Biomethanization of mixtures of fruits and vegetables solid wastes and sludge from a municipal wastewater treatment plant

• Published in: Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering Vol. 42; no. 4; pp. 481 - 487
• Main Authors: Gomez-Lahoz, C., Fernández-Giménez, B., Garcia-Herruzo, F., Rodriguez-Maroto, J. M., Vereda-Alonso, C.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.03.2007
• Subjects: Allelochemicals; Anaerobic digestion; Biodegradation, Environmental - drug effects; Calcium Hydroxide - pharmacology; Carbon - analysis; energy recovery; Fruit; Fruits; Hydrogen - analysis; Hydrogen-Ion Concentration; Kinetics; Methane; Methane - biosynthesis; Nitrogen - analysis; Phosphates - analysis; recycling; Reduction; Refuse Disposal - methods; Sewage - analysis; Sludge; Sodium Bicarbonate - pharmacology; soil amendment; Soils; Solid wastes; Vegetables; Waste Disposal, Fluid; waste management; Wastewater treatment
• ISSN: 1093-4529; 1532-4117
• DOI: 10.1080/10934520601187856

The possible management of Fruit and Vegetable Solid Wastes (FVSWs) through their simultaneous digestion with the primary sludge of Municipal Wastewater Treatment plants is investigated. This alternative allows the recovery of energy and a solid product that can be used as an amendment for soils that generated the residue, while is not expensive. Results indicate that the ratio of FVSWs to sludge and the pH control are the main variables determining the methane production and concentration. NaHCO 3 was selected to achieve the pH control. The results for a ratio of 50% sludge together with 10 g NaHCO 3 /kg of residue are among the best obtained, with a methane yield of about 90 L per kg of volatile solids, and a methane concentration of 40% (v/v) of the biogas. A 50% reduction of the total solids; 21% reduction of the volatile solids (in terms of total solids); and a pH value of the sludge, which is 6.9 indicate that the digested sludge can be a good material for soil amendment.