title: A systematic study on the effect of substrate acidification degree and acidogenic biomass on sludge filterability.
abstract: The influence of substrate acidification on sludge filtration characteristics was systematically investigated by using short term filtration tests. Four reactors were operated with raw and acidified whey permeate in order to evaluate the effect of acidogens on sludge filterability. The results showed that feeding non-acidified substrate promoted the growth of acidogens which in return decreased the median particle size of the sludge and adversely influenced specific resistance to filtration (SRF). In addition to the presence of acidogens, the food to mass (F:M) ratio was found as an important operation parameter on sludge filterability. Various filterability indicators, such as capillary suction time (CST), SRF and supernatant filterability, tended to became worse at increased F:M ratios. The decreased filterability at high F:M ratio was attributed to the accumulation of soluble microbial products (SMP) in the reactors. Interestingly, impact of acidogens on short term critical flux tests was not significant, but this may be a consequence of the experimental set-up.
authors.affiliation: Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Watermanagement, Sanitary Engineering Section, Stevinweg 1, 2628 CN Delft, The Netherlands; Istanbul Technical University, Civil Engineering Faculty, Environmental Engineering Department, Maslak, 34469 Istanbul, Turkey; Biothane Systems International, Tanthofdreef 21, 2600 GB Delft, The Netherlands. Electronic address: R.K.Dereli@tudelft.nl.
authors.forename: Recep Kaan
authors.initials: RK
authors.lastname: Dereli
authors.affiliation: Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Watermanagement, Sanitary Engineering Section, Stevinweg 1, 2628 CN Delft, The Netherlands.
authors.forename: Lefki
authors.initials: L
authors.lastname: Loverdou
authors.affiliation: Biothane Systems International, Tanthofdreef 21, 2600 GB Delft, The Netherlands.
authors.forename: Frank P
authors.initials: FP
authors.lastname: van der Zee
authors.affiliation: Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Watermanagement, Sanitary Engineering Section, Stevinweg 1, 2628 CN Delft, The Netherlands.
authors.forename: Jules B
authors.initials: JB
authors.lastname: van Lier
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D019149:Bioreactors; D005374:Filtration / Q000379:methods; D007220:Industrial Waste; D010316:Particle Size; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D000067796:Whey / Q000737:chemistry
chemical_list: D007220:Industrial Waste; D012722:Sewage
keywords: Acidogens; Anaerobic membrane bioreactors; Filterability; Food to mass ratio; Whey