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Mechanisms for Reduced Excess Sludge Production in the Cannibal Process

Marc-André Labelle, Peter L. Dold and Yves Comeau

Article (2015)

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Cite this document: Labelle, M.-A., Dold, P. L. & Comeau, Y. (2015). Mechanisms for Reduced Excess Sludge Production in the Cannibal Process. Water Environment Research, 87(8), p. 687-696. doi:10.2175/106143015x14338845156669
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Reducing excess sludge production is increasingly attractive as a result of rising costs and constraints with respect to sludge treatment and disposal. A technology in which the mechanisms remain not well understood is the Cannibal process, for which very low sludge yields have been reported. The objective of this work was to use modeling as a means to characterize excess sludge production at a full-scale Cannibal facility by providing a long sludge retention time and removing trash and grit by physical processes. The facility was characterized by using its historical data, from discussion with the staff and by conducting a sampling campaign to prepare a solids inventory and an overall mass balance. At the evaluated sludge retention time of 400 days, the sum of the daily loss of suspended solids to the effluent and of the waste activated sludge solids contributed approximately equally to the sum of solids that are wasted daily as trash and grit from the solids separation module. The overall sludge production was estimated to be 0.14 g total suspended solids produced/g chemical oxygen demand removed. The essential functions of the Cannibal process for the reduction of sludge production appear to be to remove trash and grit from the sludge by physical processes of microscreening and hydrocycloning, respectively, and to provide a long sludge retention time, which allows the slow degradation of the “unbiodegradable” influent particulate organics (XU,Inf) and the endogenous residue (XE). The high energy demand of 1.6 kWh/m3 of treated wastewater at the studied facility limits the niche of the Cannibal process to small- to medium-sized facilities in which sludge disposal costs are high but electricity costs are low.

Uncontrolled Keywords

sludge minimization; sludge age; physical separation; hydrocyclone; microscreening; side-stream interchange; bioreactor; fermentation; energy

Open Access document in PolyPublie
Subjects: 1000 Génie civil > 1000 Génie civil
1000 Génie civil > 1006 Génie hydrologique
1000 Génie civil > 1007 Ressources et approvisionnement en eau
Department: Département des génies civil, géologique et des mines
Research Center: Non applicable
Funders: CRSNG/NSERC - Collaborative Research and Development (CRD), Veolia Water, John Meunier Inc, EnviroSim Associates, City of Saint-Hyacinthe
Date Deposited: 16 Aug 2021 13:05
Last Modified: 22 Oct 2021 16:46
PolyPublie URL: https://publications.polymtl.ca/9086/
Document issued by the official publisher
Journal Title: Water Environment Research (vol. 87, no. 8)
Publisher: Wiley
Official URL: https://doi.org/10.2175/106143015x14338845156669


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