Terms Of Chemical Oxygen Demand Research Articles

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 .

Water recovery from yarn fabric dyeing wastewater using electrochemical oxidation and membrane processes.

This study intended to evaluate and compare the efficiency of electrochemical oxidation (EO), nanofiltration (NF), and reverse osmosis (RO) membranes processes in the treatment of yarn fabric dyeing wastewater (YFDW) in terms of chemical oxygen demand (COD) removal, color removal, salinity reduction, and conductivity removal. EO tests of the textile effluent were conducted under various current densities and solution pH conditions employing a graphite electrode. Membrane filtration experiments were conducted using two different NF membranes: NP010 and NP030 and two distinct RO membranes: BW30 and SW30 flat-sheet membranes. The experimental results showed that NF membrane process is not suitable for yarn fabric wastewater treatment showing low removal efficiencies for COD, color, and conductivity. However, both EO and RO membranes could reduce COD and color to high removal performances. EO results showed more than 99% of color removal and 80% of COD elimination at pH = 6 and current density of 50 mA/cm2 after 180 min of reaction. Using RO membrane for yarn fabric wastewater treatment demonstrated relatively complete removal of color concentration and 98% of COD elimination. However, EO process showed less performance in conductivity removal efficiency compared to the RO membranes. EO treatment of YFDW decreased conductivity by 31.2%, whereas RO membrane process reduced conductivity to a greater extent and recorded 97.1% of removal elimination percentage. Therefore, the treated water by RO membrane could be recycled back to the process such as washing and dyeing, in that way offering economic profits by decreasing water consumption and wastewater treatment cost. PRACTITIONER POINTS: Electrochemical oxidation and membrane filtration processes were combined for the treatment of yarn fabric dyeing wastewater (YFDW). A 100% color removal of color and 98.5% COD elimination efficiencies were obtained for the electrochemical oxidation (EO) + RO combined process. EO treatment of YFDW decreased conductivity by 32.7%, whereas the RO membrane process reduced conductivity to a greater extent and recorded 97.7% of removal elimination percentage.

Waste sludge disintegration and bound water reduction by chemical oxidation: A comparative study

Waste sludge disintegration and bound water reduction was investigated by comparative chemical oxidation using calcium hypochlorite, hydrogen peroxide, peroxymonusulfate and peroxydisulfate in the study. Response surface methodology (RSM) with Box-Benhken Design (BBD) was used to determine operating parameters namely initial pH (2–10), oxidant dosage (5–85 mg/g TSS), and Fe2+ to oxidant ratio; 0.2-2) and disintegration time (20–100 min). According to ANOVA results, determination coefficient (R2) was found 93.2%, 76.3%, 84% and 84.8% for each oxidant, respectively. Under the optimum operating conditions, disintegration degree in terms of chemical oxygen demand (DDCOD) was calculated 11.09%, 5.23%, 10.75%, and 5.34%, respectively. Furthermore, bound water reduction (BWR) of waste sludge increased after the disintegration process, and 33.52%, 24.56%, 44.63% and 32.80% BWR values were obtained under the same operating conditions. Results show that the higher DDCOD and BWR values were achieved by calcium hypochlorite and peroxymonosulfate treatment.

A Synergistic Effect of Moringa oleifera-Based Coagulant and Ultrafiltration for the Wastewater Treatment Collected from Final ETP

Provision of safe drinking water, devoid of aetiologies, is an all-time challenge due to the usage of unsafe chemicals in most of the water treatment processes. The main objective of the present paper is to evaluate the use of Moringa oleifera (MO) as a natural coagulant in coagulation/flocculation (C/F) followed by the ultrafiltration (UF) of Final Effluent Treatment Plant wastewater treatment which can also be employed as an alternative to the present conventional methods of treatment. Process efficiency was evaluated in terms of chemical oxygen demand (COD), biochemical oxygen demand (BOD), turbidity, total hardness, alkalinity, ammoniacal nitrogen, and zeta potential along with permeability and fouling behaviour of the membrane. A significant improvement in both the physical and chemical characteristics of the effluent quality is showing a clearer colour and a greater reduction in BOD (89.74%) and COD (63.80%) values, while pH was in the acceptable range for effluent disposal. The results indicate a lower membrane fouling rate (49%), an increase in permeate flow, and better quality of the permeate, proving that the C/F-UF treatment is an effective and efficient technique for wastewater treatment. Eventually, the treated wastewater obtained with this process generates better quality water and preserves the aquatic ecosystem.

Rapid Assessment Method for Evaluation of the Weighted Contribution of Anthropogenic Pollution: A Case Study of Lake Burullus, Egypt

This paper proposes a pragmatic approach for rapid assessment of the weighted contribution of the main waste streams contributing to pollution of surface water bodies. A case study was conducted on Lake Burullus in Egypt. The lake suffers from pollution due to many human-based activities around the lake, such as domestic, industrial, agriculture, fish farming, and solid wastes. The weighted contribution of these activities was assessed in terms of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP). The results showed that the highest organic load is due to the domestic wastewater pollution component (63.2% of COD load), followed by fish aquaculture (35.4%). The highest TN (43.9%) and TP (58.3%) pollutant loads to Lake Burullus are due to the agricultural pollution component, followed by fish aquaculture with pollutant loads of 28.5% and 25.3%, respectively. The industrial wastewater pollution component has a very small effect on the pollution of Lake Burullus. The assessment of this study will help identify and magnify the key polluters and thus guide the decision-makers to prioritize investment planning for depollution intervention projects. For example, if the target is to reduce COD loads, investments must be directed toward the rehabilitation and expansion of wastewater treatment plants (WWTPs).

Synergistic thermophilic co‐fermentation of food and lignocellulosic urban waste with steam explosion pretreatment for efficient hydrogen and carboxylic acid production

AbstractThe EU's bioeconomy strategy has a strong commitment to the development of biotechnological approaches to convert municipal solid biowastes into value‐added products. In this context, the current study investigated the thermophilic co‐fermentation of pruning lignocellulosic and food wastes to co‐produce hydrogen and carboxylic acids. Steam explosion pretreatment considerably enhanced the chemical oxygen demand (COD) solubilization reaching values up to 80% even with high lignocellulosic waste content. Acidification yield in terms of COD was strongly dependent on thermal pretreatment, varying from 20–30% up to ca. 60% with thermal pretreatment of the mixed urban waste. Under the best tested conditions, thermophilic co‐fermentation produced up to 162 ± 5 mlH2 gCOD−1. This hydrogen production decreased notably with the increase in the lignocellulosic fraction in the feed, the effect being stronger in the absence of thermal treatment. The results clearly showed a positive synergy effect in the overall efficiency of acidogenic fermentation and the strong dependence of carboxylic acid distribution on the initial composition of the feed. Values up to 0.58 gCOD of carboxylic acids per gCOD added were achieved with thermal pretreatment of the mixed urban waste, resulting in 93% acidification. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Study on Treatment of Blood from Abattoir using Microbial Fuel Cell (MFC) Technology with Production of Green Energy

Zero energy technologies and sustainable energy production are the two major concerns of present day researches. Microbial fuel cells (MFCs) are bioreactors that extract chemical energy stored in organic compounds, into electric potential, through bio-degradation. The core reason for the high strength of effluent generated from slaughterhouses is animal blood. The current study evaluates the potential of MFC technology to reduce the pollution strength of cattle blood in terms of chemical oxygen demand (COD). The current study was piloted in three stages using lab scale two chambered MFC: The first stage was to determine the best oxidising agent as compared to natural aeration from three accessible options, KMnO4, diffused aeration and tape grass aquatic plant. KMnO4 was found to be the superlative with a 30% reduction in COD in 100 hrs batch reactor and a maximum power of 0.97 mW using 125 mL livestock blood. The second stage of the study optimised the concentration of KMnO4. At 500 mg/L KMnO4 concentration, 50% COD removal efficiency was acquired in a batch reactor of 60 hrs with an average energy output of 1.3 mW. In the final stage on the addition of coconut shell activated carbon with an Anolyte at a rate of 40 mL/125 mL of substrate COD removal efficiency increased to 74.9%.

Minimizing greenhouse gas emissions of an industrial wastewater treatment plant in terms of water\u2013energy nexus

In this paper, (CO2) and methane (CH4) emissions of an industrial wastewater treatment plant were monitored. GHG emissions originated from treatment processes were considered as the direct emissions and determined using closed chamber method. GHG emission due to energy consumption was regarded as the indirect emissions. In the second stage of the study, it was aimed to reduce GHG emissions in terms of water–energy nexus. If the plant is operated under design conditions, energy consumption would be lower according to water–energy nexus. Also, the effect of design conditions on GHG emissions was investigated. Firstly, the correlation was defined between GHG emissions and operational parameters in terms of chemical oxygen demand (COD) and wastewater flow rate using Monte Carlo simulation. Then, design COD and wastewater flow rate were simulated to determine the possible GHG emission for each month. The simulation results show that minimization of GHG emissions might be possible if wastewater plant is operated under design conditions. The minimum greenhouse gas emission in the result of the simulation study is 8.25 kg CO2-eq/d if the plant is operated under design COD and flow rate. Total reduction in GHG emissions is approximately 30% if the plant is operated under design conditions.

Removal of antibiotic rifampicin from aqueous media by advanced electrochemical oxidation: Role of electrode materials, electrolytes and real water matrices

One of the most commonly detected classes of pharmaceutical products in aquatic environments are antibiotics and their effective removal in sewage treatment plants is limited due to their refractory features. In this context, electrochemical technologies could be an alternative to decrease the pollution level and promote the complete elimination of antibiotics in water. For this reason, the electrochemical treatment of a synthetic effluent as well as different real water matrices polluted with antibiotic rifampicin was investigated, using different electrode materials (anodes: boron doped diamond, (BDD), Pt and PbO2; and cathodes: carbon felt (CF), graphite (Gr), stainless steel (SS) and titanium (Ti)). Effects on the variation of applied current density (j) and supporting electrolyte were examined during the degradation of the antibiotic. Comparative studies have clearly showed that the degradation of rifampicin had better results by using BDD and CF as anode and cathode, respectively, where the process efficiency increased when an increase on the j was attained. Complete color removal was achieved at all j applied (chromophore rifampicin group gives a red-orange color for solutions), whereas only at higher j leads to complete organic matter (in terms of chemical oxygen demand (COD)) removal. For a selected cathode, the efficiency of the anode materials follows the trends BDD>PbO2>Pt, whereas that of cathode follows CF>Ti>SS≈Gr for a selected anode material. Using Na2SO4, Na2CO3 or NaCl, the production of strong secondary oxidant species was favored, promoting the oxidation of dissolved organic matter in synthetic effluents. Meanwhile, when the BDD/CF electrochemical cell was employed with different real water matrices, the degradation and mineralization of the drug was independent of this parameter. Oxalic, acetic, fumaric and maleic acids were the final organic byproducts of rifampicin degradation with the release of heteroatom N under NO3‒ and NH4+ forms.

Nanophotocatalytic treatment of seawater using TiO2 immobilized and suspension system under solar irradiation

Organic fouling in desalination plants is a crucial phenomenon resulting in the deterioration of nanofiltration/reverse osmosis filtration performance of membranes and salt-rejection characteristics. In this research, the efficiency of TiO2-suspension and TiO2-immobilized photocatalysis to pretreat seawater under natural solar irradiation has been investigated. The solar nanophotocatalytic performance was evaluated in terms of chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency from feed seawater. Modelling and optimization study was performed in TiO2 suspension system to determine the effect and optimum settings of input parameters such as pH of seawater, reaction time, TiO2 dosage, initial TOC of seawater, and airflow rate into the photoreactor. In a full factorial design, the photocatalytic efficiency of TiO2 nano-thin film immobilized on borosilicate glass tubes was assessed in terms of methanol − TiO2 ratio, nitric acid − TiO2 ratio and solar irradiation time. The optimum removal efficiency of TOC and COD removal in the immobilized system was determined as 51.98% and 57.25%, respectively, at the input factor setting: methanol- TiO2 ratio = 15: 1, nitric acid- TiO2 ratio = 6:1 and solar irradiation time = 120 min. The optimum organic degradation in suspension system was found to be: TOC removal = 73.47% and COD removal = 65.48%.

Selection and optimization of a mixed culture for bioaugmentation based on BOD5 and COD reduction in tannery effluents

Most current methodologies for the treatment of tannery effluents do not succeed in bringing contaminant levels down to values that fit environmental standards in force, which means there is a need for appropriate optimization. The present work assessed effluent quality to gain further insight into their variability across time, considering both conventional parameters and those specifically related to tannery effluents, such as chromium levels. Most of the effluents analyzed exceeded the contaminant limits established by current national legislation and therefore would require treatment. To improve treatment efficiency, a mixed bacterial culture was selected on the basis of its ability to remove organic matter (OM), measured in terms of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5). The four strains analyzed, belonging to the genera Bacillus, Rhodococcus and Acinetobacter, were isolated from sediments contaminated with effluents with a high organic load. The native consortium SFC 500-1, formed by Acinetobacter guillouiae SFC 500-1 A and Bacillus toyonensis SFC 500-1E, proved to be the most effective at reducing BOD5 and COD. It was selected for bioaugmentation treatment. Dissolved oxygen was found to be key for reduction, and the inoculum size required to treat effluents with different COD values was also determined. All in all, the results confirmed previous characterization of these effluents, which should always be the basis for treatment and management strategies, and also contributed to optimizing some operational parameters so that effective and safe treatment technologies may be developed.

Technical evaluation and economic optimisation of coagulation-flocculation process for the pre-treatment of over-reused effluent of paper mills in cardboard recycling industry

ABSTRACT The aim of this study is to evaluate the performance of coagulation and flocculation (C/F) process and economic analysis for the advanced primary treatment in order to obtain a semi-closed water circuit in the pulp mills in the cardboard recycling industry. Since the high water quality level is not required in the pulpers, the dosages in this research were determined without pH changes or adjustment to decrease the capital and operational expenditures. The results showed that FeCl3 with the concentration of 2000 mg/L gave the best quality when coagulants were used solely. Moreover, using alum with the concentration of 1500 mg/L provided acceptable quality for the effluent re-circulation and the removal/reduction percentages of 42, 82, 71 and 97 were achieved for chemical oxygen demand (COD), total suspended solids (TSS), turbidity and colour, respectively. It was also found that the combination of coagulants did not improve the process performance significantly. The best combination was ferric chloride (500 mg/L) and alum (2000 mg/L) with the efficiency of 47% and 98% in terms of COD and colour removal/reduction, respectively, while the best couple in TSS removal was FeCl3 (500 mg/L) and CaCO3 (500 mg/L) with the efficiency of 88%. The chemicals coupled with cationic polyacrylamide (C-PAM) did not enhance the quality of pre-treated solutions when the settling time reduced up to 15 minutes. The cost analysis also showed that alum is the most cost-effective coagulant with the costs in the range of 0.06–0.12 $/kg removed TSS, 0.06 to 0.11 $/kg removed COD and 0.06–0.1 $/m3·reduced NTU whereas calcium carbonate is the economic coagulant regarding colour reduction with the cost of 0.003 $/m3·reduced unit and more than the reduction efficiency of 90%.

COD fractionation and solubility assessment of sonicated waste‐activated sludge

AbstractUltrasonic treatment is adopted as one of the important strategies to accelerate the hydrolysis of waste‐activated sludge (WAS). This study intends to optimize amplitude and time for ultrasonic treatment of WAS using statistically designed experiments that would render a better degree of disintegration, measured in terms of chemical oxygen demand (COD) solubilization. The main and interaction effects of nonlinear regression analysis revealed a significant interaction between amplitude and time over the degree of sludge disintegration. The ultrasonic density of 0.45 W/mL for 30 min favored a 153.84% increase in COD solubilization with a 27.65% degree of sludge disintegration. This condition also favored the minimum specific energy input of 801.58 kJ/g total suspended solids compared to other sonication conditions. Besides, the sludge volume index was reduced by 45% and 26% at the ultrasonic density of 0.45 W/mL for 60 and 30 min, respectively. Microscopic examination of WAS revealed disintegration of bacterial flocs during the ultrasonication process releasing filamentous bacteria with smaller floc sizes. The results from this study indicate that higher ultrasonic density for short time could improve the sludge disintegration with minimum specific energy input.

Treatment of Wastewater from a Food and Beverage Industry Using Conventional Wastewater Treatment Integrated with Membrane Bioreactor System: A Pilot-Scale Case Study.

This study compares the performance of the Hollow Fiber (HF) and Flat Sheet (FS) types of membrane bioreactors (MBRs) for the treatment of food and beverage (F&B) industry wastewater in a pilot-scale study of a wastewater treatment plant (WWTP). HF and FS membrane configurations were evaluated at two different Mixed Liquor Suspended Solid (MLSS) levels: 6000 mg/L and 12,000 mg/L. The performance of each configuration was evaluated in terms of Chemical Oxygen Demand (COD) and Total Suspended Solid (TSS) removals for effluent quality measurement. The transmembrane pressure (TMP), flux rate, and silt density index (SDI) were monitored and calculated for membrane fouling assessment. The results show that the rejection rates of COD and TSS for HF and FS membrane types were more than 84% for the two different MLSS levels. During the study, the HF membrane recorded 0.3 bar transmembrane pressure, which complies with the recommended range (i.e., two to three times of chemical cleaning). On the other hand, the FS membrane operates without chemical cleaning, and the TMP value was below the recommended range at 0.2 bar. It was found that the flux values recorded for both the HF and FS systems were within the recommended range of 40 L/m2/h. Analysis of SDI revealed that the calculated index ranged between 1 and 2.38 and was within the allowable limit of 3. Both types of MBR consistently achieved an 80% to 95% rejection rate of COD and TSS. Effluent quality measurement of treated F&B wastewater in this pilot-scale study using a WWTP integrated with an MBR indicated a good achievement with compliance with the Malaysia industrial effluent discharge standards.

Assessing the Surface Water Quality of Ana Sagar Lake and its Bioremediation in Modified Constructed Wetland

The present study evaluates the potential of an integrated Constructed Wetland and Microbial Fuel Cell (CW-MFC) in removing Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), nitrate and phosphate along with generating electricity from the polluted water of Ana Sagar Lake, Ajmer. Two vertical downward flow CW-MFCs have been investigated (with and without plant) in batch mode for a period of 12 months. The performance of CW-MFC with the plant (system A) was better than the CW-MFC without the plant (system B), both in terms of COD, TDS, nitrate and phosphate removal and electricity generation. Dracaena trifasciata plant species were used in this study. The maximum power density of 157 mW/m2, current density of 0.65 mA/m2, COD removal efficiency (72%), TDS reduction (74%), nitrate removal (69%) and phosphate removal (69%) were obtained with System A. The germination rate of Vigna radiata seeds was 100% with the effluent from system A. At the end of the experiment the FTIR analysis revealed the structural changes occurring on the CW-MFC media (sand) after removal of pollutants present in the lake water.

Comparative evaluation of simultaneous nitritation/denitritation and energy recovery in air-cathode microbial fuel cells (ACMFCs) treating low C/N ratio wastewater

Air-cathode microbial fuel cells (ACMFCs) can extract available electrons from the low C/N ratio wastewater (LCNW) for pollutant degradation and power generation. However, the multiple effects of operating parameters and their relationship between the performances and parameters are still lacking. In this study, several ACMFCs for simultaneous nitritation/denitritation (SND) and energy recovery were constructed and evaluated in terms of chemical oxygen demand (COD), NH4+-N, C/N ratio, phosphate buffer solution (PBS), and external resistance (Rext), and several derived parameters (e.g., organic loading rate (OLR), nitrogen loading rate (NLR)). Results indicated that ACMFCs could be used to treat LCNW successfully with high pollutant removal rates and sustainable current generation. Maximum removal efficiencies of 94% COD, 92% NH4+-N, and 92% total nitrogen (TN) were achieved. A maximum power density of 1400 mW m−2 and columbic efficiency of 69.2% were also obtained at a low C/N ratio of 1.7–2.6. Low C/N ratios promoted SND by balancing nitritation and denitritation. The microbial community and their predicated function results showed considerable nitrifiers and denitrificans were enriched in the ACMFCs, contributing to SND and power recovery. Further analyses showed that the NH4+-N could inhibit SND, but PBS and Rext had no obvious effects on this outcome. Co-occurrence network analysis demonstrated that power is positively correlated with COD and Rext; strong correlations between organic removal and COD, and between nitrogen removal and ammonia, conductivity, and C/N ratio were also noted. Overall, the appropriate control of such parameters is necessary to achieve efficient SND in ACMFCs for LCNW treatment.

Sono-assisted electrocoagulation treatment of rice grain based distillery biodigester effluent: Performance and cost analysis

Electrocoagulation process coupled with sonication is a type of advance oxidation process (AOP) to treat different type of waste waters. Biodigester effluent (BDE) generated from distillery industry contains very high chemical oxygen demand (COD=5500 mg/dm3) with high color (510 PCU) appearance. Organics reduction of biodigester effluent (BDE) in term of chemical oxygen demand (COD) and color have been investigated in a batch sono-electrocoagulation reactor with different electrode combinations such as Fe-Fe, Al-Al, Fe-Al, and Al-Fe at ultrasound frequency of 40 kHz. The impact of different operating parameters such as electrolyte concentration, electrode combination, pH and current density (CD) on COD and color removal are evaluated. The electrode combination of Fe-Fe has provided better results in sono-electrocoagulation process as compared to sonication and electrocoagulation alone. The maximum COD and color reduction efficiency of 99.1 % and 61.6 % was found at the electrode combination of Fe/Fe, CD 69.44 A/m2, pH 8, NaCl concentration 5 mg/dm3, and process time of 125 min. On the other hand the maximum COD and color removal efficiency of 98.3 % and 58.1 % was observed with the electrode combination of Al-Al at same operating conditions as described for Fe. Finally, sludge analysis and cost optimization are also incorporated in this article. It is found that at optimum condition (electrode combination of Fe/Fe, CD 69.44 A/m2, pH 8, NaCl concentration 5 mg/dm3, and process time of 125 min) the operating cost of the process is 1.39 $/m3. Sludge obtained after the treatment process contains anodic material (0.07 kg iron for the treatment 1 m3 of BDE) and also sludge had good heating value (5.5 MJ/kg). This work demonstrated that sono-electrocoagulation process is well applicable to treat BDE.

Investigation on removal of high organic load of industrial wastewater by cascade filters (bio-filters with different media)

Industrial wastewater is one of the most significant environmental pollutants, and most industry owners shirk this responsibility due to the excessive expenses. Thus, the present research attempts to provide a suitable and highly efficient method with lower investment expenses in order to encourage industry owners to use this system and propose the best option for industrial wastewater treatment. The research aims to control water pollution, maintain ecosystem balance and reuse wastewater in industry. In this study, the process of reducing Nitrogen, Phosphorus, Total Suspended Solids and Chemical Oxygen Demand from wastewater with high Organic load has been investigated by fixed-bed sequencing batch reactors (biological, adsorption) with a volume of 24 L. The minimum and maximum system efficiencies were 43 and 88% in terms of Chemical Oxygen Demand for the removal of organic matter, 30 and 81% for the removal of Nitrogen, 88 and 99% for the removal of Phosphorus and 43 and 77% for removal of Total Suspended Solids, respectively. Anaerobic Filters system showed good efficiency for removing the organic matter, Nitrogen and Phosphorus from industrial wastewater with high organic load. Results show a very long Solids Retention Time for essential microorganisms in the decomposition of toxic and inhibitory compounds, absorption of shock loads or non-biodegradable toxic compounds, the possibility of higher volumetric loading compared to aerobic processes and lower cell mass efficiency followed by important economic and environmental benefits in relation to the recycling and disposal of the produced cell mass.

Optimization of coagulation–flocculation process in the treatment of surface water for a maximum dissolved organic matter removal using RSM approach

Abstract The aim of this research work is the optimization of the coagulation/flocculation process in the treatment of surface water for maximum dissolved organic matter (DOM) removal using response surface methodology (RSM). For this purpose, several jar test experiments were performed in order to identify the most influencing factors. Afterwards, RSM was done to investigate the effects and the interactions of three chosen variables (coagulant concentration, flocculant concentration, and initial pH), whereas the responses were the DOM removal in terms of chemical oxygen demand (COD), in terms of absorbance at the wavelength 254 nm (UV-254), and the final pH. The optimal conditions were as follows: 133 mg/L of coagulant, 60 mg/L of flocculant and an initial pH equal to 6.91. Under these conditions, the efficiency removals were 56% in terms of COD and 59% in terms of UV-254 with a final pH equal to 6.78. High variance coefficient R2 values, with 0.96 for the removal in terms of COD and 0.92 in terms of UV-254, confirm the reliability and the validity of the obtained model.

Study of Different Membranes in Microbial Fuel Cell Through Different Cathodes

The two chambered Microbial Fuel Cell (MFC) was designed and used for studying efficiency of different membranes for the real wastewater treatment from a non-steroidal anti-inflammatory pharmaceutical plant. The removal of the contaminants was expressed in terms of Chemical Oxygen Demand (COD) removal, as measured by spectrophotometry experiments. Experiments were divided into two sections. First phase of experiments was performed using Pt-coated Ti as the cathode and Stainless Steel as the anode, using NAFION® 324 membrane while in the second phase PTFE membrane was replaced with NAFION. The results indicate that using NAFION membrane could increase the maximum power density and COD removal rate to 20.5w/m3 and 92 % respectively.