Treatment Of Biologically Treated Distillery Effluent - A Case Study

The paper addresses physico-chemical treatment of biologically treated distillery effluent using conventional and non-conventional coagulants. Conventional coagulants, viz. ferrous sulphate, ferric sulphate, and alum were used during the study. Ferrous sulphate in combination with lime was found to be optimal which could remove 78.50 percent COD with efficient removal of colour. Further, commercially available polyelectrolyte aid, Percol 47 was found to be suitable for the reduction of ferrous sulphate requirement from 20?gL ?1 to 10?gL ?1 , which produced the same quality of effluent without affecting the overall efficiency of the treatment. Non-conventional coagulants viz. wastewater from an iron pickling industry and titanium ore processing industry were also evaluated. The iron pickling wastewater also removed 86.8 percent and 92.5 percent residual COD and BOD, respectively, from the biologically treated distillery effluent. Further, commercial activated carbon was assessed for polishing the effluent after treatment with coagulants. A dose of 8?gL ?1 of carbon with contact time of 45 minutes was found to be optimal. The effluent generated after treatment with activated carbon had COD concentrations less than the discharge standard for inland surface water as prescribed by Central Pollution Control Board (CPCB), Ministry of Environment and Forests (MOEF), Government of India.     

Treatment of wastewater from the meat manufacturing industry‐case study

Meat manufacturing mill wastewaters (MMM) originating from meat processing units are the most polluted wastewaters of the food industry. Discharged wastewater was characterized by high values of COD, BOD and TSS (6612, 2550 and 6220) mg/l, respectively. Moreover, the wastewater contains significant concentrations of oil and grease amounting to 4482 mg/l. Treatment processes namely, plain sedimentation, plain flotation, pressurized dissolved air flotation, chemical coagulation and biological treatment via a completely mixed activated sludge process, were chosen for this study. The results obtained revealed that plain sedimentation, column flotation and dissolved air flotation (DAF) exhibited good efficiency in removing flotation fats (93.5, 96, and 97.3%, respectively). Alum, ferrous sulfate and ferric chloride precipitation in‐combination with lime at their optimum operating conditions as minimal pre‐treatment procedures for the removal of organic matter contents exhibited good efficiency of COD, BOD, and oil and grease. The chemically treated effluent doesn't comply with the Law No.4/1994 (Egyptian Standards which regulating the discharge of industrial wastewater to the sewerage network). This is due to the high concentration of soluble organics. Activated sludge plant (ASP) with long aeration time (8hr) was suitable for the case under consideration. Results show that average residual COD, BOD, TSS and oil and grease were 270, 62, 78 and 9.8 mg/l, respectively. The biologically treated effluent is complying with Standards of discharge wastewaters to the sewerage network.     

Treatment of dye wastewater containing acid orange II using a cell with three-phase three-dimensional electrode.

The removal of color and chemical oxygen demand (COD) from simulated dye wastewater containing Acid Orange II was experimentally investigated using coagulation-electrooxidation. Two kinds of coagulation methods, ferrous-mediated coagulation and electrocoagulation were tested as pretreatment. The electrooxidation was carried out in a cell with a three-phase three-dimensional electrode using granular activated carbon as particle electrodes. Particular attention was paid to probe the effect of cell voltage, airflow rate, solution conductivity and treatment time on the electrochemical treatment efficiency. The experimental results showed that the coagulation-electrooxidation process could efficiently remove the color and the COD from the simulated dye wastewater. The overall COD and color removal efficiencies reached as high as 99% and 87%, respectively, by ferrous coagulation (molar rate of Fe(II)/ dye: 0.5) and 30-min electrolysis (cell voltage: 20.0 V and airflow: 0.1 m3 h(-1)).     

生化后置催化铁内电解工艺处理化工废水的研究

某些化工废水经常规生化工艺处理后，出水的COD和色度值仍较高，直接采用混凝处理效果不理想，且对混凝剂的消耗量大。为此，考察了催化铁内电解作为生化后处理工艺的可行性及其作用。试验结果表明，将催化铁内电解置于生化工艺之后，其出水再经絮凝沉淀处理可以取得较好的脱色效果，对COD等污染物也有一定的去除作用，说明催化铁内电解法不但可以作为难降解化工废水的生化预处理工艺，还可作为生化后处理工艺。     

物化-生化-物化工艺处理精细化工废水的中试

采用“混凝气浮＋悬浮填料A／O＋催化铁内电解＋混凝沉淀”工艺处理某精细化工废水,考察了其处理效果。结果表明,混凝、气浮对COD、色度、TP的去除率分别为20％、49％、56％;生化段的最佳水力停留时间约为33h,对BOD5的去除率达95％,对氨氮的去除率仅为19％;由于废水经生化处理后大部分有机物得到去除,催化铁内电解工艺置于生化工艺后可有效避免催化铁表面出现有机物黏附层;向催化铁内电解出水中投加100mg／L的PAC及1mg／L的PAM,经混凝沉淀后对残余COD的去除率可达40％。整个系统对COD、色度、TP的去除率分别可达85％、95％、91％。     

Treatment of landfill leachate by combined aged-refuse bioreactor and electro-oxidation

Two-stage aged-refuse bioreactor (ARB) was applied to treat landfill leachate in Shanghai Waste Laogang Disposal Plant. The removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), total organic carbon (TOC), total nitrogen (TN) and ammonia nitrogen (NH(3)-N) of landfill leachate treated by the two-stage bioreactor system were 98.5%, 99.9%, 98.0%, 64.2% and 99.9%, respectively. The COD and BOD in the second stage effluent were 239 and 7 mg l(-1), respectively. Thus three types of electrolysis were employed to further treat the second effluent, undivided electrolysis (UDE), divided electrolysis (DE) with Ti/PbO(2) cathode and DE with gas diffusion cathode. All electrolysis processes possessed good color removal effect, while the DE with gas diffusion cathode had the best TOC removal effect. The optimum electrolysis time of leachate was 30 min. The TOC removal efficiencies were 51.4% and 39.7% in anolyte and catholyte, respectively, after 30 min electrolysis at 5 V. In addition, the DE with gas diffusion cathode showed the least energy consumption of 9.8 k Whm(-3) at 30 min. The organic pollutants in the leachate were analyzed through a gas chromatography coupled with mass spectrometry (GC-MS) system. Through the two-stage ARB, the species and concentrations of organic pollutants in landfill leachate reduced greatly. Several chlorinated organic compounds were detected in the effluent after the UDE and the anolyte of the DE. In addition, the concentration of absorbable organic halogens (AOX) increased greatly during the electrolysis. Hence, careful consideration should be given in the application of electro-oxidation into the treatment of chloride-containing wastewater.     

污泥调理废水的特性及其处理工艺

采用离子色谱法及化学分析法分析了污泥调理废水的水质特性,在氨吹脱及混凝试验的基础上开展了氨吹脱—厌氧—SBR工艺处理该废水的研究。结果表明,污泥调理废水是一种高浓度含氮有机废水,其中有机污染物主要以溶解态存在,不宜采用混凝处理。该废水具有较好的生物可降解性能,当HRT为24h、进水COD为8658.7~9650.3mg/L时,厌氧对COD的去除率可达62.1%,厌氧/好氧交替运行的SBR对COD、氨氮的去除率分别为92.1%、88.4%。动态运行结果显示,氨吹脱—厌氧—SBR工艺对该废水水质具有良好的适应性,处理出水水质能稳定地达到GB8978—1996的二级标准。     

Physico-chemical treatment of strong municipal wastewater

Direct chemical flocculation-clarification of strong new wastewater followed by adsorption on activated carbon has been investigated. The fate of specific organic components (low organic acids, carbohydrates, proteins, fats as well as BOD and COD) in the chemical treatment process was also studied. Excellent removals of phosphates, fats and suspended solids and a clear effluent were obtained in the chemical treatment. The clear ‘primary chemical’ effluent is, however, of high soluble organic content, the largest fraction being the soluble (low) organic acids and carbohydrates. Adsorption of the chemically treated wastewater on activated carbon gave a 60 per cent removal and a final effluent of a relatively high organic content including BOD. The high concentration of remaining organics is ascribed to poor adsorbability of the low organic acids anions on activated carbon.The significance of the findings for process considerations is discussed.     

Olive mill wastewater treatment by anodic oxidation with parallel plate electrodes

Olive mill wastewater is characterized by very high chemical oxygen demand (COD) values and contains high concentrations of polyphenols that inhibit the activity of micro-organisms during biological oxidations. In this paper, the applicability of electrochemical oxidation of a real olive-mill wastewater was studied by performing galvanostatic electrolysis using parallel plate electrodes. A mixed titanium and ruthenium oxide (Ti/TiRuO2) was used as anode and stainless steel as cathode. The effect of chloride concentration and applied current on the removal of COD, aromatic content and colour was investigated. The experimental results showed that an effective electrochemical oxidation was achieved in which the wastewater was decolourised and the COD and aromatic content completely eliminated. In particular, the mineralisation took place by indirect oxidation, mediated by active chlorine, and the COD removal rate was enhanced by the addition of 5 g L(-1) of NaCl to the wastewater and by increasing the applied current.     

DO对催化铁内电解预处理混合化工废水的影响

上海市西北某工业区排放的污水以化工和医药废水为主，其水量占排放总量的75％以上，属于典型的混合化工废水。目前该区的污水处理厂采用SBR工艺，但出水水质达不到有关的排放标准，尤其是色度超标严重。为此，开展了催化铁内电解法预处理该混合化工废水的生产性试验研究。结果表明，溶解氧浓度对预处理效果影响较大，在缺氧（DO〈0．5mg／L）条件下，对色度的去除效果较为明显，平均去除率可达42％，但对COD的平均去除率仅为14％左右；在高氧（DO=5．3～5．9mg／L）条件下，对COD的平均去除率可达44％左右，对色度的平均去除率为34％；在低氧（DO=0．9～1．4mg／L）条件下，对COD的平均去除率可达54．5％，对色度的平均去除率为43％，是比较理想的工况。     

某再生水厂混凝/沉淀/过滤工艺的处理效果评估

某再生水厂的供水能力为10×104m3/d,采用混凝、沉淀、过滤工艺,原水为城市污水厂的二级处理出水.结合实际运行数据,分析了该工艺及其各单元对几种主要指标的去除效果.监测结果显示,该工艺对COD、SS、TP具有较好的去除效果,但对TN、BOD5的去除率较低,对此可在前端增加曝气生物滤池等单元加以解决.该研究对于污水再生处理工艺的选择具有指导意义.     

Performance evaluation of a pure oxygen‐based activated sludge system treating a combined paint industry wastewater and domestic sewage

Activated sludge system based on pure oxygen has been developed to increase the biodegradation of wastewater. This system was used for the treatment of combined wastewater from the paint industry effluent and sewage. The results of continuous test showed that it is possible to achieve 87.8–93.6% COD, and 97.7–99.2% of BOD removal resulting in an effluent quality of 55–90mg/L of COD and less than 10.0mg/L of BOD. Dissolved oxygen content through out the tank showed a concentration, ranging between 3.26 and 3.9mg/L, indicating good oxygenation in the system. Excess sludge generated in the ASP was found to be 3.0kg/d and it has a good manurial value with NPK of 112, 68 and 32mg/L, respectively. Moreover the sludge showed very good settling character with a capillary suction time of 8.0 seconds.     

Application of ferrous hydrogen peroxide for treatment of DSD-acid manufacturing process wastewater

A pretreatment method for the biological treatment of wastewater from 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD-acid) manufacturing processes, a refractory dye intermediate wastewater, based on combined ferrous hydrogen peroxide oxidation and coagulation-flocculation, was developed. When the wastewater was treated with ferrous hydrogen peroxide oxidation ([Fe2+] = 2.7 mmol/L, [H2O2] = 0.21 mol/L) after a flocculation using an organic flocculant TS-1 at a dosage of 3 g/L, the overall COD and color removals were 64 and 62%, respectively. BOD5/COD value of the effluent was 0.3. Ferrous hydrogen peroxide oxidation treatment can reduce the solubility of organic molecules with sulfonic group and increase the efficiency of coagulation treatment. The COD and color removals were both more than 90% when FeCl3 was used as the coagulation (dosages of two-step coagulation were 0.031 and 0.012 mol/L respectively) after a ferrous hydrogen peroxide oxidation pretreatment at a H2O2 dosage of 0.06 mol/L.     

Soil aquifer treatment of artificial wastewater under saturated conditions

A 2000 mm long saturated laboratory soil column was used to simulate soil aquifer treatment under saturated conditions to assess the removal of chemical and biochemical oxygen demand (COD and BOD), dissolved organic carbon (DOC), nitrogen and phosphate, using high strength artificial wastewater. The removal rates were determined under a combination of constant hydraulic loading rates (HLR) and variable COD concentrations as well as variable HLR under a constant COD. Within the range of COD concentrations considered (42 mg L⁻¹-135 mg L⁻¹) it was found that at fixed hydraulic loading rate, a decrease in the influent concentrations of dissolved organic carbon (DOC), biochemical oxygen demand (BOD), total nitrogen and phosphate improved their removal efficiencies. At the high COD concentrations applied residence times influenced the redox conditions in the soil column. Long residence times were detrimental to the removal process for COD, BOD and DOC as anoxic processes and sulphate reduction played an important role as electron acceptors. It was found that total COD mass loading within the range of 911 mg d⁻¹-1780 mg d⁻¹ applied as low COD wastewater infiltrated coupled with short residence times would provide better effluent quality than the same mass applied as a COD with higher concentration at long residence times. The opposite was true for organic nitrogen where relatively high concentrations coupled with long residence time gave better removal efficiency.     

Electro-oxidative abatement of low-salinity reverse osmosis membrane concentrates

The present study encompasses the application of electrolysis as novel treatment technique for the abatement of low-salinity concentrates generated from the filtrative treatment of water and wastewater. Four different materials have been tested as anode for a number of brine samples in a one-compartment electrolytic cell in galvanostatic mode. It was found that PbO(2) and SnO(2) anodes initiated electrochemical precipitation through an increase of the pH. Boron-doped diamond (BDD) and RuO(2) anodes successfully oxidised the pollutants in the brine and a linear removal of total ammonia nitrogen (TAN) and chemical oxygen demand (COD) was observed during the first phase of oxidation. Oxidation was predominantly achieved through indirect hypochlorite bulk oxidation; the higher oxidation rate and extent for the BDD anode was attributed to the higher selectivity and activity of the latter. Overall performance of the BDD electrode was higher than for RuO(2): higher rates for TAN (17.9 vs. 13.5mg/Ah) and COD (74.5 vs. 20.0mg/Ah) removal as well as higher overall current efficiencies (35.2% vs. 14.5%). Extensive colour removal was observed for both anodes (>90% decrease in absorbency at 455 nm).     

Treatment of dairy effluents by electrocoagulation using aluminium electrodes

This work sets out to examine the efficiency of an electrolytic treatment: electrocoagulation, applied to dairy effluents. The experiments were carried out using a soluble aluminium anode on artificial wastewater derived from solutions of milk powder. The flocks generated during this treatment were separated by filtration. The analysis of the filtrates showed that the chemical oxygen demand (COD) was reduced by up to 61% while the removal of phosphorus, nitrogen contents, and turbidity were 89, 81 and 100%, respectively. An analogous treatment applied to phosphate and lactose solutions revealed that lactose was not eliminated, a fact that could account for the rather poor lowering of the COD. Compared to the chemical coagulation treatment with aluminium sulphate, the efficiency of the electrocoagulation technique was almost identical. However the wastewaters treated by electrocoagulation differed by the fact that they exhibited a lower conductivity and a neutral pH value (by contrast to the acid nature of the solution treated by the chemical coagulation). This result (low conductivity, neutral pH) tends to show that it may be possible to recycle the treated water for some industrial uses. Moreover, the electrocoagulation process uses fewer reagents: the mass of the aluminium anode dissolved during the treatment is lower compared to the quantity of the aluminium salt used in chemical coagulation. These two observations clearly show that the electrocoagulation technique is more performing.     

催化铁内电解/生物膜法处理化工废水

化工废水因含有难降解和对生物有抑制性的物质而较难处理，为此以某工业区的化工废水为研究对象，考察了催化铁内电解／悬浮填料生物膜法的处理效果，并同现有工艺进行比较。结果表明，催化铁内电解可提高废水的可生化性，整个工艺对COD、BOD5、NH3-N、色度等的去除效果较现有工艺有明显改善。     

气浮—帕式氧化沟工艺处理再生纸废水

结合实际工程,介绍了气浮—帕式（Pasveer）氧化沟工艺在再生纸废水处理中的应用。该工艺对COD、BOD5和SS的总去除率分别达到94.5%、93.1%和98.8%,出水水质达到国家行业排放标准;运行成本低,通过纸浆回收和废水再生循环利用,企业的运行费用仅为11.4万元/a,占直接运行费用的16.9%。对培菌和驯化过程中遇到的问题进行了分析,并采取了相应的处理措施,可为同类型再生纸废水处理工程的调试运行提供参考。     

硝化棉生产废水处理工程的启动

采用混凝/两段活性污泥法组合工艺处理硝化棉生产废水,经过一个月左右的调试运行后,高负荷曝气池和CASS池对COD的去除率分别为65%和50%,对BOD5的平均去除率分别为64%和75%,出水水质达到<污水综合排放标准>(GB 8978-1996)的二级标准.     

水解/接触氧化/气浮工艺处理印染废水

以青岛市某印染废水处理工程为例,介绍了水解/接触氧化/气浮工艺处理印染废水的工艺设计参数、处理效果、工程投资和运行成本.该工程处理水量为300m3/d,进水COD、BOD5和色度分别为644mg/L、151 mg/L和688倍.运行结果表明,对COD、BOD5和色度的去除率分别为88%、92%和95%,相应的出水水质分别为78 mg/L、12 mg/L和31倍,达到<纺织染整工业水污染物排放标准>(GB 4287-1992)的一级排放标准,处理费用为1.01元/m3.该工艺具有运行费用低、处理效果好、操作管理方便等优点.