Impact of Organic Loading Rates on Variable-Temperature Biodigesters
MetadataShow full item record
Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Food, Agricultural and Biological Engineering Honors Theses; 2012
Anaerobic digestion has been studied under variable temperature conditions, but not to the extremes that occur in temperate climates. This experiment and analysis examine the performance of several organic loading rates under varying temperature conditions in order to make recommendations for improved management strategies for variable temperature digesters in temperate climates. Eight lab-scale digesters paired into four treatments were studied to assess the effects of temperature and organic loading rate (OLR) on digester performance when temperature was varied to simulate an annual cycle of a temperate climate (27ºC to 10ºC). Four loading rates were studied: high (1.3 kg VS (m3day)-1), medium (0.8), low (0.3), and inoculum (0.19). The HRT of these treatments ranged from 43 days ( high loading rate) to 188 days ( low loading rate). The digesters were subject to a temperature schedule designed to mimic the seasonal cycles of a temperate climate. After the beginning of the experiment at 27ºC, the temperature was gradually decreased to 10ºC before returning to 27ºC. The performance of all treatments declined as temperature decreased. The digester with the lowest loading rate recovered from its low performance once the temperature started increasing, but the digesters with the high and medium loading rates remained sour, with low pH and biogas production.
Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.