scholarly journals An investigation on using MDCs for an efficient desalination process as pretreatment of reverse osmosis

2020 ◽  
Vol 69 (4) ◽  
pp. 322-331
Author(s):  
Avin Habibi ◽  
Madjid Abbaspour ◽  
Amir H. Javid ◽  
Amir H. Hassani
Keyword(s):  
Reverse Osmosis ◽  
Oxygen Demand ◽  
Electrical Energy ◽  
Synthetic Wastewater ◽  
Electrochemical Technique ◽  
Continuous Mode ◽  
Fed Batch ◽  
Nacl Concentration ◽  
Middle Chamber ◽  
Microbial Desalination Cell

Abstract Microbial desalination cell (MDC) is a new bio-electrochemical technique which converts chemical energy into electrical energy, and at the same time desalinates water and treats wastewater. In this study, MDC performance and water biofouling conditions were tested as an efficient pretreatment desalination process of reverse osmosis (RO). The experiments were designed in a three-chamber reactor to compare the performance of batch and continuous fed modes, using bio-cathode and synthetic wastewater in four different hydraulic retention times and 17 and 35 g/L NaCl concentrations. According to the results, maximum salt removal of about 52.3% was obtained in the continuously fed MDC at 35 g/L NaCl concentration. The maximum salt removal at 17 g/L NaCl was also observed in continuous mode. The anolyte pH in both batch and continuous modes dropped from 7 to 6.32, 6.47 and 6.37, 6.48 in 17 and 35 g/L NaCl concentrations respectively. The chemical oxygen demand (COD) removal values in the continuous mode were 61 and 65% in the anolyte and catholyte respectively, higher than those of fed-batch MDC. The biofouling of the middle chamber solution was confirmed by conducting bio-microbial tests. Our results suggest that the type of hydraulic flow can improve the performance of MDC in different concentrations of NaCl.

scholarly journals Simultaneous Desalination of Sea water and Electricity Production with New Membrane Technology, Air-Cathode Microbial Desalination Cells

2015 ◽  
Vol 10 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mahdi Asadi-Ghalhari ◽  
Nasser Mehrdadi ◽  
Gholamreza Nabi-Bidhendi
Keyword(s):  
Electrical Conductivity ◽  
Sea Water ◽  
Low Energy ◽  
Electricity Production ◽  
Synthetic Wastewater ◽  
Air Cathode ◽  
Middle Chamber ◽  
Microbial Desalination Cell ◽  
Voltage Generation ◽  
Maximum Voltage

Water and energy shortages, has increased the need for methods that can provide low energy for desalination of sea water. Microbial desalination cell is one of the most important of these methods. In this study we use air cathode MDC for desalination of seawater. The maximum voltage, power and current density was 607mV, 521mW/m2 and 858mA/m2 (25mM PBS) and 701mV, 695mW/m2 and 992mA/m2 (50mM PBS) respectively. During the period of the voltage generation in 50mM PBS was about 1.5 times of 25mM PBS. Under this situation, EC of seawater with initial electrical conductivity declined by 48.31±3% (25mM PBS) and 46.71±2.73% (50mM PBS). As well as decrease of salt from sea water in the middle chamber, EC in synthetic wastewater and catholyte slightly increased. So that Change percent of EC in synthetic wastewater was 44.20 ± 11.94(25mM PBS) and 27.94 ± 3 (50 mM PBS) and in catholyte was 211.66 ± 22.41(25mM PBS) and 119.24 ± 11.25 (50 mM PBS) respectively. These results show that the MDC can also be used as a pretreatment to reverse osmosis; simultaneously the energy required in this process is also partly meet.

scholarly journals Electrodegradation of Acid Mixture Dye through the Employment of Cu/Fe Macro-Corrosion Galvanic Cell in Na2SO4 Synthetic Wastewater

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4580
Author(s):  
Mateusz Kuczyński ◽  
Mateusz Łuba ◽  
Tomasz Mikołajczyk ◽  
Bogusław Pierożyński ◽  
Agnieszka Jasiecka-Mikołajczyk ◽  
...  
Keyword(s):  
Electrochemical Techniques ◽  
Electrical Energy ◽  
Galvanic Cell ◽  
Synthetic Wastewater ◽  
Acid Mixture ◽  
Ac Impedance Spectroscopy ◽  
Wastewater Purification ◽  
Physical Chemical ◽  
Iron Anode ◽  
Biological Methods

Traditional wastewater purification processes are based on a combination of physical, chemical, and biological methods; however, typical electrochemical techniques for removing pollutants require large amounts of electrical energy. In this study, we report on a process of wastewater purification, through continuous anodic dissolution of iron anode for aerated Cu/Fe galvanic cell in synthetic Na2SO4 wastewater solution. Electrochemical experiments were conducted by means of a laboratory size electrolyzer, where electrocoagulation along with electrooxidation phenomena were examined for wastewater containing Acid Mixture dye. The above was visualized through the employment of electrochemical (cyclic voltammetry and ac impedance spectroscopy techniques) along with instrumental spectroscopy analyses.

scholarly journals Batch and Semi-Continuous Anaerobic Digestion of Industrial Solid Citrus Waste for the Production of Bioenergy

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 648
Author(s):  
Erik Samuel Rosas-Mendoza ◽  
Andrea Alvarado-Vallejo ◽  
Norma Alejandra Vallejo-Cantú ◽  
Raúl Snell-Castro ◽  
Sergio Martínez-Hernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Continuous Mode ◽  
Citrus Industry ◽  
Batch Mode ◽  
Volatile Solids ◽  
Working Volume ◽  
Plant Level ◽  
Citrus Waste ◽  
Mesophilic Conditions

The aim of this paper is to describe a study of the anaerobic digestion of industrial citrus solid waste (ISCW) in both batch and semi-continuous modes for the production of bioenergy without the elimination of D-limonene. The study was conducted at the pilot plant level in an anaerobic reactor with a working volume of 220 L under mesophilic conditions of 35 ± 2 °C. Cattle manure (CM) was used as the inoculum. Three batches were studied. The first batch had a CM/ISCW ratio of 90/10, and Batches 2 and 3 had CM/ISCW ratios of 80/20 and 70/30, respectively. In the semi-continuous mode an OLR of approximately 8 g total chemical oxygen demand (COD)/Ld (4.43 gVS/Ld) was used. The results showed that 49%, 44%, and 60% of volatile solids were removed in the batch mode, and 35% was removed in the semi-continuous mode. In the batch mode, 0.322, 0.382, and 0.316 LCH4 were obtained at STP/gVSremoved. A total of 24.4 L/d (34% methane) was measured in the semi-continuous mode. Bioenergy potentials of 3.97, 5.66, and 8.79 kWh were obtained for the respective batches, and 0.09 kWh was calculated in the semi-continuous mode. The citrus industry could produce 37 GWh per season. A ton of processed oranges has a bioenergy potential of 162 kWh, which is equivalent to 49 kWh of available electricity ($3.90).

Assessing the potential of a UV-based AOP for treating high-salinity municipal wastewater reverse osmosis concentrate

2013 ◽  
Vol 68 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Muhammad Umar ◽  
Felicity Roddick ◽  
Linhua Fan
Keyword(s):  
Reverse Osmosis ◽  
Municipal Wastewater ◽  
High Salinity ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Secondary Effluent ◽  
Biological Processes ◽  
Fluorescence Excitation ◽  
H2o2 Treatment ◽  
Humic Compounds

The UVC/H2O2 process was studied at laboratory scale for the treatment of one moderate (conductivity ∼8 mS/cm) and two high salinity (∼23 mS/cm) municipal wastewater reverse osmosis concentrate (ROC) samples with varying organic and inorganic characteristics. The process efficiency was characterized in terms of reduction of dissolved organic carbon (DOC), chemical oxygen demand (COD), colour and absorbance at 254 nm (A254), and the improvement of biodegradability. The reduction of colour and A254 was significantly greater than for DOC and COD for all samples due to the greater breakdown of humic compounds, as confirmed by fluorescence excitation-emission matrix spectra. Fairly small differences in the reduction of DOC (26–38%) and COD (25–37%) were observed for all samples, suggesting that the salinity of the ROC did not have a significant impact on the UVC/H2O2 treatment under the test conditions. The biodegradability of the treated ROC samples improved markedly (approximately 2-fold) after 60 min UVC/H2O2 treatment. This study indicates the potential of UVC/H2O2 treatment followed by biological processes for treating high-salinity concentrate, and the robustness of the process where the characteristics of the secondary effluent (influent to RO) and thus resultant ROC vary significantly.

scholarly journals Treatment of low strength wastewater using compact submerged aerobic fixed film (SAFF) reactor filled with high specific surface area synthetic media

2019 ◽  
Vol 80 (4) ◽  
pp. 737-746
Author(s):  
Rishi Gurjar ◽  
Akshay D. Shende ◽  
Girish R. Pophali
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Synthetic Wastewater ◽  
Utilization Rate ◽  
Kinetic Coefficients ◽  
Fixed Film ◽  
Synthetic Media

Abstract Studies on laboratory-scale submerged aerobic fixed film reactor (SAFF) packed with synthetic media having specific surface area of 165 m2/m3 with a void volume of 89% were carried out to assess its performance under various organic loading rates (OLR) and hydraulic retention times (HRT). Synthetic wastewater having chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of 400 ± 10% and 210 ± 10% mg/L respectively was fed and the reactor was subjected to OLRs ranging from 0.37 to 1.26 kg COD/m3.d. It was observed that steady sloughing of biofilm occurs within the SAFF reactor all the times and average concentration of sloughed biomass in the effluent was 26 mg/L. The COD and BOD removal efficiencies varied between 85 and 89% and 86 to 94%, respectively. The kinetic studies demonstrated that SAFF reactor followed Stover–Kincannon and Grau models, with high correlation coefficients (R2) of 0.9977 and 0.9916, respectively. Thus, the values of kinetic coefficients such as maximum substrate utilization rate, Umax = 64.1 g/(L.d); saturation value constant, KB = 72.31 g/(L.d) and Grau second-order substrate removal rate constant, Ks = 2.44 day−1 can be useful to develop and design large scale SAFF reactors. Finally, the study reveals that the optimum range for OLR can vary within 0.68–0.94 kg COD/m3.d.

scholarly journals Assessing local materials for the treatment of wastewater in open drains

2019 ◽  
Vol 79 (5) ◽  
pp. 895-904 ◽  
Author(s):  
Priyanka Jamwal ◽  
Daniel Phillips ◽  
Kim Karlsrud
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Green Infrastructure ◽  
Low Cost ◽  
Oxygen Demand ◽  
Synthetic Wastewater ◽  
Significant Difference ◽  
Biological Contaminants ◽  
Local Materials ◽  
Aggregate Material

Abstract 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.

scholarly journals Application of electrochemical treatment for the removal of triazine dye using aluminium electrodes

2020 ◽  
Vol 69 (4) ◽  
pp. 345-354 ◽  
Author(s):  
Sakthisharmila Palanisamy ◽  
Palanisamy Nachimuthu ◽  
Mukesh Kumar Awasthi ◽  
Balasubramani Ravindran ◽  
Soon Woong Chang ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Electrical Energy ◽  
Reactive Dye ◽  
Product Formation ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Spectral Studies ◽  
Textile Dye ◽  
Electrode Consumption ◽  
Electrocoagulation Process

Abstract Textile effluents contain triazine-substituted reactive dyes that cause health problems such as cancer, birth defects, and hormone damage. An electrochemical process was employed effectively to degrade azo reactive dye with the aim of reducing the production of carcinogenic chemicals during biodegradation. Textile dye C.I. Reactive Red 2 (RR2), a model pollutant that contains dichloro triazine ring, was subjected to the electrocoagulation process using aluminium (Al) electrodes. A maximum of 97% of colour and 72% of chemical oxygen demand (COD) removal efficiencies were achieved and 9.5 kWh/kg dye electrical energy and 0.8 kg Al/kg dye electrode consumption were observed. The dye removal mechanism was studied by analysing the results of UV-Vis spectra of RR2 and treated samples at various time intervals during electrocoagulation. Fourier transform infrared (FTIR) spectra and energy dispersive X-ray (EDX) spectral studies were used for analysing the electrocoagulated flocs. The results indicate that in this process the dye gets removed by adsorption and there is no significant carcinogenic by-product formation during the degradation of dye.

Biodegradation of aniline

1997 ◽  
Vol 36 (10) ◽  
pp. 53-63 ◽  
Author(s):  
Shabbir H. Gheewala ◽  
Ajit P. Annachhatre
Keyword(s):  
Activated Sludge ◽  
Ammonia Oxidation ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Inhibitory Effect ◽  
Synthetic Wastewater ◽  
Nitrifying Bacteria ◽  
Aquatic Life ◽  
Oxidation Rates ◽  
Batch Tests

Discharge of aniline to the environment must be controlled as aniline is toxic to aquatic life and also exerts additional oxygen demand due to nitrification reaction involved during its biodegradation. Organic carbonaceous removal by heterotrophs during aniline biodegradation releases NH4+ which is the substrate for autotrophic nitrifying bacteria. However, aniline is toxic to nitrifying bacteria and severely inhibits their activity. Accordingly, batch and continuous studies were conducted to assess the biodegradation of aniline and its inhibitory effect on nitrification. Synthetic wastewater was used as feed with aniline as sole carbon source for mixed microbial population. Experiments were conducted at ambient temperatures of 30–32°C. An aerobic activated sludge Unit was operated at an HRT of about 13 hours and SRT of about 12 days. Biomass from aerobic activated sludge process treating domestic wastewater was acclimatized to synthetic wastewater Containing aniline. Removal efficiencies more than 95% were obtained for feed aniline concentrations upto 350 mg/l with insignificant inhibition of nitrification due to aniline. Ammonia oxidation rates of about 20–115 mgNH4N/l/d were observed. Batch tests were carried out to test the inhibitory effects of high initial aniline concentrations on nitritication. Carbonaceous removal by heterotrophs proceeded rapidly within 4–6 hours with nitrification picking up as soon as aniline concentration dropped below 3–4 mg/l. For higher initial aniline concentration more than 250 mg/l, complete nitrification did not take place even after aniline Concentration dropped below 3–4 mg/l.

Multi-component kinetics of activated sludge treatment of bleached kraft mill effluent

2004 ◽  
Vol 50 (3) ◽  
pp. 11-20
Author(s):  
S.S. Helle ◽  
S.J.B. Duff
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Fed Batch ◽  
Removal Rates ◽  
Kinetic Measurements ◽  
Sludge Treatment ◽  
Batch Tests ◽  
Degradation Rates ◽  
Kraft Mill Effluent ◽  
Kraft Mill

This study investigated the discrepancies between the BOD removal rates measured during short term assays and those measured during continuous activated sludge treatment of bleached kraft mill effluent (BKME). A combination of batch tests and fed batch tests with oxygen uptake rate (OUR), chemical oxygen demand (COD), biochemical oxygen demand (BOD), and mixed liquor volatile suspended solids (MLVSS) measurements were used to characterize the degradation rates for the activated sludge treatment of BKME and to divide the soluble readily biodegradable substrate into two to five separate fractions based on biodegradation rates. The removal rates varied by over an order of magnitude between the most readily degradable substrates (1 × 10-3 mg COD/mg MLVSS minute), and the more slowly degradable substrates (2 × 10-5 mg COD/mg MLVSS minute). If the readily biodegradable fraction of BKME was modeled as one substrate, initial rate kinetic measurements from batch tests were heavily influenced by the fractions with the greatest degradation rates, while any remaining BOD in the treated effluent was predominantly from the slowly degradable fraction, giving inconsistent results. Taking the multi-component nature of the wastewater into account, batch test results can be used to predict fed-batch and continuous activated sludge reactor performance.

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