Australian Centre for Water
and Environmental Biotechnology

AWMC Seminar Program: Shao Dong Yap & Yifeng Xu

Pilot-scale leachbed digestion of livestock production residues: Effect of leachate recirculation mode (Shao Dong Yap)

Abstract: A leachbed is a high-rate, relatively low-cost anaerobic digestion technology suitable for high-solids agricultural residues. However, performance characteristics and optimal configuration of leachbed are not well-understood for such residues. Pilot-scale leachbeds were operated on digestion of spent straw bedding from swine/pigs, to assess the effects of hydraulic configuration (trickling and flood-anddrain). Results showed comparable biodegradable substrate solubilisation (60-70%) and methane conversion (50% of maximum extent) between trickling and flood-and-drain modes, indicating that digestion performance was insensitive to hydraulic configuration. However, upon closer investigation it was found that the flood-and-drain mode mobilised more of the unwanted non-biodegradable particulates into the leachate than the trickling mode, which could hinder performance at full-scale. Post digestion tests suggested that the leachbeds may be inhibited by microbial diversity or biological inhibition. Inoculation with digestate from a previous leachbed at inoculum-to-substrate ratio (ISR) of 0.22 expedited subsequent leachbed start-up, but conversion of organic matter into methane remained moderate at 50% of the maximum extent. Overall, the leachbeds demonstrated good potential for digesting agricultural residues, but there is a future need/opportunity to improve overall digestion performance.


Title: Biodegradation of atenolol by an enriched nitrifying sludge (Yifeng Xu)

Abstract: Biodegradation of â-blocker atenolol was investigated using an enriched nitrifying culture at controlled ammonium concentration and without ammonium addition. The results showed that atenolol biodegradation was clearly linked to the activity of ammonia-oxidizing bacteria following cometabolism. Four products were formed during atenolol biodegradation with ammonium oxidation, including P267, P117, P167, and an unknown product P227. In comparison, only P267 and P227 were identified without ammonium oxidation. A tentative biodegradation pathway of atenolol is suggested, which involves two steps independent on the presence of ammonium: i) microbial amide-bond hydrolysis to P267 and ii) formation of P227, and other two cometabolically induced reactions iii) breakage of ether bond in the alkyl side chain and formation of P117 and iv) N-dealkylation and loss of acetamide moiety from the aromatic ring, yielding P167.


Host: Advanced Water Management Centre
Event Details
Date & Time: 
Friday, 19 February 2016
9am - 10am
Venue: AIBN Building 75, Level 1 Seminar Room

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