Treatment of thermophilic hydrolysis reactor effluent with ceramic microfiltration membranes
- 110 Downloads
For an undisturbed operation of two-stage high-pressure fermentation up to 100 bar, a particle-free hydrolysate appears to be necessary. This is even more important if the second stage, i.e., the methane reactor, is designed as fixed bed. Here, we present the potential of microfiltration membranes as separation unit after the first stage, which is the hydrolysis. The study included the selection of membrane material, membrane performance investigations, and long-term-behavior during the filtration period. In a series of experiments, the optimum type of membrane material and the mode of operation [either crossflow (CF) or submerged (S)] were determined. Ceramic membranes proved to be the better option to treat the process stream due to their chemical and temperature resistance. The crossflow filtration achieved a sustainable flux of up to 33 L/(m2 h), while long-term experiments with the submerged membranes confirmed a critical flux of 7 L/(m2 h). Comparative analyses of hydrolysate and permeate showed that the rejected chemical oxygen demand (COD) as well as total organic carbon (TOC) fraction and thereby the loss of organic carbon in the permeate does not reduce the methane yield.
KeywordsMicrofiltration Ceramic membranes Thermophilic treatment Anaerobic filtration Hydrolysis reactor High-pressure fermentation
This research was supported by the German Ministry for Education and Research (BMBF), funding code 03EK3526B.
- 4.Merkle W, Baer K, Haag NL, Zielonka S, Ortloff F, Graf F, Lemmer A (2017) High-pressure anaerobic digestion up to 100 bar: influence of initial pressure on production kinetics and specific methane yields. Environ Technol 38(3):337–344. https://doi.org/10.1080/09593330.2016.1192691 CrossRefPubMedGoogle Scholar
- 8.Martinez-Sosa D, Helmreich B, Netter T, Paris S, Bischof F, Horn H (2011) Anaerobic submerged membrane bioreactor (AnSMBR) for municipal wastewater treatment under mesophilic and psychrophilic temperature conditions. Biores Technol 102(22):10377–10385. https://doi.org/10.1016/j.biortech.2011.09.012 CrossRefGoogle Scholar
- 15.Qiao W, Takayanagi K, Niu Q, Shofie M, Li YY (2013) Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas. Biores Technol 149:92–102. https://doi.org/10.1016/j.biortech.2013.09.023 CrossRefGoogle Scholar
- 16.Qiao W, Takayanagi K, Shofie M, Niu Q, Yu HQ, Li Y-Y (2013) Thermophilic anaerobic digestion of coffee grounds with and without waste activated sludge as co-substrate using a submerged AnMBR: System amendments and membrane performance. Biores Technol 150:249–258. https://doi.org/10.1016/j.biortech.2013.10.002 CrossRefGoogle Scholar
- 17.Wijekoon KC, Visvanathan C, Abeynayaka A (2011) Effect of organic loading rate on VFA production, organic matter removal and microbial activity of a two-stage thermophilic anaerobic membrane bioreactor. Biores Technol 102(9):5353–5360. https://doi.org/10.1016/j.biortech.2010.12.081 CrossRefGoogle Scholar
- 28.VDI Society Energy and Environment (2016) VDI 4630:2016-11: Fermentation of organic materials - Characterization of the substrate, sampling, collection of material data, fermentation testsGoogle Scholar