ratio was 100%, the removal rate was low; when the reflux ratio increases the range from 100% to 300%, the removal rate was correspondingly increased. Under the efficient interception of membrane, water turbidity was always less than 0.05NTU, and the composite film was controlled at (12 ± 0.5) L x (m2 x h)(-1) flux, the operation was uninterrupted for 52 days without any cleaning process of the membrane, the average rate of membrane fouling is 13.22 Pa x h(-1) and the process of membrane fouling was very slow. After FTIR analysis, we confirmed that polysaccharide and protein is a main composition of organic pollutants. LB is further proved to be the main pollutants from micro acting force between the membrane and the pollutants, which is consistent with FTIR analysis.

Nutrient release, recovery and removal from waste sludge of a biological nutrient removal system.

The uncontrolled release of nutrients from waste sludge results in nitrogen and phosphorus overloading in wastewater treatment plants when supernatant is returned to the inlet. A controlled release, recovery and removal of nutrient from the waste sludge of a Biological Nutrient Removal system (BNR) are investigated. Results showed that the supernatant was of high mineral salt, high electrical conductivity and poor biodegradability, in addition to high nitrogen and phosphorus concentrations after the waste sludge was hydrolysed through sodium dodecyl sulphate addition. Subsequently, over 91.8% of phosphorus and 10.5% of nitrogen in the supernatants were extracted by the crystallization method under the conditions of 9.5 pH and 400 rpm. The precipitate was mainly struvite according to X-ray diffraction and morphological examination. A multistage anoxic-oxic Moving Bed Biofilm Reactor (MBBR) was then adopted to remove the residual carbon, nitrogen and phosphorus in the supernatant. The MBBR exhibited good performance in simultaneously removing carbon, nitrogen and phosphorus under a short aeration time, which accounted for 31.25% of a cycle. Fluorescence in situ hybridization analysis demonstrated that nitrifiers presented mainly in floc, although higher extracellular polymeric substance content, especially DNA, appeared in the biofilm. Thus, a combination of hydrolysis and precipitation, followed by the MBBR, can complete the nutrient release from the waste sludge of a BNR system, recovers nutrients from the hydrolysed liquor and removes nutrients from leftovers effectively.

[Membrane fouling based on change of membrane characteristic parameters during ultrafiltration of protein].

In order to further understand membrane fouling mechanism of various protein systems during ultrafiltration, polyethersulfone (PES) ultrafiltration membrane with relative molecular weight cut off of 50 x 10(3) was used, the ultrafiltration processes of three kinds of protein solution were investigated: lysozyme ( LYS), bovine serum albumin ( BSA), and LYS + BSA. Contact angle meter, field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) were adopted to determine the change of membrane characteristic parameters at different fouling stages. The results indicated that the changes of ultrafiltration membrane flux obviously exhibited three stages: sharp flux decline in the initial stage (approximately between 0-5 min), slow flux decline during the transition stage (approximately between 5-60 min), and stable flux in the late stage (approximately between 60-120 min). During the whole ultrafiltration process, the LYS-fouled membrane had the largest flux decline, followed by the LYS + BSA-fouled membrane, and the BSA-fouled membrane had the least decline. The changes of membrane characteristic parameters clearly indicated that the initial filtration stage of LYS was controlled by pore constriction, while pore blocking and pore constriction were the main fouling mechanism at the transition stage. Pore blocking was the main fouling mechanism of BSA in the initial fouling stage, while the transition stage was controlled by pore constriction. Cake filtration was the main fouling mechanism of LYS and BSA in the late stage. The membrane fouling of binary mixtures LYS + BSA appeared to be dominated by LYS.

[Copper and cadmium toxicities to activated sludge investigated with ToxTell biosensor].

Effects of different concentrations of Cu2+, Cu2+ and Cd2+ combined pollution on the removal performance of COD in activated sludge system were investigated, and the ToxTell biosensor with activated sludge was constructed to determine the toxicity of Cu2+, Cu2+ and Cd2+ combined pollution. The results showed that there was no significant impact on the activated sludge process when Cu2+ concentration was lower than 10 mg x L(-1), and the addition of Cd2+ enhanced the inhibition of COD removal, and the maximum inhibition efficiency of COD reached at about 1.5 h. With the increase of aeration time, the COD removal efficiency increased slowly again. The toxicity measurement with ToxTell biosensor was close to the biological effects (inhibition efficiencies of COD), which showed that the ToxTell biosensor could be used well in the early warming determination of Cu2+ and Cd2+ in the activated sludge process.

[Biodegradation under UV irradiation and microbial community changes].

Photolytic circulating-bed biofilm reactor (PCBBR) and internal loop photolytic-biological reactor (ILPBR) were respectively used for degradation of phenol, 2, 4, 6-trichlorophenol (TCP) and sulfamethoxazole (SMX). Experimental results indicated that the rates of phenol, TCP and SMX removal by coupled photolysis with biodegradation (P&B) reached at 0.65, 0.11 and 0.17 mg x (L x min)(-1), which was clearly higher than that by photolysis alone (P), biodegradation alone (B), except phenol removal rate by B,which was similar to the rates by P&B. The COD removal percentages of phenol and TCP were 99.5% and 72.1%, and TOC removal percentage of SMX was 57.3, which all were higher that by P and B. The biofilms under UV irradiation were taken as samples for molecular biological analysis to get the significant results that microbial communities in biofilms took great change compared with that without UV irradiation, but they still kept bioactivity degrading organic pollutants. That is significant results for technological innovation on recalcitrant organic wastewater treatment.

[Acute toxicity analysis performance of CellSense biosensor with E. coli].

E. coli microbial electrodes for CellSense biosensor were prepared by polycarbonate membrane immobilization process, and their performance for heavy metals and toxic organic compounds acute toxicity determination were studied. The results showed that when E. coli was in logarithmic and stationary phase, the CellSense biosensor with E. coli showed good performance in heavy metal ions and organic pollutants acute toxicity analysis, when E. coli was in its decline phase, the stability and sensitivity of the CellSense biosensor was poor. The EC50 values of Hg2+, Cu2+, Zn2+, o-chlorophenol (2-CP) and p-nitrophenol (4-NP) detected by CellSense biosensor with E. coli were 0.6, 3.1, 5.8, 180 and 94 microg/mL, respectively. The immobilized E. coli electrodes could still suit for acute toxicity assessment after 2 months storage at 4 degrees C.

[Flocculation characteristics of the return sludge in chemical-biological flocculation process].

The chemical-biological flocculation (CBF) process was used to treat municipal wastewater in Shanghai, and the effect of its return sludge on pollutant removal was studied through stopping chemical addition, simulating different return sludge ratio, and analyzing extracellular polymeric substances (EPS). The results show that the return sludge in CBF exhibits strong pollutant removal capability, and chemical in its return sludge can further TP removal and enhance CBF's adaptability to the influent TP impulse. After stopping PAFC (Al2 O3 : 10.8%, Fe2 O3: 1.8%) addition, COD removal efficiency is achieved at about 50%, and removal rates of PO4(3-) and TP gradually decline. It is also found that chemical addition plays an important role in promote sludge sedimentation in CBF. EPS extracted from CBF is 145.89 mg/g, while EPS from CEPT is only 17.24 mg/g, which indicates that there is strong biological flocculation behavior in CBF. With the increase of return sludge ratio, TP and COD removal efficiencies decrease in CEPT, which reveals that chemical in waste sludge has poor flocculation capability, while CBF return sludge exhibits good flocculation behavior due to its biological flocculation. Chemical flocculation and biological flocculation work collaboratively in CBF process.

[Toxicity assessments of landfill leachate based on CellSense biosensor].

The toxicity of landfill leachate of domestic wastes in different treatment unites landfill leachate pretreatment (No.1), facultative lagoon (No.2), aerated lagoon (No.3), mineralized refuse bioreactor (No.4) and catalysis iron inner electrolysis (No.5) of leachate treatment process in Shanghai was determined based on CellSense biosensor with E. coli. The results showed that the toxicity of the effluent in different treatment unites for landfill leachate increased during the treatment process due to the influence of matrix effect and intermediate toxic products of refractory organic matters. The toxicity of the effluent from No.1 to No.5 unites are 90% (EC10), 80% (EC30), 60% (EC50), 80% (EC50) and 2% (EC50), respectively. This showed no significant correlation with their corresponding COD and ammonia nitrogen concentrations.

[Using high-density universal 16S rRNA microarray in microbial molecular ecology research].

High-density universal 16S rRNA Microarray was used to detect the microbial community in membrane bioreactor (MBR). The results showed MBR had high microbial diversity. 1019 bacteria were detected by Microarray in MBR. Proteobacteria was the predominant phylum. It had 657 OTUs, occupying 64.5% of the total bacteria, gamma Proteobacteria was the main class of Proteobacteria, which occupied 35.8% of Proteobacteria, but the average fluorescence intensity of was not very high. Despite the bacteria diversity of beta Proteobacteria was lower than gamma Proteobacteria. However, it occupied 40% and 36% in the 25 and 50 dominant bacteria according to relative average fluorescence intensity. Clostridia had a relative high concentration when compare the average fluorescence intensity of the whole bacteria in MBR. Some common nitrify bacteria such as Nitrosomonadaceae and Nitrospiraceae were also detected and had high fluorescence intensity in the system. Microarray is a newer molecular method and has some advantages such as real time, high efficiency and exact results. It's very suitable for investigation of microbial diversity in wastewater treatment.

[Influence of community structure of phosphorus removing bacteria under oxygen contain in processes for phosphorus removal].

It was studied for community structure of microorganisms in the phosphorus removal processes under the circulating situation, and analyzed for microorganism's structure and behavior characteristics by the molecular biology technique with direct obtaining of DNA from samples of activated sludge, and by nested PCR and DGGE. It was also determined community structure of microorganisms. It was analyzed structures of Proteobacteria and Acidobacterium by 16S rDNA V3 area gene fragments sequences in activated sludge. By comparing gene sequences in the National Center of Biological Information (NCBI), were determined the kinds of part of microorganisms. Analyzing the low of changes of preponderant bacteria in anaerobic/aerobic and anaerobic/anoxic conditions takes to know, that under the stable situation of phosphorus removing, the system of microorganism's structure can kept mostly constant. Minority races that have changed in amount or kind has something to do with the variation of oxygen level in the system, but structure totally can adapt the environmental conditions of the processes, while it placed in dynamic varieties.

Production and application of a novel bioflocculant by multiple-microorganism consortia using brewery wastewater as carbon source.

The flocculating activity of a novel bioflocculant MMF1 produced by multiple-microorganism consortia MM1 was investigated. MM1 was composed of strain BAFRT4 identified as Staphylococcus sp. and strain CYGS1 identified as Pseudomonas sp. The flocculating activity of MMF1 isolated from the screening medium was 82.9%, which is remarkably higher than that of the bioflocculant produced by either of the strains under the same condition. Brewery wastewater was also used as the carbon source for MM1, and the cost-effective production medium for MM1 mainly comprised 1.0 L brewery water (chemical oxygen demand (COD) 5000 mg/L), 0.5 g/L urea, 0.5 g/L yeast extract, and 0.2 g/L (NH4)2SO4. The optimal conditions for the production of MMF1 was inoculum size 2%, initial pH 6.0, cultivating temperature 30 degrees C, and shaking speed 160 r/min, under which the flocculating activity of the MMF1 reached 96.8%. Fifteen grams of purified bioflocculant could be recovered from 1.0 L of fermentation broth. MMF1 was identified as a macromolecular substance containing both protein and polysaccharide. It showed good flocculating performance in treating indigotin printing and dyeing wastewater, and the maximal removal efficiencies of COD and chroma were 79.2% and 86.5%, respectively.

Particle size distribution and removal by a chemical-biological flocculation process.

The particle characterization from the influent and effluent of a chemical-biological flocculation (CBF) process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment (CEPT) process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes of CBF process, CEPT process, and PST process (primary sediment tanks). The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.

Community analysis of ammonia and nitrite oxidizers in start-up of aerobic granular sludge reactor.

A lab-scale sequencing batch reactor (SBR) was set-up and the aerobic granular sludge was successfully incubated using anaerobic granular sludge as seed sludge. Nitrogen was partially removed by simultaneous nitrification and denitrification (SND) via nitrite with free ammonia (FA) of about 10 mg/L. The denaturing gradient gel electrophoresis (DGGE) method was used to investigate community structure of alpha-Proteobacteria, beta-Proteobacteria, ammonia oxidizing bacteria (AOB), and Nitrospira populations during start-up. The population sizes of bacteria, AOB and Nitrospira were examined using real-time PCR method. The analysis of community structure and Shannon index showed that stable structure of AOB population was obtained at day 35, while the communities of alpha-Proteobacteria, beta-Proteobacteria, and Nitrospira became stable after day 45. At stable stage, the average cell densities were 1.1 x 10(12), 2.2 x 10(10) and 1.0 x 10(10) cells/L for bacteria, AOB and Nitrospira, respectively. The relationship between characteristics of nitrifying bacteria community and nitrogenous substrate utilization constant was discussed by calculating Pearson correlation. Certain correlation seemed to exist between population size, biodiversity, and degradation constant. And the influence of population size might be greater than that of biodiversity.

[Study on biodegradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols].

Purpose of this study was to determine the treatability of 2,4-dichlorophenol (2,4-DCP) by anaerobic granular sludge which was acclimated by mixed mono-chlorphenols (2-CP, 4-MCP). The characteristic of degradation of 2,4-DCP by anaerobic sludge acclimated by mixed mono-chlorphenols was investigated through shake flask study and performance of continuous flow anaerobic bioreactors. The difference of degradation of 2,4-DCP by acclimated and unacclimated sludge was also compared. 2,4-DCP was degraded at 50 h and 180 h respectively for acclimated and unacclimated sludge, which testified that acclimated sludge could more effectively degrade 2,4-DCP. Although the intermediate product 4-MCP was present in both reaction system, 4-MCP could be degraded completely after 400 h in the acclimated sludge but accumulated in the unacclimated sludge. Therefore, acclimation by the mixed mono-chlorphenols (2-CP, 4-MCP) could enhance the ability of para- and meta-dechlorination for anaerobic sludge and increase the treatability of 2,4-DCP. The results of continuous anaerobic sludge-suspended carrier bioreactor (ASSCB) indicate that inoculation of the acclimated sludge by mixed mono-chlorphenols can degrade two mono-chlorphenols simultaneously, shorten the setup period, and increase the efficiency of degrading 2,4-DCP. 2-CP was easily degraded with removal rate of over 80% . While the removal rate of 4-MCP was fluctuating within 30% - 80% with changes of its influent concentration.

[Analysis on mechanism of the chemical-biological flocculation process].

Zeta potential, particle size distribution and molecular weight distribution of dissolved TOC were studied to elementarily disclose the mechanism of the chemical-biological flocculation (CBF) process to treat municipal wastewater. Chemically enhanced primary treatment (CEPT) process and primary sedimentation tank process were taken as the parallel-compared wastewater treatment processes. The experimental results show that under the same dosage, Zeta potential of the CBF process effluent is equal to that of the CEPT process, which indicates that flocculant in return sludge does not change the stabilization of particles in CBF reactor, and the biological flocculation is the key reason for CBF is superior to CEPT. In CBF process, good removal results are achieved for particles >10 microm and dissolved TOC with molecular weight >6 ku by chemical dosage, and biological flocculation can not only promote the removal of particles >10 microm and dissolved TOC with molecular weight >6 ku, but also have high capacity to remove small particles and dissolved TOC with small molecular weight, with the results that particles >3 tpm are removed completely and TOC with molecular weight of 2-6 ku are removed by 42.5% .

The effect of Fe0/Fe2+/Fe3+ on nitrobenzene degradation in the anaerobic sludge.

The influence of Fe(0)/Fe(2+)/Fe(3+) on the nitrobenzene (NB) degradation in the anaerobic granular sludge was studied and the results demonstrated that: adding iron powder into the anaerobic sludge could exert an accelerative effect on the NB degradation and the degradation rate was faster than that by using iron or the anaerobic sludge alone. The external addition of Fe(2+)/Fe(3+) exhibited different influences on the NB degradation depending on the concentrations of Fe(2+)/Fe(3+) and the solution's pH. When Fe(2+)/Fe(3+) are less than 100 mg/L at pH 6, Fe(2+)/Fe(3+) inhibited the NB degradation slightly, and when Fe(2+)/Fe(3+) was 100-200 mg/L, the NB degradation was enhanced. When pH was shifted to 9, Fe(2+) of lower than 100 mg/L promoted the NB degradation, and 200 mg/L Fe(2+) inhibit the NB degradation. The synergism of combined use of iron and the anaerobic sludge in treating NB wastewater was proposed, and adjusting the concentrations of Fe(2+)/Fe(3+) in the anaerobic sludge according to the pH of the wastewater could be an effective method to obtain a high removal rate of NB.

Biosorption of cadmium(II) and lead(II) ions from aqueous solutions onto dried activated sludge.

The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions(Cd(lII) and Pb(ll)) followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd(ll) and Pb(II) biosorption onto dried activated sludge was their binding with amide I group.

Operation of three parallel AN/AO processes to enrich denitrifying phosphorus removing bacteria for low strength wastewater treatment.

Three parallel anaerobic-anoxic/anaerobic-aerobic (AN/AO) processes were developed to enrich denitrifying phosphorus removal bacteria (DPB) for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN (anaerobic-anoxic) process and an AO (anaerobic-aerobic) process. In the AO process, the common phosphorus accumulating organisms (PAOs) was dominate, while in the AN process, DPB was dominate. The volume of anaerobic zone(V(ana)):anoxic zone(V(ano)): aerobic zone (V(aer)) for the parallel AN/AO process is 1:1:1 in contrast with a V(ana):V(aer) and V(ano):V(aer) of 1:2 and 1:4 for a traditional biological nutrient removal process (BNR). Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L.