Maximum BOD Research Articles

Evaluation of Textile Wastewater Treatment via ETP in Bangladesh

Textile liquid waste possesses a substantial biochemical oxygen demand and total suspended solids, hence posing a significant risk of contaminating adjacent water bodies if not appropriately managed. The primary aim of the study is to examine the pH condition of water from the inlet and outlet of the ETP (Effluent Treatment Plant) in two specific regions. Two natural groups in Bangladesh include Tonga Bari, Ashulia, Savar, and Dhaka. Another natural group is “The Emakulet Textile Ltd,” located in Purboponchash, Dhamrai, Dhaka. Raw liquid waste was collected from two textile industry and applied some test procedure in the laboratory by varying different design parameters such as pH, DO (Dissolved Oxygen), BOD5 (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), TDS (Total Dissolved Solids), TSS (Total Suspended Solids), Turbidity, Fe2+, pH was tested by a pH meter at 25℃ temperature. DO also tested by a sensor machine (FLEXA) which shows the values of dissolved oxygen in ETP waste water. To collect BOD5 value needed 5 days minimum also used MnSO4, H2SO4 to get BOD5 value from the incubator. Turbidity was tested by Digital Turbidity meter. The results showeds that the pH condition of water from the inlet is satisfied but others parameter from the inlet sample is not in the range of ECR, 1997. The selected two areas of ETP given the maximum and minimum parameters found, DO in the inlet of two selected areas was (0) from the inlet. The maximum BOD5 value was 126 mg/l from the inlet which crosses the limit of ECR-1997 but after treatment it was 47 mg/l. The detailed experimental results demonstrated that, ETP water is fully treated and all parameter acceptable according to ECR, 1997. In this analysis, it is anticipated that the implementation of a cost-effective treatment approach could serve as an incentive for industrial proprietors to engage in effluent treatment, so contributing to the enhancement of water body quality in Bangladesh.

Evaluating Pilot-Scale Floating Wetland for Municipal Wastewater Treatment Using Canna indica and Phragmites australis as Plant Species

Floating treatment wetlands (FTWs), also called constructed floating wetlands or floating islands, are a recent innovation in constructed wetlands (CWs) inspired by natural wetlands. In FTWs, emergent plants grown hydroponically on buoyant mats are used for wastewater treatment, which makes them far more economical than other CWs. The objective of this study was to evaluate the performance of FTWs for the treatment of municipal wastewater from an urban drain using native plant species Canna indica and Phragmites australis. A pilot-scale experiment was carried out using four FTW treatment cells with different plant coverages for pollutant removal: C1 (Canna indica, 100% coverage), C2 (Phragmites australis, 100% coverage), C3 (Phragmites australis, 50% coverage), and C4 (control). Overall, treatment cells with Canna indica and Phragmites australis showed reductions in BOD5, COD, EC, TDS, NO3−, and PO43− compared with the control. Maximum BOD5 and COD removal was 53% and 50%, respectively, at 50% coverage of Phragmites australis (C3). The maximum reduction in NO3− (61%) was achieved using Canna indica at 100% coverage (C1). Conversely, moderate removal of PO43− (27%) was obtained in the control (C4) with a visibly high amount of algal growth, indicating the influence of algae on pollutant removal. This study highlights the significance of Phragmites australis for organic matter removal and Canna indica for nutrient removal, mainly NO3− from municipal wastewater. Furthermore, this study suggests that FTWs perform well for BOD5 and COD removal at 50% plant coverage (Phragmites australis) and NO3− removal at 100% coverage (Canna indica).

Determining heavy metal concentrations and physicochemical properties in wastewater

Wastewaters are frequently harmful to both the environment and human health since they are both directly and indirectly released into surface waters. The aim of this study was to determine physicochemical properties and to assess the levels of heavy metals in wastewater. Wastewater samples were collected from Koka and Mojo from the Oromia region, Ethiopia. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) was used to determine the concentration of these heavy metals. The conductivity of wastewater obtained from the Mojo and Koka sites ranged from 1141.33 to 1498.32µS/cm and 1066.33 to 1243.72µS/cm, respectively. The maximum and minimum BOD effluent from Mojo and Koka sites were 1044.78mg/L and 794.73mg/L, and 883.00mg/L and 772.67mg/L, respectively. The COD value was found to range between 1466.08mg/L and 1615.38mg/L in the Mojo area and 1352.65mg/L to 1530.83mg/L in the Koka area, respectively. High BOD levels are a sign of contamination and could indicate a lack of oxygen for living things. In every one of the sample sites, it exceeds the recommended level. High COD levels suggest hazardous conditions and the presence of organic compounds that are resistant to biological processes. The maximum TDS of the effluents, which is more than the recommended limit, were found to be 2417.08mg/L and 2317.06mg/L in Mojo and Koka areas, respectively. Overall concentrations of heavy metals (As, Pb, B, Zn, Cd Hg, Cu, Ni, Co, Fe, Mn and Cr) in mg/L were found to be in the permissible range except for mercury (Hg). The wastewater had heavy metal Hg that was higher than the limits advised by the WHO and US EPA. The studies’ findings imply that the effluents are harmful by nature and need considerable treatment before being released into the ecosystem on land.

Photocatalytic, electrochemical, antibacterial and antioxidant behaviour of carbon-sulphur Co-doped zirconium (IV) oxide nanocomposite

In this work, carbon-sulphur co-doped ZrO2 nanocomposites were synthesised using the aqueous leaves extract of Plumeria acuminate, zirconia salt precursor, polyvinylpyrrolidone and sodium hydrosulphide. The structural, elemental and morphological properties of the synthesized nanomaterials were examined by different analytical techniques UV-visible spectrophotometer, HRSEM-EDS, HRTEM-SAED, XRD and BET. HRSEM analysis of C-S-ZrO2 revealed the presence of spherical and irregular hexagonal shapes. The XRD pattern demonstrated formation of crystalline tetragonal and a mixture of tetragonal and orthorhombic phases for ZrO2 and C-S-ZrO2 composite with an average size of 20.03 nm and 12.40 nm respectively. The band gap values of 5.2 eV and 3.4 eV were obtained for ZrO2 and C-S-ZrO2 respectively. The adsorptive and photocatalytic properties of ZrO2 based nanomaterials for the removal of azo dye in local dyeing wastewater were investigated. The electrochemical activities of the nanomaterials were assessed using cyclic voltammetry, while Agar well diffusion, DPPH and ABTS methods were followed for the determination of antibacterial and antioxidant activities of ZrO2 and C-S-ZrO2. The maximum COD, BOD, TOC, SO42-, CO32, Cl− and NO3−removal efficiencies of 77.3%, 87.6%, 97.7% 63.9%, 84.4%, 70.3% and 83.3 % at 120 min were obtained using C-S-ZrO2 composite due to its higher surface area (80.165 m2/g) and lower band gap (3.4 eV) compared with ZrO2 (10.682 m2/g). Carbon-sulphur co-doped ZrO2 composite exhibited moderate antioxidant activity and increased peak current than other ZrO2 based nanomaterials due to its highest surface area than ZrO2 alone. The order of antibacterial activity of the nanomaterials against the Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli is ZrO2-C-S (15.40±1.11 mm, 25.10±1.80 mm, 20.03±2.50 mm) > C-ZrO2 (9.45±2.65 mm, 11.18±0.33 mm, 15.45±3.25 mm) > S-ZrO2 (7.52±1.55 mm, 12.45±0.11 mm, nil) >ZrO2 (6.33±0.90 mm, 4.25±0.52 mm, nil). The experimental data best described by pseudo-first-order, followed by parabolic-diffusion and modified Freundlich models. The results showed that the synthesized C-S-ZrO2 nanocomposite is highly efficient with excellent regenerative potential even after five cycles.

Trends of surface water quality of the Krishna River, India during the urbanization process

AbstractIn the present study, Amaravati, the proposed city of India is considered to assess the impacts of urbanization on water quality of the Krishna River in the vicinity. Long‐term surface water quality data of various parameters of Krishna River are obtained from Central Water Commission (CWC). Trends of various parameters are analyzed using a modified version of Mann‐Kendall (M‐K) test; bootstrapped M‐K trend test with optional bias corrected pre‐whitening and R programming are used affecting water quality prior to and at the commencement of urbanization. During the onset of urbanization, minimum BOD is decreased from 0.49 to 0.2 mg/L, while the maximum BOD is increased by 67.7%. Dissolved oxygen's (DO) minimum value is decreased by 29.33% while maximum DO value is decreased by 4.47% at the beginning of urbanization. During the process of urbanization, total coliform's minimum count is increased to 330 from 2 MPN/100 ml while the maximum count of total coliforms is increased to 16,000 from 2400 MPN/100 ml. Faecal coilform's minimum count is increased from 2 to 80 MPN/100 ml while maximum count is increased to 16,000 from 800 MPN/100 ml during urbanization. It is found that due to urbanization, pH, DO values exceed the allowable limit.

Evaluation of Natural and Chemical Coagulants Performance in Treatment of Municipal Wastewater of Behshahr City

Municipal wastewater is one of the largest volumes of wastewater which contains various organic compounds from proteins and fats to carbohydrates and nucleic acids. Municipal wastewater of Behshahr city (Mazandaran, Iran) was evaluated using aluminum sulfate and iron chloride as chemical coagulants and pectin and sodium alginate as natural ones. Biological oxygen demand was investigated at different temperatures and coagulant concentrations. The fraction of full factorial statistical method and Qualitek-4 software were applied for designing experiments and analyzing the results to determine the optimal conditions for achieving the highest reduction in wastewater organic load and biological oxygen demand. In the case of biological oxygen demand, the optimal condition was achieved at 25°C, using 1, 0.02, 1.5 and 1 g/L of aluminum sulfate, sodium alginate, iron chloride and pectin, respectively. Under the optimal condition, the percentage of biological oxygen demand reduction was equal to 34.5%. Maximum BOD removal of 40.9% was obtained at 25°C using aluminum sulfate, sodium alginate, iron chloride, and pectin at concentrations of 0.6, 0.02, 1.5, and 6 g/L, respectively. The contribution of aluminum sulfate, sodium alginate, iron chloride, and pectin concentration in biological oxygen demand removal of the studied wastewater was 3.8%, 22.4%, 16.3%, and 14.4%, respectively. Coagulation temperature and aluminum sulfate concentration with approximately 42.7% and 3.8% contribution values were determined as the most and the least effective factors in biological oxygen demand reduction.

Modelling of pollutants removal in Integrated Vermifilter (IVmF) using response surface methodology

Mathematical models of vermifiltration are not only valuable tools for design and optimization of the processes, but could be also employed for output prediction and system control. In this work, Response Surface Methodology (RSM) technology has been applied to evaluate both individual effect of different parameters as well as their interaction effect simultaneously on system performance. A two stage integrated Vermifilter (IVmF) consisting of Eisenia fetida and Canna indica was developed with vertical flow (VF) system as first stage unit and horizontal flow (HF) system as second stage unit. Box-Behnken Design (BBD) model was implemented for optimization of BOD removal in treatment process. HLR, biodegradable organic strength and VF unit active layer depth were considered as the major affecting factors on performance of the filter. Subsurface flow mode was selected in operation as earthworm may not survive for long time in submerged condition. According to developed model, the optimal conditions (numerical optimization technique) for achieving maximum BOD removal for the designed system were at influent concentration of 1701.00 ​mg/L, HLR of 0.39 ​m 3 /m 2 /d 1 and active layer depth of 34.40 ​cm. Experimental BOD removal of 86.45% was obtained against predicted value of 87.08% at optimum condition. Above data can be used for the implementation of vermifiltration system in field scale with minimal deviation. Growth rate of Eisenia fetida was tracked which shows 20.29%–27.82% increase in earthworm population. Similarly, Canna indica number increased from initial number of 3 to final number 13–18 in different experimental conditions. • A RSM based BBD model was utilized to optimize the biodegradable organics removal. • Macrophyte Canna indica and earthworm Eisenia fetida worked symbiotically to remove pollutants. • 87.08% BOD was removed in optimized condition. • Earthworm number increased 20.29–27.82% and number of Canna indica increased 4–6 times.

An investigation of monthly variation of different physicochemical parameters of dairy industry effluent

ABSTRACT Industrialization no doubt enhances the productivity, but also results in release of toxic substances into the environment, creating health hazards. Dairy industry ranks as one of the most polluted industries in India. For cleaning and washing procedures, dairy industry plants generate large volumes of waste water, which is 2.5 times milk volume processed. Dairy effluent contains high load of organic matter. This study was aimed at assessing the monthly variation of different physicochemical parameters of effluent like pH, Temperature, Turbidity, Electrical Conductivity, Chemical Oxygen Demand, Biological Oxygen Demand, Total Solids, Total Dissolved Solids, Total Suspended Solids, Chlorides, Sulfates, Oil & Grease, Proteins, Lipids etc. The pH was recorded for values between 7.3 to 8.2 whereas overall mean value was 7.7±0.37 (S.D.) in all month’s data collected which is ambient for the microbial population to grow. Maximum temperature was reported in May (33°C) while lowest value was reported in December (24°C). Mean value of turbidity was recorded as 762±207 NTU. Maximum EC value was reported in January (650 µS/cm) while minimum value was reported in May (354 µS/cm). BOD values reported were between 268 to 950 mg/lit. Maximum BOD values were reported in August and October while minimum was reported in the month of July. Mean value was recorded at 597±208 mg/lit. COD mean value was recorded at 2184±417 mg/lit. Maximum COD values were observed during August and September while minimum during February to April. TDS was noted down to be between 960 to 1362 mg/lit. TS mean value was around 1412 ± 108 mg/lit. TSS was found to be between 245 to 365 mg/lit during the year 2013-14. Maximum TSS value was reported in November and September while minimum in March. Maximum chloride value was reported in March (562 mg/lit) while minimum in September (256 mg/lit). Mean value of sulfate was 247 ± 98 mg/lit. Mean value for oil and grease was recorded as 163 ± 44 mg/lit. Maximum protein value was reported in November (260 mg/lit) while minimum in the months of May and September (154 mg/lit). Mean value of lipid was recorded to be 600±63 mg/lit indicating obvious variation during batches. The present study has been aimed at procuring dairy industry effluents & characterizing them for different parameters in order to check the fluctuation in organic loads.

Effect of design and operational parameters on nutrients and heavy metal removal in pilot floating treatment wetlands with Eichhornia Crassipes treating polluted lake water.

Though having an economic and ecological impact on Marriott Lake management in Egypt, water hyacinth (Eichhornia crassipes) is an aquatic floating macrophyte with a known phytoremediation potential. In order to assess its remediation potential, pilot floating treatment wetlands (FTWs) with E. crassipes were built in duplicates to evaluate the removal of nutrients and heavy metals from the polluted lake water. The experimental design included units with different water depths (15, 25, and 35 cm; D15, D25, and D35, respectively) and plant coverage (90, 70, 50, and 0%; P90, P70, P50, and P0, respectively). The pilot FTWs were monitored over a 7-day operation cycle to identify the optimum combination of design (plant coverage, water depth) and operation (hydraulic retention time; HRT) parameters needed for maximum BOD5, TN, NH4-N, and TP removal. NH4-N removal reached 97.4% in the D25P50 unit after 3 days, BOD5 75% in the D15P90 after 3 days, TN 82% in the D25P70 after 4 days, and TP 84.2% in the D35P70 after 4 days. The open-water evaporation rate was higher than the evapotranspiration rate in the planted units, probably due to the warm climate of the study area. Metals were also sufficiently removed through bioaccumulation in plant tissues in the order of Fe > Pb > Cu > Ni (62.5%, 88.9%, 81.7%, and 80.4% for D25P50, D25P70, D25P50, and D25P90, respectively), while most of the assimilated metal mass was translocated to the plant roots. The biochemical composition of the plant tissue was significantly different between the shoot and root parts. Overall, the FTW with 70% E. crassipes coverage, 25-cm water depth, and an HRT of 3-5 days was identified as the optimum design for effective remediation of the polluted Marriott Lake in Egypt.

An investigation of monthly variation of different physicochemical parameters of dairy industry effluent

ABSTRACT Industrialization no doubt enhances the productivity, but also results in release of toxic substances into the environment, creating health hazards. Dairy industry ranks as one of the most polluted industries in India. For cleaning and washing procedures, dairy industry plants generate large volumes of waste water, which is 2.5 times milk volume processed. Dairy effluent contains high load of organic matter. This study was aimed at assessing the monthly variation of different physicochemical parameters of effluent like pH, Temperature, Turbidity, Electrical Conductivity, Chemical Oxygen Demand, Biological Oxygen Demand, Total Solids, Total Dissolved Solids, Total Suspended Solids, Chlorides, Sulfates, Oil & Grease, Proteins, Lipids etc. The pH was recorded for values between 7.3 to 8.2 whereas overall mean value was 7.7±0.37 (S.D.) in all month’s data collected which is ambient for the microbial population to grow. Maximum temperature was reported in May (33°C) while lowest value was reported in December (24°C). Mean value of turbidity was recorded as 762±207 NTU. Maximum EC value was reported in January (650 µS/cm) while minimum value was reported in May (354 µS/cm). BOD values reported were between 268 to 950 mg/lit. Maximum BOD values were reported in August and October while minimum was reported in the month of July. Mean value was recorded at 597±208 mg/lit. COD mean value was recorded at 2184±417 mg/lit. Maximum COD values were observed during August and September while minimum during February to April. TDS was noted down to be between 960 to 1362 mg/lit. TS mean value was around 1412 ± 108 mg/lit. TSS was found to be between 245 to 365 mg/lit during the year 2013-14. Maximum TSS value was reported in November and September while minimum in March. Maximum chloride value was reported in March (562 mg/lit) while minimum in September (256 mg/lit). Mean value of sulfate was 247 ± 98 mg/lit. Mean value for oil and grease was recorded as 163 ± 44 mg/lit. Maximum protein value was reported in November (260 mg/lit) while minimum in the months of May and September (154 mg/lit). Mean value of lipid was recorded to be 600±63 mg/lit indicating obvious variation during batches. The present study has been aimed at procuring dairy industry effluents & characterizing them for different parameters in order to check the fluctuation in organic loads.

SUGARCANE BAGASSE ADSORPTION EVALUATION AND APPLICATION ON BOD AND COD REMOVAL FROM TEXTILE WASTEWATER TREATMENT

Without properly treated Wastewater released from textile industry contains organic and inorganic pollutants and causes environmental problems. Textile wastewater contains: BOD, COD, toxic heavy metals, organic and inorganic particle matter, colour and etc. The multi-component pollutions needs latest technology treatment. Butch adsorption process is one of the best selective unit operations for such treatment using organic waste material. Sugarcane bagasse was used for this experimental study in butch adsorption process. The variable affects the adsorption process are adsorbent dose changes 0.5 g to 2 g in 200mL sample, pH ranges 3 to 11 and retention time 3 to 7 days. The maximum BOD removed was 85% at 0.5 g, 3days and 8.32 dose, retention time and pH values respectively, and the maximum COD removed was 86% at 1 g, 3 days and 8.24 adsorbent dose, retention time and pH value respectively. Adsorbent dose, pH and retention time are significant factors on the competitive pollutant removal.

Sustainable reuse options of treated effluents: a case study from Muscat, Oman

Oman, being a semi-arid country, is in great need for extensive reuse practices of treated wastewater effluents. However, these practices need to be environmentally and economically feasible under the prevailing sophisticated treatment systems, inadequate infrastructure including sewers and wastewater-treatment plants (WWTPs). This study attempts to provide decision makers with a comprehensive characterisation of treated wastewater effluents in Muscat and to assess public opinions towards various reuse options of treated wastewater. Results from characterisation of the treated wastewater indicate great performance of the WWTPs in removing biological oxygen (O2) demand (BOD) and chemical oxygen demand (COD), as the maximum BOD and COD observed were less than 4 and 60 mg/l, respectively. The turbidity was found very low (below 3 nephelometric turbidity units), including total suspended solids of 13 mg/l. Most of the results showed relatively low counts of the total coliform bacteria except where a high variation was observed (400–2400 most probable number/100 ml). However, the aforementioned water quality indicators were able to meet Omani standards with the exception of a few parameters. In addition, the survey showed that the public had a general understanding of the different options of treated wastewater applications including their treatment procedures.

Assessment of Anthropogenic and Natural Factors on Cheliff River Waters (North-West of Algeria) at Two Contrasted Climatic Seasons

Cheliff River is the most important permanent river of North-west Algeria which plays an essential role for irrigation and drinking water supply, but suffers from high anthropogenic pressure. Multi-dimensional and multi-factorial aspects of water pollution in Cheliff River and its tributary Mina River were evidenced during two contrasting climatic seasons. Urban discharges were identified as a major source of water organic pollution. The inputs of untreated sewages were characterized by maximum concentrations of tryptophan-like (5.7 µmol l−1) and tyrosine-like (9.8 µmol l−1) compounds during the dry period, confirming these amino acids as fingerprints of untreated urban discharges. The synchronous monitoring and assessment of physicochemical parameters, fluorescent organic compounds and metallic elements of Cheliff River waters highlighted its global contamination, mainly in its downstream part. Cheliff River was mainly affected by organic pollution with maximum COD (1536 mg O2 l−1) and BOD5 (12 mg O2 l−1) during the wet period, and by metallic contamination with maximum Fe (287 ± 4.4 µg l−1) and Al (422.4 ± 9.4 µg l−1) during the dry period, exceeding the guideline limits. This chronic contamination was related to untreated domestic sewages, agricultural effluents and technical landfill center discharges in this area. Diffuse pollutions were also evidenced, which made the identification of different contamination sources complicated. Mina River was mostly affected by non-treated domestic sewages with maximum COD (3161 mg O2 l−1) during the wet period and maximum BOD5 (12 mg O2 l−1) during the dry period, exceeding the guideline limits. The correlation Li/Sr showed the contribution of natural influence from saline soils of Mina valley, particularly during the dry period.

Assessing local materials for the treatment of wastewater in open drains.

In the present study, three low-cost filter aggregate materials were tested and compared for organic matter and fecal coliform (FC) removal at the laboratory scale. Setups were subjected to synthetic wastewater at two hydraulic loading rates (HLR), i.e. 4 cm/day and 40 cm/day. The hydraulic retention time (HRT) at the two HLRs varied from 4 days to 12 h, respectively. The result obtained shows that the biochemical oxygen demand (BOD5) removal efficiency of aggregate materials decreased with the increase in HLR. Both at high and low HLR, the terracotta aggregate material exhibited maximum BOD5 loading removal and without significant difference for the case of FC removal efficiency for all the three aggregate materials. At higher HLR, cell debris and biofilm loss from the aggregate material contributed to the chemical oxygen demand (COD) levels in the treated water. The terracotta aggregate material provided best organic matter removal at both HLRs. The study demonstrates the potential of incorporating inexpensive and readily available local materials into decentralized, frugal green infrastructure interventions capable of lowering the quantum of harmful biological contaminants in open storm water channels in rapidly urbanizing cities of developing countries, and that the terracotta aggregate material provided best organic removal at both HLRs.

The potential application of an autochthonous fungus from the northwest of Argentina for treatment of sugarcane vinasse.

Vinasse is a waste material from distillery industries, which causes major environmental problems around the world. Argentina alone produces about 4 billion liters of vinasse annually; consequently, diverse biological eco-friendly treatments are evaluated for their ability to reduce the detrimental effects. The present study reports on the degradation of a 50% (v/v) local vinasse sample by an autochthonous fungus identified as Aspergillus sp. V1. The Bioprocess was conducted for 15 d at 30 °C after inoculation of spores at an end concentration of 1 × 106 CFU/mL. Effluent neutralization was detected after 6 d of treatment, with maximum COD and BOD removal after 12 d (49% and 59%, respectively). Effects of vinasse before and after treatment were predicted using Caco-2 cells and Triticum aestivum L. (wheat) seeds as toxicological indicators. Only 13% viability was observed for Caco-2 cells exposed to untreated vinasse, but this percentage increased more than 3-fold for cells exposed to the treated effluent. While vinasse without treatment completely inhibited germination of seeds, exposure to treated effluent demonstrated a germination percentage of 60%. The present study highlights the use of a dual-purpose biotechnological process that aimed at reducing the detrimental effects of vinasse, enhancing its quality for agricultural practices.

Semi-continuous measurement of oxygen demand in wastewater using biofilm-capacitance

Bio-capacitive coulombs were tested for determination of the 5-day biochemical oxygen demand (BOD5) using a dual-chamber microbial electrochemical cell (MxC) operated at charging (open circuit) and discharging (close circuit) conditions. For acetate medium, the cumulative coulombs charged in a capacitive biofilm anode (open circuit) were well correlated with BOD concentrations (R2 ~ 0.9). The maximum detectable BOD5 concentration with the bio-capacitance MxC was close to 250 mg/L, and the cumulative coulombs were saturated for above the maximum BOD5 concentration (Monod pattern). The bio-capacitance MxC sensor consistently showed high linearity between the cumulative coulombs and BOD5 concentrations for domestic wastewater influent (R2 = 0.93–0.99), despite of 1 min charging. High correlation between the coulombs and BOD5 concentration was also obtained for wastewater effluent at 1 min charging, which indicates that the bio-capacitance MxC sensor can semi-continuously measure BOD5 concentration in wastewater at every 2 min (1 min charging and 1 min discharging).

Integration of photocatalytic and biological processes for treatment of pharmaceutical effluent

This paper aims to investigate integration of biological process with photocatalytic oxidation for treating pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory compounds. An integrated lab-scale biological system with a photocatalytic reactor (containing Degussa P25 TiO2 in slurry mode) was operated in batch mode to treat simulated wastewater containing 10 mg/L of the model compound, Atenolol (ATL). Biodegradability (BOD5/COD ratio) increased from 0.23 to 0.42 after 4 h of photocatalytic treatment (1.5 g/L TiO2) with COD removal of 69.7% when using a solar simulator. In the independent biological treatment, the amount of sludge was varied as 2, 5, 10 and 15% in simulated wastewater, to optimize sludge concentration at three different temperatures of 20, 27 and 37 °C. The maximum BOD and COD removal of 46.3% and 46.2% respectively was achieved with 5% activated sludge at 37 °C for 48 h at natural pH of 6.9 under continues aeration. By employing 4 h of photocatalytic treatment using TiO2 (1.5 g/L) followed by 48 h of biological treatment (37 °C, 5% Sludge concentration) resulted in 90.5% and 80.8% removal of COD and BOD, respectively. The study shows integration of the two processes can be a promising technology.

Application of high rate integrated anaerobic-aerobic/biogranular activated carbon sequencing batch reactor (IAnA-BioGACSBR) for treating strong municipal landfill leachate

The aim of the present study is to evaluate the application of high rate integrated anaerobic-aerobic/biogranular activated carbon sequencing batch reactor (IAnA-BioGACSBR) to treat raw strong leachate from open dumping of municipal solid waste. The influence of two important and effective independent variables, COD concentrations and volumetric filling rate with GAC, onto the leachate treatment were investigated. Three responses such as TKN, BOD and COD were considered for evaluating the interaction of parameters. The results showed that maximum BOD5 removal of 98.9% in anaerobic zone and 99% in aerobic zone was obtained at the highest values of COD (~30000 mg/L) and filling ratio (~50%). The highest values of COD removal efficiency were found to be 98.54% and 98%, at COD rate of 10000 mg/L and GAC of 35%, respectively. The highest removal values of TKN was 77.2% and 78.9% in anaerobic and aerobic zone, respectively. Under optimal conditions, compared with the SBR and the GAC-SBR performances, results reveal that the application of the GAC-SBR has shown better effluent characteristics. Based on the results, it can be asserted that the application of the high rate IAnA-BioGACSBR for the treatment of biodegradable landfill leachate was more effective.

Removal of Biological Organic Matter and Suspended Solid from Textile Wastewater Using Anaerobic-Aerobic Process: A Review of an Industrial Implementation

Effective and cost efficient wastewater treatment is one of the major challenges for textile sectors of Bangladesh. The present study was an attempt to address the removal efficiency of organic matter and suspended solid of textile waste water by industrial scale combined anaerobic and aerobic treatment system. The experiments were performed at 6, 12, 18 and 24 hr hydraulic retention times (HRTs) and removal efficiency of different parameters (BOD5, COD and TSS) was measured. The average BOD5 and COD removal efficiency were in the range of 71% to 91% and 52% to 75% respectively at different HRTs in this plant. 73% - 82% range of TSS of wastewater was reduced by this method. Maximum BOD5 (88.2-92.5%) removal was occurred in aerobic treatment system whereas, high amount of COD (49.2-71.7%) removal efficiency reported in the anaerobic treatment system at different HRTs. The result indicated that the industrial scale combined treatment system can treat wastewater effectively.

Toxicity Removal of Pulp and Paper Mill Effluent by Employing Chemicals

<em>Pulp and paper are manufactured from raw materials containing cellulose fibers, generally wood, recycled paper, and agricultural residues. In developing countries, about 60% of cellulose fibers originate from nonwood raw materials such as bagasse (sugar cane fibers), cereal straw, bamboo, reeds, esparto grass, jute, flax, and sisal. Large amount of toxic effluent is released during process of paper production. Pulp and paper mill spent wash (raw effluent) is highly acidic in nature with high BOD, COD, TDS, TSS, phenol, sulphate, nitrogen, phosphorus, potassium and metals viz. Mn Zn Cu Ni Fe and Na . Effluent was treated with chemicals FeCl3 and KMnO4. pH was found to increase from 7.8 to 8.4 on increasing concentration (1 gl-1 to 5 gl-1) of KMnO4. Similarly colour, COD and BOD were decreasing with increasing concentration of KMnO4. Maximum colour, COD and BOD reduction were recorded 21.25%, 93.79% and 81.48% respectively at 5g l-1 concentration of KMnO4. Decrease in pH was recorded from 3.3 to 2.0 on increasing concentration (1 gl-1 to 5 gl-1) of FeCl3 (Ferric chloride). Decrease in colour, COD and BOD were also observed with increasing concentration of FeCl3. Maximum colour, COD and BOD reduction were recorded 99.10%, 54.16% and 85.92% respectively at 5g l-1 conc. of FeCl3.</em>