Effects of water quality on the coagulation performances of humic acids irradiated with UV light

The presence of humic acid in drinking water treatment has received significant attention in recent years because of its adverse effects on the removal of many pollutants in coagulation. In this paper, the effects of water quality including pH, turbidity, alkalinity, and hardness on the removal of humic acid were investigated in a UV light hybridized coagulation process. Our results suggested that UV light radiation could effectively improve the removal rate of humic acid in coagulation under both neutral and basic conditions, and the variations of the selected water quality parameters had little adverse effect on the function of UV light. After UV light radiation, the removal rate of the nitro-humic acid (NHA) increased from 20% to 60% in coagulation, and increased further to 75% and 85% for the raw waters with 10.0 NTU kaolin and 100 mg·L^-1 hardness, respectively. In addition to NHA, the removal rates of the humic acid extracted from peat coal (PHA) and the humic acid provided by Japan metals and chemicals company (JHA) in coagulation were also improved, both in the range of 80%–90% after undergoing UV light radiation. By changing the radiation location from prior to coagulation to the flocculation process, similar experimental results were obtained. The formation of positive charged sites after UV light radiation was considered to be the primary factor that led to an enhanced removal of the humic acid in coagulation.     

不同基质的浮床对浮床植物及废水脱氮效果的影响

研究3种不同材料作为生态浮床(Floating beds,FBs)基质而组建的组合生态浮床(hybrid FB,HFBs)以及一种无基质的传统生态浮床(C-FB)脱氮效果和性能。3种组合生态浮床分别由竹丝、稻草和轻质陶粒为基质。实验结果表明:当原水中总氮(TN)和总磷(TP)质量浓度分别为8.21~9.38,5.49~5.84mg/L,3 d后经过C-FB、轻质陶粒组合生态浮床(HFB-C)、稻草组合生态浮床(HFB-RS)、竹丝组合生态浮床(HFB-FB)处理后,出水中TN和TP的质量浓度分别为6.54~7.35,5.54~6.65,0.52~0.92,1.19~1.55 mg/L和2.81~2.90,3.81~3.96,2.67~2.79,2.49~2.58 mg/L。大型水生植物代谢酶及其生长速度依次为:HFB-FBHFB-RSC-FBHFB-C,水体温度对大型水生植物生长特性和生化特性有着显著地影响,影响最大是过氧化物酶(CAT),其次是叶绿素,过氧化物酶(POD)和丙二醛(MAD)变化不明显。实验结果说明基质差异对组合式生态浮床的脱氮效果具有显著影响。     

A lab-scale study on heterotrophic nitrification-aerobic denitrification for nitrogen control in aquatic ecosystem

Environmental Science and Pollution Research - Nitrogen (N) loss is generally caused by denitrification under anaerobic conditions and the N loss in the heterotrophic nitrification_aerobic...     

Horseradish peroxidase microcapsules based on layer-by-layer polyelectrolyte deposition

Polyelectrolyte multilayer microcapsules have been prepared for encapsulating horseradish peroxidase (HRP). The CaCO₃ microparticles containing HRP molecules were prepared and subsequently enwrapped with layer-by-layer (LbL) deposited multilayer films. The LbL films were constructed via an alternate electrostatic adsorption of poly(allylamine) and poly(styrene sulfonate). The CaCO₃ templates were then dissolved in an ethylenediaminetetraacetic acid solution, leaving HRP in the microcapsules. Optical microscope and fluorescence microscope observations indicated that the microcapsules are homogeneous spheres with an average diameter about 7 μm. The encapsulated HRP showed catalytic activity in the oxidation of pyrogallol, suggesting the microcapsules provide a suitable environment for enzymatic reaction. A leakage of HRP from the microcapsules was negligibly small. Therefore, the HRP-containing microcapsules is promising for detection and treatment of phenolic compounds.     

浙江省农业清洁生产技术体系构建的探讨

通过对农业清洁生产的内涵特征以及农业清洁生产对技术需求的全面分析,阐明了农业清洁生产技术体系的构建思路,提出了以标准化生产技术、农产品质量安全监测技术、农业投入品替代及农业资源高效利用技术、产地环境修复和地力恢复技术、农业废弃物资源化及其清洁化生产链接技术、农业信息技术等为主要内容的农业清洁生产技术体系框架.通过稻田清洁生产实施案例,验证了农业清洁生产技术在实际中的成功应用.