Integrated anaerobic treatment of dairy industrial wastewater and sludge

Performance parameters were studied in an alternative full-scale dairy effluent treatment system comprising two anaerobic sludge-blanket reactors in parallel arrangement with upward flow, internal fat-separation by flotation, external lamella settler and floated material digester. Reactors were initially inoculated with flocculent sludge and granulated in a high-load stage. Using loading rates up to a maximum 5.5kgCOD/m(3).d-hydraulic residence time of 17 hours-reactor efficiency was found to remain stable around 90% of COD. Average sludge digester efficiency using a loading rate of 3.5kgVS/m(3).d with a lipid content of 47% of COD amounted to 78% of VS (87% of lipid removal). LCFA inhibition as assayed using palmitate was found to depend not only on the palmitate concentration but also on the palmitate-to-biomass concentration ratio.