Biological response of high-back crucian carp (Carassius auratus) during different life stages to wastewater treatment plant effluent

This study presents the adverse effects of endocrine disrupting chemicals (EDCs) in effluent of wastewater treatment plants (WwTPs) on fish health. A study of chronic exposure to WwTPs effluent for 10 months was undertaken in high-back crucian carp (Carassius auratus) during different life stages, covering early-life-stage (ELS), prespawning period, and postspawning period. Condition factor (CF), gonadosomatic index (GSI), hepatosomatic index (HSI), and plasma vitellogenin (VTG) levels were employed as indicators to assess biological effects of effluent on this gynogenesis species. Meanwhile, some high-back crucian carp were caged in Demonstration Base of Biological Purification for Filter-feeding Fish (hereinafter, Demonstration Base), as WwTPs effluent exposure controls. In the meantime, a depuration study was carried out to determine whether or not the estrogenic effects caused by effluent exposure could be reduced after moving fish into EDCs-free water. CF, HSI, GSI, and plasma Vtg levels of high-back crucian carp caged in Demonstration Base were generally in accordance with seasonal change. Effluent exposure inhibited gonadal growth, reducing GSI in ELS while increasing it around spawning, sharpened liver burdens, increasing HSI, and induced abnormal Vtg expression in juvenile high-back crucian carp, augmenting Vtg concentrations in plasma. Around spawning period, Vtg in high-back crucian carp were mainly induced by endogenous estrogens, and EDCs in effluent had less influence on them. Staying in EDCs-free water for 30 days made high-back crucian carp recover from effects of previous effluent exposure, relieving inhibition of gonadal development and hypertrophy of liver as well as reducing Vtg induced by EDCs in effluent. The results revealed that high-back crucian carp in ELS are more sensitive to WwTPs effluent exposure. Additionally, the depuration study showed a clearance of the estrogenic effects caused by effluent.     

Characteristics of penicillin bacterial residue

A hybrid selective noncatalytic reduction/selective catalytic reduction (SNCR/SCR) system that uses two types of technology, low-temperature SCR process and SNCR process, was designed to develop nitrogen oxide (NO_x) reduction technology. SCR was conducted with space velocity (SV) = 2400 hr^?1 and hybrid SNCR/SCR with SV = 6000 hr^?1, since the study focused on reducing the amount of catalyst and both achieved 98% NO_x reduction efficiency. Characteristics of NO_x reduction by NH₃ were studied for low-temperature SCR system at 150 °C using Mn-V₂O₅/TiO₂ catalyst. Mn-added V₂O₅/TiO₂ catalyst was produced, and selective catalyst reduction of NO_x by NH₃ was experimented. NO_x reduction rate according to added Mn content in Mn-V₂O₅/TiO₂ catalyst was studied with varying conditions of reaction temperature, normalized stoichiometric ratio (NSR), SV, and O₂ concentration. In the catalyst experiment according to V₂O₅ concentration, 1 wt.% V₂O₅ catalyst showed the highest NO_x reduction rate: 98% reduction at temperature window of 200~250 °C. As a promoter of the V₂O₅ catalyst, 5 wt.% Mn was added, and the catalyst showed 47~90% higher efficiency even with low temperatures, 100~200 °C. Mn-V₂O₅/TiO₂ catalyst, prepared by adding 5 wt.% Mn in V₂O₅/TiO₂ catalyst, showed increments of catalyst activation at 150 °C as well as NO_x reduction. Mn-V₂O₅/TiO₂ catalyst showed 8% higher rate for NO_x reduction compared with V₂O₅/TiO₂ catalyst in 150 °C SCR. Thus, (5 wt.%)Mn-(1 wt.%)V₂O₅/TiO₂ catalyst was applied in SCR of hybrid SNCR/SCR system of low temperature at 150 °C. Low-temperature SCR hybrid SNCR/SCR (150 °C) system and hybrid SNCR/SCR (350 °C) showed 91~95% total reduction rate with conditions of SV = 2400~6000 hr^?1 SCR and 850~1050 °C SNCR, NSR = 1.5~2.0, and 5% O₂. Hybrid SNCR/SCR (150 °C) system proved to be more effective than the hybrid SNCR/SCR (350 °C) system at low temperature.

Implications:?NO_x control is very important, since they are the part of greenhouse gases as well as the cause of acid rain and ozone hole. A technology, so-called hybrid SNCR/SCR process, was tested using Mn-V₂O₅/TiO₂ monolithic catalyst for NO_x reduction, and the method is promising. The results of this study would provide some ideas to parties such as policy makers, environmental engineers, and so on.     

Removal of Cu, Zn, and Cd from aqueous solutions by the dairy manure-derived biochar

Purpose

Biochar derived from waste biomass is now gaining much attention for its function as a biosorbent for environmental remediation. The objective of this study was to determine the effectiveness of biochar as a sorbent in removing Cd, Cu, and Zn from aqueous solutions.

Methods

Biochar was produced from dairy manure (DM) at two temperatures: 200°C and 350°C, referred to as DM200 and DM350, respectively. The obtained biochars were then equilibrated with 0–5 mM Cu, Zn or Cd in 0.01 M NaNO₃ solution for 10 h. The changes in solution metal concentrations after sorption were evaluated for sorption capacity using isotherm modeling and chemical speciation Visual MINTEQ modeling, while the solid was collected for species characterization using infrared spectroscopy and X-ray elemental dot mapping techniques.

Results

The isotherms of Cu, Zn, and Cd sorption by DM200 were better fitted to Langmuir model, whereas Freundlich model well described the sorption of the three metals by DM350. The DM350 were more effective in sorbing all three metals than DM200 with both biochars had the highest affinity for Cu, followed by Zn and Cd. The maximum sorption capacities of Cu, Zn, and Cd by DM200 were 48.4, 31.6, and 31.9 mg g^?1, respectively, and those of Cu, Zn, and Cd by DM350 were 54.4, 32.8, and 51.4 mg g^?1, respectively. Sorption of the metals by the biochar was mainly attributed to their precipitation with PO ₄ ^3? or CO ₃ ^2? originating in biochar, with less to the surface complexation through –OH groups or delocalized π electrons. At the initial metal concentration of 5 mM, 80–100 % of Cu, Zn, and Cd retention by DM200 resulted from the precipitation, with less than 20 % from surface adsorption through phenonic –OH complexation. Among the precipitation, 20–30 % of the precipitation occurred as metal phosphate and 70–80 % as metal carbonate. For DM350, 75–100 % of Cu, Zn, and Cd retention were due to the precipitation, with less than 25 % to surface adsorption through complexation of heavy metal by phenonic –OH site or delocalized π electrons. Among the precipitation, only less than 10 % of the precipitation was present as metal phosphate and more than 90 % as metal carbonate.

Conclusions

Results indicated that dairy manure waste can be converted into value-added biochar as a sorbent for sorption of heavy metals, and the mineral components originated in the biochar play an important role in the biochar's high sorption capacity.     

UASB反应器反硝化处理对氨基二苯胺生产废水

采用UASB工艺处理橡胶助剂对氨基二苯胺（RT培司）生产废水。实验结果表明：UASB启动初期（1~16 d）,COD去除率由60.8%降至24.2% ,TOC去除率由75.6%降至37.2%;UASB运行16 ~50 d,COD去除率逐渐提高;运行50 d时COD去除率为69.4%,TOC去除率高达90.0%。在进水COD负荷不超过6 kg/（m³·d）的条件下,UASB对COD的去除率为42.7%~69.4%,TOC去除率为58.0%~90.0%,NO_{3^--N去除率接近100%。本实验最佳进水TOC 与TN 比为2.0,UASB进水pH可调节为4.5左右,反应温度为18~34 ℃时对UASB反硝化处理效果影响不大。UASB对苯系化合物的去除率从高至低顺序为对硝基酚>苯酚>苯胺。}     

复合光催化材料Ag-AgCl/石墨烯的制备及性能

以原位化学沉淀;光还原法制备了Ag-AgCl/石墨烯复合光催化材料。以罗丹明B为模型降解物,研究了其可见光催化性能。实验结果表明：石墨烯的引入使Ag-AgCl/石墨烯催化剂催化活性提高;当初始罗丹明B质量浓度为5 mg/L时,可见光照射60 min后罗丹明B的降解率可达99%;降解率随初始罗丹明B质量浓度的增加而减小。Ag-AgCl/石墨烯具有很高的可见光催化活性和稳定性。     

利用盐泥制取轻质氧化镁

采用二氧化碳法提取盐泥中的镁,研究了使之转化为轻质氧化镁的影响因素以及主要反应的动力学性质。实验确定的最佳条件为固液比1∶15、二氧化碳通入时间90min、水解温度90℃、水解时间25min,在此条件下,盐泥中镁的总提取率为75%;采用微分法求得氢氧化镁与二氧化碳反应的反应级数和活化能分别为1.7和68.1kJ/mol。     

溶液环境对纳米Fe2O3/水界面NOM吸附过程中疏水效应的影响

以腐殖酸和纳米Fe2O3为对象,着重研究了腐殖酸分子在纳米Fe2O3表面的吸附过程中的疏水效应,借助红外光谱和热重等分析方法研究了腐殖酸吸附前后的疏水性随溶液环境变化的规律。结果表明,当离子强度为0、0.005、0.01和0.05 mol/kg,pH从7变到12时,纳米Fe2O3吸附溶解性腐殖酸分子后形成的复合体的热失重量随着pH的升高先减小后增大。当pH从7升高到10时,亲水性降低,疏水性增强;当pH从10升高到12时,亲水性增强,疏水性降低。当离子强度为0.001 mol/kg,pH从7变到12时,复合体的热失重量随着pH的升高而减小,亲水性降低,疏水性增强。当pH为定值,离子强度变化时,纳米Fe2O3吸附溶解性腐殖酸分子后形成的复合体的热失重量随着离子强度的增加不断变化,曲线呈现出波动趋势,亲、疏水性在交替变化。红外光谱分析结果说明,对纳米Fe2O3吸附溶解性腐殖酸分子后形成的复合体的亲疏水性起主要影响的官能团可能是亲水性的羟基—OH、羰基CO和疏水性的CH2烷烃。     

镇江市典型合流管网旱天污水排放规律

为给镇江市合流制污水管网(简称合流管网)系统的改造提供参考依据,选择镇江市内一条具有代表性的合流管网,并从2010年7月至2011年3月(2月除外,4次/周)对管网中5个采样点的生活污水水质进行旱天监测。结果表明,生活污水中COD、SS、TP、NH3-N浓度在不同月份之间具有明显的变化差异,并且波动幅度较大,冬、春季生活污水中COD浓度皆高于夏、秋季;居民混合区排出的生活污水中污染物浓度显著高于其他4个采样点。     

电絮凝处理油田生化出水

为了减轻对后续处理中超滤膜的污染,采用电絮凝法处理油田生化出水,降低油田生化出水中的有机物含量。研究了电流强度、曝气时间和pH值对水中总有机碳（TOC）和浊度除去效果的影响以及pH值随曝气时间的变化趋势,通过红外光谱对絮凝处理前后水中总溶解固体进行了分析,优化了电絮凝的工艺条件。研究表明,当水流速度控制在50mL/s,电流强度为2 A,500 mL絮凝出水的曝气时间为30 min时,整套絮凝工艺对TOC的去除率为48%,浊度去除率为42.9%,COD去除率为44%。     

Lactate oxidation in pyrite suspension: a Fenton-like process in situ generating H2O2

Pyrite is a common mineral at many mining sites. In this study, the mineral pyrite was studied as a Fenton-like reagent for environmental concerns. We selected lactate as a model target molecule to evaluate the Fenton-like catalytic efficiency of pyrite upon organic oxidation. A complete set of control experiments in both aerobic and anaerobic atmospheres unequivocally established that the pyrite in aqueous solution could spontaneously in situ generate OH and H₂O₂, serving as a Fenton-like reagent to catalyze the oxidation of lactate to pyruvate with no need for additional H₂O₂. We called it the pyrite-only Fenton-like (PF) reagent. Monitoring concentration changes of lactate and pyruvate with the time indicated that the pyrite mediated the favorable pyruvate formation at pH 4.5, 60 °C, under air atmosphere. The PF reaction could be stimulated by visible light illumination. Under the optimum conditions, up to 50% of lactate was degraded within 10 d. The results suggest that pyrite and its Fenton-like processes may be potentially practical in wastewater treatment.