Preliminary evaluation of Sharon-Anammox process feasibility to treat Ammonium-rich effluents produced by double-stage anaerobic digestion of food waste

In this study, a Sharon-Anammox system was started up and fed with an ammonium-rich (1,500 mgNH4-N L−1) synthetic medium simulating the effluent produced by double-stage anaerobic digestion of food waste (AD-FW). The effects of different process parameters (e.g., hydraulic retention time, nitrogen loading rate, etc.) and influent characteristics (e.g., influent alkalinity) on reactors performance were thoroughly evaluated. As to the Sharon reactor, reducing the hydraulic retention time did not cause any detrimental effect on overall process performance (the observed NH4-N removal efficiency and effluent NO2-N/NH4-N molar ratio were 60.8 ± 4.5% and 1.58 ± 0.27, respectively), although a slightly longer time was required to achieve process stability. The Anammox reactor was able to withstand the same nitrogen loading rates applied to the Sharon unit, and the observed nitrogen removal rate was high (89.9 ± 0.5%), indicating good process performance. The information gathered in this preliminary study will be useful for the treatment of real AD-FW wastewater.