树空坪矿区磷矿废石磷素的浸出特性

研究不同液固比条件下磷矿废石磷素浸出特性,为磷矿废石利用及治理提供理论依据和技术指导,进行磷矿废石磷素静态淋溶实验。结果表明：磷矿废石磷素释放过程中,液固比直接影响磷矿废石中磷素释放速率;低液固比条件下（液固比小于5.0 mL·g-1）,固相和液相传质过程未达到平衡,溶液与磷矿废石相互作用在快速进行,高液固比条件下（液固比大于5.0 mL·g-1）,固相和液相传质过程趋于稳定;液固比淋溶实验过程中总磷浓度没有明显变化,而磷素累加释放量随着液固比呈现出线性变化,说明pH浸提液对于磷矿废石中磷素释放作用属于溶解度控制。     

Control of membrane fouling during hyperhaline municipal wastewater treatment using a pilot-scale anoxic/aerobic-membrane bioreactor system

Membrane fouling limits the effects of long-term stable operation of membrane bioreactor (MBR). Control of membrane fouling can extend the membrane life and reduce water treatment cost effectively. A pilot scale anoxic/aerobic-membrane bioreactor (A/O-MBR, 40 L/hr) was used to treat the hyperhaline municipal sewage from a processing zone of Tianjin, China. Impact factors including mixed liquid sludge suspension (MLSS), sludge viscosity (μup), microorganisms, extracellular polymeric substances (EPS), aeration intensity and suction/suspended time on membrane fouling and pollution control were studied. The relationships among various factors associated with membrane fouling were analyzed. Results showed that there was a positive correlation among MLSS, sludge viscosity and trans-membrane pressure (TMP). Considering water treatment efficiency and stable operation of the membrane module, MLSS of 5 g/L was suggested for the process. There was a same trend among EPS, sludge viscosity and TMP. Numbers and species of microorganisms affected membrane fouling. Either too high or too low aeration intensity was not conducive to membrane fouling control. Aeration intensity of 1.0 m³/hr (gas/water ratio of 25:1) is suggested for the process. A long suction time caused a rapid increase in membrane resistance. However, long suspended time cannot prevent the increase of membrane resistance effectively even though a suspended time was necessary for scale off particles from the membrane surface. The suction/suspended time of 12 min/3 min was selected for the process. The interaction of various environmental factors and operation conditions must be considered synthetically.     

磷加工工艺废水电化学处理与利用研究

本文采用化学方法对湖北黄麦岭磷矿选矿废水进行了处理与利用研究,提出了电化学处理最佳条件,处理水回用比.结果表明,尾水经电化学处理返回选别流程,不仅可大大减少 Na_2CO_3用量,而且还获得较清水流程更好的选矿指标.     

重庆某铅污染场地稳定化修复技术研究

以重庆市某铅污染场地为研究对象,选用多种稳定化药剂对土壤开展稳定化修复技术研究,着重探讨了不同单一药剂与复配药剂对土壤铅浸出浓度的影响。实验结果表明:磷酸二氢钠(MSP)、磷酸氢二钠、磷酸钠和石灰4种无机药剂中MSP的稳定化修复效果最佳,且磷酸盐类的稳定化修复效果整体上优于石灰;MSP与少量有机药剂腐殖酸复配施用的稳定化修复效果优于单独施加MSP;在MSP投加比(与土壤的质量比)为5%、腐殖酸投加比为2%、养护时间为7 d的最优工艺条件下,土壤中铅的浸出浓度由41.70 mg/L降至0.16 mg/L,低于《生活垃圾填埋场污染控制标准》(GB 16889—2008)中规定的0.25 mg/L浓度限值。     

AEB反应器反硝化处理高浓度硝酸盐废水

采用缺氧膨胀床(AEB)反应器处理高浓度硝酸盐废水,研究了反应器的快速启动和挂膜特性,以及在反硝化连续流运行条件下对废水的处理效果。实验结果表明:采用自然挂膜方式,填料层从下至上生物膜厚度逐渐增加;AEB的快速启动8 d可完成,COD去除率由44.9%升至92.3%,NO_3~--N去除率由39.8%升至98.4%;稳定运行阶段(进水COD 4 628～5 548 mg/L、ρ(NO_3~--N) 1 339～1 505 mg/L),COD去除率稳定在95%左右,NO_3~--N去除率稳定在98%～99%,COD和NO_3~--N的容积负荷去除量最高可达27.8 kg/(m~3·d)和7.3 kg/(m~3·d)。     

Heavy metal concentrations in plants and different harvestable parts: A soil-plant equilibrium model

A mathematical interaction model, validated by experimental results, was developed to modeling the metal uptake by plants and induced growth decrease, by knowing metal in soils. The model relates the dynamics of the uptake of metals from soil to plants. Also, two types of relationships are tested: total and available metal content. The model successfully fitted the experimental data and made it possible to predict the threshold values of total mortality with a satisfactory approach. Data are taken from soils treated with Cd and Ni for ryegrass (Lolium perenne, L.) and oats (Avena sativa L.), respectively. Concentrations are measured in the aboveground biomass of plants. In the latter case, the concentration of metals in different parts of the plants (tillering, shooting and earing) is also modeled. At low concentrations, the effects of metals are moderate, and the dynamics appear to be linear. However, increasing concentrations show nonlinear behaviors.     

响应面法优化MAP沉淀去除回收尿液中磷的研究

基于模拟尿液的组成特点,利用Box-Behnken Design实验及响应面法对磷酸铵镁(MAP)沉淀去除回收尿液磷过程中反应pH值、Mg²⁺与PO₄^3-物质的量比(Mg/P比)及Ca²⁺与PO₄^3-物质的量比(Ca/P比)3个重要影响因素(分别表示为X₁、X₂、X₃)及各因素之间的交互式影响进行考察,并利用SEM、FTIR、ICP和XRD表征手段分析结晶沉淀组成和晶形特征.实验结果表明,回归方程中X₁、X₂、X₃、X₁X₃、X₂X₃、X₁²、X²₂、X₃²对磷去除率影响显著;当反应pH值和Mg/P比范围分别在8.5~9.5和1.0~1.2之间时,磷去除率响应值能达到99%.产物表征结果表明,模拟尿液中K⁺和Na⁺对结晶干扰较小;当Ca²⁺的浓度相对较低(Ca/P比小于0.25)时,沉淀中MAP的纯度高于85%,晶体形状大部分为斜方形;当Ca²⁺的浓度相对较高(Ca/P比大于0.25)时,沉淀中的MAP下降明显,晶体形状开始不规则,杂质增多;当模拟尿液中Ca/P比为0.5时,MAP纯度仅有约70%.     

亚硝酸盐型同步硝化反硝化耦合除磷研究

采用序批式活性污泥法,对人工配制的城市污水,通过控制泥龄成功实现亚硝酸盐型同步硝化反硝化,同时取得很好的生物除磷效果。实验结果显示:适宜的泥龄下,在控制适宜的COD及DO的条件下,COD、氨氮、总氮和总磷的去除率分别可达93%、99.6%、84.58%和99%。因此,利用排泥的方法控制反应器内适宜的泥龄,可以取得很好的同步脱氮除磷效果。     

灭菌和非灭菌土壤中高氯酸盐污染对水稻幼苗的影响

采用温室盆栽试验,研究灭菌与非灭菌土壤条件下2个品种水稻(GN和IR)幼苗对ClO₄-(高氯酸盐)污染的响应. 结果表明:无ClO₄-污染时,土壤灭菌可促进2个品种水稻的株高、根长和生物量的增长,但有ClO₄-污染时,灭菌处理反而显著抑制水稻生长;当施入ρ(ClO₄-)为0.1 mg/L时,土壤灭菌降低了水稻对ClO₄-的吸收积累,非灭菌组GN和IR分别有69.70%和88.55%的ClO₄-迁移到植物体内,而灭菌组则分别有21.55%和13.98%的ClO₄-迁移到植物体内;ρ(ClO₄-)为50.0 mg/L时,土壤灭菌反而增加了水稻对ClO₄-的吸收积累,灭菌组GN和IR叶片中的w(ClO₄-)分别是非灭菌组的3.67和5.88倍,但无论土壤是否灭菌,迁移到植物体内的ClO₄-所占比例均小于2%;灭菌组93%以上的ClO₄-残留在土壤中,而非灭菌组则有98%以上的ClO₄-转化成为其他物质. 土壤灭菌、ρ(ClO₄-)为50 mg/L处理能够显著降低土壤脲酶和过氧化氢酶的活性.      

磷酸三丁酯(TBP)对苯酚的络合萃取

基于可逆络合反应的萃取分离方法对极性有机物稀溶液具有高效性和高选择性.本文系统进行了磷酸三丁酯(TBP)对苯酚稀溶液的络合萃取的实验研.负载有机相的红外谱图分析表明,TBP与苯酚通过氢键缔合形成萃合物.以TBP-煤油为萃取剂对工业含酚废水进行了萃取平衡和错流萃取实验.讨论了其应用的可能性及开发新的有效的络合萃取剂的途径.