Effect of Inoculums to Substrate Ratio on Thermophilic Anaerobic Digestion of the Dairy Wastewater

• Main Authors: B. Kheiredine, K. Derbal, M. Benchilehoucine
• Format: Article
• Language: English
• Published: AIDIC Servizi S.r.l. 2014-06-01
• Series: Chemical Engineering Transactions
• Online Access: https://www.cetjournal.it/index.php/cet/article/view/5839

This work focuses on the biodegradability of the organic pollution load of the dairy industry. The effects of various reports substrate/inoculums (S/I) are considered, respectively for (0), (0.2), (0.4), (0.8) and (1.6) in the thermophilic phase (55 °C). In addition, the monitoring of the variation of COD in all reactors is considered. The preliminary characterization of substrate (dairy waste), shows that it is rich in volatile matter (88.67%). Which encourages the treatment of the latter by anaerobic biological process. Similarly, the analysis results of alkalinity, ammonia nitrogen, organic nitrogen and phosphorus after incubation period for the considered organic loading rate (OLR), are below the values that can inhibited the anaerobic digestion process, although pH values (between 7.84 and 8.56) seems to be important. The cumulative volume of produced biogas increases with respect of the ratio (S / I), where the maximum production of biogas (1,553mL) corresponding to the highest ratio (S / I = 1.6), with a daily average production of 28.26 L / day. This is more than three times the lowest ratio (S / I = 0.2) and twice the average ratio (S / I = 0.4). However, qualitatively the ratio (S / I = 1.6) is less rich in methane (50.7 %) compared to the ratios (S / I = 0.8 and 0.4) which are of the order of 54.5 % and 58.3 %, respectively, but quantitatively, this decrease is largely compensated by the produced methane. Also, the abatement of total COD is considerable (84 %).