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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.

This study investigated the degradation of anthraquinone reactive dye C.I. Reactive Blue 19 (RB-19) with initial concentration of 100mg L(-1) in aqueous solution by ozone oxidation. The results of UV/VIS and FTIR spectra showed that the anthraquinone structures, nitrogen linkages and amino groups of RB-19 were destroyed under direct ozone reaction. The identification by LC-MS and GC-MS analyses indicated that some organic acids (e.g., phthalic acids) and 1,3-indanone could be the primary degradation products, respectively. The Microtox toxicity of the ozonated RB-19 solution initially increased but subsequently decreased when ozonation time increased. This detoxification accompanied biodegradability enhancement revealed by BOD/COD ratio increasing from 0.15 to 0.33 after 10min of ozonation.

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 paper describes the treatment of chemical mechanical polishing (CMP) wastewater from a semiconductor plant through membrane-based ultrafiltration (UF) and reverse osmosis (RO) processes to improve the removal efficiency under different water recovery and to determine the possible mechanisms of membrane blocking and rejection. UF pretreatment led to 42.1–46.9% conductivity, 98.1–99.4% turbidity, and 4.5–24.5% total organic carbon (TOC) removal. These contaminants were almost completely rejected after performing subsequent RO processing: the values of the conductivity, turbidity, and TOC were reduced to 6 μS/cm, 0.01 NTU, and 1.6 mg/L, respectively. The water quality of the permeates after UF or RO membrane filtration could meet the water reuse standards for tap water, cooling water, boiler water, and the feed for a water purification machine. The variation with time of the permeate flux for the UF process was fitted to the Hermia model to examine the possible blocking mechanisms during the filtration ...

This investigation evaluated the photocatalytic degradation of monochlorobenzene (MCB) in an aqueous TiO 2 suspension. In accordance with the experimental results, the degradation of MCB was a function of the initial substrate concentration, incident light intensity, and TiO 2 dosage. However, the solution pH had insignificant effect on the degradation efficiency. The heterogeneous photocatalytic degradation of MCB followed the Langmuir–Hinshelwood kinetics. The adsorption coefficient of MCB ( K ) and the observed degradation rate constant ( k ) were calculated as 13.4 mM −1 and 0.0054 mM min −1 , respectively. In addition, a 0.255 dependency of the initial degradation rate on the light intensity revealed the considerable adverse effect of e − –h + pair recombination. Both mineralization and dechlorination occurred during the photocatalytic degradation of MCB. Under the operating condition of initial MCB concentration of 0.1 mM, light intensity of 5.68 μEinstein s −1 , TiO 2 dosage of 1.0 g L −1 , and solution pH of 7, about 93.7% of MCB was mineralized after 240 min of irradiation. Nevertheless, 64.3% of the stoichiometric amount of Cl − ions was released into the bulk solution. The simulation results derived from the X-ray photoelectron spectroscopy (XPS) analysis was suggested that the interaction between Cl − ions and TiO 2 surface tended to lower the released amount of Cl − ions.

The objective of this study is to investigate membrane fouling caused by ultrafiltration (UF) when reusing tertiary effluent in an industrial park. A bench-scale membrane system was performed. Experimental results showed that the removal of iron, manganese, and turbidity were 62%, 30%, and 77%, respectively. From the infrared ray analysis of membrane fouling, one can see that the organic functional groups were aromatic rings and a few linear chain compounds of chromophore and auxochrome found in dyestuff. Therefore, tertiary effluent may induce both colloidal and organic fouling into the UF system.

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.

Sewage sludge ash (SSA) is a recycled material and can be used in cement mortar as pozzolan. To improve the mortar properties, this research utilized mechanical grinding to adjust the fineness of SSA. Finely ground SSA with Blaine fineness of 500–1000 m2/kg was added to mortar to replace 20% of portland cement. The initial and final setting times of SSA–cement paste simultaneously prolonged when SSA fineness increased. Because of the lubricant effect and morphology improvement, the workability of SSA mortar increased when fineness increased. In addition, the pozzolanic activity of SSA and the compressive strength of mortar increased when SSA fineness did. The strength activity index (SAI) value approximately increased 5% when SSA fineness increased per 100 m2/kg. According to the results, the application of mechanical grinding to adjust SSA fineness was an effective modification to improve SSA mortar properties including workability and compressive strength.

The sewage sludge ash (SSA) can potentially be used for removal of heavy metals from wastewater due to its similar chemical composition to that of fly ash and blast-furnace slag. This study investigated the adsorptive characteristics of SSA including specific surface area, cation-exchange capacity (CEC), and pH of zero point of charge (pHZPC). In addition, the adsorption isotherms of SSA with synthetic wastewater containing copper ions were tested. Experimental results indicated that the CEC and pHZPC of SSA were 24.1–25.7 meq/100 g and 3.1–3.4, respectively, which exhibited the capability of removing heavy metals from wastewater. The adsorption test of applying SSA into synthetic wastewater revealed that the adsorption isotherm of SSA for copper ions generally followed the Langmuir model. The estimated maximum capacity of copper adsorbed by SSA was 3.2–4.1 mg/g and close to that of fly ash. The primary mechanisms of copper removal by SSA included electrostatic attraction, surface complex formation, and cation exchange. The precipitation of copper hydroxide occurred only when the dosage of SSA and the equilibrium pH of wastewater were at a high level (30–40 g/l and greater than 6.2, respectively). In general, similar to fly ash and blast-furnace slag, the SSA can be reused as an adsorbent for copper removal from wastewater and the removal efficiency was greater than 98%.

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.

The semiconductor factory generally requires ultra pure deionized water to rinse their integrated circuit (IC) crystal chips in Taiwan. When tap water is used as the source of deionized water supply system, the reject from the devices of producing pure water (e.g. reverse osmosis, RO) usually contains less inorganic and allowed to be reused as make-up in cooling water system. The aim of this study is to evaluate the appropriateness and effectiveness of reusing the reject as cooling water for semiconductor plant. A representative semiconductor plant was selected as a case study in this paper. Calculating the typical results of water samples analysis, it was found that the cycles of concentration of this cooling water system was only 1.5, and the water stabilization index were −0.11, 8.32 and 8.86 for Langelier Saturation Index (LSI), the Ryznar Stability Index (RSI) and the Practical Scale Index (PSI), respectively. This means that the current operational condition of the cooling water system had less tendency to scale formation. Consequently, further increasing the cycles of concentration (CC) and reducing the quantity of make-up in the cooling water system would be preferable. Furthermore, the related mass balance data of used water quantities in the whole plant indicated the reuse and recovery of used water could be appropriately carried out in the plant.

Co-metabolic degradation of trichloroethylene (TCE) by Pseudomonas putida F1 was investigated in a novel bioreactor with a fibrous bed. A pseudo-first-order rate constant for TCE degradation was 1.4 h−1 for 2.4 to 100 mg TCE l−1. Competitive inhibition of toluene on TCE removal could be prevented in this bioreactor. 90% TCE was removed over 4 h when 95 mg toluene l−1 was presented simultaneously.

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 sole ozone used in cooling water treatment has raised some critical questions concerned with what happens chemically, that may describe why it can control corrosion, scale and microorganism. The pilot cooling tower (PCT) test presented the effects of ozone as a sole cooling water treatment. Except the higher pH and alkalinity in the PCT test, proper residual ozone concentration produced an oxidative film (protective film) on the metal surface of carbon steel, brass and type 316 stainless steel, the corrosion rate may also be decreased. Ozone was still unpredictable for scale control except for the existence of organic matter. The excellent control of fouling was also attained, that could be determined by the presence of ozone. The strong biocide properties of ozone resulted in excellent biological control. A mechanism is proposed to explain the results.

The cooling water is the major part of industrial wateruse in Taiwan, either from the view of demand priority or supply volume. In order to save water, the loading of supply system can be reduced if the cooling water can be recovered and reused. For this reason, exploration of the recent operation status of the cooling water system has become essential in Taiwan. This study was initially focused on the current applications and reuse trends of cooling water in oil refineries, chemical industry, steel mills, food industry, electronics works, textile plants and power stations. According to the statistical analysis, the portable water and groundwater are the primary sources of makeup water for cooling systems. The multiple-chemicals method and makeup treatment are increasingly accepted for the reclamation of cooling water. On the other hand, sidestream treatment and blowdown reuse are not popular in Taiwan. The recovery rate of blowdown is only 26.8%. The fact of higher cost is the major reason to depress the willingness of recovery. Some representative plants had been selected for case study. However, most cooling water systems are only operated by operator’s experience according to field investigation. In each case, the water quality indexes were used to evaluate the operational condition of cooling water systems. There was no case plant found to be operated at appropriate cycles of concentration. This paper also presented the bottlenecks of conservation technologies of cooling water in Taiwan. These bottlenecks include increasing the cycles of concentration, the reuse of wastewater, and the blowdown treatment for reuse. This paper also demonstrates that the recovery and reuse of cooling water has great potential and is feasible for the available technologies in present Taiwan, but the industries are still unwilling to upgrade because of initial cost. Finally, some approaches associated with technology, economics, environment and policy are proposed to be a reference for the industries and the government authorities.

A novel trickling fibrous-bed bioreactor was developed for biofiltration to remove pollutants present in contaminated air. Air containing benzene as the sole carbon source was effectively treated with a coculture of Pseudomonas putida and Pseudomonas fluorescens immobilized in the trickling biofilter, which was wetted with a liquid medium containing only inorganic mineral salts. When the inlet benzene concentration (C gi ) was 0.37 g/m 3 , the benzene removal efficiency in the biofilter was greater than 90% at an empty bed retention time (EBRT) of 8 min or a superficial air flow rate of 1.8 m 3 /m 2 .h. In general, the removal efficiency decreased but the elimination capacity of the biofilter increased with increasing the inlet benzene concentration and the air (feed) flow rate. It was also found that the removal efficiency decreased but the elimination capacity increased with an increase in the loading capacity, which is equal to the inlet concentration divided by EBRT. The maximum elimination capacity achieved in this study was ∼11.5 g/m 3 .h when the inlet benzene concentration was 1.7 g/m 3 and the superficial air flow rate was 3.62 m 3 /m 2 .h. A simple mathematical model based on the first-order reaction kinetics was developed to simulate the biofiltration performance. The apparent first order parameter K 1 in this model was found to be linearly related to the inlet benzene concentration (K 1 =4.64-1.38 C gi ). The model can be used to predict the benzene removal efficiency and elimination capacity of the biofilter for benzene loading capacity up to ∼30 g/m 3 .h. Using this model, the maximum elimination capacity for the biofilter was estimated to be 12.3 g/m 3 .h, and the critical loading capacity was found to be 14 g/m 3 .h. The biofilter had a fast response to process condition changes and was stable for long-term operation; no degeneration or clogging of the biofilter was encountered during the 3-month period studied. The biofilter also had a relatively low pressure drop of 750 Pa/m at a high superficial air flow rate of 7.21 m 3 /m 2 .h, indicating a good potential for further scale up for industrial applications.

This study found that MCB photolysis, attacked by ·OH radicals, yielded 2-chlorophenol (2CP), 4-chlorophenol (4CP), 3-chlorocatechol (3-CC), chlorohydroquinone (CHQ), and 4-chlorocatechol (4-CC) as the aromatic intermediates. Oxalic acid was also found as ring opened intermediate. Experimental results showed that hydroxylation occurred prior to the dechlorination preceding ring cleavage. The illumination times for complete dechlorination and ring cleavage of the MCB were 20 minutes and 40 minutes, respectively. After ring cleavage, other reactions were needed to mineralize the organic acids into carbon dioxide and water.

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.

Waste materials with pozzolanic characteristics, such as sewage sludge ash (SSA), coal combustion fly ash (FA), and granulated blast furnace slag (GBS), were reused as partial cement replacements for making cement mortar in this study. Experimental results revealed that with dual replacement of cement by SSA and GBS and triple replacement by SSA, FA, and GBS at 50% of total cement replacement, the compressive strength (Sc) of the blended cement mortars at 56 days was 93.7% and 92.9% of the control cement mortar, respectively. GBS had the highest strength activity index value and could produce large amounts of CaO to enhance the pozzolanic activity of SSA/FA and form calcium silicate hydrate gels to fill the capillary pores of the cement mortar. Consequently, the Sc development of cement mortar with GBS replacement was better than that without GBS, and the total pore volume of blended cement mortars with GBS/SSA replacement was less than that with FA/SSA replacement. In the cement mortar with modified SSA and GBS at 70% of total cement replacement, the Sc at 56 days was 92.4% of the control mortar. Modifying the content of calcium in SSA also increased its pozzolanic reaction. CaCl(2) accelerated the pozzolanic activity of SSA better than lime did. Moreover, blending cement mortars with GBS/SSA replacement could generate more monosulfoaluminate to fill capillary pores.

In this study, marble sludge, sewage sludge, drinking water treatment plant sludge, and basic oxygen furnace sludge were used as replacements for limestone, sand, clay, and iron slag, respectively, as the raw materials for the production of cement in order to produce eco-cement. It was found that it is feasible to use marble sludge to replace up to 50% of the limestone and also that other materials can serve as total replacements for the raw materials typically used in the production of cement. The major components of Portland cement were all found in eco-cement clinkers. The eco-cement was confirmed to produce calcium hydroxide and calcium silicate hydrates during the hydration process, increasing densification with the curing age. The compressive strength (S(c)) and microstructural evaluations conducted at 28 d revealed the usefulness of eco-cement. It was observed that the S(c) data correlated linearly with the pore volume (P) data at 28 d. The proposed model equation could be represented as S(c)=178-461P (correlation coefficient, R(2)=0.96). Two parameters, the large capillary pore volume and the medium capillary pore volume, were evaluated using multiple regression analysis.

The isolation and preliminary characterization of the indigenous dioxin-biotransformation bacteria of Taiwan was conducted in this study. After that, the culture enrichment, and strains acclimation were also carried out for the isolated strains. The soil samples, Tainan#1, Tainan#2 and Tainan#3 were gathering from the downstream of the announced dioxin contamination site in southern part of Taiwan, and analyze PCDDs/PCDFs concentration to confirm the contamination of the soil. According to the results, Tainan#3 has the highest total toxic equivalence about 2450 ng-TEQ/kg of the contaminants. After go through ten sub-culture inoculums, four bacteria strains which can survive in dioxin media were isolated. The identification results shown these strains were Achromobacter xylosoxidans, Ochrobactrum anthropi, Ralstonia mannitolilytica, and Agromyces sp.. The morphology of the strains revealed that all of the strains are gram's negative. The configuration of the strains presented that Ochrobactrum anthropi and Agromyces sp. obtain the length and width of 2µm and 1µm, which are bigger than others. Phylogenetic analysis showed that Agromyces sp. is the closest with Mycobacterium chlorophenolicum strain PCP-1, which is a PCP degrading bacterium in which the relationship with bootstrap value of 95.

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 reaction sequence for the photocatalytic degradation of monochlorobenzene (MCB) in UV/TiO 2 process, including substrate adsorption, degradation, and mineralization, was studied. The theoretical maximum quantity of MCB that could be adsorbed onto TiO 2 surface in aqueous phase was 0.18 ± 0.04 μmol m −2 of TiO 2 . In accordance with the upper limit of the relative surface coverage of MCB molecules to surface hydroxyls of TiO 2 was around 2.2%, the water molecules as the major adjacent species near TiO 2 surface would compete with MCB molecules. Increasing the initial substrate concentration to an appropriate value or enhancing the affinity between the MCB and the TiO 2 surface by adjusting the solution pH would promote the photocatalytic degradation. Experimental results revealed that the neutral medium was beneficial for the degradation of MCB. In comparison, the mineralization was most improved at acidic condition. Generally, 90% of the total organic carbon (TOC) was mineralized after 240 min illumination time in the examined pH range except solution pH 11. The suppressed mineralization of MCB at solution pH 11 was ascribed to the lack of adsorption. A simplified 2-step consecutive kinetic model was used to simulate the mineralization.

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.

The surface characteristics of zero-valent iron (ZVI) and the efficiency of reductive dechlorination of trichloroethylene (TCE) in the presence of ferrous ions were studied. The experimental results indicated that the acid-washing of a metallic iron sample enhanced the efficiency of TCE degradation by ZVI. This occurred because acid-washing changed the conformation of oxides on the surface of iron from maghemite (γ-Fe 2 O 3 ) to the more hydrated goethite (α-FeOOH), as was confirmed by XPS analysis. However, when ferrous ions were simultaneous with TCE in water, the TCE degradation rate decreased as the concentration of ferrous ion increased. This was due to the formation of passive precipitates of ferrous hydroxide, including maghemite and magnetite (Fe 3 O 4 ), that coated on the surface of acid-washed ZVI, which as a result inhibited the electron transfer and catalytic hydrogenation mechanisms. On the other hand, in an Fe 0 -TCE system without the acid-washing pretreatment of ZVI, ferrous ions were adsorbed into the maghemite lattice which was then converted to semiconductive magnetite. Thus, the electrons were transferred from the iron surface and passed through the precipitates, allowing for the reductive dechlorination of TCE.

The growth properties and biodegradation mechanism of a Gram-negative bacterium, Pseudomonas nitroreducens TX1 that was able to grow on branched octylphenol polyethoxylates (OPEO(n), average n=9.5) as the sole carbon source over a wide concentration range (1-100,000 mgl(-1)) were studied. Analysis of growth factors indicated the highest specific growth rate (micro) of 0.53 h(-1) was obtained at an initial concentration of 5,000 mgl(-1) OPEO(n). An optimal C/N ratio of 12 was obtained for (NH(4))(2)SO(4) as the nitrogen source in a cultivated medium at pH 7. The kinetic analysis demonstrated that bacterial growth and OPEO(n) degradation followed the Monod equation and were based on a substrate concentration inhibition model and pseudo-first-order reaction, respectively. The substrate inhibition coefficient was over 18,000 mgl(-1) and this indicates that the strain has an ability to sustain growth at high concentrations of OPEO(n) and use it as the sole carbon source under such a stress condition. Furthermore, LC-MS analysis showed that the biodegradation mechanism of dodecyl octaethoxylate (AEO8) by P. nitroreducens TX1 was the sequential cleavage of the ethoxylate chain.

Octylphenol polyethoxylate (OPEO(n)) surfactants are used in numerous commercial and industrial products. Large amounts of such surfactants and their various residual biodegradation by-products are ultimately released into the environment. OPEO(n) biodegradation was performed in this study using pure cultures of Pseudomonas species and strains under different environmental conditions. Environmental factors including the pH, nitrogen sources, and growth kinetics of the cells were investigated. The intermediates of Triton X-100 biotransformation were detected by high performance liquid chromatography-mass spectrophotograph (HPLC-MS). We found the highest specific growth rate (mu) was 0.56 h(-1) and this was achieved by strain E with an initial concentration of Triton X-100 of 5000 mg L(-1). A pH level of 7 was most favorable for cell growth for all five strains. The highest specific growth rate was achieved using (NH(4))(2)SO(4) as the sole nitrogen source for strain E. Strain A showed an enhancement of growth when between 0.2 and 1.4 mg L(-1) of H(2)O(2) was added. Detection of intermediates was possible after four days of transformation and the octylphenol triethoxylate (OPEO(3)) peak was predominant, while the high molecular weight peaks had all disappeared. The kinetic analysis demonstrated that the greatest maximum specific growth rate (mu(max)) and the greatest saturation constant (K(s)) of 0.83 h(-1) and 5.24 mg L(-1), respectively, were obtained for strain E in 5000 mg L(-1) Triton X-100. The higher K(i) revealed that strain A was resistant to higher Triton X-100 concentrations.

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.

Studies were conducted to investigate the feasibility and effectiveness of solidification/stabilization of hazardous heavy metal‐laden sludges with portland cement. The results indicated that the sludge properties had a significant effect on the compressive strength of the solidified samples. Additives such as lime, sodium silicate, calcium chloride, and fly ash could enhance the compressive strength and reduce the leachability of heavy metal. Also, leaching studies indicated that stabilization minimized or prevented the release of heavy metals and created a nonhazardous product.

Experiments were conducted to investigate the treatment efficiency of a sequencing batch reactor (SBR) for treating a synthetic phenolic wastewater at the conditions of various influent organic loadings and various aerated strategies during fill period of an SBR cycle. Additionally, a kinetic study was performed in order to realize the fact of substrate utilization and microorganism growth in the SBR. Experimental results indicated that excellent treatment efficiency was obtainable at the volumetric organic loading in the range of 0.15 to 0.74 Kg COD/M3-day. No matter whether the fill was aerated or not, greater than 90% COD and 99% phenol removal ratios were achieved. Also, excellent sludge settling property was observed in the study. In addition, a simple Monod kinetic model proved to be adequate in predicting reactor performance.