Applied Mechanics and Materials Vols. 209-211

Abstract: Non-point source pollution (NPSP) is an important factor that affects water quality. To study the effect of the pollution on water quality, the Soil and Water Assessment Tool (SWAT) is applied to simulate runoff and nutrient concentrations in the Lianshui Watershed. In the monthly time step, the model’s Nash-Sutcliffe coefficient and the coefficient of determination indicated that the values of simulated runoff, nutrient concentrations are acceptably closer to the measured data. Then, the study concluded that NPSP is the dominant factor affecting the water quality of the Lianshui River. Finally, the study also explored the temporal and spatial distribution characteristics of NPSP in the watershed.

Abstract: Four indices which include surface runoff, soil erosion, agricultural nutrient loss, human and animal feces were selected and method to evaluate risk of non-point source pollution in watershed was constructed based on GIS. As a case, non-point source pollution in Dayanghe was evaluated. Results showed that very high risk area of non-point source pollution accounted for 3.41% area of the watershed, mainly located in farmland with steep slope along upper valley of the watershed. High risk area of non-point source pollution was located in farmland and human settlement placecs, accounted for 16.40% area of the watershed. Areas with low risk of non-point source pollution was riverbeds, shrub and grassland in eastern and western hilly with steep slope. Areas with lower risk of non-point source pollution located in middle of the watershed and accounted for 60.55% area. GIS-based risk evaluation system of non-point source pollution can reflect real map of pollution in the Dayanghe watershed and give implication for protection plan.

Abstract: Phenol is the most common pollutant which can be found in several types of industries. It is highly toxic to human beings. To seek the best phenol-degrading bacteria, we collected activated sludge from an aeration tank of the coking wastewater treatment plant, Benxi Iron and Steel Corporation. Five phenol-degrading strains, designated BS3, BS4, BS23, BS28 and BS29, were isolated and screened from activated sludge. Under the conditions of initial phenol 500 mg•L-1,170 rpm and 28°C, the removal efficiencies of BS3, BS4, BS23, BS28 and BS29 strains reached to 79.6%±1.8%, 55.2%±1.0%, 62.4%±2.6%, 78.6%±2.0% and 61.2%±1.9% within 24 h, respectively. By a series of morphological and biochemical and physiological tests, the five phenol-degrading bacteria were identified. The results indicated that they were Pseudomonas spp.. Hence these strains can be effectively used for bioremediation of phenol contaminated water.

Abstract: Aiming at the distribution characteristics and treatability of EEDs (Environmental Endocrine Disrupters), the EEDs in the influent of a WWTP in Xi’an were monitored for a long time. Then, the distribution characteristics of three categories of EEDs including phthalate esters (PAEs), chlorophenols and estrogens in the municipal wastewater were analyzed. At the same time, the treatability of EEDs was analyzed through utilizing different seven treatment processes to remove the EEDs in wastewater such as enhanced primary treatment, secondary biological treatment, etc. As for the distribution characteristics of EEDs, PAEs and Estrogens are the main EEDs in municipal wastewater. As for the treatability, enhanced primary treatment and biological secondary treatment could remove EEDs to certain extent. Moreover, disinfection by ozone could make up for the shortcomings of chlorination. Furthermore, EEDs could be removed more efficiently by advanced treatment processes among which O3-BAC is the optimal process.

Abstract: A full-scale nitrogen removal system composed of an anoxic tank, an anaerobic tank, a micro-aerobic tank and an aerobic tank (A2O2) was established to treat 15,000 t/d high strength ammonia wastewater of a nitrogenous fertilizer factory. After the first stage of commissioning test, the stable operation of short-cut nitrification and denitrification has been realized at the normal temperature. The results showed that under the conditions of COD/TN ratio of only 1~2, the average removal efficiency of COD、NH3-N and TN achieved 80%, 96% and 54%, respectively without extra addition of alkalinity or carbon source, and the effluent quality was better than the requirement of the《Synthetic ammonia industrial water contamination emission standard》(draft for comment). The variation of nitrogen compounds concentration and operational parameters of pH, DO were investigated in each tank of A2O2 system. The results showed that the short-cut nitrification was stabilized in the micro-aerobic tank through the control of DO concentration (about 0.6 mg/L). Although the pH of micro-aerobic tank was only 6.6 which inhibited the growth of nitrite bacteria, the nitrite accumulation ratio reached about 48 %, closing to the criteria for judgment of short-cut nitrification of 50%. During operation, the process parameters of the A2O2 system such as reflux ratio of the mixed liquids, sludge load, sludge concentration, sludge age and SVI were all maintained in normal range, and small fluctuation of process parameters didn’t show obvious influence on short-cut nitrification.

Abstract: The invasion of indigenous flora from the open system into the biological enhanced activated carbon(BEAC) system can inhibit the development of dominant bacteria and also decrease the biodegradability and biological activity of dominant bacteria. Therefore, this study aimed to investigate the effect of backwashing on the indigenous flora and dominant bacteria in the BEAC system and to study the optimal operation process of backwashing. In order to control the inhibition of the indigenous flora, the optimal backwashing conditions were set as 7-10d of operation period and 8-10 L/(m2•s) of air backwashing intensity. In addition, the PCR-DGGE results showed the indigenous flora could be removed under the optimal backwashing process, and the dominant bacteria could also be updated to maintain the biological stability well in this system.

Abstract: A lab-scale sequencing batch biofilm reactor (SBBR) was developed to treat domestic wastewater. After one year’s operation, the results were obtained as follows: when the reaction carried out in 3 h, COD removal efficiency approached or reached the maximal value, up to 90%. The nitrification process of NH3-N needed 4 h, and NH3-N removal efficiency reached the maximal value. Moreover, according to the variation of TN , NO3--N and NO2--N concentration in the nitrification and denitrification process, when NH3-N degraded to zero or the minimal value, just two cycles ending, it means that the SBBR system completed the nitrification and denitrification process.

Abstract: The effect of bed material heights on treatment performance of pollutants from micro-polluted raw Water was studied in zeolite - Ceramics biological aerated filter(ZCBAF) technology. The test results showed the removal rate of CODMn, NH4+-N and UV254 will improve with the increase of media height, most of CODMn and UV254 were removed within the first 440mm , when the media height over 440mm, the effect of increase height is inconspicuous removal, and ammonia-nitrogen removal has evident improvement during 220-440mm. At the media height of 20mm, 40mm and 60mm in ZCBAF respectively, the removal efficiency of CODMn is 18.05%，31.6% and 38.62% respectively, NH4+-N removal efficiency is 29.78%,81.28% and 93.02% respectively , and UV254 removal efficiency is 7.81%，10.11% and 11.26% respectively under the air/water ratio of 1:1 and the hydraulic loading of 1.2m3/(m2.h). Removal rate of CODMn was decreased with the increase of hydraulic loading, and removal effect of NH4+-N and UV254 had not big influence.

Abstract: Ferrum manganese composite materials (1-3μm) had been successfully synthesized by low-cost ferruginous manganese ore in wet granulation to treat the arsenic wastewater effectively. The experiment showed when the cement content was 10%, the amount of saw dust was 5% and roasting temperature was 250°C, the composite materials was able to meet the demand of the particles strength and the removal rates of As(Ⅲ) and As(Ⅴ) were up to 85.25% and 80.13% respectively. The analysis for the materials of adsorption effect factors indicated as pH value increased, the removal rate reduced. The temperature was in an opposite way. Within 0-40min, the adsorption of arsenic became better and better. After 60min, the process basically reached the adsorption equilibrium. In addition, the removal rate also reduced following with the increasing dosing quantity of SO42- and HPO42-. Especially the HPO42- influenced it heavily. Therefore, it was important to control the content of HPO42- for the arsenic removal.

Abstract: The feces and livestock wastewater is characterized with complicated and high level in pollutant and foul odor, great change with loading. Humus activated sludge process with anaerobic-intermittent aeration mode were adopted to treat feces and livestock wastewater complex. The design and operation result showed that the process could remove effectively high concentration organic matter, TN,TP and SS, no foul gas release in residual sludge and during operation, the system has strong tolerance to the high hydraulic load through adjusting aeration period and reflux ratio. The feces and livestock treatment in China can draw lessons from the Yongin feces and livestock wastewater complex treatment system in Korea