Effect of Ca(OH) 2 dosing on thermophilic composting of anaerobic sludge to improve the NH 3 recovery.

Autor: Koyama M; School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan. Electronic address: koyama.m.ad@m.titech.ac.jp., Nagao N; Department of Aquaculture, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor Darul Ehsan, Malaysia., Syukri F; Department of Aquaculture, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor Darul Ehsan, Malaysia., Yusoff FM; Department of Aquaculture, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor Darul Ehsan, Malaysia., Toda T; Faculty of Science and Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo 192-8577, Japan., Quyen TNM; School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan., Nakasaki K; School of Environment and Society, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2019 Jun 20; Vol. 670, pp. 1133-1139. Date of Electronic Publication: 2019 Mar 21.
DOI: 10.1016/j.scitotenv.2019.03.320
Abstrakt: The primary biological treatment method for organic sludge is composting and/or anaerobic digestion, but their product (compost or biogas) is of little economic benefit; therefore, an improved process to produce a high-value product is required to make sludge management more sustainable. Maximizing NH 3 gas recovery during composting processes has the potential benefit of producing high-value microalgal biomass. However, the majority of produced ammonia does not evaporate as NH 3 gas but retains as NH 4 + -N in the compost after fermentation. The present study investigates the effects of the timing of Ca(OH) 2 dosing (on days 2, 5, and 9), and the Ca(OH) 2 dose (1.1-2.6 mmol/batch), on lab-scale thermophilic composting of anaerobic sludge. The effects on NH 3 recovery, organic matter degradability, and microbial activity are evaluated. Ca(OH) 2 dosing immediately improved the emission of NH 3 , with yields 50-69% higher than those under control conditions. The timing of the dosing did not influence NH 3 recovery or organic matter degradability. Higher Ca(OH) 2 doses resulted in higher NH 3 recovery, while microbial activity was temporarily and marginally inhibited. The pH of the compost reached 10-11.5 but quickly dropped to 8-8.5 within a day, probably because of neutralization of Ca(OH) 2 by the emitted CO 2 and release of NH 3 , which maintained the microbial activity. The present study indicated that Ca(OH) 2 dosing would be useful to apply during thermophilic composting for NH 3 recovery to cultivate high-value microalgal biomass, which enables this process to obtain a more economic benefit.
(Copyright © 2019 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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