Reduction of Biological Sludge Production Applying an Alternating Oxic/anoxic Process in Water Line.

Alternating oxic/anoxic process, applied for the main objective of the improvement of nitrogen performances, was studied in terms of secondary effect of biomass reduction. The process was carried out in one real water resource recovery facility and the data were compared with the previous conventional period when a conventional process was adopted. The main mechanism of the process for the sludge minimization is recognized in the metabolic uncoupling. In fact, an increase of the specific oxygen uptake rate in the biological reactor was recorded stimulated by the change of the oxidation reduction potential environment. Moreover, the heterotrophic growth yield was measured equal to 0.385 kgVSS/kgCOD. The global percentage of reduction was tested with the mass balance of solids. The process is able to decrease the observed sludge yield up to 20%. The specific energy consumption was evaluated.