Effect of Organic Load and Alkalinity on Dairy Wastewater Biomethanation

Abstract

This study aimed to evaluate the effect of variations in organic load (hydraulic retention times -HRTs: from 2 to 0.5 day) and in alkalinity (NaHCO3 from 4,000 to 1,000 mg.L -1 ) on methane production. Biomass of sewage sludge was inoculated and stabilized on 1" polypropylene rings. The rings were immersed in the liquid phase (8.41 L) of an upflow anaerobic filter reactor (12.22 L). A solution of 5 g of whole milk powder per liter was used to simulate effluent from the dairy industry. Process effectiveness was measured by chemical oxygen demand reduction, biogas production, and biogas methane content. Biogas production started at a 2-day HRT and synthetic effluent alkalinization with 4,000 mg.L -1 NaHCO3. The best operation condition was at 1-day HRT and with the addition of 4,000 mg.L -1 NaHCO3. Biogas production reached 1.5 NL of biogas per L of reactor liquid phase, with 68% of methane and a concomitant reduction in COD of 57%.

Methane and Electricity Production from Poultry Litter Digestion in the Amazon Region of Brazil: A Large-Scale Study

“…4 that the area with the highest peak corresponds to 52.5% CH 4 followed by the CO 2 peak that corresponds to 47.5%. These average values are close to those found by Kispergher et al [32], in which the percentage of CO 2 was in the range of 48% and 53% of methane. The values of CH 4 concentrations per unit area, in the two types of substrates, are very close, indicating that the change in the type of inoculum that supplies the reactors studied here, did not interfere in the variation of methane produced in the biogas plant.…”