Zr（OH）4沉淀物对铬鞣废水Cr3+的吸附实验

用Zr(OH)4模拟锆鞣废水中的沉淀物作为吸附剂处理低浓度铬鞣废水,考察了吸附时间、Zr(OH)4投加量、溶液pH值、盐离子(Na+、Ca2+)浓度等因素对Cr3+去除效果的影响,结果表明,在pH<4.5时,Cr3+的去除为吸附过程,当pH>4.5后,为沉淀和吸附混合过程;Cr3+在Zr(OH)4上的吸附过程可以用Freundlich模型进行模拟;Na+和Ca2+对铬的吸附有一定的抑制作用.实际锆鞣废水中的杂质成分与Cr3+产生竞争吸附,使去除率略有降低,最低去除率可达71.29%以上.     

微量金属对硫酸盐有机废水厌氧处理颗粒污泥活性的影响

采用厌氧反应装置,接种取自UASB反应器的硫酸盐有机废水厌氧处理颗粒污泥,以人工配制的含硫酸盐有机废水(蔗糖提供有机物)为原水,分别添加不同质量浓度的微量金属(Fe2+、Co2+、Ni2+),通过间歇试验,研究了不同质量浓度的微量金属(Fe2+、Co2+、Ni2+)条件下,厌氧反应装置中COD和硫酸盐的去除率及产甲烷情况。试验结果表明,在Fe2+质量浓度0~12 mg·L-1、Co2+质量浓度0~0.5 mg·L-1、Ni2+质量浓度0~0.6 mg·L-1范围内,厌氧颗粒污泥的COD去除率和产甲烷速率分别随Fe2+、Co2+、Ni2+浓度的增加而增高。在Fe2+质量浓度0~12 mg·L-1范围内,厌氧颗粒污泥对SO42-去除率随Fe2+浓度的增加略有增高,但在Co2+质量浓度0~0.5 mg·L-1、Ni2+质量浓度0~2.0 mg·L-1范围内,厌氧颗粒污泥的SO42-去除率分别随Co2+和Ni2+浓度的增加而降低。因此,在一定浓度范围内,Fe2+的投加能同时激活MPB和SRB,Co2+和Ni2+的投加能激活MPB但对SRB活性产生抑制作用,为硫酸盐有机废水厌氧处理提供一定的理论指导。     

不同作物原料热裂解生物质炭对溶液中Cd2+和Pb2+的吸附特性

选择由小麦秸秆、玉米秸秆和花生壳经350~500℃热裂解制成的生物质炭,研究生物黑炭对水溶液中Cd2+和Pb2+的吸附特性,分析了pH值、吸附时间、溶液初始质量浓度、生物质炭粒径和投加量对吸附效果的影响。结果表明:生物质炭对Cd2+和Pb2+的吸附约10 min即达平衡;3种生物质炭对Cd2+和Pb2+的等温吸附均可用Langmuir方程和Freundlich方程拟合,玉米秸秆炭对Cd2+和Pb2+的最大吸附量远大于小麦秸秆炭和花生壳炭;在生物黑炭投加量为150 mg(6 g.L-1)时,3种生物黑炭对溶液Cd2+的去除率均在90%以上,玉米秸秆炭对溶液Pb2+的去除率达90.30%,而小麦秸秆炭和花生壳炭的去除率仅为52%和47%,玉米秸秆炭有望成为处理重金属污染废水的新型吸附材料。     

改性沸石及添加CaCl2和MgCl2对重金属离子Pb2+吸附特性的影响

研究天然沸石和改性沸石对Pb2+吸附的性能,探讨不同因素对沸石吸附Pb2+的影响.结果表明,天然沸石经过3种不同方法改性后均可促进其对Pb2+的吸附.氢氧化钠改性沸石吸附Pb2+效果最好,其次是硝酸钾改性沸石,氯化铵改性沸石吸附Pb2+效果稍差一些.不同Pb2+初始浓度、沸石使用量、pH和温度均对天然沸石和改性沸石吸附Pb2+有影响.天然沸石和改性沸石对Pb2+的等温吸附可用Langmuir方程和Freundlich方程来拟合,其中Langmuir方程的拟合效果较好,相关系数在0.9203—0.9840之间.CaCl2和MgCl2可影响天然沸石和改性沸石对Pb2+的吸附.当CaCl2和MgCl2的浓度均为10 mmol.L-1时,天然沸石吸附Pb2+量分别比对照处理提高66.6%和54.5%.添加2—10 mmol.L-1CaCl2和MgCl2导致氯化铵改性沸石吸附Pb2+分别比对照处理提高16.4%—18.8%和16.8%—19.9%.研究结果表明,采用沸石去除废水中的Pb元素时必须考虑不同因素的影响,以达到重金属去除效率的最大化.     

厌氧颗粒污泥膨胀床（EGSB）反应器处理高硫酸盐有机废水的厌氧生物脱硫试验

采用人工配制的高硫酸盐有机废水模拟青霉素废水,研究其经过EGSB反应器厌氧处理后的出水,在厌氧条件下采用生物法将其转化为单质硫的脱硫工艺.当保持S2-/NO3-在1.7—1.8时,S2-保持高去除率且不会进一步生成硫酸盐.脱硫反应器与EGSB反应器联合运行,处理系统运行参数为：进水COD浓度为6000 mg·L-1,硫...     

磺胺甲恶唑在土壤上的吸附及其与Ca2+、Mg2+、Zn2+的共吸附

研究了磺胺甲恶唑(SMX)在11种土壤上的吸附行为.相关性分析表明,单一的土壤性质与表观吸附没有表现出明显的相关关系,SMX在土壤中的吸附可能受憎水性作用、阳离子交换、表面积等多个机理或因素的共同作用.进而研究了Ca2+、Mg2+、Zn2+3种金属离子与SMX在土壤中的共吸附.其中,Zn2+显著地促进了SMX的表观吸附,而Ca2+、Mg2+两种离子对SMX的吸附没有明显的影响.同时,SMX的存在也影响了3种离子的吸附行为,Ca2+和Mg2+的吸附降低,而Zn2+的吸附受SMX的影响不大.可能是由于Zn2+在土壤中是内界吸附,占据了内部的位点,取代了大量的H原子,使表面的负电荷减弱,降低了土壤与SMX的排斥作用,从而使其吸附增加.     

生物硫铁生成菌的选育及其在重金属废水处理中的应用

为开发高效经济、环境友好的重金属废水处理技术,采用亨盖特(Hungate)厌氧技术分离出一株产生物硫铁复合材料的硫酸盐还原菌(Sulfate reducing bacteria,SRB),命名为SRB2,并对该菌株进行了生理特性、培养工艺和废水处理研究.菌体杆状稍有弯曲,革兰氏阴性菌,最佳碳源为乳酸钠.pH范围5.0～9.0,最适pH 7.0,最适温度为35℃,培养3 d生物硫铁量和硫化物含量能达最大值,分别为2.85 g L-1、358.048 mg L-1.正交试验结果表明,乳酸钠9.0 g L-1+组合氮源1.5 g L-1+硫酸亚铁10.0 g L-1时生物硫铁产量最高.16S rDNA序列分析表明,菌株与脱硫弧菌属Desulfovibriodesulfuricans strain 734同源性为99%.采用生物硫铁处理重金属Cu2+、Pb2+、Cd2+废水,结果表明生物硫铁能快速处理含Cu2+、Pb2+、Cd2+废水,2 min去除率达99.8%以上.因此,生物硫铁在各类重金属废水处理与重金属废水污染事故应急处理中具有较好的应用前景.     

离子强度对恒电荷土壤胶体吸附Cu2+和Pb2+的影响

采用平衡法研究了离子强度、表面电位对恒电荷土壤胶体吸附Cu2+和Pb2+的影响.结果表明,离子强度越小,表面电位越高,土壤胶体对Cu2+和Pb2+的吸附量越大.在离子强度小于1.0mol*kg-1范围内,土壤胶体对Cu2+和Pb2+的吸附包括静电吸附和专性吸附;离子强度大于1.0mol*kg-1以后,土壤胶体对Cu2+和Pb2+的吸附受专性吸附控制.     

铋膜丝网印刷电极现场快速测定工业废水中Pb2+、Cd2+

采用丝网印刷电极,通过同位镀铋膜阳极溶出伏安法对工业废水中重金属Pb2+和Cd2+进行了快速测定,考察并优化了镀铋膜及测定金属离子的实验条件.实验结果表明,Pb2+和Cd2+在铋膜电极上可得到灵敏的溶出峰,在优化的实验条件下Pb2+和Cd2+在50—500μg.L-1范围内呈现良好的线性关系,相关系数分别为0.9947、0.9969,检测限分别为4.45μg.L-1和2.98μg.L-1.测定了工业废水中的Pb2+、Cd2+,结果与ICP-MS方法一致.     

Ca2+添加对微生物矿化固结Cd2+的影响

微生物诱导碳酸盐沉淀(MICP)可将游离的重金属离子转化为稳定的矿化物,在修复土壤重金属污染方面具有广阔的应用前景.本研究从铜陵矿区周边土壤中筛选得到1株产脲酶且耐镉矿化菌株CZW-1,16S rDNA鉴定为芽孢杆菌(Bacillus sp.),并将其利用于添加外源Ca²⁺的矿化固结Cd²⁺实验中.通过扫描电镜(SEM)、傅立叶红外光谱(FT-IR)以及X射线衍射(XRD)对矿化产物进行表征和分析.结果表明,添加一定浓度的Ca²⁺可促进细菌的生长,其最佳浓度为20 mmol·L^-1.且Ca²⁺的添加可提高细菌的最小抑制浓度和促进脲酶活性,提高对Cd²⁺的矿化率,加钙前后的矿化率由68.93%提高到75.95%.通过对矿化物的定性分析,可知加钙前后的矿物沉淀由单一CdCO₃变为CdCO₃和CaCO₃的复合沉淀,其表面也由严密紧实变成填满了小颗粒CdCO₃的多孔状.     

Combined Fenton process and sulfide precipitation for removal of heavy metals from industrial wastewater: Bench and pilot scale studies focusing on in-depth thallium removal

Addition of alkali to pH 10 is effective for precipitation of precipitable metals. Fenton treatment is effective for substantial removal of Tl, Cd, Cu, Pb, and Zn. Sulfide precipitation is a final step for removal of trace Tl, Cd, Cu, Pb, and Zn. Bench and pilot studies demonstrated the effectiveness of this combined technique. Thallium (Tl) in industrial wastewater is a public health concern due to its extremely high toxicity. However, there has been limited research regarding Tl removal techniques and engineering practices to date. In this investigation, bench and pilot studies on advanced treatment of industrial wastewater to remove Tl to a trace level were conducted. The treatment process involved a combination of hydroxide precipitation, Fenton oxidation, and sulfide precipitation. While hydroxide precipitation was ineffective for Tl+ removal, it enabled the recovery of approximately 70%–80% of Zn as Zn hydroxide in alkaline conditions. The Fenton process provided good Tl removal (>95%) through oxidation and precipitation. Tl was then removed to trace levels (<1.0 µg/L) via sulfide precipitation. Effective removal of other heavy metals was also achieved, with Cd<13.4 µg/L, Cu<39.6 µg/L, Pb<5.32 µg/L, and Zn<357 µg/L detected in the effluent. X-ray photoelectron spectroscopy indicated that Tl2S precipitate formed due to sulfide precipitation. Other heavy metals were removed via the formation of metal hydroxides during hydroxide precipitation and Fenton treatment, as well as via the formation of metal sulfides during sulfide precipitation. This combined process provides a scalable approach for the in-depth removal of Tl and other heavy metals from industrial wastewater.     

Metallic wastewater treatment by sulfate reduction using anaerobic rotating biological contactor reactor under high metal loading conditions

An-RBC reactor is highly suited to treat metallic wastewater. Metal removal is due to sulfide precipitation via sulfate reduction by SRB. Cu(II) removal was the best among the different heavy metals. Maximum metal removal is achieved at low metal loading condition. Metal removal matched well with the solubility product values of respective metal sulfide salts. This study was aimed at investigating the performance of anaerobic rotating biological contactor reactor treating synthetic wastewater containing a mixture of heavy metals under sulfate reducing condition. Statistically valid factorial design of experiments was carried out to understand the dynamics of metal removal using this bioreactor system. Copper removal was maximum (>98%), followed by other heavy metals at their respective low inlet concentrations. Metal loading rates less than 3.7 mg/L?h in case of Cu(II); less than 1.69 mg/L?h for Ni(II), Pb(II), Zn(II), Fe(III) and Cd(II) are favorable to the performance of the An-RBC reactor. Removal efficiency of the heavy metals from mixture depended on the metal species and their inlet loading concentrations. Analysis of metal precipitates formed in the sulfidogenic bioreactor by field emission scanning electron microscopy along with energy dispersive X-ray spectroscopy (FESEM-EDX) confirmed metal sulfide precipitation by SRB. All these results clearly revealed that the attached growth biofilm bioreactor is well suited for heavy metal removal from complex mixture.     

硅藻土和膨润土对重金属离子Zn~（2＋）、Pb~（2＋）及Cd~（2＋）的吸附特性

以硅藻土和膨润土作为吸附剂,考察微波加热与否条件下,不同吸附时间、不同吸附剂用量和不同pH值对硅藻土和膨润土分别吸附Zn2＋、Pb2＋、Cd2＋重金属离子的影响.实验结果表明,硅藻土和膨润土对3种重金属离子均有很好的吸附效果,吸附时间对去除率影响不大,数分钟即可达到吸附平衡,微波加热、增加吸附剂用量和提高pH值,都有利于提高3种重金属离子的去除率.     

Selective recovery of Cu2+ and Ni2+ from wastewater using bioelectrochemical system

As the bioelectrochemical system, the microbial fuel cell (MFC) and the microbial electrolysis cell (MEC) were developed to selectively recover Cu²⁺ and Ni²⁺ ions from wastewater. The wastewater was treated in the cathode chambers of the system, in which Cu²⁺ and Ni²⁺ ions were removed by using the MFC and the MEC, respectively. At an initial Cu²⁺ concentration of 500 mg·L^-1, removal efficiencies of Cu²⁺ increased from 97.0%±1.8% to 99.0%±0.3% with the initial Ni²⁺ concentrations from 250 to 1000 mg·L^-1, and maximum power densities increased from 3.1±0.5 to 5.4±0.6 W·m^-3. The Ni²⁺ removal mass in the MEC increased from 6.8±0.2 to 20.5±1.5 mg with the increase of Ni²⁺ concentrations. At an initial Ni²⁺ concentration of 500 mg·L^-1, Cu²⁺ removal efficiencies decreased from 99.1%±0.3% to 74.2%±3.8% with the initial Cu²⁺ concentrations from 250 to 1000 mg·L^-1, and maximum power densities increased from 3.0±0.1 to 6.3±1.2 W·m^-3. Subsequently, the Ni²⁺ removal efficiencies decreased from 96.9%±3.1% to 73.3%±5.4%. The results clearly demonstrated the feasibility of selective recovery of Cu²⁺ and Ni²⁺ from the wastewater using the bioelectrochemical system.     

二段生物接触氧化法处理含硫废水的中试研究

用二段生物接触氧化法探索炼油过程中所产生的含硫废水的处理新方法． 结果表明：经此工艺处理后的出水 Ｃ Ｏ Ｄ、氨氮、硫化物和酚的质量浓度ρ分别为２６６ ．９ ｍｇ／ Ｌ、８２ ．８５ ｍｇ／ Ｌ、１ ．１８ ｍｇ／ Ｌ 和１ ．４３ ｍｇ／ Ｌ,相应的去除率分别为８６ ．３ ％ 、４０ ％ 、９２ ．７ ％ 和９９ ．３ ％ ,出水水质达到国家三级排放标准． 进出水水质的变化曲线表明,生物接触氧化法处理含硫废水对进水水质变化的适应能力比较强,出水水质比较稳定,显示了二段接触氧化法处理含硫废水的可行性     

Assessment of contamination by percolation of septic tank effluent through natural and amended soils

Fly ash has been found to be a potential material for the treatment of municipal and industrial wastewater, and may be useful in the treatment of septic tank effluent. Laboratory columns (30 cm) were used to determine the sorption capacity and hydraulic properties of lagoon fly ash, loamy sand, sand, and sand amended by lagoon fly ash (30 and 60%) and red mud gypsum (20%). The removal of chemical oxygen demand (COD) was high in all column effluents (71-93%). Extent of nitrification was high in Spearwood sand, Merribrook loamy sand and 20% red mud gypsum amended Spearwood sand. However, actual removal of nitrogen (N) was high in columns containing lagoon fly ash. Unamended Spearwood sand possessed only minimal capacity for P sorption. Merribrook loamy sand and red mud gypsum amended sand affected complete P removal throughout the study period of 12 weeks. Significant P leakage occurred from lagoon fly ash amended sand columns following 6-10 weeks of operation. Neither lagoon fly ash nor red mud gypsum caused any studied heavy metal contamination including manganese (Mn), lead (Pb), zinc (Zn), cadmium (Cd) and chromium (Cr) of effluent. It can be concluded that Merribrook loamy sand is better natural soil than Spearwood sand as a filter medium. The addition of lagoon fly ash enhanced the removal of P in Spearwood sand but the efficiency was lower than with red mud gypsum amendment.     

Effective removal of Cd2+ and Pb2+ pollutants from wastewater by dielectrophoresis-assisted adsorption

Dielectrophoresis (DEP) process could enhance the removal the Cd²⁺ and Pb²⁺ with less absorbent. The removal rates of both Cd²⁺ and Pb²⁺ increased with the increase of voltage. The overall removal rate of Cd²⁺ and Pb²⁺ in the binary system is higher than that of Cd²⁺ or Pb²⁺ in the single system. DEP could cause considerable changes of the bentonite particles in both surface morphology and microstructure. Dielectrophoresis (DEP) was combined with adsorption (ADS) to simultaneously and effectively remove Cd²⁺ and Pb²⁺ species from aqueous solution. To implement the process, bentonite particles of submicro-meter size were used to first adsorb the heavy metal ions. These particles were subsequently trapped and removed by DEP. The effects of the adsorbent dosage, DEP cell voltage and the capture pool numbers on the removal rate were investigated in batch processes, which allowed us to determine the optimal experimental conditions. The high removal efficiency, 97.3% and 99.9% for Cd²⁺ and Pb²⁺, respectively, were achieved when the ions are coexisting in the system. The microstructure of bentonite particles before and after ADS/DEP was examined by scanning electron microscopy. Our results suggest that the dielectrophoresis-assisted adsorption method has a high capability to remove the heavy metals from wastewater.     

Optimization of phosphorus removal in uniFed SBR system for domestic wastewater treatment

The characteristic of phosphorus removal and appropriate change of the traditional operation modes were investigated in UniFed sequencing batch reactor (SBR) laboratory-scale apparatus (40 L), treating actual domestic wastewater with low ratios of C/N (2.57) and C/P (30.18), providing theoretical basis for actual application of wastewater treatment plant. UniFed SBR system with its unique operation mode had the distinct superiority of phosphorus removal. On this occasion, the effect of volumetric exchange ratio (VER) and the method of influent introduction for phosphorus removal were studied. When the carbon source became the limiting factor to phosphorus release, the higher the VER, the lower the phosphorus concentration in the effluent. Three different influent patterns, including one-time filling, four-time filling, and continuous filling with the same quantity of wastewater could increase the release rate of anaerobic phosphorus from 0.082 to 0.143 mg·P·(L·min)^-1. Appropriate change of the traditional operation modes could optimize the efficiency of phosphorus removal. When the feed/ decant time was extended from 2 h to 4 h, the phosphorous removal efficiency increased from 59.93% to 88.45% without any external carbon source. In the mode of alternation of anoxic-aerobic (A/O) condition, phosphorous removal efficiency increased from 55.07% to 72.27% clearly. The carbon source in the influent can be used adequately, and denitrifying phosphorus removal was carried out in anoxic stage 2 (A2). This mode was optimal for the treatment of actual domestic wastewater with low C/N and C/P ratios.