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R. A. Pandey S. Malhotra A. Tankhiwale S. Pande P. P. Pathe S. N. Kaul 《The International journal of environmental studies》2013,70(3):263-275
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. 相似文献
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M. H. El‐Awady 《The International journal of environmental studies》2013,70(3):345-356
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. 相似文献
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Treatment of dye wastewater containing acid orange II using a cell with three-phase three-dimensional electrode. 总被引:9,自引:0,他引:9
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)). 相似文献
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物化-生化-物化工艺处理精细化工废水的中试 总被引:1,自引:0,他引:1
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%。 相似文献
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Treatment of landfill leachate by combined aged-refuse bioreactor and electro-oxidation 总被引:8,自引:0,他引:8
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. 相似文献
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污泥调理废水的特性及其处理工艺 总被引:2,自引:1,他引:2
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。 相似文献
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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. 相似文献
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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. 相似文献
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DO对催化铁内电解预处理混合化工废水的影响 总被引:5,自引:0,他引:5
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。 相似文献
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Shanta Satyanarayan S. N. Kaul 《The International journal of environmental studies》2013,70(4):445-457
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. 相似文献
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Application of ferrous hydrogen peroxide for treatment of DSD-acid manufacturing process wastewater 总被引:6,自引:0,他引:6
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. 相似文献
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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. 相似文献
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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). 相似文献
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Serge Tchamango Charles P. Nanseu-Njiki Dimiter Hadjiev 《The Science of the total environment》2010,408(4):947-251
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. 相似文献
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水解/接触氧化/气浮工艺处理印染废水 总被引:2,自引:0,他引:2
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. 相似文献