Biological Decolorization of C.I. Basic Green 4 Solution by Chlorella sp.： Effect of Operational Parameters

In recent years, the ability of microorganisms to decolorize textile wastewater has received great attention due to the environmental persistence and toxicity of these pollutants. In this paper biological decolorization of triphenylmethane dye, C.I. Basic Green 4 (BG 4), by Chlorella species was investigated. The effect of operational parameters (temperature, pH, initial dye concentration and algal concentration) on decolorization efficiency was examined. Results indicated that the desired initial pH was 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was employed to describe the apparent correlation between the decolorization rate and dye concentration. The optimal kinetic parameters, Vmax (specific decolorization rate) and Km (maximum specific decolorization rate) were 4.6 mg dye g cell-1 h-1and 151.0 mg L-1, respectively. Fig 10, Tab 2, Ref24     

Biogeochemistry of two types of permeable reactive barriers, organic carbon and iron-bearing organic carbon for mine drainage treatment: Column experiments

Permeable reactive barriers (PRBs) are an alternative technology to treat mine drainage containing sulfate and heavy metals. Two column experiments were conducted to assess the suitability of an organic carbon (OC) based reactive mixture and an Fe⁰-bearing organic carbon (FeOC) based reactive mixture, under controlled groundwater flow conditions. The organic carbon mixture contains about 30% (volume) organic carbon (composted leaf mulch) and 70% (volume) sand and gravel. The Fe⁰-bearing organic carbon mixture contains 10% (volume) zero-valent iron, 20% (volume) organic carbon, 10% (volume) limestone, and 60% (volume) sand and gravel. Simulated groundwater containing 380 ppm sulfate, 5 ppm As, and 0.5 ppm Sb was passed through the columns at flow rates of 64 (the OC column) and 62 (the FeOC column) ml d^− 1, which are equivalent to 0.79 (the OC column) and 0.78 (the FeOC column) pore volumes (PVs) per week or 0.046 m d^− 1 for both columns. The OC column showed an initial sulfate reduction rate of 0.4 µmol g (OC)^− 1 d^− 1 and exhausted its capacity to promote sulfate reduction after 30 PVs, or 9 months of flow. The FeOC column sustained a relatively constant sulfate reduction rate of 0.9 µmol g (OC)^− 1 d^− 1 for at least 65 PVs (17 months). In the FeOC column, the δ³⁴S values increase with the decreasing sulfate concentration. The δ³⁴S fractionation follows a Rayleigh fractionation model with an enrichment factor of 21.6‰. The performance decline of the OC column was caused by the depletion of substrate or electron donor. The cathodic production of H₂ by anaerobic corrosion of Fe probably sustained a higher level of SRB activity in the FeOC column. These results suggest that zero-valent iron can be used to provide an electron donor in sulfate reducing PRBs. A sharp increase in the δ¹³C value of the dissolved inorganic carbon and a decrease in the concentration of HCO₃⁻ indicate that hydrogenotrophic methanogenesis is occurring in the first 15 cm of the FeOC column.     

垃圾填埋场爆炸灾害的发生与控制途径

论述了垃圾填埋场爆炸灾害的严重性，探讨了垃圾填埋场爆炸灾害发生的影响因素。并以此提出了垃圾填埋场爆炸灾害的控制技术途径。     

臭氧生物活性炭工艺深度处理微污染原水

以广州东江水源为原水,研究了臭氧生物活性炭深度处理工艺对污染物的去除效果。结果表明:实验期间炭滤出水高锰酸盐指数、NH4+-N、NO2--N和浊度指标平均值分别为1.09mg/L、0.04mg/L、0.003mg/L和0.42ntu,平均去除率达65.34%、96.03%、98.24%和96.33%。所测项目相对于国家新颁布的《生活饮用水卫生标准》(5479-2006)达标率为100%。     

单甲脒农药对大豆—土壤系统的生态影响

研究了单甲脒农药（DMAH）对大豆－土壤系统的生态影响．结果表明：除CK外，5个设置浓度［（DMAH）／mL·L－1］0．25、0．5、2．5、5.0、25均对大豆虫害有不同的防治效果．其中＞2．5时可防治大豆多种虫害；大豆对DMAH稀释液的pH值反应敏感，高浓度处理的叶片因酸度大而出现药害；推荐浓度［（DMAH）＝0．25mL·L－1］，对植株的生长和生理功能有促进作用．可使总生物量及产量分别增加20％左右，且籽粒中农药无残留，土壤农药残留量也小；当处理pH值＜5时会对叶片有伤害．生理功能被抑制，总生物量及产量都不如CK；DMAH在植物器官及土壤都有不同程度的残留量．其中叶残留量大于籽粒及土壤．可以认为，低浓度DMAH处理不会对植物－土壤系统造成污染．     

Bi_2MoO_6可见光催化去除4BS染料实验研究

以Bi(NO_3)_3·5H_2O和(NH_4)_6M_o7O_(24)·4H_20为原料,采用预超声-水热法合成可见光催化剂Bi_2MoO_6,考察了在可见光催化条件下,催化剂的用量、污染物初始浓度、溶液pH值等因素对偶氮染料直接耐酸大红4BS去除效果的影响.结果表明,4Bs溶液初始浓度为20mg·l~(-1)、原始pH值6.90条件下,催化剂的最佳投加量为2g·l~(-1),光照60min后,4BS去除率达到92.7%;在实验浓度20-100mg·l~(-1)的范围内,催化剂投加量为2.0g·l~(-1),光照210min后染料去除量最大可达到约50mg·l~(-1),溶液在弱酸或弱碱性条件下脱色较为稳定,在强酸或强碱性条件下脱色较快,效果明显;催化剂重复使用前后结构和成分稳定,但光催化活性有所下降.     

改性Ti4O7阳极对氯霉素的高效电氧化降解

针对传统电化学氧化中阳极是污染物催化氧化的核心,寻找一种具有高析氧电位,高反应活性面积,优良催化活性的阳极是当下亟待解决的问题。为此,选取了亚氧化钛(Ti₄O₇)电极作为基础电极且对其进行过渡金属元素掺杂改性。通过各种表征及降解性能研究发现,所制备改性电极相对于纯Ti₄O₇电极催化性能有所提高。其中,锆(zirconium, Zr)元素掺杂后使得改性电极具有更高的析氧电位和更好的电催化活性。在电流密度为30 mA·cm⁻²,初始pH为6.1,电解质为100 mmol·L⁻¹ Na₂SO₄和10 mmol·L⁻¹ NaCl的最优条件下,氯霉素的去除率为97.4%。并且该电极具有很好的抗干扰性和稳定性,在不同pH干扰下对氯霉素依然具有较高的降解率(均高于81.1%)。此外,Zr元素掺杂的Ti₄O₇改性电极对氟苯尼考和双氯芬酸钠等药物也具有很好的降解效果,降解率分别为93.4%和85.5%,本研究结果可为电化学去除污染物阳极改性研究提供参考。     

全过程除臭工艺在北京某再生水厂的应用及其中气液两相污染物的削减过程

全过程除臭是一种以微生物法为核心的低碳除臭方式。为评估其应用效果,分析了北京市某再生水厂的产排污关键环节中的气液两相污染物削减情况。结果表明：初始污水中[NH₄⁺-N]高于H₂S的质量浓度,分别为55 mg·L⁻¹和6 mg·L⁻¹,二者随污水反应进程呈逐渐降低的趋势,分别在生化段和粗格栅处去除效果最好;气相污染物主要为NH₃和H₂S,其中NH₃在粗格栅处排放通量较高,质量浓度为0.4 mg·m⁻³,化学浓度贡献率为71%~91%,H₂S在污泥储池处质量浓度较高,为0.16 mg·m⁻³;对粗格栅处进行模拟换气实验,H₂S、NH₃和臭气的浓度分别为 0.027~0.036 mg·m⁻³、0.023~0.031 mg·m⁻³和10~15;厂界的NH₃和H₂S质量浓度在上风向的检测值均低于下风向,最高值为0.100和 0.007 mg·m⁻³,臭气 (无量纲) ,甲烷体积分数为1.7×10⁻⁶,粗格栅模拟换气和厂界排放浓度均达到北京市《大气污染物综合排放标准》 (DB11/501-2017) 和《城镇污水处理厂污染物排放标准》 (GB18918-2002) 。该研究结果对北京某再生水厂进行气液两相污染物削减分析,证明了全过程除臭工艺应用的有效性,可为同类水厂的除臭问题提供参考。     

微量肼对厌氧氨氧化生物膜长期运行效果的影响

为探究微量肼(N₂H₄)对厌氧氨氧化生物膜的长期影响,采用3个移动床生物膜反应器(moving bed biofilm reactor, MBBR)处理低浓度氨氮(50.9±3.6) mg·L⁻¹废水,分别加入0 mg·L⁻¹ (对照组,R1)、5 mg·L⁻¹ (R2)和10 mg·L⁻¹(R3)的微量N₂H₄后连续运行35 d,考察N₂H₄对MBBR系统中总氮去除速率(total nitrogen removal rate, TNRR)、生物量、胞外聚合物(extracellular polymeric substances, EPS)、血红素和微生物群落的影响。结果显示,运行末期相对于R1,R2和R3的NRR分别下降了53%和 64%。N₂H₄ 质量浓度为5 mg·L⁻¹时,生物膜的EPS分泌量提高,触发了生物膜保护机制;当N₂H₄ 质量浓度为10 mg·L⁻¹时,生物膜的EPS和血红素含量均明显下降,N₂H₄对生物膜产生抑制作用。长期添加微量N₂H₄导致门水平中Planctomycetes和Candidatus_Kuenenia的相对丰度降低,可见,N₂H₄的加入可以使NRR短暂增长,但长期加入会对厌氧氨氧化生物膜产生生物毒性,抑制厌氧氨氧化菌(AnAOB)的活性。整体而言,5 mg·L⁻¹和10 mg·L⁻¹的N₂H₄的加入都难以维持MBBR长期稳定高效运行,其对厌氧氨氧化生物膜的负面影响更为明显。     

Ag3PO4-MnO2/g-C3N4非均相臭氧催化对页岩气钻井废水的深度处理

采用热缩聚合成法、水热法制备Ag3PO4-MnO2/g-C3N4三元复合催化剂。利用XRD和SEM对其进行结构表征,并考察催化剂用量、废水pH、臭氧投加量等因素对页岩气钻井废水深度处理效果的影响。结果表明,Ag3PO4-MnO2/g-C3N4三元复合催化剂中,立方晶型Ag3PO4、纳米纤维状MnO2与经模板剂制得的管孔状g-C3N4成功复合,改变了其晶面的有序性并增大了比表面积。通过复合提高了Ag3PO4的稳定性及其与MnO2协同作用对臭氧的催化活性。在催化剂投加量为0.5 g·L-1,废水pH为11,臭氧投加量为3.2 mg·min-1,反应时间为40 min的条件下,对预处理后的页岩气钻井废水（COD含量为1 076 mg·L-1）COD的去除率为85.1%,该复合催化剂重复使用5次后仍保持良好的活性和稳定性。