Simultaneous COD removal and denitrification of wastewater by bio-electro reactors

1997 ◽  
Vol 35 (8) ◽  
pp. 161-168 ◽  
Author(s):  
M. Kuroda ◽  
T. Watanabe ◽  
Y. Umedu
Keyword(s):  
Organic Matter ◽  
Electric Current ◽  
Denitrifying Bacteria ◽  
Hydrogen Gas ◽  
Cod Removal ◽  
Hydrogen Donor ◽  
Continuous Treatment ◽  
Synthetic Wastewater ◽  
Internal Source ◽  
Nitrogen Gas

Application of a bio-electro reactor process for the treatment of wastewater containing nitrate and internal source of hydrogen donor as organic matter was experimentally investigated. The bio-electro reactor consisted of immobilized denitrifying bacteria electrode as cathode and carbon electrode as anode. Hydrogen gas was produced on the cathode surface by the electrolysis of water when electric current was applied, and immediately utilized to reduce biologically nitrate to nitrogen gas by the cathodic immobilized denitrifying bacteria. Consumption characteristics of organic matter and utilization of hydrogen gas derived from the electrolysis of water for denitrification was studied by batch experiments. Continuous treatment experiments using a synthetic wastewater containing nitrate and organic matter were carried out to investigate the denitrification and organic matter removal performances. Denitrification occurred with simultaneous utilization of organic matter existed as internal source of hydrogen donor in the wastewater and hydrogen gas by electrolysis of water. Hydrogen gas was utilized efficiently for denitrification even if excess amount of organic hydrogen donor existed in wastewater. In this bio-electro reactor system, it was confirmed that COD as well as nitrate was removed simultaneously by applied electric current in continuous experiment, though further investigation are necessary to analyze the COD removal by applied electric current in detail.

Simultaneous oxidation and reduction treatments of polluted water by a bio-electro reactor

1996 ◽  
Vol 34 (9) ◽  
pp. 101-108 ◽  
Author(s):  
M. Kuroda ◽  
T. Watanabe ◽  
Y. Umedu
Keyword(s):  
Aqueous Solution ◽  
Organic Matter ◽  
Electric Current ◽  
Removal Efficiency ◽  
Concentration Ratio ◽  
Nitrate Removal ◽  
Hydrogen Gas ◽  
Polluted Water ◽  
Simultaneous Oxidation ◽  
Denitrifying Microorganisms

Application of a bio-electro reactor for treatment of various kinds of polluted water was investigated experimentally. Aqueous solution of nitrate, ammonium and/or organic matter were used as synthetic polluted water. Denitrification of the nitrate polluted water without organic matter proceeded effectively by utilizing hydrogen gas produced by electrolysis of water in the reactor. The bio-electro reactor was also available for the treatment of nitrate polluted water containing organic matter when the C/N concentration ratio was up to 1.0 under the condition of 100 mA of applied electric current. The nitrate removal efficiency from nitrate polluted water containing acetate at C/N=1.0 was more than 90% at 5 hours of HRT and 80% even at 2.8 h HRT. For the treatment of ammonium polluted water, nitrification and denitrification proceeded simultaneously in a bio-electro reactor where nitrifying and denitrifying microorganisms were immobilized on the electrodes. The results obtained in this study suggested that the bio-electro reactor system was capable to application for oxidation and reduction treatments of the nitrate and ammonium polluted water.

scholarly journals Indigenous Lipase Producing Bacteria for Lipid-rich Wastewater Treatment

2022 ◽  
Vol 31 (2) ◽  
pp. 135-142
Author(s):  
Lovely Aktar ◽  
Mohammad Moniruzzaman ◽  
Yasuzo Sakai ◽  
Mihir Lal Saha
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Organic Matter ◽  
Wastewater Treatment ◽  
Bacillus Subtilis ◽  
Plant Tissue ◽  
Stenotrophomonas Maltophilia ◽  
Treatment Plant ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Removal Efficiencies

This study was undertaken to evaluate the removal of lipid-rich organic matter from wastewater by lipase producing bacteria. Ten potential lipase producing bacteria were isolated from lipid-rich environments in and around Dhaka Metropolitan city. Three of them produced lipase higher than 10 U/ml. These three isolates and their consortium were used for synthetic wastewater treatment in the laboratory. The initial COD value of synthetic wastewater was 1,200 mg/l. COD removal efficiencies in the synthetic wastewater were 74.75, 73.33 and 66.67% by the Stenotrophomonas maltophilia e-a22, Pseudomonas aeruginosa 12 and Bacillus subtilis 20B, respectively. Stenotrophomonas maltophilia showed better COD removal performance (74.75%) in case of monoculture. But consortium showed better COD removal (83.33%) than that of monoculture. Therefore, it could be concluded that consortium of three isolates will be more useful for wastewater treatment as seed cultures in the wastewater treatment plant associated with the lipid-rich wastewater. Plant Tissue Cult. & Biotech. 31(2): 135-142, 2021 (December)

Application of a bio-electrochemical reactor process to direct treatment of metal pickling wastewater containing heavy metals and high strength nitrate

2004 ◽  
Vol 50 (8) ◽  
pp. 111-118 ◽  
Author(s):  
T. Watanabe ◽  
H.W. Jin ◽  
K.J. Cho ◽  
M. Kuroda
Keyword(s):  
Heavy Metals ◽  
Electric Current ◽  
Ph Value ◽  
Electrochemical Reactor ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Synthetic Wastewater ◽  
Carbon Anode ◽  
Lead Removal ◽  
Direct Treatment

The fundamental performance of a bio-electrochemical reactor for the direct treatment of metal ickling wastewater was investigated experimentally. In the reactor, carbon anode and cathode were installed. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions, copper and lead, under different operating conditions. Acetate as well as the electric current was supplied at the minimum amount for stoichiometry of the dissimilatory denitrification reaction. The results indicated that the dissolved copper and lead removal, denitrification and neutralization could be achieved simultaneously in a single bio-electrochemical reactor. The dissolved heavy metals were removed by electrochemical deposition on cathode and by the other phenomena such as the formation of insoluble suspensions and the sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both added acetate and hydrogen gas generated by electrolysis of water. The pH value increased up to around neutral due to the occurrence of denitrification in the reactor, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with increasing the current density. The applied electric current was indispensable for sustaining the stable treatment in the reactor.

Upgrading Wastewater Treatment by Water Hyacinth in Developing Countries

1990 ◽  
Vol 22 (7-8) ◽  
pp. 153-160 ◽  
Author(s):  
Pradeep Kumar ◽  
R. J. Garde
Keyword(s):  
Wastewater Treatment ◽  
Water Hyacinth ◽  
Treatment Plant ◽  
Cod Removal ◽  
Treatment System ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Treatment Unit ◽  
Batch Studies ◽  
New Treatment

With increasing stress on existing wastewater treatment systems, it is necessary either to upgrade the treatment unit(s) or install an entirely new treatment plant. Obviously, the upgrading is preferred over the alternative of having a new system. Keeping this in view, in the present project, an attempt has been made to explore the possibility of upgrading existing facultative ponds using water hyacinth. Bench-scale batch studies were designed to compare the performance of hyacinth treatment system with facultative ponds. Investigations were carried out with synthetic wastewater having COD in the range of 32.5-1090 mg/l. The efficiency of COD removal in water hyacinth ponds was 15-20 percent more than the facultative ponds. Based on the results, an empirical model has been proposed for COD removal kinetics. In the second phase of the project a hyacinth pond was continuously operated. BOD, COD, TS, TN, TP, pH, and DO were regularly monitored. However, the DO of the effluent from hyacinth treatment system was considerably reduced. Effluent should be aerated before it is discharged. The results indicate that the existing facultative ponds can be stalked with water hyacinth to improve their performance as well as hyacinth treatment systems can be installed to support the conventional treatment.

Hydrolysis of organic wastewater particles in laboratory scale and pilot scale biofilm reactors under anoxic and aerobic conditions

1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës
Keyword(s):  
Organic Matter ◽  
Mass Balance ◽  
Particulate Organic Matter ◽  
Removal Rate ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Synthetic Wastewater ◽  
Aerobic Conditions ◽  
Biofilm Reactors ◽  
Hydrolysis Of

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.

scholarly journals Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
Author(s):  
M. Alkhatib ◽  
P. A. del Giorgio ◽  
Y. Gelinas ◽  
M. F. Lehmann
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bottom Water ◽  
Estuarine Sediments ◽  
Internal Source ◽  
Lawrence Estuary ◽  
Element Partitioning ◽  
Sediment Porewaters ◽  
St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Treatment of Sugar Containing-Low Strength Wastewater at 20°C by Anaerobic Granular Sludge Bed Reactor

2010 ◽  
Vol 5 (3) ◽  
Author(s):  
W. Yoochatchaval ◽  
K. Kubota ◽  
T. Kawai ◽  
T. Yamaguchi ◽  
K. Syutsubo
Keyword(s):  
Stable Process ◽  
Growth Yield ◽  
High Growth ◽  
Granular Sludge ◽  
Post Treatment ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Anaerobic Granular Sludge ◽  
Treatment Technology ◽  
Low Strength

To investigate the feasibility of anaerobic wastewater treatment technology for low strength sugar refinery wastewater (0.4 - 0.5 g COD/L), an 8.8 L volume of anaerobic granular sludge bed reactor was operated at 20°C for 400 days. The operation mode was combination of one pass flow (UASB, 50 min) and effluent-recirculation (EGSB, 10 min) mode. The aerobic down-flow hanging sponge (DHS) reactor was installed as a post-treatment. During the started-up period, reactors were fed with synthetic wastewater at overall HRT of 3 hours (anaerobic 2 hours, aerobic 1 hour). After day 85, feed was changed to real wastewater together with supplement of nutrients, trace elements and NaHCO3. The sufficient COD removal efficiency (85% SD±6.2) and stable process performance were elicited from the granular sludge bed reactor.Also, post-treatment (DHS reactor) offered good quality of effluent (45 mg COD/L, 7 mg BOD/L) and it achieved the discharge standard. Increasing of sulfate concentration of wastewater caused higher contribution of sulfate reducing bacteria for COD removal. The sludge concentration and settleability were well maintained thoroughly. However, floatation of large size granule was observed in the later part of experiment. This phenomenon may attribute to the high growth yield of retained sludge at 20°C.

scholarly journals Theoretical Study on the Mechanism of Hydrogen Donation and Transfer for Hydrogen-Donor Solvents during Direct Coal Liquefaction

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 648 ◽  
Author(s):  
Haigang Hao ◽  
Tong Chang ◽  
Linxia Cui ◽  
Ruiqing Sun ◽  
Rui Gao
Keyword(s):  
Density Functional ◽  
Hydrogen Gas ◽  
Hydrogen Donor ◽  
Coal Liquefaction ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Donor Solvent ◽  
National Energy Security ◽  
Liquefaction Process ◽  
Direct Coal Liquefaction

As a country that is poor in petroleum yet rich in coal, it is significant for China to develop direct coal liquefaction (DCL) technology to relieve the pressure from petroleum shortages to guarantee national energy security. To improve the efficiency of the direct coal liquefaction process, scientists and researchers have made great contributions to studying and developing highly efficient hydrogen donor (H-donor) solvents. Nevertheless, the details of hydrogen donation and the transfer pathways of H-donor solvents are still unclear. The present work examined hydrogen donation and transfer pathways using a model H-donor solvent, tetralin, by density functional theory (DFT) calculation. The reaction condition and state of the solvent (gas or liquid) were considered, and the specific elementary reaction routes for hydrogen donation and transfer were calculated. In the DCL process, the dominant hydrogen donation mechanism was the concerted mechanism. The sequence of tetralin donating hydrogen atoms was α-H (C1–H) > δ-H (C4–H) > β-H (C2–H) > γ-H (C3–H). Compared to methyl, it was relatively hard for benzyl to obtain the first hydrogen atom from tetralin, while it was relatively easy to obtain the second and third hydrogen atoms from tetralin. Comparatively, it was easier for coal radicals to capture hydrogen atoms from the H-donor solvent than to obtain hydrogen atoms from hydrogen gas.

A Study of Anaerobic Treatment for Highly Concentrated SO42− + Ca2+-Rich Organic Wastewater and Purified Water Reclamation

1991 ◽  
Vol 24 (5) ◽  
pp. 123-132 ◽  
Author(s):  
Ding Zhou ◽  
Yanmin Chen ◽  
Xianlin Meng
Keyword(s):  
Single Cell ◽  
Removal Efficiency ◽  
Anaerobic Treatment ◽  
Single Cell Protein ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Cell Protein ◽  
Water Reclamation ◽  
Volume Loading ◽  
Fermentation Temperature

This paper reports the effects of anaerobic treatment for synthetic wastewater and SO2−+Ca2+- rich single-cell protein (SCP) wastewater in a factory. The results show that with the increase of SO2−4+Ca2+concentration, methane productivity will decrease, and that Ca2+ affects the COD removal in wastewater greatly. However, if certain compounds are added in, and acclimated, these disadvantages will be overcome satisfactorily. For SCP wastewater, the COD removal efficiency can reach 75% and methane productivity 260-320 1 CH4/kg COD under the conditions of fermentation temperature of 36±l°C and COD volume loading of 2.3-2.8 kg/m3d. Besides, the purified wastewater can basically be reclaimed.

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