Advanced Materials Research Vols. 518-523

Abstract: Constructed wetland was recognized as an economic and ecological-friendly technique to reduce excess nitrogen (N) and phosphorus (P) in secondary effluent from sewage treatment plants. In this study, the removal capacity of non-planted control treatment, one stage constructed wetland with different feeding strategies, and multi-stage constructed wetland on chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4⁺-N) and total phosphorus (TP)were evaluated. The results showed that all the planted treatments displayed superior removal efficiency for COD and nutrients in compare with the non-planted control treatment. The feeding strategy could influence COD andN removal rate that the averageremoval rate of the COD, TN, and NH4⁺-N in intermittent feeding treatment (61.3%, 52.6% and 88.7%) was much higher than continuous feeding treatment (46.8%, 20.6% and 73.9%). Higher TN and TP removal rate was observed in multi-stage constructed wetland (74.1% and 98.1%) than the single-stage constructed wetland (20.6% and 96.9%). This implied that intermittent feeding strategy and the multi-stage constructed wetland may have a good potential for removing nutrients from secondary effluent.

Abstract: This paper introduced the principle of inner-furnace desulfurization system of CFB boilers by injecting limestone, and investigated the factors of the desulfurization efficiency. The desulfurization efficiency and stability of 480t/h CFB boilers manufactured by DongFang Boiler (Group) Co., Ltd were greatly increased by retrofitting the limestone injection position from dense region to the down secondary-air inlet of the back-wall. The improvement was achieved by increasing the oxygen concentration as well as optimizing the temperature of the reaction zone.

Abstract: The treatment of landfill leachate by Fenton process was carried out in a batch mode. The effect of operating conditions such as reaction time, pH, dosage of H2O2 and [H2O2]/[Fe2+] molar ratio and temperature on the efficacy of Fenton process was investigated. It is demonstrated that Fenton’s reagent can effectively degrade leachate organics in 30 min. The optimal conditions were pH was 3, dosage of H2O2 was 2 times of theoretical stoichiometry, [H2O2]/[Fe2+] molar ratio was 5, temperature influence the removal efficency relatively small compared to other factors.

Abstract: Animal waste causes environmental problems like eutrophication of ground and water. The objective of this study was to fix the total nitrogen (TN) and total phosphorus (TP) in swine waste into biomass by investigating the performance of sole and mixed algae species culture with fast growth algae Scenedesmus obliquus and wild algae Chlorella sp. Wastewater concentrations varied from 25 to 100% and initial pH varied from 6 to 9 were conducted. The results indicated that the initial wastewater concentration and pH are crucial to biomass growth and the removing rate of TN and TP. It was found out that the maximum biomass growth rate of 73 mg/l/d was achieved with mixed species culture in 75% piggery wastewater (with TN and TP of 54 and 12 mg/l) with pH 7, meanwhile, the removing rate of TN and TP reached 87.3% and 64.3% with 10 days culture, respectively.

Abstract: In this paper, using Sulphydryl Cotton as solid absorptive enrichment agent of mercury, the best enrichment eluting method of mercury is confirmed by conditions trials in order to apply to the determination of mercury in rainwater in Guilin City. The practice proves that the adoption of this technology can simply concentrate the trace mercury in rainwater for scores of or even more than 100 times and can effectively enhance the precision of instruments detecting mercury.

Abstract: In recent years, the numbers of odor pollution sources and odor pollution events are increasing rapidly, along with the high growth of life quality and the growing of people's environmental awareness. Odor pollution has been one of the hottest and most difficult problems that the environmental management department is facing. Evaluating and classifying the odor pollution is important basis for analyzing the odor pollution. This article has discussed the classification of odor pollution preliminary.

Abstract: Perfluorinated surfactants have emerged as priority environmental contaminants due to their detection in environmental and biological matrices as well as concerns regarding their persistence and toxicity. They have been found in groundwater, particularly at sites used for training firefighters. They do not biodegrade easily in groundwater, and are not retarded during transport. The most common chemical is Perfluorooctanyl Sulphonate (PFOS), which is mainly used in aqueous film forming foam (AFFF) to extinguish hydrocarbon-fuel fires. It is also used in many herbicide and insecticide formulations, cosmetics, greases and lubricants, paints, polishes, and adhesives. PFOS and related fluoro-organic chemicals have been used since the 1950s. A quantity of fluorosurfactants and related products are still in use all over the world. Intensive studies over the last few years discovered that PFOS and certain by-products were both ubiquitous in the environment and highly persistent. PFOS does not biodegrade in the environment and very limited degradation has been observed in wastewater treatment. The breakthrough curves of a single-well push-pull test indicated that there was no retardation for PFOS as well. It was detected in part-per-billion levels in blood samples obtained from blood banks in the United States, Japan, Europe, and China. There have been more and more reports on the accumulation and effect of PFOS in wild animals’ liver, serum and muscle as well. This suggests that PFOS can bioaccumulate to higher levels of the food chain.

Abstract: The soft measuring model, for pollutants release from coal combusting in power plant boiler, was combined with the test data obtained from boiler operation, established on the basis of technology for CMAC artificial neural network, and adopted the hyper CMAC structure and algorithm. The characteristic data about coal quality from boiler operation and combusting conditions in the furnace were took as its input parameters, to achieve precise prediction and on-line measurement of concentration of sulfur and nitrogen pollutant emission. It was effective to guide operator in the power plant to optimize combustion and control pollutants emission.

Abstract: Sediments from 29 stations within Wenruitang River basin were sampled to investigate the spatial distribution patterns of heavy metals in sediments and to assess the pollution status of heavy metal elements (Cd, Cr, Cu, Ni, Zn and Pb). Heavy metal concentrations showed significant spatial variation in sediments from different areas. Enrichment factors (EF) indicated that the order of pollution level was as follows: Cd＞Cu＞Zn＞Ni＞Cr＞Pb. The major heavy metal contaminants were derived from human impacts. Correlation analysis suggested that Cu, Zn, Ni, Cd and Pb were significantly related to total organic carbon (TOC); Cu, Ni, Pb, Zn and Cr had a close association with each other; Cd was closely associated with Zn.

Abstract: The available states of Manganese (Mn) and zinc (Zn) in soil exert important roles in same biochemical reactions. Their deficiency can result in plant micronutrient disorders, but the excess contents may contribute to several environmental issues. Their spatial distribution and influential factors in the middle reaches of Tuojiang River Basin, a typical region with the broken terrain and densely populated hill, were studied with the combination of statistics, geostatistics, global positioning system (GPS) and geographic information system (GIS). According to the data of the contents in topsoil (0~20 cm) from the 296 random sampling points,the contents of soil available Mn and Zn were 5.95 and 1.05 mg kg-1, respectively. The highest value regions (>11 mg kg-1) of Mn contents were mainly distributed in the central parts of study area, and first decreased to the both sides from the central and then increased towards the northwest. The highest value regions (>1.8 mg kg-1) of Zn contents were mainly distributed in the northwest parts, and then reduced gradually towards to the southeast and southwest presenting zonal shapes. Almost 30% of the area had higher than 50% probability to exceed the threshold value (7.00 mg kg-1) of the soil available Mn based on probability kringing, Similarly, more than 70% part of the area with the probability more than 50% exceed the threshold value (0.50 mg kg-1) of soil available Zn. The content and spatial distribution of soil Mn and Zn were affected by parent materials, landform types, slopes, landuse patterns, textures, pH and organic matters (OM). While the above factors except for OM and texture (P>0.05) had significant influence on soil available Mn (P<0.05). On the contrary, only OM was the significant influent factor to soil available Zn (P<0.05).