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A one-dimension aerobic granule mathematical model was established, basing on mathematical biofilm model and activated sludge model. The model was used to simulate simple aerobic granule process such as nutrients removal, granule diameter evolution, cycle performance as well as depth profiles of DO and biomass. The effluent NH4(+) -N concentration decreased as the modeling processed. The simulation effluent NO3(-)-N concentration decreased to 3 mg x L(-1) as the granules grew. While the granule diameter increased from 1.1 mm on day 30 to 2.5 mm on day 100, the TN removal efficiency increased from less than 10% to 91%. The denitrification capacity was believed to enhance because the anoxic zone would be enlarged with the increasing granule diameter. The simultaneous nitrification and denitrification occurred inside the big aerobic granules. The oxygen permeating depth increased with the consumption of substrate. It was about 100-200 microm at the beginning of the aeration phase, and it turned to near 800 microm at the end of reaction. The autotrophs (AOB and NOB) were mostly located at the out layer where the DO concentration was high. The heterotrophic bacteria were distributed through the whole granule. As hydrodynamic shear coefficient k(de) increased from 0.25 (m x d)(-1) to 5 (m x d)(-1), the granule diameter under steady state decreased form 3.5 mm to 1.8 mm. The granule size under the dynamic steady-state decreased with the increasing hydrodynamic shear force. The granule size could be controlled by adjusting aeration intensity.

The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/ anoxic mode (AOA MBR) was examined under three aeration intensities [2.5, 3.75 and 5.0 m3 x (m2 x h)(-10]. The results showed that the averaged removals of COD were over 90% at different aeration intensities. And the higher aeration intensity was, the more ammonia nitrogen removal rate achieved. The removal rates of NH4(+) under the three aeration intensities were 84.7%, 90.6% and 93.8%, respectively. Total nitrogen removal rate increased with the increasing aeration intensity. But excessive aeration intensity reduced TN removal. The removal rates of TN under the three aeration intensities were 83.4%, 87.4% and 80.6%, respectively. Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR. The ratio of denitrification phosphorus removal under the three aeration intensities were 20%, 30.2% and 26.7%, respectively.

Based on the consistent anaerobic status of outer layer of membrane-aerated biofilm reactor (MABR) and internal anaerobic baffled reactor (ABR), MABR and ABR were started up separately. The aerating membrane module was installed into a compartment of anaerobic baffled bioreactor to form the Hybrid MAB-ABR (HMABR). After the installation of membrane module, total COD and VFA concentrations in the HMABR effluent were deceased by 59.5% and 68.1% respectively, with increased nitrogenous pollutant remove efficiency by 83.5%, at influent COD concentration of 1600 mg/L and NH4+ -N concentration of 80 mg/L. When organic loading rate was increased by 50%, the effluent COD concentration was still below the level of 60 mg/L, indicating its good capability of counteracting influent organic loading fluctuation. Due to the decreased COD concentration and increased nitrate concentration in the third compartment after installing the membrane module, the biogas volume and methane contents in the third compartment were decreased, resulting in the steady and excellent effluent quality. In this hybrid process, the improved simultaneous removal of carbon and nitrogen for high-strength nitrogenous organic pollutants was realized in a single reactor.

A membrane bioreactor (MBR) was developed successfully to carry out partial nitrification process. Temperature, and dissolved oxygen (DO) were investigated as the factors which may affect the results. It has been proved that the optimal operational parameters were at 35 degrees C, ammonia loading 0.45 kg x (m3 x d)(-1) and < 0.5 mg/L, respectively, with the effluent NO3(-) -N concentration below 20 mg x L(-1) and rho(NO2(-) -N)/rho(NH4(+) -N) ratio being close to 1.0. It is not observed severe membrane fouling during all the experiment. Fluorescence in situ hybridization analysis indicated that aerobic ammonium oxidizers were the dominant population, and nitrite-oxidizing bacteria were inhibited. The microbiological community analysis further provided the necessary biological information for the realization of partial nitrification.

The self-designed MUCT-MBR simplifies the MUCT process with reducing reactors from 5 to 2, which greatly reduces land occupied by equipment. Instead of secondary sedimentation tank, the membrane effluent quality is quite safe, and the operation is simple. In the investigation about simultaneous phosphorus and nitrogen removal of MUCT-MBR, the results showed that: when the proportions of C, N and P in the influent were 33.3/5/1-25/5.5/1, the average removal rate of COD, TN and TP in the whole experimental process were 89.3%, 75.4% and 79.2%, respectively. And the sludge settling capacity had no influence on the membrane effluent quality. The key factor of N and P removal rates is denitrifying phosphorus removal in anoxic condition. The proportion of denitrifying phosphate accumulating organisms (DPAOs) and the rate of denitrifying phosphorous removal were 84.2% and 67.07% on the 58th day, respectively.

To alleviate membrane fouling and reduce the price of membrane module, polyvinyl alcohol microsphere pre-coated dynamic membranes (PVA-MS/PCDMs) were investigated detailedly. It was prepared when the polyvinyl alcohol microsphere of the pre-coated reagent deposited on the surface and entered the pores of porous substrate common filter cloth which was low-cost by means of circulatory filtration. The morphology and structure of PVA-MS/PCDMs were examined using scanning electron microscope (SEM), and approximate maximal separated aperture, water contact angle, pure water permeation resistance and relative Zeta potential of the membrance surface were also determined. The results showed that pure water permeation resistance of PVA-MS/PCDMs was between 0.64 x 10(10) m(-1) and 3.84 x 10(10) m(-1) and the approximate maximal separated aperture reached microfiltration level. The hydrophilicity of PVA-MS/PCDMs increased with increasing PVA-MS pre-coated mass. The relative Zeta potential of the PVA-MS/PCDMs, which were measured using 0.01 mol x L(-1) KCl solution, pH 8.0 +/- 0.2 and at 20 degrees C, reached a peak value of -36.4 mV with pre-coated mass of 15.7 g x m(-2) PVA-MS on the membrance surface. In addition, evolutions of PVA-MS/PCDMs flux versus time were investigated using a 4 hours short-term filtration experiment at 9.5 kPa in an SMBR and the permeability coefficient of PVA-MS/PCDMs were measured by the extracellular polymeric substances (EPS) diffusion experiments. Results indicated that the PVA-MS/PCDMs presented dramatically high anti-fouling characteristics when the pre-coated mass of PVA-MS was 23.9-61.9 g x m(-2).

The performances of A/O-MBR/RO system for the removal of nitrogen and COD were investigated. Result indicated that most organic was removed in the A/O-MBR and the average removal efficiency was 95.6%. The water quality of RO effluent which in terms of TOC < 0.9 mg x L(-1), TN < 12.65 mg x L(-1), total rigidity < 0.038 mol x L(-1), total alkalinity < 14.6 mg x L(-1) could meet the water quality requirements for the town wastewater reuse. The average removal efficiency of organic was almost unaffected by COD/N, but the process of TN removal was affected by COD/N. TN removal was primarily based on simultaneous nitrification and denitrification (SND) process occurred in the aerobic zone and the average removal efficiency of TN was 89.4% with average COD/N of 10.2. Both aerobic SND and conventional biological nitrification/denitrification contributed to nitrogen removal, the average removal efficiency of TN was 72%, 74% with average COD/N of 7.1 and 5.6. The fouling cake layer formed on the RO membrane surface was observed by scanning electric microscopy. The membrane fouling was characterized by Fourier transform infrared spectroscopy technique which showed that the major components of the foulants were soluble microbe products.

An improved three-stage vertical flow constructed wetland (CW) was used for tertiary treatment of effluent from two typical Dalian municipal wastewater treatment plants. The experiments were carried out under ambient condition in Dalian for the whole year. Performances of the CW for COD, TN, NH4(+) -N and TP removal in summer (Jun.-Aug.), winter (Nov.-Jan. the second year) and spring (Feb.-Apr.) were compared. In summer, the removal rates of COD, TN, NH4(+) -N and TP reached 88.5%, 76%, 100% and 98%, respectively. While in winter they reached 88%, 85.3%, 86.4% and 97%, respectively. In spring, the removal rates reached 87.7%, 76.7%, 70.3% and 95.5%, respectively. The effluent water quality for summer, winter and spring were: COD 2.8, 3.8 and 3.9 mg x L(-1), respectively; TP 0.02, 0.05, and 0.07 mg x L(-1), respectively; TN 6.8, 2.9, and 9.2 mg x L(-1), respectively; NH4(+)-N 0.01, 0.3, and 8.1 mg x L(-1), respectively. Results showed good performance of CW for Dalian municipal wastewater tertiary treatment, especially for COD and TP removal. The effluent COD and TP meet the needs of Environmental Quality Standard for Surface Water (GB 3838-2002) III, whereas the effluent TN and NH4(+)- N meet the needs of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002) class I A and B, separately. The pollutant removal loads in summer, winter and spring were as flow: COD 4.9, 5.1, and 5.0 g x (m2 x d)(-1); TN 3.4, 3.0, and 5.5 g x (m2 x d)(-1); NH4(+) -N 0.2, 0.6, and 3.7 g x (m2 x d)(-1); TP 0.15, 0.30, and 0.28 g(m2 x d)(-1). It is indicated that no significant influence of seasons on pollutant removal is found by comparing the removal rates as well as pollutant removal loads in different seasons, however, the removal of NH4(+) -N and TN in CW is mainly influenced by influent pollutant loads.

To investigate the removal efficiency of synthetic wastewater and characteristics of simultaneous nitrification and denitrification (SND) performances, a new type of moving bed membrane bioreactor (MBMBR) had been developed by using carriers instead of activated sludge in membrane bioreactor (MBR). Results showed that good organics removal and SND performances was achieved during the 67 d experimental period. COD, ammonium and total nitrogen removal efficiencies of MBMBR remained 88.3%-99.2%, 72.1%-99.8% and 62.0%-96.3% respectively as influent COD were 573.5-997.7 mg/L and ammonium nitrogen were 45.5-99.2 mg/L. Moreover, batch experiments results showed the optimum DO for nitrogen removal was 1 mg/L, ammonium and total nitrogen removal efficiencies were 100% and 60.0%, respectively. Aerobic denitrification may occur in biofilm system. When DO concentration was 3 mg/L and the organic carbon source was abundant, 99.0% total nitrogen removal efficiency and 99.8% SND efficiency was achieved in batch experiment. The microstructure of biofilm was examined using SEM. Results showed that some cavities were present, which would be favorable to enhance substrate and oxygen to transfer from the bulk to the interior of biofilm.

A carbon membrane-aerated biofilm reactor was developed to treat municipal wastewater, in which the carbon and nitrogen were removed simultaneously. The results showed that COD removal, NH4+-N removal and TN removal efficiency could reach 82.5%, 95.1% and 84.2%, respectively, under the conditions of intra-membrane pressure of 13.6 kPa, HRT of 14 h, influent COD and NH4+-N concentrations of 338 mg/L and 75 mg/L. However, in the last period during the operation of the reactor, the TN removal efficiency dramatically decreased because of the excessive growth of biomass on the nonwoven fiber, which also had serious negative effect on nitrification course. The microbiological community and spatial profiles were observed by fluorescence in situ hybridization and scanning electron microscopy. The anaerobic and anoxic bacteria were mainly located in the outer anaerobic region of the biofilm, while the aerobic ammonium oxidizing bacteria were mainly located in the inner aerobic region of the biofilm. The co-existing and coupling effect of aerobic nitrifying bacteria and anaerobic denitrifying bacteria provided the large biological potential for the simultaneous nitrification and denitrification in the carbon membrane-aerated biofilm reactor.

A sequencing batch airlift reactor (SBAR) was conducted to study the performance of physical characteristics and respirometric activities during reactivation of aerobic granules after a 2-month storage time. Results showed that the color of the aerobic granules had completely become dark, the size and settleability did hardly change during the storage period. The color turned to be brownish-yellowish when the reactor was restarted for 2 weeks. The MLSS, granule size, and settleability increased rapidly along with reactivation. The heterotrophic activity resumed 86% within 1 day and was fully reactivated after 5 days. Then the COD removal rate was stabilized above 80%. Higher aeration rate and longer cycle time facilitated the reactivation of nitrifiers. When aeration rate was increased from 0.05 m3 x h(-1) to 0.10 m3 x h(-1) at 41st day, activities of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were improved from 88% and 82% to 122% and 92%, respectively. The removal rate of ammonium-nitrogen promptly reached above 96%. Nitrite-oxidizing bacteria were fully reactivated after the cycle time was prolonged from 4 h to 6 h.

The effect of alkaline thermal hydrolysis method on excess sludge and its characteristic parameters(such as soluble chemical oxygen demand, volatile fatty acids, ammonia-nitrogen, pH value, sludge concentration, etc.) were investigated. The results show that the addition of alkali can reduce the resistance of the sludge cells to high temperature and enhance the release and the hydrolysis of organic materials from the sludge cells with the increase of temperature, pH value and reaction time. The concentration of SCOD reached 17,950 mg/L and SCOD/TCOD was 0.65 on the conditions of pH 13, 170 degrees C and 75 min. The maximal dissolving rate of suspended solids (SS) was 67% and 72% for volatile suspended solids (VSS) at pH 13 with 60 min. The concentration of SCOD after alkaline thermal hydrolysis treatment increased with the increase of sludge concentration, in which the nice linear relation was reached and the correlation coefficient (R2) was above 0.97. The increasing rate of the SCOD was improving with the increase of the pH value and the SCOD of unit sludge reached 672 mg/g at pH 13. The effect of three factors on the SCOD was investigated through orthogonal experiment at the temperature of 170 degrees C, the importance was sludge concentration,pH value and reaction time in turn.

The effect of extra-cellular polymeric substances (EPS) on filtration of polyvinyl alcohol modified polypropylene non-woven in submerged membrane bioreactor (SMBR) was investigated by statistical method. The results show that soluble extra-cellular polymeric substances (EPSs) of activated sludge on the non-woven modules surface, components (protein/carbohydrate, P/C) of EPSs and relative hydrophobicity (RH) have a significant influence on filtration performance of module B, the Pearson's correlation coefficient (r(p)) related to membrane fouling resistance are 0.868, 0.840, 0.890, respectively. Modified module can effectively restrict the adsorption of EPSs, can reduce the ratio of P/C in EPSs and can decrease the accumulation of activated sludge. After hydrophilic modification of non-woven, the filtration performance is improved obviously and the un-fouling performance is increased.

This study investigated the physical performances of mature aerobic granules in SBAR, including granular shape and structure, mean size and granular relative strength, and cell metabolic activities to excrete extracellular polymeric substances (EPS), and nitrification and microbial activity, which performed visible differences at superficial upflow velocity of 1.8 cm x s(-1) and 0.9 cm x s(-1) respectively. Results show that granular surface was more irregular at the low aeration intensity than that at the high aeration intensity and granular interstice performed increasing with it. In 55 days, comparing with high aeration intensity, the sludge productivity and the mean size of aerobic granules at the low aeration intensity were increased by 33% and 25%, respectively, while the granular relative strength and EPS were reduced by 6% and 12%, respectively. The sludge volume index in two reactors were about between 10 mL x g(-1) and 15 mL x g(-1), which implied that granules at both aerations behaved well settling ability. The two reactors still performed well nitrification characteristic and ability to remove COD. The activity of nitrifying bacteria in aerobic granules at the low aeration intensity was lower than that at the high aeration intensity, while heterotrophs performed higher activity at the low aeration intensity.

New type hybrid biological reactor was developed by initiating the carbon membrane aeration in ABR which was augmented with carbon aerated membranes to improve wastewater treatment by removing COD, NH4(+) -N and TN. The results showed that on the conditions of intra-membrane pressure of 0.025 MPa, HRT 24 h, influent COD 2000 mg/L, NH4(+) -N 50 mg/L, simultaneous nitrification and denitrification was happened, and COD and NH4(+) -N decreased from 156 mg/L, 36 mg/L to 45 mg/L, 6 mg/L respectively after the membrane aeration with biofilm was initiated in the third compartment of ABR.TN removal reached 87.66%, and VFA and biogas was decreased by 77.12% and 30%, respectively.

A laboratory-scale membrane-aerated biofilm bioreactor (MABR) equipped with nonwoven fabrics support around the gas-permeable carbon tube was developed for single-stage autotrophic nitrogen removal based on partial nitrification and anaerobic ammonium oxidization. Initially, the reactor was inoculated with nitrifying biomass. By decreasing the air pressure in the lumen of carbon tube step by step, We can obtain stable nitrite accumulation. Subsequently, the reactor was reinoculated with Anammox biomass to construct a quite stable biofilm system for completely autotrophic N removal. After 120 d of operation, 88.7% of NH4(+) -N removal rate, 48.65 mg/L of average TN in the effluent, 83.77% of maximal TN removal efficiency was achieved under the following conditions: air pressure of 0.015 MPa, HRT of 6 h, and influent NH4(+) -N of 200 mg/L +/- 10 mg/L.

Further research was made on precoating reagents in dynamic membrane process, in which novel precoating reagent-polyvinyl alcohol microsphere (PVA-MS) was prepared through emulsive polymerization of PVA and glutaraldehyde (GA). Furthermore, polymerization mechanism and anti-fouling characteristics through adsorption of membrane major fouling substances EPS upon PVA-MS were studied. The results showed that hemiacetals reaction played a major role in emulsive polymerization process, as the quantity of hydroxyl on PVA was decreased a little, PVA-MS surface behaved good hydrophilic, and the adsorption of protein and amylose upon PVA microsphere was stable and low, which was 0.543 mg x g(-1) and 0.694 mg x g(-1) respectively. In addition, PVA-MS surface behaved electronic negativity, which acted electrostatic repulsion to active sludge floc. Upon this characteristics and data, it was concluded that membrane fouling was delayed in microscopy structure. Diameter of PVA-MS in precoating liquid was about 1.14 microm, and Zeta-potential of precoating liquid with different precoating reagent concentration was less than - 39 mV, which made PVA microsphere diffused and stable from each other, then sedimentate rapidly on porous support membrane surface and internal wall of hole path. Besides, the morphology of PVA-MS and dynamic membrane formed from PVA-MS on support membrane were observed through SEM.

The enrichment and characteristics of denitrifying phosphate accumulating organisms (DPAO), which are capable of utilizing nitrate as electron acceptor, was investigated in a laboratory-scale sequencing batch membrane bioreactors (SBMBR). The results demonstrated that the proportion of DPAO increased from 19.4% to 69.6% of total phosphate accumulating organisms after anaerobic-aerobic and anaerobic-anoxic-aerobic phases. SBMBR system could operate steadily when 120 mg nitrate was added continuously during the anoxic phase every period. Simultaneous phosphate uptake and biological denitrification with good performance could be obtained in SBMBR operated in steady-state. Nitrate and phosphorus removal efficiency were above 100% and 84% respectively during anoxic phase, however, the effluent TP concentration was low than 0.5 mg/L, the total phosphorus removal efficiency was 96.1%. Furthermore, the ammonium nitrogen removal efficiency of SBMBR could be maintained at 92.2%, and the cumulation of nitrite and nitrate was not observed clearly.

A carbon membrane-aerated biofilm reactor was developed to treat municipal wastewater. Tests were conducted to investigate oxygen transfer ability of carbon membrane, the bacteria adhesion and reactor's set-up performance. The optimum parameters were determined in terms of intra-membrane pressure, COD and nitrogen ratio and hydraulic retention time (HRT). The results showed that compared with that of other hollow fibres, bacterial suspended exhibited a high degree of adhesion onto carbon membrane and that oxygen transfer coefficient of carbon membrane was 0.36 m/h, so that it was feasible to serve as both biofilm carrier and aerator. NH4(+) -N removal, denitrification and COD removal efficiency could reach 95%, 92% and 88%, respectively, under the conditions of intra-membrane pressure of 0.025 MPa, carbon nitrogen ratio of 5 and HRT of 8 h, and effluent quality could be up to A standard in the national discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002) . Furthermore, the system displayed better resistance to shock loads.

Two SBMBRs run in AO and A2O mode were operated in parallel to compare their ability of simultaneous phosphorus and nitrogen removal. The results showed that the removals of COD and ammonium nitrogen were averaged over 90% and 95%, respectively. A2O MBR has the stronger anaerobic phosphorus release ability; its SPRR30 outdoes 47.5% compared to AO MBR. SPUR30 of A2O MBR was lower which may attribute to the higher effluent TP content. The ratio of DPAO was enhanced 57% compared to AO MBR. And when nitrate as the only electron accepter, the phosphorus uptake mass with unit electron transfer was 30% higher in A2O MBR. This two factors lead to the stronger denitrifying phosphorus removal ability of A2O MBR. Furthermore, the membrane fouling was mitigated in A2O MBR though the aerobic time was half to that of AO MBR. The membrane filter function made SBMBR's effluent free of the sludge settlement ability.

The rheological behaviour of the low sludge concentration liquor in MBR was investigated and made a conclusion that this liquor approximated to the Newtonian fluid while the concentration of the sludge was less than 8000 mg x L(-1). Furthermore, when the laminar flow boundary layer thickness on the surface of flat membrane came up to the thickness of precoated dynamic membrane (PDM), the steady aeration intensity was calculated by using the boundary layer theory in the Newtonian hydrodynamics. In order to ensure the stability of the pre-coated dynamic membrane bioreactor (PDMBR), oxygen supply aeration intensity was chosen to supply the best dissolved oxygen (3-5 mg x L(-1) in the initial stages and gradually increased to the steady aeration intensity. The results indicated that this mode could enhance the stability of PDM. In the experiment period (31 d), effluent COD was less than 12.48 mg x L(-1) and its average removal rate was 97.49%, NH4+ -N was less than 5.27 mg x L(-1) and its average removal rate was 76.13%, while the operational pressure just increased to 27 kPa. During the last period of the experiment, the stability of the PDMBR was studied when the aeration intensity was more than the steady aeration intensity and it was found that the precoated layer had been brushed off from the surface of common filter cloth, so this phenomenon proved that using the boundary layer theory could determine steady aeration intensity of PDMBR.

The influence of activated sludge properties on membrane fouling was investigated using statistical method. The results show that extracelluler polymeric substances (EPS), soluble microbial products (SMP), suspended solids in the supernatant (SSs), dynamic viscosity (micro), relative hydrophobicity (RH) and Zeta potential all have a significant influence on membrane permeability during microfiltration of activated sludge wastewater. The pearson's correlation coefficient (r(p)) for linear correlations between membrane fouling resistance and these sludge properties are 0.898, 0.712, 0.810, 0.691, 0.837, -0.881, respectively. The statistical results also show that SMP, micro, SSs, Zeta potential, and RH are mostly determined by EPS, indicating that EPS is the main and essential factor affecting membrane fouling in activated sludge properties. The pearson's correlation coefficient (r(p)) for linear correlations between total EPS and other sludge properties are 0.682, 0.633, 0.783, -0.953, 0.877, respectively. EPS should be controlled in the operation of membrane bioreactor to achieve a suitable permeation.

A novel process, microwave assisted catalytic wet air oxidation (MW-CWO), was applied for the degradation of H-acid (1-amino-8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon (GAC), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC.

Cultivation of aerobic granules for simultaneous nitrification and denitrification in two sequencing batch airlift bioreactors was studied. Conventional activated floc and anaerobic granules served as main two inoculated sludge in the systems. Morphological variations of sludge in the reactors were observed. It was found that the cultivation of aerobic granules was closely associated with the kind of inoculated sludge. Round and regular aerobic granules were prevailed in both reactors, and the physical characteristics of the aerobic granules in terms of settling ability, specific gravity, and ratio of water containing were distinct when the inoculate sludge was different. Aerobic granules formed by seeding activated floc are more excellent in simultaneous nitrification and denitrification than that by aerobic granules formed from anaerobic granules. It was concluded that inoculated sludge plays a crucial role in the cultivation of aerobic granules for simultaneous nitrification and denitrification.