Treatment of Slaughterhouse Waste Water Mixed with Serum from Lacteal Industry of Extremadura in Spain to Produce Clean Energy

• Published in: Energies (Basel) Vol. 10; no. 6; p. 765
• Main Authors: Marcos, A. C., Al-Kassir, A., Cuadros, Francisco, Yusaf, Talal
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-06-2017
• Subjects: Abattoirs; Acetic acid; Acidity; Alternative energy sources; anaerobic biodigestion; Anaerobic digestion; Anaerobic processes; Anaerobic treatment; Biochemical oxygen demand; Biogas; Carbon dioxide; Chemical oxygen demand; Clean energy; Clean technology; Contaminants; Effluents; Fermentation; Flow velocity; lacteal serum; Lactose; Load distribution; Meat industry; Membrane reactors; Methane; Milk; Organic chemistry; Organic compounds; Pollution load; Propionic acid; Public health; slaughterhouse waste water; treatment; Waste treatment; Wastewater; Wastewater treatment; Water treatment; Mexico; Spain
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en10060765

[...]although anaerobic treatment is an efficient process, the slaughterhouse wastewater organic strength makes it difficult to achieve complete stabilization of the organic compounds [1,9]. According to experiment 1 (codigestion of slaughterhouse waste, Table 7), approximately similar values are obtained as for the input effluent of experiment 2 (codigestion of slaughterhouse waste + animal serum, Table 7), except for the case of chemical and biochemical oxygen demand and volatile acidity. [...]there are signs of propionic fermentation, which is carried out by the action of bacteria of the Propionibacterium type, fermenting lactic to propionic acid, acetic acid, CO2 and water. According to the optimal data described above, for the optimal flow rate of 350 mL/day, the influent, effluent, and degraded COD values are (Table 7): CODinfluent = 50,000 mg L−1 CODeffluent = 15,375 mg L−1 (HRT = 18 days) CODdegraded = CODinfluent − CODeffluent = 50,000 mg L1 − 15,375 mg L−1 = 34,625 mg L−1 - The laboratory digester used has a capacity of 6.2 L. The degraded COD from this reactor would be: 34,625 mg L−1 × 6.2 L = 214,675 mg = 0.2147 kg - In this experiment the total biogas production was 238 L. Hence, m3 CH4kgCODdegraded=0.238 m3 biogas0.2147 CODdegraded=1.1087 - Assuming a methane percentage of 74%, m3 CH4kgCODdegraded=1.1087×0.74=0.8204 - For a flow rate of 0.35 L/day, with a contaminant load of 50 g COD/L, the productivity is: 0.35 L day−1 × 50 g COD.L−1 = 0.0175 kg COD day−1 - It can be concluded that 1.1087 m3 N of biogas per kg COD can be obtained, with a concentration of 74% methane.