Fast Start-Up of a Deammonification SBR Treating Sludge Digestate

Due to environmental considerations, the energy savings become an important topic in water treatment. Sludge digestion represents an easy way to create energy in a plant, but one of its major effects is the impact of the return effluent on the main wastewater liquid line treatment. The contribution from the recycled digester supernatant to the plant influent may represent up to 20% of the total nitrogen load. This article presents the results obtained on a full-scale pilot plant processing supernatant coming from digested biosolids and implementing a deammonification treatment. This process is economically very attractive as only a part of ammonia is oxidized to nitrite and deammnification without any external biodegradable carbon converts the residual ammonia and nitrite to nitrogen gas. Two major results are obtained. Deammonification was installed without external biomass addition in a few months and this activity was very stable and well regulated over the one year pilot study.