The effect of temperature reduction on the performance and stability of UASB reactors treating synthetic sewage

Masood Abdusalam Ghanem Ali

Abstract


The objective of this investigation is to determine the effect of temperature reduction on the performance and stability of laboratory-scale up-flow anaerobic sludge blanket (UASB) treating synthetic sewage. The work was carried out using four 4-litre continuously fed UASB reactors. The operation started at a constant hydraulic retention time of ~24 hours (up flow velocity ~0.02 m hour-1) and an influent COD concentration of ~2250 mg l-1, with an organic loading rate of ~2.25 g COD l-1 day-1. During the experiment, the operating temperature was reduced in a single step from 35 to 30 ⁰C, then stepped down to 25 ⁰C. COD removal efficiency fell slightly from ~96 % in all reactors to ~93%. Effluent TSS concentrations remained below 20 mg l-1 and TSS removal efficiency ranged between 93-98%. Gas production showed a slight disturbance following the initial drop in temperature to 30 ⁰C, but stabilised at around 0.74 l CH4 l-1, 0.30 l CH4 g-1 COD added and 0.31 l CH4 g-1 COD removed. The subsequent drop to 25 ⁰C produced a stronger disturbance, but both volumetric and specific methane production recovered to the previous values by about day 412. The average biogas methane content in all reactors was unchanged or marginally higher at 78-79%.


Keywords


Methane (CH4); Chemical Oxygen Demand (COD); Total Suspended Solid (TSS); Organic Loading Rate (OLR); Hydraulic Retention Time (HRT); Specific Methane Production (SMP); Volumetric Methane Production (VMP)

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References


Azbar, N., et al. (2009) ‘Comparative evaluation of bio-hydrogen production from cheese whey wastewater under thermophilic and mesophilic anaerobic conditions’, International Journal of Green Energy, 6(2), pp. 192-200

Bodik, I., Herdova, B., & Kratochvil, K. (2000) ‘The application of anaerobic filter for municipal wastewater treatment’, Chemical Papers-Slovak Academy of Sciences, 54(3), pp. 159-164

Gómez, R. R. (2011) Upflow Anaerobic Sludge Blanket Reactor: Modelling’, Licentiate thesis, Chemical Engineering, School of Chemical Science and Engineering, Department of Chemical Engineering and Technology, Royal Institute of Technology, Stockholm, Sweden

Halalsheh, M. M. (2002) Anaerobic pre-treatment of strong sewage: a proper solution for Jordan, Wageningen Universiteit

Idrus, S. (2013) ‘Washing of wheat straw to improve its combustion properties with energy recovery by anaerobic digestion of the washwater’, PhD Thesis, Faculty of Engineering and the Environment University of Southampton, UK

Lettinga, G., Roersma, R., & Grin, P. (1983) ‘Anaerobic treatment of raw domestic sewage at ambient temperatures using a granular bed UASB reactor’ Biotechnology and Bioengineering, 25(7), pp. 1701-1723

Lew, B., Belavski, M., Admon, S., Tarre, S., & Green, M. (2003) ‘Temperature effect on UASB reactor operation for domestic wastewater treatment in temperate climate regions’, Water Science & Technology, 48(3), pp. 25-30

Seghezzo, L., et al. (1998) ‘A review: the anaerobic treatment of sewage in UASB and EGSB reactors’. Bioresour Technol, 65(3), pp. 175-190

Singh, K. S. and T. Viraraghavan (1996) ‘Low strength wastewater treatment by a UASB reactor’, Bioresource Technology, 55(3), pp.187-194

Singh, K. S. and T. Viraraghavan (1998) ‘Start-up and operation of UASB reactors at 20°C for municipal wastewater treatment’, Journal of Fermentation and Bioengineering, 85(6), pp. 609-614

Takahashi, M., Ohya, A., Kawakami, S., Yoneyama, Y., Onodera, T., Syutsubo, K., Yamakzaki, S., Araki, N., Ohashi, A, Harada, H., Yamaguchi, T. (2011). ‘Evaluation of treatment characteristics and sludge properties in a UASB reactor treating municipal sewage at ambient temperature’, International Journal of Environmental Research, 5(4), pp. 821-826

van Haandel, A. C. and G. Lettinga (1994) Anaerobic sewage treatment: a practical guide for regions with a hot climate, John Wiley & Sons

Whalley, C.P. (2008) ‘Performance of variable climate waste stabilisation ponds during the critical spring warm-up period’ PhD Thesis, University of Southampton, Southampton UK




DOI: https://doi.org/10.21776/ub.afssaae.2019.002.02.3

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