Journal of Fundamentals of Renewable Energy and Applications
Open Access
ISSN: 2090-4541
ISSN: 2090-4541
A E Maragkaki and T Manios
Technological Educational Institute of Crete, Greece
Posters & Accepted Abstracts: J Fundam Renewable Energy Appl
Anaerobic co-digestion of sewage sludge and other organic wastes at a wastewater treatment plant is a promising method for both energy and material recovery. Some agro-industries such as olive oil mills and cheese factories represent a considerable share of the Mediterranean countries economy. The by-products of olive oil production such as olive mill wastewaters pose a serious environmental risk. Cheese whey is a by-product during cheese manufacturing. This article focuses on a thermal pre-treatment mixture of food waste and two representatives, seasonally produced agro-industrial wastes, for Greece: olive mill waste water and cheese whey. Optimization of biogas production from sewage sludge was attempted by co-digesting with a mixture of food waste, cheese whey and olive mill wastewater (FCO). A series of laboratory experiments were performed in continuously-operating reactors at 37oC, fed with thermal pre-treated mixtures of FCO at various concentrations 3%, 5% and 7% (v/v). FCO addition can boost biogas yields, if the mixture exceeds 3% concentration in the feed. Any further increase of 5% FCO causes a small incensement in biogas production. The reactor treating the sewage sludge produced 287 ml CH4/Lreactor/d before the addition of FCO and 815 ml CH4/ Lreactor/d (5% in the feed). The extra FCO-COD added (7% FCO) to the feed showed no negative effect on reactor performance, but seemed to have the same results (fig.1). In all cases, biodegradability of mixtures estimated to be higher than 80%, while the VS removal was 22% for the maximum biomethane production (5%). For the concept of co-digestion a mixture of pre-treated food waste, cheese whey and olive mill wastewater could be a promising perspective at wastewater treatment plants as it increases methane production significantly. Results show a great ascendancy of 5% and 7% FCO mixtures with sludge, as they improve significantly the biogas production rate.
Email: amaragkaki@staff.teicrete.gr