Deammonification of Dewatering Sidestream from Thermal Hydrolysis-Mesophilic Anaerobic Digestion Process

Abstract

In 2014, DC Water will begin operating a new solids processing train at the Blue Plains Advanced Wastewater Treatment Plant consisting of the CAMBI thermal hydrolysis process for solids pretreatment prior to mesophilic anaerobic digestion. DC Water has chosen sequencing batch reactors capable of nitritation-denitritation or deammonification (using the DEMON process) for separate biological treatment of the dewatering sidestream. As part of the sidestream treatment alternatives evaluation, studies were conducted using sidestream generated from an existing CAMBI-digestion plant to confirm the suitability of the DEMON process to treat such a sidestream and to provide insight on design loading rates and related issues. Experimental results reveal a significant reduction in nitrogen conversion rates-rather for the aerobic ammonia oxidizers than for the anammox organisms. Both biomass acclimation and decrease in refractory soluble COD concentrations could alleviate inhibitory impacts.

Impacts of feed dilution and lower solids retention time on performance of thermal hydrolysis/anaerobic digestion

“…Another potential advantage of feed dilution is that the concentration of sCOD leaving the digester is lower, and this could reduce inhibition of sidestream processes. For example, deammonification has been used to treat return liquors from THP‐AD systems and components in the filtrate have been shown to be inhibitory (Figdore et al., ; Zhang et al., ). Figdore et al.…”

Treating Liquors from Enhanced Digestion Facilities; Start-up, Commissioning and Optimization of a SHARON LTP at Whitlingham STC

“…At this lower ammonia concentration, the filtrate feed could be increased rapidly, showing nitritation rates typical for the SHARON process. Inhibition of nitritation in the treatment of digested CAMBI liquors was already observed in the laboratory tests and has also been reported by Figdore et al (2011). Possibly the cause of inhibition is related to high concentrations of volatile fatty acids (VFAs) in filtrate, upto 10,000 mg/l.…”

Design Considerations for a Multiple-Reactor DEMON Process Treating Sludge Liquors from a Thermal Hydrolysis Anaerobic Digester

“…Pilot testing was carried out to test removal rates for sludge liquors from a CAMBI system in order to determine if the DEMON process would be inhibited by them (Figdore, 2011). It was found that significant inhibition did occur, most notably to the AOBs, but that diluting the CAMBI liquors 1:1 with plant water reduced the inhibition to an acceptable level that enabled the DEMON process to remove ammonia at a volumetric loading rate of 0.6 kgN/m3/d.…”