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1.
Few studies have been carried out to connect nutrient recovery as struvite from wastewater and sustainable utilization of the recovered struvite for copper and zinc immobilization in contaminated soil. This study revealed the effect of struvite on Cu and Zn immobilization in contaminated bio-retention soil in the presence of commonly exuded plant organic acids. The research hypothesis was that the presence of both struvite and organic acids may influence the immobilization of Cu and Zn in soil. The outcome of this research confirmed that more than 99% of Cu and Zn was immobilized in bio-retention filter media by struvite application. Water-soluble Cu and Zn concentrations of struvite treated soil were less than 1.83 and 0.86 mg/kg respectively, and these concentrations were significantly lower compared to the total Cu and Zn content of 747.05 mg/kg in the contaminated soil. Application of struvite to Cu- and Zn-contaminated soil resulted in formation of compounds similar to zinc phosphate tetrahydrate (Zn3(PO4)2?4H2O) and amorphous Cu and Zn phases. Struvite was effective in heavy metal remediation in acidic soil regardless of the presence of Ca impurities in struvite and the presence of plant organic acids in soil. Overall, this study revealed that struvite recovered from wastewater treatment plants has potential for use as an amendment for heavy metal remediation in contaminated bio-retention soil. 相似文献
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采用粉煤灰、高岭土、泥渣(取电厂澄清池排泥作脱水干燥处理)作为吸附剂深度处理污水中的磷,对比分析了3种吸附剂的吸附速度、吸附性能及除磷效果。结果表明:粉煤灰和高岭土用时20 min完成对磷的有效吸附,沉降泥渣用时5 min即可实现同等吸附效果;沉降泥渣对污水中磷的吸附能力较好,投加量为0.2 g/L的泥渣对磷的去除率可达98.1%,而投加量为0.2 g/L粉煤灰或高岭土对磷的去除率仅达到77.2%。 相似文献
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Sulphate leaching losses may reduce the long-term possibility of maintaining the S supply of crops in low input farming systems. The ability of catch crops (Italian ryegrass (Lolium multiflorum Lam), winter rape (Brassica napus L.) and fodder radish (Raphanus sativus L.)) to reduce soil sulphate concentrations in autumn and make it available to a succeeding crop was investigated in 1996–1998 on sandy loam soil in Denmark. All catch crops reduced soil sulphate concentrations in the autumn compared to bare soil. Especially, the cruciferous catch crops had the ability to deplete efficiently soil sulphate levels and thus, reduce the sulphate leaching potential. The S uptake in aboveground catch crop was 8, 22 and 36 kg S per ha for ryegrass, winter rape and fodder radish, respectively. In the following spring, sulphate levels of the autumn bare soil were low in the top 0.5 m and a peak of sulphate was found at 0.75–1 m depth. In contrast, where a fodder radish catch crop had been grown, high sulphate levels were present in the top 0.5 m, but only small amounts of sulphate were found at 0.5–1.5 m depth. In spring barley (Hordeum vulgare L.), that followed catch crops, S concentrations at heading and maturity revealed that the availability of soil S increased following winter rape and fodder radish, whereas there were indications that following ryegrass, the S availability was reduced compared to bare soil. This initial study showed that catch crops have a high potential for reducing sulphate leaching and may be used to synchronise S availability with plant demand in a crop rotation. 相似文献
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浅议影响污水生物除磷的因素 总被引:11,自引:0,他引:11
针对目前水体富营养化严重,污水除磷要求高的现状,着重分析阐述了在目前条件下的对污水生物除磷产生较显著影响的因素,如,溶解氧及氧化还原电位,硝酸盐,泥龄,进水营养比等,以期对生产实践有所帮助。 相似文献
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焦化废水中有机污染物的特性及处理工艺方法的研究 总被引:2,自引:0,他引:2
研究了焦化废水中有机物的特性及有机污染物处理技术的发展动态和新方法。研究表明 ,生物法和物化新方法的联合工艺是处理焦化废水有机污染物的有效方法 相似文献
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G.L. Feng J. Letey A.C. Chang M. Campbell Mathews 《Agriculture, ecosystems & environment》2005,110(3-4):219-229
Large scale dairy operations are common. In many cases the manure is deposited on a paved surface and then removed with a flushing system, after which the solids are separated, the liquid stored in ponds, and eventually the liquid applied on adjacent crop land. Management of liquid manure to maximize the fertilizer value and minimize water quality degradation requires knowledge of the interactive effects of mineralization of organic N (ON) to NH4+, crop uptake of mineral N, and leaching of NO3− on a temporal basis. The purpose of the research was to use the ENVIRO-GRO model to simulate how the amount of applied N, timing of N application, ON mineralization rates, chemical form of N applied, and irrigation uniformity affected (1) yields of corn (Zea mays) in summer and a forage grass in winter in a Mediterranean climate and (2) the amount of NO3− leached below the root zone. This management practice is typical for dairies in the San Joaquin Valley of California. The simulations were conducted for a 10-year period. Steady state conditions, whereby an equivalent amount of N applied in the organic form will be mineralized in a given year, are achieved more rapidly for materials with high mineralization rates. Both timing and total quantity of N application are important in affecting crop yield and potential N leaching. Major conclusions from the simulations are as follows. Frequent low applications are preferred to less frequent higher applications. Increasing the amount of N application increased both the crop yield and the amount of NO3− leached. Increasing irrigation uniformity increased crop yields but had variable effects on the amount of NO3− leached. A winter forage crop following a summer corn crop effectively reduced the leaching of residual soil N following the corn crop. 相似文献