Advanced Materials Research Vols. 518-523

Abstract: Carbon source used as electron donors is critical to heterotrophic denitrification. Addition of external carbon source is necessary when internal organics are deficient. A review was conducted on the use of external carbon source in denitrification. Traditional carbon sources such as methanol and ethanol, alternative carbon sources such as cellulose-rich materials, biodegradable polymers and primary sludge are included in external carbon sources. Present situation and problems of its biodegradability and effects in denitrification are summarized. Focus in external carbon source includes further study on the biodegradation mechanism of the media, slow release performance and nitrate removal rate of available carbon source and continuous research on new kinds of substrates. Recommendations on further study of carbon source are put forward.

Abstract: To alleviate the water pollution, the original wastewater treatment process was transformed based on the existing structures. Anaerobic-anoxic-aerobic process (A2/O process) was used as the main process, instead of the original two-stage aeration process (AB process). Pretreatment process and advanced treatment process were strengthened. After transformation, the effluent quality could meet the first class of A standard of the "municipal wastewater treatment plant emission standards" (GB18918-2002) and all the quality indexes of the treated water met the requirements of discharge standard of sewage treatment. The original structures were fully used in this transformation, saving investment, which provided a practical reference for the transformation of the wastewater treatment plants.

Abstract: The objective is to explore degradation and removal of nitrogen and phosphorus in each unit of pond when using an artificially enhanced ecological system treats petrochemical wastes. The system consists of anoxic pond, the aerobic pond and aquatic plants pond, aiming to achieve a coordinate treatment effect in the multi-habitat system. The system combines treatment effects including assimilation, decomposition, interception, absorption, adsorption and filtration of microorganisms, aquatic plants and soil in the anaerobic, anoxic and aerobic state. It shows that the system has a good removal effect on COD, NH3-N, TN, and TP, and the removal rate range for each is 26.7% ~ 48.6%, 55.4% ~ 91.3%, 20.4% ~ 43.6% and 25.7% ~ 46.4%, respectively. It is also found that the treatment effects change with seasons, which are the best in summer because of vigorous plant growth and strong microbial activity. In conclusion, the system has a higher efficiency to remove nitrogen and phosphorus than the traditional stabilization pond technology.

Abstract: An improved allocation method was proposed to determinate SO2 emission control quantum for certain control area, which was achieved by least square optimization with environmental constraints. In order to avoid local air pollution happening, the concept of potential pollution distribution factor was introduced to determine SO2 actual environmental capacity. In the method, more SO2 emission right and emission trading chances among sub control areas were offered. The case analysis indicated the method was more suitable for emission trading compared with equal-right function method.

Abstract: The aerobic granular sludge was cultivated in the self-designed sequencing batch reactors (SBR) using ordinary flocculent activated sludge as seeding sludge. In this experiment the effect of different load on the formation of aerobic granular sludge is studied. The formation process of aerobic granular sludge and the capacity of denitrification and phosphorus performance are discussed and characterized. It shows that higher sludge loading is beneficial to the formation of aerobic granular sludge, and mature aerobic granular sludge has high sedimentation speed and the very good decontamination ability. The removal rates of COD, NH4⁺_{Subscript text}-N and TP are 97%, 85% and 95%.

Abstract: With the increasingly prominent problem regarding rapid economy development and a gradually serious environmental pollution, the waste gas pollution processing have received significant attention. Z12V190 diesel engine for petroleum drilling has high fuel consumption and releases large amounts of harmful waste gas into the atmosphere to cause serious environmental pollution. In this work, the mainly harmful components of Z12V190 exhaust gas are analysed, the corresponding methods of purification and processing about Z12V190 exhaust gas pollution discussed. In order to purify treatment pollution, and ultimate to lay the foundation for pollution treatment, the process flows of the exhaust gas pollution processing are preliminary designed.

Abstract: A focused microwave-assisted extraction (FMAE) was optimized and coupled to gas chromatography–mass spectrometry for the determination of organochlorine pesticides in soil samples. According to the result, the combination of 20 min extraction time at 48 °C and a mixture of 1+1 of n-hexane-acetone as extraction solvent is the best conditions. The recovery values is 72.8%～96.4% in the above conditions. The relative standard deviation was 4.39%~13.18%. We have good recovery values when spiked 20ng, 40ng and 60ng standard into 5.00g soil sample.

Abstract: Organochlorine pesticides and polychlorinated biphenyls content can be obtained By measuring Wanzhou of the Yangtze River and Wanzhou Zhuxi River in sediment : Sediment content of organochlorine pesticides and polychlorinated biphenyls are increased the river down. Organochlorine pesticides in sediments are β-HCH> δ-HCH> α-HCH> γ-HCH, and pp'-DDE> pp '-DDD> op'-DDT> pp'-DDT. Organochlorine pesticides and PCBs of Wanzhou of the Yangtze River sediment in the distribution of the sampling points are similar characteristics. The main source of pollution is the direct discharge of industrial wastewater, agricultural pollution and soil erosion of farmland. Although OCPs and PCBs in water environment are very low, the impact on human health can not be ignored. Therefore certain measures are taken to clean emissions from industrial wastewater and agricultural non-point source pollution control.

Abstract: Based on investigation of current situation of the water environment of middle section of Inner Qinhuai River in Nanjing city, the water quality was assessed using single factor index method. The results showed that the water quality of Inner Qinhuai River was worse than Grade V of surface water environment quality standard(GB3838-2002).The key pollutants were total nitrogen, total phosphorus and ammonia nitrogen. The characteristics and genesis of water pollution were discussed as well, and strategy and suggestion to improve water quality was put forward.

Abstract: In this paper, different physicochemical processes are used to remove heavy metals in electroplating wastewater containing nickel, chromium and fluorine. More, the three items of phosphate, NH₄⁺-N and COD_cr are also needed to be decreased to meet discharge standards. Based on the various characteristics of electroplating wastewater, biochemistry technologies are used to improve the effluent quality after pretreatment for actual origin wastewater. Anoxic reactor and biological aerated filter are employed as biological processes (A/O process) to decrease the effluent concentration of COD_cr and NH₄⁺-N. The results show that the system effluent meets the national standard of “Emission Standard of Pollutants for Electroplating” (GB 21900-2008), and NH₄⁺-N item reaches the local standard of “Discharge Standard of Main Water Pollutants for Municipal Wastewater Treatment Plant & Key Industries of Taihu Area” (DB 32/1072-2007). The modified A/O process realizes a high denitrification removal of 80%, and the operation cost is only 2.67 Yuan/m³.