Facing drawbacks in process stability of anaerobic sludge treatment at high shares of energy-rich co-substrates using biomass retention by microfiltration
This study focuses on sludge treatment by anaerobic digestion using high shares ofco-substrates (up to 90 % of total COD load) of a dairy processing industry.Limits on increasing shares and organic loading rates of a conventional CSTR are investigated using the sludge load as process parameter and compared to potentials of a system with biomass retention by microfiltration.At sludge retention times of 20 d,anaerobic degradation was extensively stable with additions ofco-substrate up to 70 % of total COD.While maximum sludge loads for stable operation differ on shares ofco-substrates and its degree of degradation,maximum COD removal rates ofrx,m =1.5 kg COD/(kg VS·d) were independent from shares of co-substrates.Therefore,the compliance with this maximum removal rate is the significant process parameter for operation at usual standard deviation of COD concentration and composition of feed sludge leading to maximum sludge loads of 2.2 kg COD/(kg VS·d) for a sludge mixture with a COD degradation of 70 % and a share of float sludge of 70 %.Higher shares of co-substrates (>70 %) resulted in lower process reliability as a result of the usual standard deviation of COD concentration and composition of feed sludge.In this case,digester systems with biomass enrichment for reduction of sludge load are recommended and can further lead to smaller reactor volumes.However,benefits and drawbacks,such as additional energy demands for membrane operation (2.5-4 kWhel/m3) and investment costs for the membrane (flux ~ 10 L/(m2·h),must be considered.
Industrial sludge treatment membrane filtration,co-digestion sludge load
R.Lutze J.Rühl M.Engelhart
Technische Universit(a)t Darmstadt, Institute IWAR, Franziska-Braun-Str.7, 64285 Darmstadt, Germany
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
169-172
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）