Abstract
A vacuum thermal stripping process coupled with acid absorption has been developed at laboratory scale to recover ammonia in anaerobic digestate. To make this ammonia recovery process scalable, this study investigated the effects of feed depth on vacuum thermal stripping in a pilot system, developed sodium hydroxide dosages required to raise feed pH for stripping, and simulated the dynamics of ammonia reduction in batch stripping tests. As feed depth was increased from 8.5 to 34.0 cm, the ammonia mass transfer coefficient and ammonia stripping efficiency decreased while the mass of stripped ammonia increased. Digested municipal sludge had a greater ammonia mass transfer coefficient than digested dairy manure at each feed depth, which could be attributed to the difference in suspended and dissolved solids concentrations. The optimum feed depth was 18 cm of the digested sludge and 14 cm of the digested manure. Sodium hydroxide dosage for the digested manure was higher than that for the digested sludge and co-digested foodwaste. The dosages were correlated to concentrations of total dissolved solids and ammonia. Total ammonia concentration decreased exponentially in batch stripping of the digested sludge at 25.5 cm deep, with a first-order stripping rate coefficient of 0.087-0.144 h-1.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
