PILOT-SCALE EVALUATION OF ENZYME PRE-TREATMENT TO ENHANCE DEWATERING: EFFECTS OF SHEAR AND POLYMER
The effect of enzyme pre-treatment on dewaterability of anaerobically digested biosolids was investigated at both laboratory and pilot scale. Similar to previously reported results, laboratory results revealed a significant increase in cake solid content (33% cake solids compared to 20% without enzyme pretreatment), using an enzyme dose of only 15 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington wastewater treatment plant, using a pilot-scale centrifuge. However, the dewatering efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content reached only 20% with different enzyme doses. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment could weaken the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation. Different polymers with different chemical structures were tested, however, only 2 pts increase in cake solids were observed in pilot centrifugation. Pilot or full scale testing with belt filter press devices is needed to verify the observed increase in cake solids with the Crown Press simulator.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 2007-01-01
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 These proceedings are not peer reviewed.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