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891.
Cecilia Sundberg Dan Yu Ingrid Franke-Whittle Sari Kauppi Sven Smårs Heribert Insam Martin Romantschuk Håkan Jönsson 《Waste management (New York, N.Y.)》2013,33(1):204-211
A major problem for composting plants is odour emission. Slow decomposition during prolonged low-pH conditions is a frequent process problem in food waste composting. The aim was to investigate correlations between low pH, odour and microbial composition during food waste composting. Samples from laboratory composting experiments and two large scale composting plants were analysed for odour by olfactometry, as well as physico-chemical and microbial composition. There was large variation in odour, and samples clustered in two groups, one with low odour and high pH (above 6.5), the other with high odour and low pH (below 6.0). The low-odour samples were significantly drier, had lower nitrate and TVOC concentrations and no detectable organic acids. Samples of both groups were dominated by Bacillales or Actinobacteria, organisms which are often indicative of well-functioning composting processes, but the high-odour group DNA sequences were similar to those of anaerobic or facultatively anaerobic species, not to typical thermophilic composting species. High-odour samples also contained Lactobacteria and Clostridia, known to produce odorous substances. A proposed odour reduction strategy is to rapidly overcome the low pH phase, through high initial aeration rates and the use of additives such as recycled compost. 相似文献
892.
采用UASB-SBR-絮凝工艺处理地沟油制生物柴油废水,考察了各个阶段的废水处理效果。实验结果表明:UASB稳定运行阶段进水COD约为15000mg/L时,COD去除率约为87%,出水COD在2500mg/L以下,出水挥发性脂肪酸(VFA)浓度为4~6mmol/L,最佳容积负荷为15.0kg/(m3·d);采用SBR处理UASB出水,当容积负荷为1.5kg/(m3·d)时,出水COD在200mg/L以下,COD去除率在83%以上,ρ(NH3-N)在5mg/L以下,TP约为25mg/L。向SBR出水中加入质量分数为5%的聚合氯化铝进行化学除磷,加入量为5mL/L,处理后废水TP为4~6mg/L。处理后废水的COD,ρ(NH3-N),TP均达到CJ343-2010《污水排入城市下水道水质标准》的A类要求。 相似文献
893.
制备了改性SiO2气凝胶,考察了经不同类型、不同配比的改性剂改性的SiO2气凝胶对模拟含Fe3+废水的吸附处理效果。实验结果表明:改性SiO2气凝胶的最佳制备条件为三甲基氯硅烷(TMCS)作改性剂,V(TMCS)#x02236;V(正己烷)=1#x02236;5;当改性SiO2气凝胶加入量为75g/L、吸附时间为4h、Fe3+质量浓度为10mg/L时,模拟含Fe3+废水的Fe3+去除率为98.32%,剩余Fe3+质量浓度为0.168mg/L;采用改性SiO2气凝胶动态吸附处理流量为420mL/h、Fe3+质量浓度为100mg/L的模拟含Fe3+废水,吸附后废水中剩余Fe3+质量浓度仅为0.196mg/L。 相似文献
894.
895.
Xiuyi Hua Deming Dong Xiaoou Ding Fan Yang Xu Jiang Zhiyong Guo 《Environmental science and pollution research international》2013,20(1):413-420
The effects of solution pH on adsorption of trace metals to different types of natural aquatic solid materials have been studied extensively, but few studies have been carried out to investigate the effect of pH at which the solid materials were formed on the adsorption. The purpose of present study is to examine this effect of culture pH on metal adsorption to natural freshwater biofilms. The adsorption of Pb and Cd to biofilms which were developed at different culture pH values (ranging from 6.5 to 9.0) was measured at the same adsorption pH value (6.5). The culture pH had considerable effects on both composition and metal adsorption ability of the biofilms. Higher culture pH usually promoted the accumulation of organic material and Fe oxides in the biofilms. The culture pH also affected the quantity and species of algae in the biofilms. The adsorption of Pb and Cd to the biofilms generally increased with the increase of culture pH. This increase was minor at lower pH range and significant at higher pH range and was more remarkable for Cd adsorption than for Pb adsorption. The notable contribution of organic material to the adsorption at higher culture pH values was also observed. The profound impacts of culture pH on adsorption behavior of biofilms mainly resulted from the variation of total contents of the biofilm components and were also affected by the alteration of composition and properties of the components. 相似文献
896.
Shi-Ling Ding Xi-Kui Wang Wen-Qiang Jiang Xia Meng Ru-Song Zhao Chen Wang Xia Wang 《Environmental science and pollution research international》2013,20(5):3195-3201
This work aimed to investigate the effectiveness of ultraviolet (UV) radiation on the degradation of the antimicrobial triclocarban (TCC). We investigated the effects of several operational parameters, including solution pH, initial TCC concentration, photocatalyst TiO2 loading, presence of natural organic matter, and most common anions in surface waters (e.g., bicarbonate, nitrate, and sulfate). The results showed that UV radiation was very effective for TCC photodegradation and that the photolysis followed pseudo-first-order kinetics. The TCC photolysis rate was pH dependent and favored at high pH. A higher TCC photolysis rate was observed by direct photolysis than TiO2 photocatalysis. The presence of the inorganic ions bicarbonate, nitrate, and sulfate hindered TCC photolysis. Negative effects on TCC photolysis were also observed by the addition of humic acid due to competitive UV absorbance. The main degradation products of TCC were tentatively identified by gas chromatograph with mass spectrometer, and a possible degradation pathway of TCC was also proposed. 相似文献
897.
Yong Li Shanshan Zhang Wusheng Jiang Donghua Liu 《Environmental science and pollution research international》2013,20(2):1117-1123
The aquatic plant Pistia stratiotes L. (water lettuce) was studied due to its capability of absorption of contaminants in water and its subsequent use in wetlands constructed for wastewater treatment. The effects of Cd on root growth, accumulation of Cd, antioxidant enzymes, and malondialdehyde (MDA) content in P. stratiotes were investigated. The results indicated that P. stratiotes has considerable ability to accumulate Cd. Cadmium induced higher superoxide dismutase (SOD) and peroxidase (POD) activities than catalase activity, suggesting that SOD and POD provided a better defense mechanism against Cd-induced oxidative damage. The accumulation of Cd promoted MDA production. 相似文献
898.
Responses of earthworm to aluminum toxicity in latosol 总被引:1,自引:0,他引:1
Jia’en Zhang Jiayu Yu Ying Ouyang Huaqin Xu 《Environmental science and pollution research international》2013,20(2):1135-1141
Excess aluminum (Al) in soils due to acid rain leaching is toxic to water resources and harmful to soil organisms and plants. This study investigated adverse impacts of Al levels upon earthworms (Eisenia fetida) from the latosol (acidic red soil). Laboratory experiments were performed to examine the survival and avoidance of earthworms from high Al concentrations and investigate the response of earthworms upon Al toxicity at seven different Al concentrations that ranged from 0 to 300 mg kg?1 over a 28-day period. Our study showed that the rate of the earthworm survival was 100 % within the first 7 days and decreased as time elapsed, especially for the Al concentrations at 200 and 300 mg kg?1. A very good linear correlation existed between the earthworm avoidance and the soil Al concentration. There was no Al toxicity to earthworms with the Al concentration ≤50 mg kg?1, and the toxicity started with the Al concentration ≥100 mg kg?1. Low Al concentration (i.e., <50 mg kg?1) enhanced the growth of the earthworms, while high Al concentration (>100 mg kg?1) retarded the growth of the earthworms. The weight of earthworms and the uptake of Al by earthworms increased with the Al concentrations from 0 to 50 mg kg?1 and decreased with the Al concentrations from 50 to 300 mg kg?1. The protein content in the earthworms decreased with the Al concentrations from 0 to 100 mg kg?1 and increased from 100 to 300 mg kg?1. In contrast, the catalase (CAT) and superoxide dismutase (SOD) activities in the earthworms increased with the Al concentrations from 0 to 100 mg kg?1 and decreased from 100 to 300 mg kg?1. The highest CAT and SOD activities and lowest protein content were found at the Al concentration of 100 mg kg?1. Results suggest that a high level of Al content in latosol was harmful to earthworms. 相似文献
899.
Lei Tong Xu Liao Jinsheng Chen Hang Xiao Lingling Xu Fuwang Zhang Zhenchuan Niu Jianshuan Yu 《Environmental science and pollution research international》2013,20(4):2603-2615
With the rapid urbanization, the southeast coastal cities of China are facing increasing air pollution in the past decades. Large emissions of VOCs from vehicles and petrochemical factories have contributed greatly to the local air quality deterioration. Investigating the pollution characteristics of VOCs is of great significance to the environmental risk assessment and air quality improvement. Ambient VOC samples were collected simultaneously from nine coastal cities of southeast China using the Tedlar bags, and were subsequently preprocessed and analyzed using a cryogenic preconcentrator and a gas chromatography–mass spectrometry system, respectively. VOC compositions, spatial distributions, seasonal variations and ozone formation potentials (OPFs) were discussed. Results showed that methylene chloride, toluene, isopropyl alcohol and n-hexane were most abundant species, and oxygenated compounds, aromatics and halogenated hydrocarbons were most abundant chemical classes (62.5–95.6 % of TVOCs). Both industrial and vehicular exhausts might contribute greatly to the VOC emissions. The VOC levels in the southeast coastal cities of China were sufficiently high (e.g., 6.5 μg?m?3 for benzene) to pose a health risk to local people. A more serious pollution state was found in the southern cities of the study region, while higher VOC levels were usually observed in winter. The B/T ratio (0.26?±?0.09) was lower than the typical ratio (ca. 0.6) for roadside samples, while the B/E (1.6–7.6) and T/E (7.2–26.8) ratios were higher than other cities around the world, which indicated a unique emission profile in the study region. Besides, analysis on ozone formation potentials (OFPs) indicated that toluene was the most important species in ozone production with the accountabilities for total OFPs of 22.6 to 59.6 %. 相似文献
900.
Xiaoxuan Jiang Yanlin Wu Peng Wang Hongjing Li Wenbo Dong 《Environmental science and pollution research international》2013,20(7):4947-4953
Degradation of bisphenol A (BPA) in aqueous solution was studied with high-efficiency sulfate radical (SO4 ?·), which was generated by the activation of persulfate (S2O8 2?) with ferrous ion (Fe2+). S2O8 2? was activated by Fe2+ to produce SO4 ?·, and iron powder (Fe0) was used as a slow-releasing source of dissolved Fe2+. The major oxidation products of BPA were determined by liquid chromatography-mass spectrometer. The mineralization efficiency of BPA was monitored by total organic carbon (TOC) analyzer. BPA removal efficiency was improved by the increase of initial S2O8 2? or Fe2+ concentrations and then decreased with excess Fe2+ concentration. The adding mode of Fe2+ had significant impact on BPA degradation and mineralization. BPA removal rates increased from 49 to 97 % with sequential addition of Fe2+, while complete degradation was observed with continuous diffusion of Fe2+, and the latter achieved higher TOC removal rate. When Fe0 was employed as a slow-releasing source of dissolved Fe2+, 100 % of BPA degradation efficiency was achieved, and the highest removal rate of TOC (85 %) was obtained within 2 h. In the Fe0–S2O8 2? system, Fe0 as the activator of S2O8 2? could offer sustainable oxidation for BPA, and higher TOC removal rate was achieved. It was proved that Fe0–S2O8 2? system has perspective for future works. 相似文献