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Soluble microbial products (SMP) that persist in the effluent of membrane bioreactors (MBRs) impact not only discharge quality, but also the performance of advanced filtration processes. This study investigated the effect of SMP on the characteristics and fouling potential of a laboratory-scale MBR effluent. First, the domestic wastewater influent, mixed liquor supernatant, and effluent were assessed. Variations in specific ultraviolet adsorption (SUVA) and molecular weight distribution (MWD) confirmed the degradation of pollutants, generation of SMP, and permeation of SMP through the membrane. The effluent contained more carbohydrates than proteins, but the two species combined had minority contribution to the total organic load. Instead, humic acids were the most abundant as confirmed by excitation–emission matrix (EEM) fluorescence spectroscopy analysis. Second, the MBR effluent was subjected to crossflow ultrafiltration (UF). The UF membrane quickly lost 60% of its initial flux, and dramatic transformations in surface morphology and roughness occurred. It also had poor SMP removal efficiency, as most of the carbohydrates and humic acids were not rejected. More proteins were identified on the fouled membrane surface, suggesting that they have a significant role in UF membrane fouling formation.

In this study, the performance of sequencing batch reactor (SBR), aerobic membrane bioreactor (AMBR), anaerobic-oxic membrane bioreactor (AOMBR) and AOMBR/RO processes treating the synthetic textile dyeing wastewater (Reactive Black 5) was investigated and compared. After more than 2 year process operation, the average SS concentration for SBR, AMBR, AOMBR, and AOMBR/RO process effluent were 96, 0, 0, and 0 mg L−1, respectively. Furthermore, the COD of the above effluent were 133, 95, 37, and 38 mg L−1, respectively. It was found that the anaerobic tank of AOMBR and AOMBR/RO can lower the COD concentration. In addition, the BOD of the above effluent were 68, 3, 3, and 0 mg L−1, respectively. For this parameter, the membrane unit also showed an excellent performance. Finally, the true color of the above effluent were 548, 513, 196 and 32 ADMI, respectively, revealed that the anaerobic tank and RO unit could achieve higher color removal performance. This revealed that the processes containing membrane unit performed excellent efficiencies on SS and BOD removal. Additionally, the anaerobic tank can enhance the COD and true color removal, while the RO unit can further remove the true color. According the experiment result, all the processes containing membrane unit meet the Taiwan EPA effluent criteria, but only the AOMBR/RO process meets the water reclamation criteria for toilet flushing, landscaping, irrigation, sprinkling, and cooling water usage. This study also isolated higher decolorized performance microorganisms by using TGE, PDA and TGC mediums. Only 3 isolates performed more than 90% Reactive Black 5 degrading efficiencies by using both TGE and aerobic PDA mediums. On the contrary, no isolate was obtained by using anaerobic PDA mediums, implied that there is no strictly anaerobic fungi in the anaerobic tank. Furthermore, 18 isolates cultured from anaerobic TGC medium showed more than 90% Reactive Black 5 removal efficiency, revealed that the anaerobic tank did enhance the growth of the high decolorizedmicroorganisms, especially anaerobic bacteria.

This study is aimed using ozonation to remove the fouling that occurs on ultrafiltration membranes. Polyvinylidene fluoride (PVDF) was utilized for the membrane material. The tertiary effluent from industrial park wastewater plant was treated by an ultrafiltration membrane process. A bench-scale system was performed to evaluate the efficiency of fouling removed by an ozonation process. The results should be a valuable reference encouraging the recovery of tertiary effluent by the membrane process. The ozonation process was done via the direct continuous dosing of ozone into the influent. The ozone gas mass flow rate was 8.79 mg/min; the residual ozone concentration in the influent flow was maintained at about 4.02 mg/L throughout the test. It was demonstrated that without ozonation the permeate flux dropped to 60% after 1 h, but that with ozonation it could be maintained at 90% through the test. The SEM observations showed that much fouling that had clogged the membrane was effectively removed by ozonation. The mechanism of fouling removed was also illuminated by the IR analysis. It was observed that the ozone could oxidize and destroy the organic fouling, and the cross flow could flush away any loose fragments on the filtration cake.

Both the relationship between the flux and the fouling mechanism of ultrafiltration (UF) membrane and the effects of pretreatment before reverse osmosis (RO) process on the treatment of the effluent of industrial park wastewater treatment plant (IPWTP) were investigated to examine the application of membrane processes on the water reuse treatment. For the former, the flux data was first fitted to the Hermia model to give the implication of the fouling mechanism. Then, the fouling mechanism was further identified with the aid of the SEM morphology of membrane surfaces. For the latter, the changes of both water characteristics (turbidity, TOC, conductivity, particle size distribution, and organic solute molecular weight) and membrane properties (surface zeta potential and surface morphology) before and after the treatment of membrane processes were measured. It was found that the major blocking mechanisms of UF membrane process at initial and final stage were standard blocking of pore (causing from colloid materials) and cake blocking of pore (causing from suspended particles), respectively. On the other hand, it was concluded that the permeate from 1 μm/UF/RO process was suitable for the reuse of cooling water and low pressure boiler water.

The biotransformation of octylphenol polyethoxylate surfactant (Triton X-100) and bacterial communities in soil microcosms was investigated. The soil microcosms were designed to simulate real sites of bioremediation. The soil used in this study was contaminated with pesticides and alkylphenol polyethoxylate surfactants over a long period of time. The nitrogen source, (NH4)2SO4 and the mineral salt basal solution were added to the microcosm and the water content was adjusted to 50% with distilled water. The microcosms were aerated using an aeration system with an air flow rate of 0.3 l min(-1). The exogenous bacterial strain Pseudomonas sp. SH4 was added to the microcosms to increase the rate of biotransformation of the Triton X-100. The number of microorganisms and the theoretical extent of formation of carbon dioxide were estimated to evaluate the biotransformation of Triton X-100 in the microcosms. The analytical results revealed that the exogenous bacteria could increase the rate of transformation of Triton X-100 by approximately 50%. Aeration of the microcosm increased the biotransformation of Triton X-100 by 45%. Bacterial count of 6.8x10(10) MPN g(-1) of soil was achieved in the M5 microcosm. Analysis of the bacterial community by 16S rDNA sequences revealed that Pseudomonas sp. SH4 could dominate all the microcosms to which it was added as an exogenous bacteria. The quantity of the indigenous bacterial strains Stenotrophomonas maltophilia, Stenotrophomonas sp. and clone 4-70 were also enhanced in the microcosms by the aeration, and the addition of carbon and nitrogen source.

This study investigated the characteristics of SSA in Taiwan area. The potential applications of SSA reuse were also evaluated. Four major characteristics of SSA, including chemical compositions, pozzolanic properties, physical properties, and surface properties were analyzed. Experimental results found that SSA was a complex mixture of burnt residues of sludge biomass and minerals. The major chemical compositions of SSA were silicon oxide, aluminium oxide, and iron oxide. The most predominant silicon oxide occupied 41.3 to 56.1% of overall SSA weight and approximately 60% weight of silicon oxide in SSA was amorphous type. Due to the effect of amorphous silicon oxide, the SSA exerted pozzolanic activity. The strength activity index (SAI) value of SSA was between 53.6 and 74.3%. The SSA particles were also the agglomeration of finer grains between 0.1 and 1μm of size. Therefore the SSA was porous with irregular particles with significant pore surface area. Additionally, the SSA exerted negative surface charge and cation-exchange capacity in neutral aqueous phase. Based on the SSA characteristics found in this study, four potential applications of SSA reuse were evaluated. These technologies included reusing as fine aggregate, reusing as pozzolanic material, melting or vitrification treatment, and reusing as adsorbent. In addition, the advantages and disadvantages of the above potential applications of SSA were discussed.

A novel fibrous-bed trickling filter was developed to remove toluene present in contaminated air. Pure culture of Pseudomonas putida F1 was attached on fibrous-bed and utilized toluene as the carbon source. Experimental results indicated the removal efficiency decreased with the increase of inlet concentration. In general, the removal efficiency of toluene was greater than 90% when the inlet loading capacity was below 70 g m-3h-3. The elimination capacity increased with increasing inlet loading capacity, but the increased rate decreased gradually. When the inlet loading capacity increased to 300 g m-3h-1, the elimination capacity could approach to 130 g m-3h-1. The first order kinetics model was useful to describe the removal of toluene in this filter and an excellent linear relationship was found between the apparent first order parameter and inlet concentration (ranging from 1.2 g m-3 to 3.5 g m-3). Also, the performance of fibrous-bed trickling filter was relatively stable during the four-month period of continuous operation. Slight clogging phenomena of filters were observed only under high loading capacity.

The potential advantages of the UV/H2O2 process treating petrochemical wastewater as the tertiary treatment or the direct pre-treatment were demonstrated. While the high alkalinity of wastewater was not reduced, the UV/H2O2 process as the tertiary treatment could not obtain removal efficiency of wastewater. If the system pH adjusts to 3, this process will polish the effluent of the current biological process to meet the National Effluent Standards of 1998. The results of the direct pre-treatment with the UV/H2O2 process revealed that the recalcitrant compounds presented in raw wastewater would be destroyed to small molecules and might reduce some degree of activity inhibition to bioculture. In the detoxified investigation of spiking aromatic compounds, this process could obtain a good removal efficiency, including a lot of COD removal and the complete detoxification.

Inoculation of pure microbial culture to biodegrade recalcitrant organic compounds has had increased interest in the field of biological treatment of polluted waters or wastewater effluents. The removal of benzo(a)pyrene by the free cells of Phanerochaete chrysosporium strains, including ATCC 24725, ATCC 32639, and ATCC 34541, in a shaking vessel with a nitrogen-limited incubation medium was observed. This study also investigated the removal efficiencies of naphthalene, fluoranthene, and benzo(a)pyrene by immobilized white-rot fungus in a shaking flask and an aeration batch bioreactor. The biocarrier used in this investigation was a mixed gel composed of alginate and powdered activated carbon (PAC). The results showed that these polycyclic aromatic hydrocarbons (PAHs) were removed with an increased rate during the stationary growth phase, and strain ATCC 24725 exhibited the best PAH removal efficiency. No PAH residuals could be detected by HPLC from the immobilized-cell cultures in the shaking flask or aeration bioreactor during the incubation. However, a likely metabolite of PAH was identified in the chromatogram. The alginate-PAC biocarriers presented availability accessible pore volume for the colonization of fungus mycelia, moreover, the PAC fraction of the biocarrier obviously affected adsorptive capacities of PAHs.

The decolorization and transformation of the anthraquinone dye, Reactive Blue 19 (RB-19), by ozonation with a semi-batch reactor were investigated. The effects of different operating parameters, such as the initial RB-19 concentrations, ozone feed rates and initial pH, on the performance of color, dye and total organic carbon (TOC) removal were also evaluated based on their pseudo-first-order rate constants and removal efficiencies. The experimental results indicated that the removal of color and the dye itself was more rapid and complete than that of TOC in all the ozonation tests. However, increasing the initial RB-19 concentration had a significant effect on decreasing the rate constant of RB-19 reduction. In addition, increasing the ozone feed rate had positive effects on the color, dye and TOC removal, particularly on the TOC diminution. The rate constant and efficiency of color removal were highest at initial acidic pH conditions, but the dye and TOC removal were more effective at initial basic pH values, possibly due to the more powerful and non-selective hydroxyl radical oxidation.

The textile industry, which produces toxic and low biodegradable wastewater, is a major industry of Taiwan. Thus, this study compared the performance of the membrane bioreactor (MBR) and sequencing batch reactor (SBR) process for treating real textile dyeing wastewater. The microbial diversity of the MBR process was also identified by a combined culturing method and molecular biotechnology. The results show that the removal efficiencies for color, COD, BOD, and SS with the MBR process were 54, 79, 99, and 100%, respectively, all higher than the corresponding parameters for the SBR process: 51, 70, 96, and 60%. All the above four parameters for the MBR effluent meet the criteria of the Taiwan EPA, while on the other hand for the SBR process, only color and COD meet the Taiwan EPA effluent criteria. Furthermore, the genus Microbacterium, especially the Microbacterium aurum, was the most predominant population, contributing 70.6% of the total isolates, and might be responsible for the degradation of the dyeing wastewater. Another two textile dyeing degradation bacteria, Paenibacillus azoreducens and Bacillus sp., as predominant bacteria in MBR sludge, were also observed.

This study examined the factors that influence the reductive dechlorination of trichloroethylene (TCE) when direct current is externally supplied to a laboratory scale iron wall. Experimental results indicated that an anode electrode was placed in contact with the iron filling near the inlet of the column, and then a cathode was located on the top of the column. Excellent TCE degradation efficiency was displayed. The surface of the iron particles was acid-washed by H+, owing to water oxidation around the anode, and large quantities of Fe2+ were produced as a reductant which enhanced the TCE degradation, due to iron corrosion caused by the supply of external electrons. The cathode should be placed in sand fill atop the iron filling in order to avoid the formation of iron (hydr) oxide precipitates on the surface of the iron particles when the pH increases as a result of the release of OH+ around the cathode. Due to more H+ being released, which benefited the acid-washing of the iron filling, the TCE removal efficiency increased from 32% to 100% when the electric potential increased to 60V. However, black precipitates of iron (hydr) oxide were observed coated on the iron surface, causing the blocking of pores in the iron wall with the increase in the electric potential application. The efficiency of TCE degradation was almost equal regardless of groundwater velocity when direct current was applied to the iron wall. Based on observations of TCE degradation during long-term operations, the TCE removal efficiency in the effluent reached 100% after seven days of operation and maintained this high level after 25 days of operation. Thus, iron wall by electroremediation displayed excellent potential for development in long-term operations.

Inoculation of pure microbial culture to biodegrade recalcitrant organic compounds has had increased interest in the field of biological treatment of polluted waters or wastewater effluents. The removal of benzo(a)pyrene by the free cells of Phanerochaete chrysosporium strains, including ATCC 24725, ATCC 32639, and ATCC 34541, in a shaking vessel with a nitrogen-limited incubation medium was observed. This study also investigated the removal efficiencies of naphthalene, fluoranthene, and benzo(a)pyrene by immobilized white-rot fungus in a shaking flask and an aeration batch bioreactor. The biocarrier used in this investigation was a mixed gel composed of alginate and powdered activated carbon (PAC). The results showed that these polycyclic aromatic hydrocarbons (PAHs) were removed with an increased rate during the stationary growth phase, and strain ATCC 24725 exhibited the best PAH removal efficiency. No PAH residuals could be detected by HPLC from the immobilized-cell cultures in the shaking flask or aeration bioreactor during the incubation. However, a likely metabolite of PAH was identified in the chromatogram. The alginate-PAC biocarriers presented availability accessible pore volume for the colonization of fungus mycelia, moreover, the PAC fraction of the biocarrier obviously affected adsorptive capacities of PAHs.

The potential advantages of the UV/H 2 O 2 process treating petrochemical wastewater as the tertiary treatment or the direct pre-treatment were demonstrated. While the high alkalinity of wastewater was not reduced, the UV/H 2 O 2 process as the tertiary treatment could not obtain removal efficiency of wastewater. If the system pH adjusts to 3, this process will polish the effluent of the current biological process to meet the National Effluent Standards of 1998. The results of the direct pre-treatment with the UV/H 2 O 2 process revealed that the recalcitrant compounds presented in raw wastewater would be destroyed to small molecules and might reduce some degree of activity inhibition to bioculture. In the detoxified investigation of spiking aromatic compounds, this process could obtain a good removal efficiency, including a lot of COD removal and the complete detoxification.