Using the entrapped bioprocess as the pretreatment method for the drinking water treatment receiving eutrophic source water.

Control of organic matter, nutrients and disinfection byproduct formation is a major challenge for the drinking water treatment plants on Matsu Islands, Taiwan, receiving source water from the eutrophic reservoirs. A pilot entrapped biomass reactor (EBR) system was installed as the pretreatment process to reduce organic and nitrogen contents into the drinking water treatment plant. The effects of hydraulic retention time (HRT) and combination of preceding physical treatment (ultraviolet and ultrasound) on the treatment performance were further evaluated. The results showed that the EBR system achieved higher than 81%, 35%, 12% and 46% of reduction in chlorophyll a (Chl a), total COD (TCOD), dissolved organic carbon (DOC) and total nitrogen (TN), respectively under varied influent concentrations. The treatment performance was not significantly influenced by HRT and presence/absence of physical pretreatment and the effluent water quality was stable; however, removal efficiencies and removal rates of Chl a, TCOD and DOC showed strong correlation with their influent concentrations. Excitation-emission matrix (EEM) fluorescence spectroscopy identified fulvic-like and humic-like substances as the two major components of dissolved organic matter (DOM) in the reservoir, and decreased intensity of the major peaks in effluent EEM fluorescence spectra suggested the effective removal of DOM without production of additional amount of soluble microbial products in the EBR. Through the treatment by EBR, about 10% of reduction of total trihalomethane formation potential for the effluent could also be achieved. Therefore, the overall results of this study demonstrate that EBR can be a potential pretreatment process for drinking water treatment plants receiving eutrophic source water.

Entrapped biomass for removal of organics and total nitrogen from anaerobic reactor effluents.

Anaerobic processes have been applied to treat low-strength domestic wastewaters with significant energy saving. However, anaerobic process effluents must be further removed of residual organics and total nitrogen before discharge. Reported here are an aerobic entrapped bio-technology (EBT) system and an EBT coupled with activated sludge (EBT + AS) system being tested as a post-anaerobic treatment. Both systems have been operated under aerobic condition to provide organics and total nitrogen removal, achieving COD removal by 74-88% and TN removal by 58-65% at hydraulic retention times of 8-24 h. ΔCOD/ΔNO3 ratios that represent the carbon usage efficiency as electron donors for denitrification were 1.82-1.93 in the EBT and 2.01-2.02 in the EBT + AS systems, with both ratios being lower (i.e. more efficient) than 6 typically required in traditional activated sludge bioreactors. Both systems demonstrate promise for polishing removal of COD and TN.

[Effect of comprehensive intervention of schistosomiasis control in construction workers in Poyang Lake region].

After the implementation of the comprehensive schistosomiasis control measures centering on health education for 3 years, the awareness rate of schistosomiasis control increased by 96.56% in construction workers of Dechang highway construction engineering projects in Poyang Lake region, the number of workers adopting preventive measures increased significantly, and no schistosome infection occurred. It is suggested that the comprehensive measures focusing on health education, combined with environment depollution and public administration can prevent schistosome infection effectively among construction workers.

Biodegradation and bio-sorption of antibiotics and non-steroidal anti-inflammatory drugs using immobilized cell process.

In the present study, the removal mechanisms of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine, and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen, and naproxen) in immobilized cell process were investigated using batch reactors. This work principally explores the individual or collective roles of biodegradation and bio-sorption as removal routes of the target pharmaceuticals and the results were validated by various experimental and analytical tools. Biodegradation and bio-sorption were found as dominant mechanisms for the drug removal, while volatilization and hydrolysis were negligible for all target pharmaceuticals. The target pharmaceuticals responded to the two observed removal mechanisms in different ways, typically: (1) strong biodegradability and bio-sorption by acetaminophen, (2) strong biodegradability and weak bio-sorption by sulfamethoxazole, sulfadimethoxine, ibuprofen and naproxen, (3) low biodegradability and weak bio-sorption by sulfamethazine and ketoprofen, and (4) low biodegradability and medium bio-sorption by trimethoprim. In the sorption/desorption experiment, acetaminophen, sulfamethoxazole and sulfadimethoxine were characterized by strong sorption and weak desorption. A phenomenon of moderate sorption and well desorption was observed for sulfamethazine, trimethoprim and naproxen. Both ibuprofen and ketoprofen were weakly sorbed and strongly desorbed.

Reduced membrane fouling in a novel bio-entrapped membrane reactor for treatment of food and beverage processing wastewater.

A novel Bio-Entrapped Membrane Reactor (BEMR) packed with bio-ball carriers was constructed and investigated for organics removal and membrane fouling by soluble microbial products (SMP). An objective was to evaluate the stability of the filtration process in membrane bioreactors through backwashing and chemical cleaning. The novel BEMR was compared to a conventional membrane bioreactor (CMBR) on performance, with both treating identical wastewater from a food and beverage processing plant. The new reactor has a longer sludge retention time (SRT) and lower mixed liquor suspended solids (MLSS) content than does the conventional. Three different hydraulic retention times (HRTs) of 6, 9, and 12 h were studied. The results show faster rise of the transmembrane pressure (TMP) with decreasing hydraulic retention time (HRT) in both reactors, where most significant membrane fouling was associated with high SMP (consisting of carbohydrate and protein) contents that were prevalent at the shortest HRT of 6 h. Membrane fouling was improved in the new reactor, which led to a longer membrane service period with the new reactor. Rapid membrane fouling was attributed to increased production of biomass and SMP, as in the conventional reactor. SMP of 10-100 kDa from both MBRs were predominant with more than 70% of the SMP <100 kDa. Protein was the major component of SMP rather than carbohydrate in both reactors. The new reactor sustained operation at constant permeate flux that required seven times less frequent chemical cleaning than did the conventional reactor. The new BEMR offers effective organics removal while reducing membrane fouling.

[Study on an intervention model of "schools without infected students with schistosoma japonica" in heavy endemic areas].

OBJECTIVE: To study an intervention model of "schools without infected students with schistosoma japonica", to control and prevent students from schistosoma infection. METHODS: Twelve primary schools of four heavy endemic counties (districts) with schistosomiasis in the Poyang Lake areas were selected as the study fields, of which, ten schools were the experimental groups, and the other two schools were the control groups by cluster random sampling. All enrolment students were the target population. The baseline survey was carried out in 2005, and an intervention model, "information dissemination + behavior participation + behavior encouragement", was applied in the experiment groups in 2006 - 2008, then the effect of intervention was assessed. RESULTS: Before intervention (2005), the anti-schistosomiasis knowledge awareness rate of experimental and control groups were 14.75% (324/2196) and 16.58% (91/549), and the different was not significant (χ(2) = 1.14, P > 0.05); the rate of accurate attitude of anti-schistosomiasis were 14.71% (323/2196) and 11.84% (65/549) in experimental and control groups, and the difference was not significant (χ(2) = 2.98, P > 0.05); the rate of contacting infected water were 15.44% (18 988/122 976) and 15.03% (4622/30 744) in experimental and control group and the difference was not significant (χ(2) = 3.13, P > 0.05); and the infection rate of schistosomiasis of experiment control groups were 9.65% (212/2196) and 10.56% (58/549), the difference was not significant (χ(2) = 0.41, P > 0.05). After one year intervention (2006), the anti-schistosomiasis knowledge awareness rate of experimental and control groups were 97.79% (2032/2078) and 18.11% (98/541), and the different was significant (χ(2) = 1794.31, P < 0.01); the rate of accurate attitude of anti-schistosomiasis were 99.09% (2059/2078) and 13.49% (73/541) in experimental and control group, and the difference was significant (χ(2) = 2077.45, P < 0.01). After 1 - 3 years intervention (2006 - 2008), there were no any contactors with infected water and infectors with schistosome in students of the experiment group in successive 3 years. While in the control group of the same period, the rate contacting infected water were 16.12% (4884/30 296), 11.11% (3079/27 720) and 12.25% (3451/28 168); the infection rate of schistosomiasis were 8.87% (48/541), 7.47% (37/495) and 7.95% (40/503), respectively. CONCLUSION: The intervention model of health promotion, "information dissemination + behavior participation + behavior encouragement", can effectively control and prevent students from infecting schistosoma japonica in heavy endemic areas with schistosomiasis.

[Establishment and application of school-based health promotion and intervention model of schistosomiasis in lake-type endemic area].

OBJECTIVE: To establish an intervention model of school health promotion, and apply it in developing "schistosomiasis-free schools". METHODS: At the pilot stage, all students of Henghu primary school and Banshan primary school in Xinjian County of Jiangxi Province were selected as experiment group and control group, respectively. A baseline survey covered knowledge and attitude on schistosomiasis control, water contact behaviors and Schistosoma japonicum infection rate. Two health promotion intervention models, i.e. "information communication + training of protection skill + reward & punishment" (model A, 1993-1999) and "information communication + behavior participation + encouragement" (model B, 2000-2007), were implemented in Henghu school. The effect of two models was compared by infection rate. At the application stage, all students of 8 schools in Xinjian County, Nanchang County, and Jinxian County were chosen for evaluation of the effectiveness of Model B with same methods and index. RESULTS: Before intervention there was no significant statistical difference on the passed rate of anti-schistosomiasis knowledge, correct rate of anti-schistosomiasis attitude, frequency of infested water exposure and the infection rate between Henghu and Banshan schools (P > 0.05). In Henghu school, the intervention showed significant effect on the scores of knowledge and attitude after one year (P < 0.01), raised from 9.0% and 55.1% before intervention to 94.4% and 98.9% after intervention, respectively. The frequency of infested water exposure and the infection rate significantly decreased from 14.6% and 13.5% before intervention to 1.9% and 2.3%, respectively (P < 0.01). In 2-7 years after intervention, there were only one or two schistosomiasis cases each year. At the application stage, no schistosomiasis cases were found among Model B target population in two successive years after intervention. CONCLUSION: The practice of Model B can be extended to other schools in endemic area to develop "schistosomiasis-free schools".

Removal of antibiotics and non-steroidal anti-inflammatory drugs by extended sludge age biological process.

Removal of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen and naproxen) using extended sludge age biological process was investigated. The sludge age of the biological system was greater than 200d. Hydraulic retention time of 12h was maintained throughout the experiment. The extended sludge age biological process is able to treat pharmaceuticals with good and steady removal efficiencies: 64-93% removal for antibiotics over 1-5microgL(-1) influent concentrations and 94% to complete removal for acetaminophen and ibuprofen with a wide range of influent concentrations 1-100microgL(-1). For ketoprofen and naproxen the removal efficiencies are 79-96% over a range of 1-15microgL(-1) influent concentrations. The removal efficiency decreases with increasing initial concentrations for all target compounds except for ibuprofen. This indicates that the initial influent concentration is an important parameter for the studies of fate of pharmaceuticals. The amount of bio-mass and size of the reactor required to achieve good and steady removal efficiencies for known influent pharmaceutical concentrations are also suggested in this study.