Terms Of Biochemical Oxygen Demand Research Articles

The Spatiotemporal Eutrophication Status and Trends in the Paldang Reservoir, Republic of Korea

The Paldang Reservoir (PDR), the largest artificial lake in the Republic of Korea, has recently experienced increased chemical oxygen demand (COD), eutrophication, and algal blooms due to climate change. This study aimed to analyze the hydrological characteristics and water quality of the PDR and assess its spatial and seasonal eutrophication status changes using the Korean-type trophic quality index (TSIKO) and the seasonal Mann–Kendall Test (SMK). The PDR’s water was graded “good” in terms of biochemical oxygen demand (BOD) and “fair” for COD, total phosphorous (TP), and chlorophyll-a (Chl-a), according to Korean water quality standards. COD and Chl-a had a significant positive monotonic relationship. According to the TSIKO calculations, the trophic state of the PDR was mesotrophic, but eutrophic during the summer season. TSIKO (Chl-a) in summer tended to increase with a slope value of 0.22 mg/m3/year. The main causes of eutrophication in the PDR were proposed to be TP and phytoplankton overgrowth. Therefore, lake and reservoir functions need to be assessed, and solutions that can effectively protect them from excessive eutrophication to ensure sustainable clean water use and protect freshwater ecosystems need to be found.

Applicability of hybrid treatment to reduce the footprint of domestic and industrial wastewater of developing countries

Wastewater pollution is a serious concern, especially in developing countries such as Pakistan. The untreated domestic and industrial wastewater is typically discharged into sewers, natural drains, or water bodies. There is a dire need to evaluate the applicability of low-cost treatment technologies. Hybrid wastewater treatment (HWWT), comprising of chemically enhanced primary treatment (CEPT) and intermittent sand filter (ISF), was adopted to treat domestic, process and manufacturing, and food industry wastewaters. The wastewater pollution and contamination were assessed in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS). The removal efficiency (RE) performance of HWWT was compared with the CEPT system only. Considering the CEPT only, the RE of BOD was ≈70 % for domestic, >80 % for process and manufacturing, and ≈50 % for the food industry. For COD, the RE was high in process & manufacturing (RE ≈ 81 %), followed by food (RE ≈ 55 %) and domestic wastewater (RE ≈ 17 %). Furthermore, the CEPT provided >95 % TSS removal in all wastewater types. The HWWT increased TSS removal by ≈2 %, BOD removal by ≈13 %, and COD removal by ≈27 % compared to the CEPT system. Therefore, HWWT proved more efficient in treating both domestic and industrial wastewater. The HWWT reduced the greywater footprint (GWF) by 50–60 % when compared to the CEPT system. This study provided knowledge of the characteristics of domestic and industrial wastewater. Furthermore, provides a basis to assess the applicability and performance of various wastewater treatment systems under given settings.

Biomass Fuel Production through Fermentation of Lysinibacillus sp. LC 556247 in Various Ratios of Palm Oil Mill Effluent and Empty Fruit Bunch

Biomass wastes originating from palm oil milling activities can be characterized by their high biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), and oil and grease content. The utilization of oil palm wastes such as palm oil mill effluent (POME) and empty fruit bunch (EFB) has great potential for a sustainable energy biomass pellet as it reduces the reliance on conventional materials for energy production. A mixture of POME and EFB in various ratios ranging between 7:3, 8:2, 9:1, and 10:0 was fermented in the presence of Lysinibacillus sp. LC 556247 for 120 h at 37 ± 2 °C and 180 rpm with the aim of elucidating the biodegradation of complex organic material in terms of BOD, COD, TSS, total organic carbon, inorganic carbon, and total carbon content. After fermentation, the mixtures were oven dried at 105 °C overnight and then subjected to calorific energy value (CEV) determination. The highest CEV of 20.26 MJ/kg was achieved for a ratio of 10:0 (slightly higher than the control experiment with the value of 18.67 MJ/kg), with maximum removal efficiencies of COD (12.19%), BOD (11.72%), TSS (93.94%), and oil reduction of 17.43%. The addition of EFB did not positively increase the CEV.

Analysis of Pollutant Load Carrying Capacity of the River Tapi Using QUAL2Kw for Surat City

River Tapi is the prime water body for Surat city, Gujarat, India. On a long stretch of 22.39 km in Surat city (Kamrej to Causeway) of the Tapi river, there are many identified and non-identified discharge points available. Excessive discharge from these points restricts the efficiency of the self-purification process which ultimately degrades the river water quality. In this paper, an attempt has been made to estimate the pollutant load-carrying capacity at different segments of the river Tapi using the QUAL2Kw tool. The study has been undertaken with different scenarios: First, the QUAL2Kw model was trained with available river water quality and hydraulic data of the Tapi river in which the complete river segment was divided into 21 reaches. The model was calibrated and validated with the actual concentrations of the pollutants entering. In the second phase, all the point source, non-point source, and headwater characteristics were considered and the pollutant load-carrying capacity of the river in terms of BOD, ISS, and N-nitrate was found. In the third phase, all the sources of pollutants entering the river have been removed and only headwater characteristics were considered for the study. The results indicate that reach no. 21 (21.23ºN, 72.82ºE) has the maximum load-carrying capacity of Biochemical Oxygen Demand (BOD) up to 2057.7 kg/day, Inorganic Suspended Solids (ISS) up to 85633.8 kg/day, and Nitrate (NO3) up to 31688.8 kg/day. However, reach no. 4 has the minimum load carrying capacity of BOD up to 1088.1 kg/day, reach 8 carries a minimum of ISS 205341.6 kg/day and NO3 10215.57 kg/day.

Water Footprint of the Water Cycle of Gran Canaria and Tenerife (Canary Islands, Spain)

When it comes to exploiting natural resources, islands have limitations due to the quantity of these resources and the potential for harm to the ecosystem if exploitation is not done in a sustainable manner. This article presents a study of the water footprint of the different drinking water collection facilities and wastewater treatment facilities in the Canary Islands, in order to determine the blue, green, and grey water footprints in each case. The results show high percentages of drinking water losses, which raises the blue water footprint of the Canary Islands archipelago. The grey water footprint was studied in terms of Biochemical Oxygen Demand (BOD5). The green water footprint was not considered because it is a dimension of the water footprint mainly calculated for agricultural crops. Of the facilities studied, the wells for extraction of drinking water from the aquifer and the distribution network have the largest blue water footprint for the years under study (2019 and 2020). Only the wastewater treatment plants have a gray water footprint in this study, with values between 79,000 and 108,000 m3 per year. As a general conclusion, the most important factor in reducing the water footprint of the water cycle in the Canary Islands is optimization of the water resource, improving existing infrastructures to minimize losses, and implementing a greater circular economy that reuses water on a regular basis.

Surface Water Resources Assessment and Planning with the QUAL2KW Model: A Case Study of the Maroon and Jarahi Basin (Iran)

Mathematical models are useful for predicting the reactions of watercourses such as rivers due to the entry of contaminants. Some of these models are able to simulate the effects of present and future loadings as well as aid managers and officials in making decisions even if the data are sparse. In other words, river water quality preservation requires more investment in wastewater treatment and/or the installation of collection and control systems; it may also limit activity expansion in the river basin. The conservation of watersheds such as the Maroon and Jarahi basin, which provide water for drinking and for industrial and agricultural use, is socio-economically vital. Therefore, the first stage of managing the conservation of water resources is understanding their qualitative changes. For this purpose, the QUAL2KW mathematical model was utilized to simulate the river water quality in this example region. According to the reported values of water quality parameters and pollutants at monitoring stations, it was established that the river is at a critical condition in terms of biochemical oxygen demand (BOD) pollution due to the discharge of urban and industrial wastewater, as well as high electrical conductivity (EC) due to the drainage of agricultural lands. Based on the statistics calculated during the validation step, the authors concluded that the QUAL2KW water quality model is reliable in the simulation of qualitative parameters and the pollution data of the study area; namely the Maroon and Jarahi river basin located in the south-west of Iran. This will help stakeholders to better manage watersheds with sparse data. This region has been suffering from climate change which has led to droughts and the construction of several dams to retain water. For the second and third stations, the NASH (named after the mathematician John Forbes Nash) values were 0.96 and 0.92, respectively, indicating a relatively high model accuracy. The evaluation using the root mean square errors (RMSE) and NASH showed that the quality of water at the second station was better than the other two stations based on the coefficient of determination R2. Since there were three drains at station number 3, the wastewater entering the Maroon River had a higher level of contamination.

Quantity and quality characteristics of greywater from an Indian household.

A year-long study was conducted to assess the quantity and quality characteristics of greywater generated from different sources of an Indian household. The effect of source separation on greywater quantity and pollutant load contribution was also assessed. Composite samples were collected separately over a period of 24h from each of the greywater source, namely hand basin, bathroom, kitchen, and laundry, and were analysed for different physico-chemical and microbiological parameters. The mean greywater generation averaged 62 L per person per day. Quantitatively, kitchen and bathroom greywater contributed 37 and 31% of the total greywater volume, respectively, while hand basin and laundry greywater accounted for 11 and 21% of the total greywater generation. Kitchen greywater contributed about 60% of the organic load in terms of biochemical oxygen demand (BOD) and chemical oxygen demand (COD), while laundry greywater was the major contributor of heavy metals and PO4-P loads. Hand basin and bathroom greywaters were the major sources of total coliforms. The analysis shows that separation of kitchen and laundry greywater is beneficial as it reduces pollutant load considerably.

Performance evaluation of a solar still for industrial wastewater treatment

Wastewater from industries are generally highly polluted but, unfortunately in some developing countries, are discharged into the environment without proper treatment. Wastewater treatment is a process, where contaminants are removed from wastewater in order to make it suitable for discharge or reuse. In this study, a single sloped basin solar still was employed for the treatment of wastewater obtained from a paint industry. The efficiency of solar distillation in the treatment of the wastewater over a period of 8 consecutive days was examined. 20 Litres of wastewater was placed inside the solar still under outdoor conditions. Approximately 5 Litres of distillate water was obtained at the end of the experiment. The quality of the untreated wastewater and its distillate were determined. In addition, solar radiation and volume of distillate obtained for each day was measured. The distillate produced was 80% less in terms of Total Dissolved Solid (TDS), 99.3% less in terms of Total Suspended Solids (TSS), 96% less in terms of turbidity, 64.6% less in terms of Biochemical Oxygen Demand (BOD), 87.5% less in term of Chemical Oxygen Demand (COD), completely removed of phosphate, 83.8% less in terms of Calcium Carbonate, 68.6% less in terms of Nitrate, 93.7% less in terms of Chloride and 40% less in terms of Total Coliform Count. The physio-chemical characteristics of the treated wastewater fell within drinking water standards set by World Health Organization (WHO) but the bacteriological quality of the distillate did not meet WHO recommended standard for potable water .

MODELLING THE ENVIRONMENTAL KUZNETS CURVE OF WATER POLLUTION IMPACT ON ECONOMIC GROWTH IN DEVELOPING COUNTRY

This study attempts to examine the water pollution-economic growth relationship by using the environmental Kuznets curve analysis for the situation in Malaysia. This study estimates a simultaneous equation that is related to the level of pollution, the Gross Domestic Product per capita, and other covariates. Water pollution is measured in terms of Biochemical oxygen demand (BOD), Cadmium (CD) and Arsenic (AS). The per capita Gross Domestic Product was measured quarterly for the period 1996 to 2018. The study output supports the Environmental Kuznets Curve (EKC) hypothesis for all measures of water pollutants examined here. The income equation revealed the negative significant impact of pollution, BOD and physical capital's favorable influence on income. From these expected outcomes it is clear that Malaysia's relevant policies should aim primarily to overcome the pollution problems but should not neglect economic growth sustainability. This would include the implementation of policies that do not disregard the needs of economic growth and development; execute strategies that will contribute to a decrease in greenhouse gas emissions; improve public awareness on environmental issues in Malaysia; give additional incentives to industries that comply with policy requirements; implement advanced and tertiary pollution control measures to decrease pollution; implementation of financial incentives to encourage invest in appropriate technology especially sewerage systems; and development of a solid monitoring and inventory system to be implemented by the relevant government authorities.Keywords: Environmental Kuznets Curve, pollution, Gross Domestic ProductJEL Classifications: O11, Q53, Q54, Q56DOI: https://doi.org/10.32479/ijeep.11571

Pilot-Scale Investigation of the Integrated Anaerobic–Aerobic Bioreactor (IAAB) Treating Palm Oil Mill Effluent (POME): Startup and Performance Evaluation

The treatment of palm oil mill effluent (POME) has always been the topic of research in Malaysia due to the high concentration of total suspended solid (TSS) and oil and grease (O&G) ranges from 28 846 to 30 920 mg/L and 5614 to 8812 mg/L, respectively. Additionally, the release of methane gas during the treatment of POME in all of the palm oil mills has been the major contributor to greenhouse gas (GHG) effect. The main aim of this work is to evaluate the performance of the pilot-plant integrated anaerobic–aerobic bioreactor (IAAB) for POME treatment at two different phases: (a) startup and (b) long-term performance evaluation from an organic loading rate (OLR) of 10.5 to 32.5 gCOD/(L·day). Startup of the pilot-plant IAAB was successfully accomplished in 24 days with overall removal efficiencies in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solid (TSS) of at least 90% at the OLR of 8.0 gCOD/(L·day). The pilot-plant IAAB achieved high BOD, COD, and TSS removal efficiencies of more than 99% for OLR up to 30.0 gCOD/(L·day) with methane yield ranges from 0.0406 LCH₄/gCODᵣₑₘₒᵥₑd to 0.1312 LCH₄/gCODᵣₑₘₒᵥₑd. The effluent quality remained stable with BOD of 16–107 mg/L with a high percent of compliance with the discharge limit of 100 mg/L. The coupling of the Grau second-order and Stover–Kincannon models (anaerobic system) with the Stover–Kincannon model (aerobic system) will completely define the pilot-plant IAAB system. This pilot-plant research will provide valuable data and experiences required to design and commission a full-scale IAAB.

Reliability Analysis of Activated Sludge Process by Means of Biokinetic Modelling and Simulation Results

Analysis of wastewater treatment plant reliability is a difficult process, therefore it is often limited to selected aspects, e.g., mechanical reliability of equipment or technological availability of the process. The research presents a method of combining the above mentioned aspects in order to determine the complex operational availability index (CAVO). A hypothetical technological system with activated sludge (AS) in a typical layout (denitrification-nitrification) was selected for the studies. A number of operational scenarios have been developed, taking into account the possible mechanical failures of system components. Computer simulations with the use of Activated Sludge Model No.1 (ASM1), performed for selected scenarios allowed the determination of a complex operational availability of the system. Obtained results confirm high reliability of AS system in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) removal (CAVO > 0.96) and indicate the necessity of further research in order to determine representative value of reliability of total nitrogen removal (from the study, CAVO-Ntot < 0.4) and to evaluate other technological solutions in terms of their complex reliability.

Intensification of supercritical water oxidation (ScWO) process for landfill leachate treatment through ion exchange with zeolite

Over the past few years, supercritical water oxidation (ScWO) has shown great potential for application to landfill leachate treatment, providing substantial organic matter degradation in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC). However, the conversion of ammonia, which is present at high concentrations in leachates, is the rate-limiting step during ScWO and usually requires large amounts of oxidants, the addition of catalysts, or severe operating conditions. Aiming at proposing a treatment system that effectively removes both organic matter and ammonia from leachate, this paper evaluates the intensification of the ScWO process through ion exchange with zeolite. Thus, ScWO was operated under a pressure of 23 MPa at 600 and 700 °C, without the addition of oxidants. The zeolite (clinoptilolite) was used without any modification inside a glass column. The ScWO (600 °C)/zeolite system removed 90% ammoniacal nitrogen (NH3-N), 100% nitrite (NO2-N), 98% nitrate (NO3-N), color, and turbidity, 81% TOC, and 74% COD, suggesting that this system is a promising alternative for leachate treatment. However, the final NH3-N and COD values were slightly above the limits (20 and 200 mg L−1, respectively) stipulated by the Brazilian environmental legislation. These results suggest that further improvements are still required for the application of the intensified ScWO to be feasible. Notably, ammonium-saturated clinoptilolite is amenable for regeneration or can be applied to soil as a slow-release fertilizer.

Energy consumption in a baffled membrane bioreactor (B-MBR): estimation based on long-term continuous operation.

We investigated the operating conditions of a baffled membrane bioreactor (B-MBR) under which long-term stable operation can be achieved through the continuous operation of a pilot-scale B-MBR. Under appropriate operating conditions, the B-MBR was capable of achieving excellent treated water quality in terms of biochemical oxygen demand and concentration of total nitrogen. Excellent removal of total phosphorus was also achieved. In addition, the degree of membrane fouling was acceptable, indicating that stable continuous operation of a B-MBR is possible under the operating conditions adopted in the present study. Estimation of the specific energy consumption in hypothetical full-scale B-MBRs operated under the conditions recommended by the findings was also performed in this study. The results suggest that energy consumption in full-scale B-MBRs would be in the range of 0.20-0.22 kWh/m3. These results strongly suggest that energy consumption in MBR operation can be significantly reduced by applying the concept of a B-MBR.

From start-up to heavy clogging: performance evaluation of horizontal subsurface flow constructed wetlands during 10 years of operation.

The objective of this work is to evaluate the performance of two horizontal subsurface flow constructed wetlands, one planted with cattail (Typha latifolia) and the other unplanted. The distinguishing feature of this study is that it spans a period of more than 10 years, from start-up to a final operation with heavy clogging and full overland flow. For most of the time, starting in June 2007, the system received municipal sewage previously treated in an upflow anaerobic sludge blanket (UASB) reactor, but for one specific period, the pre-treatment was comprised of the UASB reactor and a trickling filter in series. The two constructed wetlands worked in parallel, each serving approximately 50 p.e. and continuously receiving a flow around 7.5 m3 d-1 for most of the time. The beds had a length of 25 m and a width of 3 m and were filled with blast furnace slag. For most of this long operational period, performance was very good in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS), with median effluent concentrations of 19/18, 46/52 and 12/8, respectively (planted/unplanted units). Clogging was noticeable in the first years of operation, soon leading to overland flow. However, treatment performance was still successful, even when the system's hydraulics were strongly deteriorated. The type of pre-treatment and the applied loads influenced more the performance of the units than the period of operation itself, evidencing the robustness of the system.

Evaluation of surface water treated with lotus plant; Nelumbo nucifera

The potential of Nelumbo nucifera in treating contaminated surface water was investigated in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, and nitrate reduction. Batch type lab-scale container cultivated with N. nucifera was exposed to the contaminated surface water for 30 days. Nitrate (NO3−) adsorption and pH level were monitored continuously to identify the plant survival and to avoid any additional contaminants into the samples such as plant decay. For comparison, water lily, Nymphaea, was prepared using the same experimental setup. After 30 days of phytoremediation, the BOD and COD values of the treated water using N. nucifera was significantly reduced to 97.1% and 55%, respectively, due to the unique gas transport mechanism that thermodynamically drive O2 gas from leaves at the water surface to the buried rhizomes located in the anoxic sediments. When treated with Nymphaea, the BOD value in water decreased by 64.5% and the COD value increased by 50.5%. The results indicate that N. nucifera was able to remove the organic contaminants from the surface water by supplying adequate amount of 0.2–2.1 mL/min O2 gas to increase the microbial activities from the control condition.

Development and evaluation of a constructed pilot-scale horizontal subsurface flow wetland treating piggery wastewater

Abstract This paper reports on the development and evaluation of a pilot horizontal subsurface flow constructed wetland (HSSFCW) for removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total nitrogen (TN) and total phosphorus (TP) from primary piggery wastewater. Two locally available plants, Pennisetum clandestinum and Pennisetum purpureum, were planted in two of three cells while the remaining unplanted cell served as the control. Monitoring of the wetland influent and effluent wastewater was carried out every two weeks for 7 months. The study revealed successful treatment of the wastewater by the wetland in terms of BOD, COD, TDS, TN and TP effluent compliance with Nigerian discharge standards. Average removal efficiencies were 66.53, 64.95, and 60.27% for BOD5; 44.85, 41.61 and 36.37% for COD; 63.61, 58.27 and 52.88% for TDS; 62.49, 58.89 and 50.14% for TN and 48.53, 44.91 and 41.27% for TP for the three wetland cells including the control respectively. Planted cells achieved the highest removal efficiency with no significant difference in pollutant removal between the two planted cells indicating their suitability for use as wetland plants. Effluent concentrations were within FEPA discharge limits except TP. The performance of the constructed wetland suggests that HSSFCW could be a suitable alternative technology for on-farm treatment of piggery wastewater in Nigeria. The study has provided a starting point for the use of HSSFCW and gives insight of the potential application of this technology for on- farm pollution control in Nigeria.

Performance of the first stage of the French system of vertical flow constructed wetlands with only two units in parallel: influence of pulse time and instantaneous hydraulic loading rate.

The technology of vertical flow constructed wetlands - French system for treating raw wastewater depends on several hydraulic factors, one of them being the duration of the pulse feeding and the resulting instantaneous hydraulic loading rate. This paper analyses two scenarios in the same system, the first of a faster feeding by pump and the second of a slower feeding by siphon, both with instantaneous hydraulic loading rate values lower than the literature recommendations. The system treated raw wastewater from a population equivalent of 100 p.e. in Brazil, and was comprised by only the first stage and two units in parallel. The shorter duration of feeding time and higher instantaneous hydraulic loading rate were associated with significantly higher chemical oxygen demand and total Kjeldahl nitrogen removal efficiencies, but with no significant differences in terms of biochemical oxygen demand (BOD) and suspended solids (SS). Oxygen concentrations and redox potential in the effluent were evaluated, together with the effluent flow rate profiles. The removal efficiencies were associated with the accumulation of solids in the upper part of the filter resulting from seven years of operation and to the operating hydraulic conditions, which are important elements in the performance of the system.

Common effluent treatment plant (CETP): Reliability analysis and performance evaluation

Common effluent treatment plants (CETPs) have been installed and are in operation at numerous industrial clusters throughout India. They serve to reduce effluent treatment cost, provide better collective treatment, and reduce land cost for small-scale industrial facilities that cannot afford individual treatment plants. Optimum working conditions for treatment of effluent to be at par with discharge standards is a major mandate for any CETP. In this study, the reliability and removal efficiencies (REs) of a CETP in the industrial area of Maharashtra State in India were examined. An established methodology was adopted to determine the effectiveness of the CETP in terms of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and oil and grease (O&G) concentrations. The CETP's compliance with respect to design standards and its operation were studied in detail. This paper highlights the results of RE and the coefficient of determination (R2) values obtained from the CETP data, estimates the pollutants removed at the highest and lowest rates over a period of time, and highlights the reasons for problem areas along with remedial measures. It was observed that, except O&G, all the parameters (BOD, COD, and TSS) showed fluctuations in removal efficiencies and their reliabilities. This situation can be improved by releasing effluent containing hydraulic and organic loading to the CETP as per standards and optimizing treatment processes, especially primary clari-flocculators and aeration tanks, both of which are important units of any CETP.

Degradation characteristics of two typical N-heterocycles in ozone process: Efficacy, kinetics, pathways, toxicity and its application to real biologically pretreated coal gasification wastewater

Ozonation of pyridine and indole was investigated both in aqueous solution and biologically pretreated coal gasification wastewater (BPCGW). Experimental results showed that the removal of indole was hardly affected by pH value. Direct reaction rate constant of ozone with pyridine increased from 0.18 M−1 s−1 (protonated pyridine) to 3.03 M−1 s−1 (molecular pyridine), and that with molecular indole was 8.6 × 105 M−1 s−1. Seven and five transformation intermediates were observed for pyridine and indole, respectively. Ozonation pathways were proposed as hydroxylation, opening and cleavage of the aromatic ring. It was found that ammonia nitrogen (NH3N) increased by 3.3 mg L−1 in ozone process, suggesting the broken of the CN bonds of pyridine, indole and other N-heterocyclic compounds. In terms of biochemical oxygen demand to chemical oxygen demand (BOD5/COD), toxicity and resazurin dehydrogenase activity (DHA), the biodegradability was improved after ozone treatment, indicating the possibility of ozone combined with biosystem for the treatment of BPCGW. The results of gas chromatograph and mass spectrometry (GC-MS) indicated that primary products during first 10 min might lead to the obstinate toxicity, which was further proved by US Environmental Protection Agency (US-EPA) test. This study would assist in obtaining a better understanding of the application of ozonation pretreatment in BPCGW.

REMOVAL OF ORGANIC MATERIALS FROM TANNERY WASTEWATER CONTAINING AMMONIA FOR REUSE USING ELECTRO-OXIDATION

Leather manufacturing process generates significant volume of wastewater. Deliming is one of the unit processes, in which about 4.5 L of wastewater is generated per one Kg of pelt. Reuse of wastewater from the unit processes, where significant volume of wastewater is generated is much important to address pollution mineralization and water conservation. Presence of significant level of organic pollutants is the primary factor that deters reuse of waste streams. In this paper, the Electro-Oxidation (EO) of deliming waste streams was carried out. It was found that EO was found to be effective in removing organic pollutants. The effect of process parameters such as pH, current density and duration on removal of organic pollutants was studied. Treatment efficiency was evaluated in terms of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Kjehldahl Nitrogen (TKN). Results indicate that the pollution reduction was better during electro-oxidation at current density 0.015 A/cm2 and pH 8.0 for 90 min. The kinetics of pollutants removed by electro-oxidation was found to obey pseudo-first order with an R2 value of 0.9963. The reduction in BOD, COD, TKN, chloride and TDS was 87.37%; 81.95%; 82.67%; 5.75% and 6.56% respectively. The possibility of reuse of treated wastewater was also assessed. Treated deliming wastewater was reused for soaking did not show any impairment in quality of pelt and leather. It is concluded that EO was very effective in treating the deliming waste streams rendering the same suitable for reusing for soaking.