改性沸石的沉积物磷钝化效果研究

通过室内模拟实验,对天然沸石及不同方法改性沸石的磷吸附性能及沉积物磷钝化效果进行了对比研究。磷吸附实验结果表明,磷吸附量大小为改性沸石Z3>改性沸石Z2>改性沸石Z1>天然沸石,35d的平均吸附量分别为832、466、168和70mg/kg。改性沸石的磷吸附量与沸石含量正相关,并随时间呈增长趋势,其中改性沸石Z3第35d的磷吸附量可达1690mg/kg。离子交换量测定结果显示,沸石经改性后促进了Ca2+的释放,同时减少了K+、Na+的释放量。沉积物磷钝化实验表明,改性沸石可有效减少沉积物TP、DRP的释放,减少释放量达80%以上。天然沸石主要通过表面吸附减少水体磷含量,其次,物理阻隔作用拓展了钝化作用的时间和空间。Al(OH)3絮凝物通过表面吸附、电中和及架桥作用可显著提高改性沸石的磷吸附量,增强沉积物磷钝化效果。     

Double catholyte electrochemical approach for preparing ferratealuminum：a compound oxidant—coagulant for water purification

Ferrate is an excellent water treatment agent for its multi-functions in oxidation,disinfection,coagulation and adsorption,but its coagulation ability depends on its dosage and is after its oxidation.This paper focuses on preparing a new kind of ferrate combined with alum to enhance its coagulation function for water purification.An effective electrolysis reactor was designed and employed in the test.Some key parameters in the process of electrolysis concerning the prepar\ation efficiency,such as the current density,temperature and alkalinity were also investigated.The proper conditions for ferrate-alum preparation were determined.Under the condition of 5V given voltage,6h electrolyzing interval,below 2% alum concentration (in weight),a combined liquid ferrate-alum products was successfully prepared,which contained 0.0294 mol/L FeO4^2- and 0.0302 mol/L total soluble ferron with 2% Al2O3.There was no insoluble ferron produced by controlling an optimum electrochemical condition.     

Mobilization and Toxicity Potential of Aluminum from Alum Floc Deposits in Kensico Reservoir,New York

There is detailed literature on the mobilization of aluminum (Al) from soil to surface waters as a result of elevated acidic deposition to base‐poor forest watersheds. There is considerably less information on the mobilization and effects of Al from the application of alum that is used in some water supplies to control turbidity during high‐flow events. We report on the results of field measurements, laboratory sediment release experiments, and chemical equilibrium calculations conducted to evaluate the potential for the mobilization of Al from alum floc deposits in sediments of Kensico Reservoir, New York. Under ambient water quality conditions, mobilization of sediment Al is not a noteworthy concern at Kensico Reservoir. However, under experimental conditions of low pH, low acid neutralizing capacity (ANC), and low temperature, the inorganic fraction of monomeric Al can be mobilized from Kensico sediments to concentrations that would likely impair the health of aquatic organisms (>2 μmol/l). Elevated concentrations of monomeric Al were observed only when ANC decreased below 50 μeq/l, which is outside the range of values observed in Kensico during the 1997‐2007 interval (120‐460 μeq/l). Concentrations of complexing ligands are relatively low in Kensico waters (i.e., fluoride, naturally occurring organic solutes) and do not appear to substantially contribute to potential Al mobilization. For other water supplies with low ANC, the potential for sediment release of Al may exist.     

Exploitation of Fenton and Fenton-like reagents as alternative conditioners foralum sludge conditioning

The use of Fenton’s reagent (Fe2+/H2O2) and Fenton-like reagents containing transition metals of Cu(II), Zn(II), Co(II), and Mn(II)for an alum sludge conditioning to improve its dewaterability was investigated. The results obtained were compared with those obtainedfrom conditioning the same alum sludge using cationic and anionic polymers. Experimental results show that Fenton’s reagent was thebest among the Fenton and Fenton-like reagents for the alum sludge conditioning. A considerable e ectiveness of capillary suction time(CST) reduction e ciency of 47% can be achieved under test conditions of Fe2+/H2O2 = 20/125 mg/g DS (dry solid) and pH 6.0. Theobservation of floc-like particles after Fenton’s reagent conditioning of alum sludge suggested that the mechanism of Fenton’s reagentconditioning was di erent from that of polymer conditioning. In spite of the lower e ciency in the CST reduction of Fenton’s reagentin alum sludge conditioning compared to that of polymer conditioning, Fenton’s reagent o ers a more environmentally safe option.This study provided an example of proactive treatment engineering, which is aimed at seeking a safe alternative to the use of polymersin sludge conditioning towards achieving a more sustainable sludge management strategy.     

钾明矾缓释除磷剂处理分散式农村生活污水

以钾明矾为主要絮凝剂,羟丙基甲基纤维素醚（HPMC）为黏结剂,二者充分混合制成缓释除磷药片,并在缓释除磷装置及低能耗分散式污水处理成套装置中分别考察了其对总磷的去除效果。缓释除磷装置除磷研究结果表明：加入羟丙基甲基纤维素醚（HPMC）后,明显延长了药片缓释时间。但加入的羟丙基甲基纤维素醚（20%）越多,则对总磷的去除效果越差（平均去除率42%）。10%羟丙基甲基纤维素醚的缓释除磷药片去除总磷效果最优,总磷平均去除率是89%。低能耗分散式污水处理成套装置除磷研究结果表明：进水总磷浓度对出水浓度影响较大,缓释除磷药片反应期间,总磷去除率稳定在57%左右（52%~69%）。适用于分散式生活污水的处理,同时当进水总磷浓度稳定在2 mg·L-1时,出水效果较好。     

壳聚糖改性铝污泥对铜绿微囊藻的絮凝去除

采用给水厂副产物铝污泥代替黏土作为下沉载体,利用壳聚糖改性,将其用于铜绿微囊藻的絮凝去除.结果表明,壳聚糖与铝污泥以1：50的质量比复合改性后除藻效果明显提高：对于藻密度约为4.88×10⁶cells/mL的含藻水,当改性铝污泥最佳投加量为0.25g/L,30min后藻密度和浊度去除率分别达到100%和98.92%,形成的絮体完整紧实,分形维数值为1.719.通过Zeta电位、SEM等表征分析,此过程主要依靠壳聚糖、铝污泥及藻类之间的"电性中和"与"吸附架桥"等的作用,混凝絮凝过程快速高效且投加量小,最佳环境pH值介于7~9.5,外加NaCl、CaCl₂在离子强度较低情况下基本不影响絮凝沉淀过程.加之铝污泥对水体中的磷具有良好的吸附作用,因此壳聚糖改性铝污泥对淡水水体中铜绿微囊藻的去除及生长抑制具有良好的效果,实现了"以废治污".     

给水厂废弃铁铝泥对镉的吸附特征及影响因素

通过批量实验探讨了给水厂废弃铁铝泥(Ferric and Alum Water Treatment Residuals,FARs)对Cd2+的吸附特征及影响因素.实验结果表明,在最初的6 h内,FARs对Cd2+的吸附量已经达到其平衡吸附量的90%,吸附较符合伪二级动力学模型(R2=0.99),并且Langmuir(R2=0.99)和Freundlich(R2=0.90)方程均能较好地描述FARs对Cd2+的等温吸附过程,其Cd2+的饱和吸附量达35.39 mg·g-1.初始溶液p H由3.0增加到8.0时,FARs对Cd2+的吸附量缓慢增加,当p H升为9.0时,其对Cd2+去除率可达97%.FARs对Cd2+的吸附量随溶液体系离子强度的增加而减小.随着柠檬酸浓度的升高,FARs对Cd2+的吸附量显著降低,而水杨酸和酒石酸则微弱促进了对Cd2+的吸附.解吸实验证明,在p H为3.0时Cd2+的解吸率最高,但仅为11%左右.分级提取结果进一步表明,被吸附的Cd2+主要以酸溶态和残渣态存在.综合实验结果表明,FARs可以作为一种高效的吸附剂用于水体除镉.     

Effects of Ca(OH)2 assisted aluminum sulfate coagulation on the removal of humic acid and the formation potentials of tri-halomethanes and haloacetic acids in chlorination

The effects of addition of calcium hydroxide on aluminum sulphate(or alum) coagulation for removal of natural organic matter(NOM) and its subsequent effect on the formation potentials of two major types of regulated disinfection byproducts(DBPs),haloacetic acids(HAAs) and trihalomethanes(THMs),have been examined.The results revealed several noteworthy phenomena.At the optimal coagulation pH(i.e.6),the coagulation behavior of NOM water solutions versus alum dose,showed large variation and a consequent great change in the formation potentials of the DBPs at certain coagulant doses.However,with addition of a relatively small amount of Ca(OH) 2,although the zeta potential of coagulated flocs remained almost the same,NOM removal became more consistent with alum dose.Importantly,also the detrimental effect of charge reversal on NOM removal at the low coagulant dose disappeared.This resulted in a steady decrease in the formation potentials of DBPs as a function of the coagulant dose.Moreover,the addition of Ca(OH) 2 broadened the pH range of alum coagulation and promoted further reduction of the formation potentials of the DBPs.The enhancement effects of Ca(OH) 2 assisted alum coagulation are especially pronounced at pH 7 and 8.Finally,synchronous fluorescence spectra showed that the reduction in DBPs formation potential by Ca(OH) 2-assisted alum coagulation was connected to an enhanced removal of small hydrophobic and hydrophilic HA molecules.Ca(OH) 2-assistance of alum coagulation appeared to increase substantially the removal of the hydrophilic HA fraction responsible for HAAs formation,prompting further reduction of HAA formation potentials.     

预氯化对铝盐混凝铜绿微囊藻过程中溶解性有机物和残余铝的影响

以铜绿微囊藻为对象,研究了预氯化过程中藻胞内代谢物释放及铝盐混凝除藻过程中残留铝的变化规律.结果表明,氯投量对胞内物质释放量和释放有机物特征有重要影响.与未投加氯的对照体系相比,在较低氯投量时(1~2 mg·L-1),水中有机物浓度升高26%~31%,UV254值升高46%~49%,且有机物主要为中等分子量(2191、2830和3168 Da)和高芳香度的有机物.增大氯投量至3~4 mg·L-1,水中有机物浓度和UV254值有所下降;就不同分子量有机物而言,大分子量有机物(16304 Da)浓度升高而中等分子量有机物(2830、3168和6163 Da)浓度下降,且出现少量小分子量有机物(180 Da).分子量较大或芳香度较高的溶解性有机物在铝盐混凝中可被优先去除.释放到水中的蛋白质能与铝盐形成可溶性蛋白质-混凝剂复合物,从而导致出水铝浓度升高,但增大铝投量可在一定程度上降低残留铝浓度.     

Effect of Hydrogen Peroxide on Industrial Waste Water Effluents: A Case Study of Warri Refining and Petrochemical Industry

This paper assessed the composition of waste water effluent generated by a Petrochemical industry and a treatment system developed to improve the quality of the discharge water. Parameters as pH, COD, TSS chloride and lead ions were analysed and treated comparatively using hydrogen peroxide. At pH 8.0 post treatment analysis showed a COD – 96 mg/l TSS – 48 mg/l Cl – 798.75 mg/l and Pb²⁺ – 2 mg/l for treatment D where 40 g/l of alum was used on 30% solution of H₂O₂ compared to systems A-C. Process treatment included activated clay with sodium ion resin which at pH 6.8 had COD – 52 mg/l, TSS – 10 mg/l, Cl – 510 mg/l and Pb²⁺ – 0.070 mg/l. This system has an overall efficiency of 79.0% TSS, 45.83% COD, 97.5% Pb²⁺ and 36.1% Cl reduction. Characteristics obtained for the study has a higher efficiency compared with FEPA and WHO standard for similar industrial water treatment.