Impact of Coagulant and Flocculant Addition to an Anaerobic Dynamic Membrane Bioreactor (AnDMBR) Treating Waste-Activated Sludge.
In this work, we investigated the effects of flocculation aid (FA) addition to an anaerobic dynamic membrane bioreactor (AnDMBR) (7 L, 35 °C) treating waste-activated sludge (WAS). The experiment consisted of three distinct periods. In period 1 (day 1-86), the reactor was operated as a conventional anaerobic digester with a solids retention time (SRT) and hydraulic retention time (HRT) of 24 days. In period 2 (day 86-303), the HRT was lowered to 18 days with the application of a dynamic membrane while the SRT was kept the same. In period 3 (day 303-386), a cationic FA in combination with FeCl₃ was added. The additions led to a lower viscosity, which was expected to lead to an increased digestion performance. However, the FAs caused irreversible binding of the substrate, lowering the volatile solids destruction from 32% in period 2 to 24% in period 3. An accumulation of small particulates was observed in the sludge, lowering the average particle size by 50%. These particulates likely caused pore blocking in the cake layer, doubling the trans-membrane pressure. The methanogenic consortia were unaffected. Dosing coagulants and flocculants into an AnDMBR treating sludge leads to a decreased cake layer permeability and decreased sludge degradation.
Department of Watermanagement, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628BC Delft, The Netherlands. guidok@gmail.com.
Guido
G
Kooijman
Department of Sanitary and Environmental Engineering, University of Paraiba State, Avenida Juvencio Arruda SN, Bairro Universitario, Campina Grande, Paraíba 58429-500, Brazil. wiltonuepb@gmail.com.
Wilton
W
Lopes
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China. zhouzhongbo-1986@163.com.
Zhongbo
Z
Zhou
Department of Watermanagement, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628BC Delft, The Netherlands. guo_hongxiao@hotmail.com.
Hongxiao
H
Guo
Department of Watermanagement, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628BC Delft, The Netherlands. m.k.dekreuk@tudelft.nl.
Merle
M
de Kreuk
Department of Watermanagement, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628BC Delft, The Netherlands. h.l.f.m.spanjers@tudelft.nl.
Henri
H
Spanjers
Department of Watermanagement, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628BC Delft, The Netherlands. j.b.vanLier@tudelft.nl.
Jules
J
van Lier
AnDMBR; anaerobic digestion; flocculant; membrane fouling reducer; viscosity