Development of a test method to assess the sludge reduction potential of aquatic organisms in activated sludge

Buys, B.; Klapwijk, A.; Elissen, H.J.H.; Rulkens, W.H.

doi:10.1016/j.biortech.2008.02.041

Cited by 46 publications

(17 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This aerobic VS reduction is in the same order of magnitude as the averaged results presented in this study, which were about 47% ± 15 for WP and 30% for extended aeration (ER-30). Similar results were reported by Buys et al [52], who showed that worm predated and endogenously respirated sludge both reached similar VS degradation levels of about 58% with a difference in incubation time of 46 days. Surprisingly Tamis et al [21] found 20-30% aerobic VS reduction by WP and an additional 40-55% VS reduction upon anaerobic storage of the worm predated sludges.…”

Section: Discussionsupporting

confidence: 90%

See 1 more Smart Citation

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

View full text Add to dashboard Cite

Worm predation (WP) on activated sludge leads to increased sludge degradation rates, irrespective of the type of worm used or reactor conditions employed. However, the cause of the increased sludge degradation rates remains unknown. This paper presents a comparative analysis of the physical and biochemical aspects of predated sludge, providing insight into the hydrolytic mechanisms underlying WP. To this end, the sessile worm Tubifex tubifex was used as a model oligochaete and was batch cultivated in an 18-L airlift reactor. Predation on activated sludge showed an average reduction rate of 12 ± 3.8%/d versus 2 ± 1.3%/d for endogenous respirated sludge. Sludge predation resulted in an increased release of inorganic nitrogen, phosphate and soluble chemical oxygen demand (sCOD). The sCOD consisted mainly of polysaccharides; however, fluorescence excitation emission matrix spectroscopy analysis also revealed the presence of Tryptophan-protein-like substances. Results suggest that the released polysaccharides contain a protein-like element. Additionally, soluble iron increased slightly in concentration after WP. The extent of hydrolysis seemed to reach an average plateau of about 40% volatile solids (VS) reduction after 4 days, which is substantially higher than the 29% VS reduction for endogenous decay of activated sludge after 30 days. Furthermore, T. tubifex predominantly consumed the protein fraction of the extracellular polymeric substances. Results suggest that that the worms specifically target a fraction of the sludge that is predominantly biodegradable under aerobic conditions, albeit at significantly higher degradation rates when compared to the endogenous decay of waste activated sludge. ARTICLE HISTORY

show abstract

Section: Discussionsupporting

confidence: 90%

“…In agreement with the recommendations by Buys et al [52] regarding WP, approximately 45 g/L wet weight worms were used, which was indeed sufficient to give a clear distinction between the WP sludge and the ER sludge within the duration of the batch experiment.…”

Section: Sludge Degradation and Physical Characteristicsmentioning

confidence: 55%

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

View full text Add to dashboard Cite

show abstract

“…Initially, research focused on extending the food web with aquatic worms that naturally occur in WWTPs. However, this process proved impossible to control and high worm densities could not be maintained [3,4]. Further research therefore focused on separate worm reactors in which conditions could be optimized for the worms [2].…”

Section: Waste Sludge Production From Waste Water Treatmentmentioning

confidence: 97%

“…However, these techniques may be costly and are mainly aimed at lowering the amount of waste sludge, without a focus on resource recovery. A biological approach for reducing the amount of waste sludge is the use of the aquatic worms [3]. Initially, research focused on extending the food web with aquatic worms that naturally occur in WWTPs.…”

Section: Waste Sludge Production From Waste Water Treatmentmentioning

confidence: 99%

Aquatic worms eat sludge: Mass balances and processing of worm faeces

Hendrickx¹,

Temmink²,

Elissen³

et al. 2010

Journal of Hazardous Materials

View full text Add to dashboard Cite

“…Treatment and disposal of sewage sludge is one of the most critical environmental issues today [2,3], with costs for these processes accounting for about half, even up to 60%, of the total wastewater treatment expense [4][5][6][7][8][9]. Thus, identifying simple technologies for sludge reduction and stabilization with low operation and maintenance costs is a high priority [10,11].…”

Section: Introductionmentioning

confidence: 99%