Process Engineering

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Browsing Process Engineering by Subject "Adsorption-Anaerobic Digestion"

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    Adsorption-Anaerobic Digestion coupling process for molasses vinasse Treating
    (Addis Ababa University, 2018-07) Mohammed, Seid; Shemelis, Kebede (PhD)
    The production of ethanol from biomass results in the co-current production of acidic material known as distillery spent wash or vinasse. It is generated at a rate of 10 to 15 times greater than the ethanol itself, and is characterized by a high dissolved organic matter content. Anaerobic digestion is the most effective methods for the treatment of such type of wastewater. In this work, a combined adsorption–anaerobic digestion treatment of distillery wastewater was studied in order to develop an effective procedure for increasing the anaerobic biodegradability of vinasse to reduce its environmental impact. The adsorption stage with banana peel as a pretreatment was evaluated for removal of phenolic compound. The removal of phenolic compound with this biosorbent was carried out using Box-Behnken experimental design taking 3 factors, adsorbent dose, contact time, and particle size. The maximum phenol removal recorded was 76.425% at the optimum condition (adsorbent dose of 20 g/L, contact time of 129.98 min, and particle size of 0.53 mm). Removals of 22% in chemical oxygen demand (COD) was obtained in this stage. Among the adsorption isotherm models analyzed, the Langmuir model fitted best to the experimental data with maximum adsorption capacity of 4.12 mg/g, and also the adsorption mechanism follows pseudo-second order model. The pretreated vinasse was undergone to an anaerobic digestion process in the second stage under mesophilic condition. After anaerobic digestion, a global removal of 84% in COD, and over 95% in phenols content were obtained. It was shown that, a combination of treatment method (i.e. banana peel biosorption and anaerobic digestion) is a promising option for simultaneous removal of phenol and COD from molasses vinasse under the stated conditions.