Multiple-stage anaerobic digestion system
The purpose of this study is to develop a new process for the stabilization of municipal sludge produced at the Allegheny County Sanitary Authority wastewater treatment plant in Pittsburgh, Pennsylvania. A multiple-stage digestion process is sought to provide good removal efficiency of high concentration of sludge and to perform high methane production. The process primarily consists of three stages of anaerobic digestion. Stage 1 is for hydrolysis and acidification and stage 2 is for acidification and methanation; both digesters are operated in the mesophilic temperature range. The last stage is for methanation which is controlled in the thermophilic range. The multiple-stage system (MS) was operated at different solids retention time (SRT) of 15, 9, and 20 days. For comparison to the performance of the multiple-stage system a conventional single-stage system (SS) was also operated at the same conditions. The COD removal, solids reduction, and the methane yield of the multiple-stage system were much greater than the single-stage system at all of the different SRT. Moreover, the results of the different SRT of the multiple-stage system study showed that a SRT of 15 days has the best performance. The maximum VS removal rates are 67% of MS and 50% of SS; and the methane yields are 6.72 SCF CH/sub 4//lb VS added of MS and 3.95 SCF CH/sub 4//lb VS added of SS with VS loading of 0.15 lb/ft/sup 3/-day at a 15 days SRT. These methane yields are equivalent to 89% and 67% biogas conversion from the removed VS (based on 75% of the sludge VS is biodegradable), respectively, for the multiple-stage and the single-stage systems.
- Research Organization:
- Pittsburgh Univ., PA (USA)
- OSTI ID:
- 5644316
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
METHANE
YIELDS
MUNICIPAL WASTES
WASTE PROCESSING
SEWAGE SLUDGE
ANAEROBIC DIGESTION
PENNSYLVANIA
WASTE PROCESSING PLANTS
ALKANES
BIOCONVERSION
DIGESTION
FEDERAL REGION III
HYDROCARBONS
INDUSTRIAL PLANTS
MANAGEMENT
NORTH AMERICA
ORGANIC COMPOUNDS
PROCESSING
SEWAGE
SLUDGES
USA
WASTE MANAGEMENT
WASTES
090122* - Hydrocarbon Fuels- Preparation from Wastes or Biomass- (1976-1989)
320604 - Energy Conservation
Consumption
& Utilization- Municipalities & Community Systems- Municipal Waste Management- (1980-)