混凝预处理油田压裂返排液试验研究

针对压裂返排液水质状况,试验采用混凝工艺预处理压裂返排液。通过单因素变量分析及正交混凝试验,以COD和浊度作为混凝效果的参照指标,试验确定了最佳的混凝工艺:絮凝剂投加量450 mg/L,助凝剂投加量5.0 mg/L,静置时间80 min。其产水浊度、COD及浊度去除率分别达到99.9%、86.5%和87.9%,且产水水质稳定。     

页岩气压裂返排废水的混凝处理效能研究

对页岩气压裂返排废水进行了混凝处理,研究了聚合氯化铝、硫酸亚铁等不同混凝剂对压裂返排废水COD的去除效果,考察了p H、混凝剂投加量和助凝剂投加量对COD去除率的影响。结果表明:在复配混凝剂为硫酸亚铁和聚合氯化铝(质量比为1∶1),混凝剂投加量为12 000 mg/L,p H为8.5,助凝剂投加量为10 mg/L的最佳混凝处理条件下,压裂返排废水的COD去除率为62.49%,出水COD由1 984.32 mg/L降至744.32 mg/L。     

新型复合混凝剂在染料废水处理中的应用

染料废水由于色度高、水质变化大、生化性差等特点,是当前工业废水处理的难点和焦点之一,混凝法是处理染料废水的主要方法之一。本实验采用矿渣、盐酸和硫酸铁、氧化铝研制了一种新型复合混凝剂,以此来处理直接耐晒大红染料废水。采用单因素法分别通过改变废水pH值,混凝的时间以及混凝剂的投加量来观察混凝剂对废水的处理效果。实验结果表明,随着pH值、混凝剂投加量和反应时间的增加,COD及色度都呈现先降低后趋于稳定的变化趋势：当pH值=11时,色度去除率达最大值84.0%,COD去除率达76.1%;当投加量为0.7g时,色度去除率达最大为88.1%,COD去除率为73.2%;当混凝时间为3min时,色度去除率最大为89.3%,COD去除率达76.2%。综上,此混凝剂的最佳反应条件为投加量0.7g,pH值11,混凝时间3min。该新型复合混凝剂处理染料废水效果好,产生的絮体大,沉降速度快,出水清澈透明。     

Treatment of tannery wastewater through the combination of a conventional activated sludge process and reverse osmosis with a plane membrane

Tannery wastewater contains high concentrations of organic matter (COD) with a significant percentage of refractory organic compounds, ammonium substances, salts (i.e. chloride and sulphate) as well as sulphur. Contaminants have to be removed in order to avoid significant environmental impacts. This paper presents the results obtained from a pilot scale study developed in the tannery district of Solofra in Southern Italy. It was aimed at evaluating the reuse of wastewater produced in the retanning process. The treatment process consisted of a biological treatment, as a pre-treatment, followed by a physico-chemical process (with a polymer as a coagulant) and reverse osmosis with a plane membrane. The biological pre-treatment was able to remove approx. 67% of COD, while the membrane system completed the purification process with the removal of the refractory organic compounds (chloride and sulphate). In the test carried out, the combination of a biological pre-treatment with a plane membrane system showed satisfactory results in terms of wastewater recovery and reuse in the tannery production cycle.     

Olive Mill and Winery Wastewaters Pre-Treatment by Coagulation with Chitosan

The pre-treatment of both winery wastewater (WW) and olive mill wastewater (OMW) by coagulation, using a natural organic coagulant, was investigated as a possible alternative to conventional metal based coagulants, in order to produce a potentially reusable organic sludge. Chitosan was chosen as a model natural organic coagulant and the coagulation process was optimized investigating different coagulant doses and pH values. In spite of the notably lower polluting load for the WW compared to the OMW, the efficiency of the chitosan coagulation was found to be high in terms of total suspended solids (81% and 80% for OMW and WW respectively) and turbidity (94% and 92% for OMW and WW respectively) removal for both wastewaters, but a notable difference was observed in terms of organic matter removal (32% and 73% in terms of COD for OMW and WW respectively). Taking into account that the best performances of the coagulation process by chitosan were achieved at the actual pH for OMW as well as no significant differences were observed for WW as the pH was changed, no chemicals addition is required to adjust pH.     

混凝-微电解预处理维生素B1生产废水

针对维生素B1生产废水成分复杂、难于生化降解、水质不稳定、固体悬浮颗粒含量高的特点,采用混凝-微电解法进行预处理.当混凝剂三氯化铁的投加质量浓度为150 mg/L,微电解反应器内pH为4.2,反应时间为50 min时,出水TOC和COD的去除率分别达到77.4%和82.3%,对SS的去除率也达95%,同时有效提高了废水的可生化性.     

强化预处理乙醇废水协同除磷试验研究

酿造行业废水具有高有机物浓度、高浊、高磷等特点,对后续生物处理的十分不利。采用混凝沉淀强化处理,能够有效提高化学需氧量（COD）、悬浮物（SS）的去除率,同时降低磷浓度,对后续生物处理具有促进作用。探讨了不同混凝剂、混凝剂的投加量对混凝沉降速度和COD、浊度、磷去除效果的影响。研究表明,三氯化铁为预处理乙醇废水最佳混凝剂,在p H值为7-8时,投加量为80mg/L,沉降速度较快,COD的去除率可达59%,磷的去除率〉90%。继续投加助凝剂聚丙烯酰胺（PAM）可以提高废水的处理效果,但是不显著。     

Simultaneous removal of organic and inorganic pollutants in tannery wastewater using electrocoagulation technique

Tannery wastewater can cause severe environmental problems related to its high chemical oxygen demand, high biochemical oxygen demand, high total suspended solids, high oil and grease contents together with the elevated chromium concentration and objectionable color. The one-step electrocoagulation process was carried out to simultaneously remove chromium and various pollutants from tannery wastewater at ambient temperature in the laboratory scale. Low-cost commercial iron plates were employed in this study as anodes and cathode materials. Effects of various parameters were investigated including types of electrode configuration, initial pH of wastewater (7–9), current density (15.7–24.6 Am⁻²) and circulating flow rate of wastewater (0–3.67 lmin⁻¹). The optimum condition was found by applying the mono-polar electrode in a parallel connection at the current density of 22.4 Am⁻², flow rate of wastewater of 3.67 lmin⁻¹ and 20 min electrolysis time. The initial pH of wastewater ranging from 7–9 provided the similar removal efficiency. At optimum condition, more than 95% of chromium and pollutants except TKN and TDS were eliminated from the wastewater and the properties of the treated wastewater met the standard and permitted to discharge into the environment. The required energy consumption at optimum condition was less than 0.13 kWhm⁻³ wastewater. In addition, the COD reduction was fit very well with the first-order kinetics model.     

硼泥复合混凝剂处理啤酒废水的研究

本文研究了硼泥复合混凝剂处理啤酒废水的影响因素和最佳处理条件。处理啤酒废水的 COD 1 0 0 0～ 2 5 0 0 mg/L ,SS 2 0 0～ 40 0 mg/L时 ,处理的最佳 p H值范围 6 .2～ 1 0 .3,最佳投药量范围 0 .4～ 0 .8g/L。COD去除率可达 71 %以上 ,SS去除率可达 93.5 %以上。搅拌速度、搅拌时间、温度对 COD及 SS去除率无显著影响。再经双层滤料过滤或曝气生化处理 ,出水达到污水排放标准     

Enhanced Coagulation/Flocculation by Combining Diatomite with Synthetic Polymers for Oily Wastewater Treatment

The objectives are to evaluate the feasibility of treating oily wastewater using synthetic polymers (polyaluminum chloride (PAC), polyferric sulfate (PFS), and polyacrylamide (PAM)) combined with natural diatomite and to refine the operating parameters using diatomite as an adsorbent and a coagulant aid. The enhanced coagulation/flocculation by combining PAC with diatomite was investigated through mechanism analysis compared to the combination of PFS/PAM with diatomite, respectively. The effects of coagulant dose, initial pH, and settling time on chemical oxygen demand (COD) and turbidity were studied using PAC-diatomite in comparison with using PAC only. The enhanced coagulation/flocculation of diatomite with PAC was better than that with PFS/PAM in terms of COD/turbidity removal and floc settling characteristics, considering costs. The PAC-diatomite system reduced more than 70% of COD and 90% of turbidity over a wide pH range (7–10) within 20 min, with the optimum dose of PAC 50 mg/l and diatomite 1250 mg/l. The added diatomite effectively saved over 85% of PAC dose and simultaneously increased over 50% of COD removal efficiency. This study provided a novel and economical approach for diatomite utilization in the treatment of oily wastewater, satisfying the demands of reuse or reinjection into the ground.     

聚合硫酸铁处理制革废水

本文研究了几种常用的国产混凝剂处理制革废水的效果，得出聚合硫酸铁是一种比较经济有效的混凝剂，配合ＰＡＭ助凝剂可以取得更好的效果。工艺上采用混凝气浮，可全部去除硫化物，出水总铬≤１ｍｇ／Ｌ，ＣＯＤ去除率可达７０％－８０％。     

Palm oil mill effluent pretreatment using Moringa oleifera seeds as an environmentally friendly coagulant: laboratory and pilot plant studies

This research paper covers the suitability of the coagulation–flocculation process using Moringa oleifera seeds after oil extraction as a natural and environmentally friendly coagulant for palm oil mill effluent treatment. The performance of M. oleifera coagulant was studied along with the flocculant KP 9650 in removal of suspended solids, organic components and in increasing the floc size. The optimum values of the operating parameters obtained from the laboratory jar test were applied in a pilot‐scale treatment plant comprised of coagulation–flocculation and filtration processes. Pilot‐scale pretreatment resulted in 99.7% suspended solids removal, 71.5% COD reduction, 68.2% BOD reduction, 100% oil and grease removal and 91% TKN removal. In pilot plant pretreatment, the percentage recovery of water was 83.3%, and 99.7% sludge was recovered after dewatering in a filter press. Copyright © 2006 Society of Chemical Industry     

Decolorization of disperse and reactive dye solutions using ferric chloride

The composition of wastewater from dyeing and textile processes is highly variable depending on the dyestuff type; typically it has a high chemical oxygen demand. This study examined the decolorization of some of the most commonly used disperse and reactive dyestuffs by destabilization using ferric chloride as a coagulant. Dye removal, distributions of zeta potential, concentration of suspended solids, changes of the SCOD/TCOD ratio and distributions of SV and SVI values were investigated in this work. Compared to reactive dyes, disperse dyes have lower solubility, higher suspended solids concentrations and lower SCOD/TCOD ratios. It was concluded that disperse dye solutions are more easily decolorized by chemical coagulation than reactive dye solutions.     

Simultaneous removal of chromium and organic pollutants in tannery wastewater by electroprecipitation technique

The simultaneous removal of chromium and other organic pollutants from tannery wastewater was investigated in a batch electrochemical membrane reactor. This reactor, having a total capacity of 1 liter, was separated into two compartments (anodic and cathodic compartments) by using an anionic membrane. A stainless steel sheet with the square holes having total surface area of 0.0215 m² and a Ti/RuO₂ grid was used as the cathode and anode, respectively. The results indicated that the optimum condition for removal of chromium from tannery wastewater was found at the current density of 60.5 A/m² at initial pH of 4.5. At this condition, more than 98% of chromium was removed within 60 min. Some organic pollutants contained in wastewater such as oil and grease, color and the level of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total kjeldahl nitrogen (TKN) were also markedly reduced.     

化学混凝法处理酸洗磷化综合废水的研究

为了确定适用于酸洗磷化废水的混凝剂及相应的最佳操作条件,以COD为主要考察指标,进行了一系列混凝试验。结果表明,在所选取的混凝剂中,氯化亚铁对试验原水的混凝效果最好,进一步试验确定的最佳操作条件为:氯化亚铁投加量为200mg/L,pH值为7.0,快速搅拌(搅拌强度300r/min)1min,慢速搅拌(搅拌强度90r/min)15min,沉降1h,此时,废水中COD的去除率可以达到40%。     

Removal of chemical oxygen demand from textile wastewater using a natural coagulant

A biomaterial was successfully synthesized from Plantago ovata by using an FeCl₃-induced crude extract (FCE). The potential of FCE to act as a natural coagulant was tested for the pretreatment of real textile wastewater. Tests were performed to evaluate the effects of FCE quantity, salt concentration, and wastewater pH on chemical oxygen demand (COD) reduction during a coagulation/flocculation process. Experimental results indicated that the wastewater could be effectively treated by using a coagulation/flocculation process, where the BOD₅/COD ratio of the effluent was improved to 0.48. A low coagulant dose, 1.5mg/L, achieved a high COD removal percentage, 89%, at operational conditions of neutral pH and room temperature. The experimental data revealed that the maximum COD removal occurred at water pH<8. Increasing the salt promoted the COD removal. The settling and filterability characteristics of the sludge were also studied. Scanning electron microscopy and energy dispersive spectroscopy studies were conducted to determine the sludge structure and composition, respectively. Overall, FCE as an eco-friendly biomaterial was revealed to be a very efficient coagulant and a promising option for the removal of COD from wastewaters.     

混凝-Fenton氧化法处理伪装涂料废水研究

通过混凝和Fenton相结合的方法处理伪装涂料废水。以COD为考察指标,讨论了混凝剂的种类、投加量、pH、助凝剂的添加等因素对混凝实验的影响及pH、H_2O_2和FeSO_4投加量对Fenton氧化实验的影响。混凝-Fenton氧化法可有效地降低废水的COD,使其达到《污水排入城市下水道水质标准》(CJ 3082—1999)的排放要求(≤500mg/L),COD的总去除率可达98.7%。     

上流式厌氧污泥床反应器处理凉果废水性能研究

采用上流式厌氧污泥床反应器(UASB)法处理凉果废水,考察废水厌氧处理过程中COD、浊度、脱色率、pH、电导率、悬浮物去除率的变化规律。结果表明:随着厌氧时间的增加,UASB反应器对废水的处理效果不断提高。在最适宜的厌氧时间条件下,废水的COD去除率达62.0%、浊度去除率达41.1%、吸光度及脱色率分别为0.498及48.4%、pH为5.4、悬浮物去除率达30.3%。故,UASB法可作为凉果废水的预处理方式,以降低后续废水的好氧处理难度。     

皮革废水处理实例

皮革加工废水存在排水量大,水质水量不均,污染物成分复杂的特点。毛皮在鞣制、染色过程中产生的废水不仅含COD,BOD,悬浮物等常见污染物,亦包含大量蛋白质,脂肪,硫化物,氯化物,三价铬盐,此外还有大量细小绒毛;这给皮革废水的处理带来极大难度。文章介绍的实例项目将含铬的复鞣废水与其它废水分开预处理,复鞣废水除铬处理后汇合至综合废水;综合废水经前处理+两级生化处理后达标排放到市政污水管网。     

Behaviour of Inorganic Coagulants in Secondary Effluents from a Conventional Wastewater Treatment Plant

An experimental laboratory scale study was conducted to compare the effectiveness of three inorganic coagulants — aluminium sulphate, ferric chloride and polyaluminium chloride (PAC) — in reducing the turbidity of secondary effluents from a conventional wastewater treatment plant. For each inorganic coagulant, the dose and the pH of coagulation were optimized. The results enabled the selection of the most appropriate coagulant, its dose and the optimal operational conditions to obtain the required water quality (3-5 NTU) for re-use in agricultural drip irrigation systems. PAC was identified as the most suitable coagulant/flocculant for reducing the turbidity of this type of water. The optimal conditions corresponded to pH 6 and a dose of PAC of 20 mg/l, but the recommended conditions are 50 mg/l for pH 8 (the initial pH of the water) to obtain a turbidity reduction of 90%, which is independent of the initial turbidity of water (i.e. 5-32 NTU).