Performance and Stability of Two-Stage Anaerobic Digestion
The performance of mesophilic staged digestion and thermophilic-mesophilic staged digestion was studied in bench-scale reactors and pilot plant reactors, respectively, using combined waste activated and primary sludge. The objective of this research was to determine the enhanced solids destruction efficiency from a two-stage mesophilic digestion system compared to a single-stage mesophilic digester operated at the same total SRT of 20 days. A new digester monitoring method that measured the digester maximum acetate utilization capacity, Vmax,ac was investigated to evaluate the potential for digester stability at different transient loadings. The ratio of the Vmax,ac value to the estimated acetate production rate for a given digester loading was termed the acetate capacity number (ACN). Values greater than 1.0 indicate excess acetate utilization capacity. The laboratory staged digester had an improved VS and VSS destruction efficiency over the single-stage system by approximately 3.2 and 5.8 percentage points, respectively, which was statistically significant. Biogas quality also improved in both stages of the two-stage system over the single-stage digester, with 67-73% methane content from the two-stage system versus 62% from the single-stage. Pilot plant testing of a TPAD process indicated similar improvement in performance due to using staged digesters. The first stage of the 20-d SRT equally staged system had an ACN number of about 1.3 compared to a value of 1.8 for the single-staged 20-d SRT digester. Thus, while the staged system operation can improve solids destruction efficiency, it has a lower capacity for higher variable loads.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
Document Type: Research Article
Publication date: 2005-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites