Browsing by Author "Ukundimana, Zubeda"

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    Anodic oxidation of effluents from stages of MBR-UF Municipal landfill leachate treatment plant
    (Mary Ann Liebert, 2020-05-18) Ukundimana, Zubeda; Kobya, Mehmet; Omwene, Philip Isaac; Gengec, Erhan; Can, Orhan Taner
    This study used boron-doped diamond electrode on niobium substrate (Nb/boron-doped diamond [BDD]) for the anodic oxidation of landfill leachate in a batch reactor. Raw leachate and biologically pretreated effluent samples were collected from each step of the existing unit operation of a municipal landfill leachate treatment plant (Kocaeli-Turkey). The influence of parameters, such as treatment time, initial pH (3.50–10.0), and applied current density (j = 76–1,060 A/m2), on the removal of total organic carbon (TOC), chemical oxygen demand (COD), and ammonium nitrogen (NH4+-N) was assessed. The highest pollutant removal efficiencies were obtained at leachate inherent pH (6.50–8.75), moreover, pollutant removal rates increased with the increase in current density. The NH4+-N removal mainly occurred by indirect oxidation and well fitted second-order kinetics, whereas COD removal followed pseudo first-order kinetics. The optimum current density ensuring simultaneous removal of COD and NH4+-N was 756 and 455 A/m2 for raw leachate and for pretreated effluents, respectively. Under these optimums, nearly complete NH4+-N removal was attained, while ≥97% removal of TOC and COD was recorded. Herein, we present anodic oxidation as a suitable alternative for treatment of both stabilized raw leachate and effluents from stages of the membrane bioreactor/ultrafiltration treatment plant for the abatement of COD, TOC, and NH4+-N.
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    Phosphorous removal from anaerobically digested municipal sludge centrate by an electrocoagulation reactor using metal (Al, Fe and Al-Fe) scrap anodes.
    (Elsevier, 2021-06-02) Kobya, Mehmet; Omwenea, Philip Isaac; Sarabia, Sanaz Mohammadzadeh; Yildirim, Sadullah; Ukundimana, Zubeda
    Phosphates are a major cause of eutrophication and growth of algal blooms in surface waters. The current study investigated phosphorus removal from sludge centrate effluent (SCE) of a municipal wastewater plant by packed-bed electrocoagulation (EC) reactor. Distinctively, iron (Fe), aluminum (Al) and Al-Fe hybrid scrap anodes were used. The influence of initial pHi, applied current and packed anode bed density were evaluated. Phosphorous removal efficiency of 99.99 % was obtained at applied current of 0.20A with anode bed densities of 0.18 kg Al/m3 (pHi 5.0) and 0.48 kg Fe/m3(pHi 7.0). Optimum operating costs entailing sludge disposal, chemical, energy and electrode consumption were calculated as 0.379 US $/m3 (6.04 $/kg PO4-P) for Fe scrap, 0.494 US $/m3 (9.46 $/kg PO4-P) for Al scrap and 0.501 US $/m3 (9.59 $/kg PO4-P) for Al-Fe hybrid scraps. Phosphorus removal per electrochemically generated metal was 191.22 mg P/g Al, 104.88 mg P/g Fe, and 61.08 mg P/g (Al + Fe). The molar metal to phosphorus ratio at optimum conditions were calculated as 5.41, 3.97 and 7.65 mol/mole for Al, Fe and Al-Fe, respectively. The key mechanisms for phosphorus removal were metal-phosphorus precipitation and adsorption. Herein, metal scrap anodes have been proved effective for phosphorous removal from SCE.