Investigation on mechanism of phosphate removal on carbonized sludge adsorbent

For the removal of phosphate (PO₄^3 -) from water, an adsorbent was prepared via carbonization of sewage sludge from a wastewater treatment plant: carbonized sludge adsorbent (CSA). The mechanism of phosphate removal was determined after studying the structure and chemical properties of the CSA and its influence on phosphate removal. The results demonstrate that phosphate adsorption by the CSA can be fitted with the pseudo second-order kinetics and Langmuir isotherm models, indicating that the adsorption is single molecular layer adsorption dominated by chemical reaction. The active sites binding phosphate on the surface are composed of mineral particles containing Si/Ca/Al/Fe. The mineral containing Ca, calcite, is the main factor responsible for phosphate removal. The phosphate removal mechanism is a complex process including crystallization via the interaction between Ca^2 + and PO₄^3 -; formation of precipitates of Ca^2 +, Al^3 +, and PO₄^3 -; and adsorption of PO₄^3 - on some recalcitrant oxides composed of Si/Al/Fe.     

粉煤灰提铝中间产物合成4A分子筛对氨氮的吸附行为研究

采用粉煤灰提铝中间产物合成4A分子筛,利用XRD、SEM、热重分析、化学成分分析、阳离子交换容量对4A分子筛进行表征.考察吸附时间、pH、分子筛投加量、氨氮初始浓度、共存阳离子对其吸附性能的影响,研究其对模拟废水中氨氮的吸附效果,并结合准二级动力学方程、吸附等温线研究吸附性能和机理.结果表明,初始浓度为50 mg·L~(-1)、4A分子筛投加量为5 g·L~(-1)、pH值为6~9、吸附时间为80 min时氨氮去除率可达71.34%;随着氨氮初始浓度升高,其去除率降低,吸附容量增加;共存阳离子Na~+、K~+、Ca~(2+)对NH_4~+有强烈的竞争吸附,Mg~(2+)无明显竞争作用.吸附过程符合准二级动力学方程和Freundlich模型.Langmuir吸附等温线显示最大吸附容量为20 mg·g~(-1).     

大伙房水库沉积物重金属形态分析及污染特征

采用BCR连续提取法对大伙房水库沉积物中7种重金属元素(Cr,Ni,Cu,Zn,As,Cd和Pb)的赋存形态进行了分析,并结合重金属总量讨论了各元素的潜在环境危害性. 结果表明,Cd主要以醋酸可提取态及可还原态存在,具有很强的环境危害; Pb主要以极高比例的可还原态存在,潜在环境危害较高; Zn,As和Cu存在较大比例的酸可提取态及可还原态,也具有一定程度的潜在环境危害; Cr和Ni以残渣态为主,产生环境危害的可能性极小. 相关分析结果显示,Cu,Zn,As,Cd和Pb各赋存形态含量及总量与沉积物性质之间的相关性均不显著,说明大伙房水库沉积物受到了这5种重金属元素外源输入的影响.      

氢化物发生-原子荧光光谱法测定废水中砷探讨

砷是对人体有害的元素,当人体每天的摄入量超过100ug或更高时,对人体就会产生严重的危害,而有些工业废水中合有一定量的砷元素,如果这些工业废水不经处理排放到水中会我们的身体造成很大程度的伤害,所以我对某工厂的工业废水进行检测,检测其排放废水中所含有砷元素的多少。火焰原子荧光和石墨炉原子荧光的检测能力无法满足测定的要求,...     

一种快腐菌剂在堆肥制作中的应用研究

在接种和未接种条件下,研究了一种菌剂YD-KFI对堆肥制作效果.结果发现,接种该菌剂加快堆肥升温速度、提高最高温度、延长高温维持时间;堆肥制作的升温期和高温期,接种菌剂分别促进了淀粉、可溶性糖和粗纤维等物质的降解,加快了堆肥的腐熟进程.采用PCR-DGGE方法,分析该菌剂对堆肥制作不同阶段微生物群落的影响,发现在堆肥制...     

感潮河段污水处理厂尾水对受纳水体的水质影响研究

感潮河段污水处理厂尾水排放对受纳水体产生一定影响,利用二维水动力水质耦合模型,以COD、NH3-N、TP为污染因子,分别以正常排放和事故排放两种条件,模拟江苏南部某污水处理厂尾水排放,分析江段大小潮时污染物浓度增量情况。实验结果表明:正常排放,尾水对排放口附近江段保护区水质影响小;事故排放,尾水对保护区水质无影响,但长江水体影响范围增大,沿岸污染物浓度增高,且小潮周期影响作用强于大潮周期,污水处理厂应加强管理,尤其在小潮时应避免污水事故排放。     

大型企业环保措施的管理与研究

21世纪,国民经济得到了大力发展,人民生活水平也相应有了极大的提高,但与此同时,全球生态环境遭到了严重破坏。因此在此背景下,大型企业环保措施的管理成为近年来社会关注的热点话题之一,大型企业和相关部门也相应的采取了一系列措施,旨在保持大型企业经济发展和生态文明之间的平衡,但是在实践的过程中,取得的成果并不是很理想。大型企业环保措施的管理最主要部分就是企业环保成本控制,因此为改善这一情况,对大型企业环保成本控制研究成为重中之重。     

Effects of irrigation,fertilization and crop straw management on nitrous oxide and nitric oxide emissions from a wheat–maize rotation field in northern China

One-year winter wheat–summer maize rotation is the most popular double cropping system in north-central China, and this highly productive system is an important source of nitrous oxide (N₂O) and nitric oxide (NO) emissions due to the high fertilizer N and irrigation water inputs. To sustain the high crop production and mitigate the detrimental impacts of N₂O and NO emissions, improved management practices are extensively applied. The aim of this study is therefore to evaluate the effects of an improved management practice of irrigation, fertilization and crop straw on grain yield and N₂O and NO emissions for a wheat–maize rotation field in northern China. Using automated and manual chamber measuring systems, we monitored N₂O and NO fluxes for the conventional (CT, 2007–2008), improved (IT, 2007–2008), straw-amended (WS, 2008–2009), straw-not-amended (NS, 2008–2009), and no N-fertilizer treatments (WS–NN, 2008–2009), respectively, for one rotation-year. The grain yields were determined for CT and IT for three rotation-years (2005–2008) and for WS, NS and WS–NN for one rotation-year (2008–2009). The improved management of irrigation and fertilization reduced the annual N fertilization rate and irrigation amount by 17% and 30%, respectively; increased the maize yield by 7–14%; and significantly decreased the N₂O and NO emissions by 7% (p < 0.05) and 29% (p < 0.01), respectively. The incorporation of wheat straw increased the cumulative N₂O and NO emissions in the following maize season by 58% (p < 0.01) and 13%, respectively, whereas the effects of maize straw application were not remarkable. The N₂O and NO emission factors of applied N were 2.32 ± 2.32% and 0.42 ± 1.69% for wheat straw and 0.67 ± 0.23% and 0.54 ± 0.15% for chemical N-fertilizers, respectively. Compared to conventional management practices using high application rates of irrigation water and chemical N-fertilizer as well as the field burning of crop straw, the improved management strategy presented here has obvious environmentally positive effects on grain yield and mitigation of N₂O and NO emissions.     

上海崇明地区大气分形态汞污染特征

2014年3月~2015年2月对上海崇明东滩湿地公园的气态零价汞(GEM)、活性气态汞(RGM)和颗粒态汞(PBM)分别进行了为期1a的连续监测.GEM、RGM和PBM的年平均浓度分别为(2.75±1.13)ng·m~(-3)、(13.39±15.95)pg·m~(-3)和(21.89±40.42)pg·m~(-3),明显高于对应北半球背景值浓度.GEM浓度在夏季最高(3.65 ng·m~(-3)),受自然源排放影响较大,秋冬季较低,受人为源排放影响较大;RGM浓度在春季最高,冬季最低,主要受风速风向的影响;PBM浓度在秋冬季节明显高于其他季节,受秋冬季节较多的细颗粒物重污染过程的影响.GEM和PBM浓度均夜间较高,白天较低,主要受空气气团混合作用影响.RGM浓度在下午较高,主要是由于GEM在下午的光氧化作用加强,利于RGM的生成.GEM和PBM浓度在偏西风向上浓度较高,受上海、江苏等地人为源排放影响较大.RGM浓度在东南风向上浓度明显高于其他方向,这是因为RGM主要来源为人为排放,其浓度受风速影响较大,东南风向上平均风速较小,持续的弱风及停滞的空气不利于RGM的扩散.     

一套民用固体燃料燃烧大气污染物排放测试系统的搭建和评测

为研究民用固体燃料燃烧的大气污染物排放特征,设计了一套箱式稀释采样测试系统.相比于常用的烟罩法和烟道采样法,该系统能减小环境空气中颗粒物对测试结果的影响,同时收集了炉具泄漏的烟气,能更准确获得固体燃料燃烧的大气污染物排放水平.本文介绍了该系统的设计思路、主要结构组成和测试系统的性能评估结果.评估结果表明:进气经过滤后颗粒物浓度显著下降至约1μg·m-3,远小于燃烧过程中排放的颗粒物浓度(约100μg·m-3),有效减少环境空气中颗粒物对测试结果的干扰;使用箱式法测得PM_(2.5)、SO2和NOx排放因子结果均高于箱体敞开的对照组测试,证明箱式法收集测试了燃烧时泄漏至室内的污染物,有效减少污染物泄漏造成的误差.利用该系统测试了12种常见民用煤和3种生物质燃料燃烧PM_(2.5)、SO2、NOx等污染物排放水平,其中民用煤PM_(2.5)、SO2和NOx排放因子分别为0.23~3.40 mg·g~(-1)、0.48~6.15 mg·g~(-1)和0.16~1.09 mg·g~(-1),生物质燃料的PM_(2.5)、SO2和NOx排放因子分别为6.26~39.76 mg·g~(-1)、0.04~0.23 mg·g~(-1)和0.05~0.76 mg·g~(-1).