声电与生物氧化联合处理医药化工废水

采用声电协同法作为预处理工艺,联合生物法处理医药化工废水,处理规模为1 000m3/d.运行实践表明,声电工艺与生物法联用,可提高废水的生物降解性.整个系统对COD的去除率达到99.26％,出水pH值为8.2、COD为233 mg/L,达到《污水综合排放标准》(GB 8978-1996)的三级标准.     

利用白腐菌对山梨酸废水进行预处理的效果研究

采用白腐菌预处理山梨酸废水,就不同菌种、反应时间及pH值等因素对预处理效果的影响进行了分析.结果表明,利用废水培养基驯化出的菌种对山梨酸废水的处理效果较纯化白腐菌和诱变菌种的效果好,反应约4 h时,3种菌种对COD的去除率增幅均达到最大,4 h以后逐渐趋于平缓,因而最佳反应时间应该是在4 h左右;在整个处理过程中,不调节原水pH值(pH值为6)时的处理效果要远远优于调节原水pH值(分别调节为4、8)时的.虽然驯化的白腐菌对废水中COD的去除效果不是十分理想,但它可明显改善废水的可生化性.首先,它可以在180 min内将山梨酸废水的BOD<,5>/COD值由0.17提高到0.39;其次,它可将经过微电解/Fenton试剂预处理的山梨酸废水的BOD<,5>/COD值由0.39提高到O.65,从而为后续的生化处理奠定了基础.     

高级氧化/生物法去除制膜废水中的强有机溶剂

采用高级氧化/生物法组合工艺处理含二甲基甲酰胺(DMF)、二甲基乙酰胺(DMAC)等强有机溶剂的制膜废水.结果表明,曝气微电解和催化电氧化技术去除强有机溶剂的最佳pH值分别为(2～3)、(5～6),最佳水力停留时间分别为120、(90～120)min;高级氧化技术可大大提高废水的可生化性,将B/C值从0.30提高到0.55左右;高级氧化/生物法组合工艺不仅具有很强的抗冲击负荷能力,且处理效果很好,出水水质达到<污水综合排放标准>(GB 8978-1996)的一级排放标准.     

微波处理洗煤废水的效果及作用机理分析

实验在单因素条件下研究了微波功率、微波辐射时间、溶液pH值对洗煤废水处理效果的影响.采用正交实验确定了它们的最佳组合为:微波功率640 W,微波辐射时间4 min,溶液pH值6,在此条件下洗煤废水中CODcr去除率达到93.2%,出水浓度降至102 mg/L,达到国家二级排放标准,同时对微波高效处理洗煤废水的机理进行了探讨.     

UASB/SBR工艺处理燃料乙醇生产废水工程设计

对燃料乙醇生产废水进行了分质处理,对高浓度废水采用UASB/SBR工艺处理,对于低浓度废水则在其水质满足设计值时,经格栅处理后直接进入预曝池进行好氧处理即可,当其水质高于设计值时则经格栅处理后与高浓度废水一并处理.运行结果表明,在实际进水浓度高于设计值的情况下,出水水质达到了<污水综合排放标准>(GB 8978-1996)的一级标准,表明工艺设计合理,处理效果良好.     

高浓度油田压裂废水降低CODCr的预处理方法

针对高浓度油田压裂废水黏度高、浊度大、含油量高等特点,强化预处理工艺,降低CODCr值.文章通过实验证明了强氧化剂(Fenton试剂)与混凝剂PAC+PAM相结合的工艺可有效降低高浓度含油废水CODCr值,进而通过Fenton试剂与混凝剂的投药量、pH值等因素对高浓度油田压裂废水的影响进行分析,得出采用该化学预处理方法出水水质清澈,可直接进入生化处理系统进行后续处理.     

铁炭微电解/Fenton预处理对叔丁酚甲醛树脂合成废水

采用铁炭微电解/Fenton试剂法联合工艺预处理对叔丁酚甲醛树脂合成废水,考察了pH、反应时间及H_2O_2投量等因素的影响.结果表明,当原水COD为12 300～17 600 mg/L时,在控制原水pH值为2.0、反应时间为120 min的条件下,铁炭微电解对COD的去除率>50%;向铁炭微电解出水中再投加2.4 mL/L的H_2O_2(30%)进行Fenton反应,在常温(20～30℃)下反应60min对COD的总去除率>83%,废水的B/C值从最初的0.034提高到0.35左右.对预处理出水(调节pH并稀释)进行后续的生化处理,出水水质能够稳定达到<污水综合排放标准>(GB 8978-1996)的二级排放标准要求.     

铁炭Fenton/SBR法处理硝基苯制药废水

为探寻硝基苯废水的适宜处理工艺，开展了铁炭Fentort／SBR工艺处理硝基苯制药废水的试验研究。结果表明，铁炭内电解结合Fenton氧化的预处理工艺可有效去除废水中的硝基苯类物质，并提高了废水的可生化性。当原水的pH值为2～3、H2O2投加量为500～600mg／L时，调节预处理出水pH值至7～8并经沉淀处理后，对COD和硝基苯类物质的总去除率分别可达47％和92％。后续混合废水经SBR工艺处理后出水水质能满足国家污水排放标准。     

铁碳内电解技术处理草制浆造纸中段废水试验研究

利用铁碳内电解技术对草制浆造纸中段废水进行预处理研究.通过正交试验确定铁碳内电解技术处理草制浆造纸中段废水的主要影响因素、顺序及其最优水平组合,废水的pH值为4.37,铁屑量(V)/原水量(V)为13%,反应时间为1.5 h,焦炭量(V)/铁屑量(V)为1.0.在正交实验的基础上,通过动态试验研究确定了最佳工艺运行条件,即在曝气条件下,原水pH值调节至4.0左右,水力停留时间HRT为1.5~2.0 h,铁碳内电解技术处理草制浆造纸中段废水的CODcr和色度的去除率分别达到65%与50%左右.     

硫酸生产废水治理的试验研究

硫酸生产废水中 pH值、悬浮物、氟化物、硫化物超标 ,污染环境 .用“石灰中和—硫酸铝沉淀—过滤”工艺处理 ,出水可达到污水综合排放标准 .试验对影响工艺流程的重要因素如氟离子浓度与 pH值、石灰、硫酸铝的投加量进行了详细研究 ,结合某硫酸厂生产废水的水量和水质变化因素 ,提出了废水综合治理方案     

Aminopolyphosphonate removal during wastewater treatment

Phosphonates are used in large quantities in industry and household products as scale inhibitors and chelating agents. They are not biodegraded during wastewater treatment but are removed by adsorption processes. Field measurements from different wastewater treatment plants affirm that they are removed almost completely during wastewater treatment. Adsorption of nitrilotrismethylenephosphonic acid onto activated sludge, amorphous iron oxide and humic acids (HAs) was studied under controlled conditions. The adsorption onto HAs decreases sharply with increasing pH with negligible adsorption at pH above 6.5. Adsorption onto amorphous iron oxide follows a Langmuir behavior. The presence of 1 mM Ca doubles the maximum surface capacity at pH 7. Adsorption onto activated sludge is not very pH sensitive and is explained to a large extent by adsorption onto amorphous iron oxides, but the contribution of organic matter or other mineral phases cannot be ruled out.     

羟基氧化铁的制备影响及污水处理中的应用

介绍了羟基氧化铁的种类、结构、表面物理化学性质,讨论了羟基氧化铁制备时反应物(如铁盐种类、沉淀剂)与反应条件(如温度、pH值、表面活性剂等)对产物的影响。最后,对羟基氧化铁在污水处理中的应用进行概述,对实际工程的应用具有重要意义。     

不锈钢生产废水的处理回用与重金属资源化利用

介绍了某工业园区不锈钢废水处理及重金属资源化工艺设计方案。针对不锈钢废水酸度高、pH值波动大、氟离子含量高、重金属浓度高、COD低的特点,采用CaCO3滤床/分级沉淀/过滤的废水处理工艺,实现50%的废水回用率和镍铬等重金属的资源化。该工艺对废水中COD、总铬、总镍、总铁和氟的去除率分别为67.3%、99.7%、99.8%、99.8%及97.0%。出水水质达到《钢铁工业水污染物排放标准》(GB 13456—92)和《污水综合排放标准》(GB 8978—1996)的一级标准,回用水水质达到不锈钢企业的用水要求。水回用及重金属资源化后的收益为4.02元/m3。     

Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment

Chemical phosphorus (P) removal during aerobic wastewater treatment induced by iron salt addition in sewer systems for sulfide control is investigated. Aerobic batch tests with activated sludge fed with wastewater containing iron sulfide precipitates showed that iron sulfide was rapidly reoxidised in aerobic conditions, resulting in phosphate precipitation. The amount of P removed was proportional to the amount of iron salts added, and for the sludge used, ratios of 0.44 and 0.37 mgP/mgFe were obtained for ferric and ferrous dosages, respectively. The hydraulic retention time (HRT) of iron sulfide in sewers was found to have a crucial impact on the settling of iron sulfide precipitates during primary settling, with a shorter HRT resulting in a higher concentration of iron sulfide in the primary effluent and thus enabling higher P removal. A mathematical model was developed to describe iron sulfide oxidation in aerated activated sludge and the subsequent iron phosphate precipitation. The model was used to optimise FeCl₃ dosing in a real wastewater collection and treatment system. Simulation studies revealed that, by moving FeCl₃ dosing from the WWTP, which is the current practice, to a sewer location upstream of the plant, both sulfide control and phosphate removal could be achieved with the current ferric salt consumption. This work highlights the importance of integrated management of sewer networks and wastewater treatment plants.     

Effect of acidity consumption/production on the pH of aeration tank during the biodegradation of acetic acid/epichlorohydrin

In order to elucidate the biologically driven pH fluctuation phenomena in industrial wastewater treatment, the contrary effects of acetic acid (AA) and epichlorohydrin (ECH) on the pH of aeration tank were investigated. Two simple equations were derived to estimate optimum neutralization pHs for the biological AA/ECH wastewater treatment, and the calculated optimum neutralization pHs were compared with experimental results. The pH in aeration tank was expected to fluctuate sharply with the smallest deviation of neutralization pH from the optimum value. However experimental results showed that real pH fluctuation is smaller than the theoretical one. It was considered that carbonate buffer in aqueous system relieves the pH fluctuation. The deviation between experimental and theoretical optimum neutralization pH could be mainly caused by volatility of AA and ECH. The deviation was larger with ECH wastewater of which volatility is larger than AA. Finally, this theory was successfully applied to the real petrochemical wastewater treatment. The pH of aeration tank was properly maintained when acidified wastewater (pH 3.4) was supplied.     

A novel hybrid nano zerovalent iron initiated oxidation--biological degradation approach for remediation of recalcitrant waste metalworking fluids

Disposal of operationally exhausted metal working fluids (MWF) through a biological route is an attractive option, since it is effective with relatively low energy demands. However, it is enormously challenging since these fluids are chemically complex, including the addition of toxic biocides which are added specifically to retard bio-deterioration whilst the fluids are operational. Nano-sized elemental iron represents a new generation of environmental remediation technologies. Laboratory scale batch studies were performed to test the degradation ability of a semi-synthetic metalworking fluid (MWF) wastewater (which was found to be resistant to initial bacterial treatment in specifically established bioreactors) by employing a novel hybrid approach. The approach was to combine the synergistic effects of nano zerovalent iron (nZVI) induced oxidation, followed by biodegradation, specifically for the remediation of recalcitrant components of MWF effluent. Addition of nZVI particles to oxygenated wastewater resulted in oxidation of organic contaminants present. Our studies confirmed 78% reduction in chemical oxygen demand (COD) by nZVI oxidation at pH 3.0 and 67% reduction in neutral pH (7.5), and 85% concurrent reduction in toxicity. Importantly, this low toxicity made the nZVI treated effluent more amenable for a second stage biological oxidation step. An overall COD reduction of 95.5% was achieved by the novel combined treatment described, demonstrating that nZVI oxidation can be exploited for enhancing the biodegradability of a recalcitrant wastewater in treatment processes.     

Fe-H2O2深度处理造纸中段废水的研究

为解决零价铁法处理废水时效率偏低的问题,采用Fe-H2O2法对造纸中段废水的二级处理出水进行了深度处理,分别考察了pH值、反应时间、铁炭比、曝气量和H2O2投量对色度和COD去除率的影响.结果表明：在pH值为3.5、铁炭比（体积比）为1.2、曝气量为1.4 L/min、铁屑粒径为60～80目、H2O2投量为40～60 mg/L的最优条件下,当处理时间控制在35 min时,对色度和COD的去除率可分别达到98%和77%左右,出水可回用.     

Removal of suspended solids by coagulation and foam separation using surface-active protein

By using several kinds of surface-active proteins as a chemical agent that combined collector with frother, removal of suspended substances by coagulation and foam separation with dispersed air was examined. Milk casein showed the greatest capability of suspension removal, and coagulating flocs formed by clay particles and iron hydroxide were almost perfectly recovered in foam generated from the liquid, even in the case of freshwater and seawater suspension at neutral pH. In contrast, the removal efficiency was extremely low using sodium dodecyl sulfate (SDS). Casein had a much greater capability for removing solids than SDS as a result of the high adsorptive activity of casein on the floc. For municipal wastewater treatment, the removal efficiency of turbidity and suspended solids was over 98% with the condition of iron coagulant (FeCl3) 20 mg-Fe/L and casein 3 mg/L and pH 5-6. Moreover, this method proved to be an effective treatment for polluted saline water (salinity 1.5%), and the suspended solids were almost perfectly recovered in foam. Here, we show a new method for quickly removing (within 7 min) suspended solids from polluted wastewater utilizing casein and bubbles.     

Cork industry wastewater partition by ultra/nanofiltration: a biodegradation and valorisation study

Wastewater from cork processing industry present high levels of organic and phenolic compounds, such as tannins, with a low biodegradability and a significant toxicity. These compounds are not readily removed by conventional municipal wastewater treatment, which is largely based on primary sedimentation followed by biological treatment. The purpose of this work is to study the biodegradability of different cork wastewater fractions, obtained through membrane separation, in order to assess its potential for biological treatment and having in view its valorisation through tannins recovery, which could be applied in other industries. Various ultrafiltration and nanofiltration membranes where used, with molecular weight cut-offs (MWCO) ranging from 0.125 to 91 kDa. The wastewater and the different permeated fractions were analyzed in terms of Total Organic Carbon (TOC), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Phenols (TP), Tannins, Color, pH and Conductivity. Results for the wastewater shown that it is characterized by a high organic content (670.5-1056.8 mg TOC/L, 2285-2604 mg COD/L, 1000-1225 mg BOD/L), a relatively low biodegradability (0.35-0.38 for BOD₅/COD and 0.44-0.47 for BOD₂₀/COD) and a high content of phenols (360-410 mg tannic acid/L) and tannins (250-270 mg tannic acid/L). The results for the wastewater fractions shown a general decrease on the pollutant content of permeates, and an increase of its biodegradability, with the decrease of the membrane MWCO applied. Particularly, the permeated fraction from the membrane MWCO of 3.8 kDa, presented a favourable index of biodegradability (0.8) and a minimized phenols toxicity that enables it to undergo a biological treatment and so, to be treated in a municipal wastewater treatment plant. Also, within the perspective of valorisation, the rejected fraction obtained through this membrane MWCO may have a significant potential for tannins recovery. Permeated fractions from membranes with MWCO lower than 3.8 kDa, presented a particularly significant decline of organic matter and phenols, enabling this permeates to be reused in the cork processing and so, representing an interesting perspective of zero discharge for the cork industry, with evident environmental and economic advantages.     

铁碳内电解预处理高浓度制药废水试验研究

针对制药废水有机物含量高、可生化性差的特点,利用铁碳微电解作为预处理方法,考察初始pH值、反应时间、铁碳质量比、铁屑投加量等因素对废水处理效果的影响,并考察了该技术对废水可生化性的影响,旨在为高浓度难降解制药废水的处理探索一条经济实用的新途径,并为其工业化应用做出铺垫。