Reduced gas pressure operation of sludge digesters

Technical Report · Mon May 01 00:00:00 EDT 1989

OSTI ID:5738014

This report describes bench-scale research for improving the digestion of sludges. The effects of reduced headspace pressure on anaerobic digester performance was evaluated. Four identical digester systems were constructed for investigating reduced headspace pressure effects. The first system served as a control and was operated with a 1.0 atmosphere gas phase pressures. The remaining three reactors had 0.83, 0.75 and 0.5 atm. gas phase pressures. The reactor systems were housed in a 35 {degrees}C walk-in incubator. Each anaerobic system was designed to simulate the operation of a typical municipal digester. Reactors were seeded with sludge and operated with a 15-day solids retention time (SRT), a typical value for a high-rate digester. This was accomplished by replacing one-fifteenth of the active volume (1.5 liters) with fresh feed daily. Headspace gas pressures were controlled by a pressure-sensitive valve located between the reactor and a large closed vacuum reservoir. Changes in reservoir pressure as a function of time were recorded and used to evaluate gas production. Municipal sludges (3, 5, and 8 percent solids) were used as feedstock for the reactors with 15-day SRTs. A 5 percent sludge was also evaluated with a 25-day SRT. Feed characteristics and reactor pH, alkalinity, total chemical oxygen demand (TCOD), total and volatile suspended solids (TSS and VSS) and gas composition (CH{sub 4}, CO{sub 2}, and H{sub 2}) and production rates were routinely monitored. Total COD, VSS and SS destruction rates along with CH{sub 4} and total gas generation rates were determined as a function of headspace pressure. 25 refs., 41 figs., 13 tabs.

• Research Organization: New York State Energy Research and Development Authority, Albany, NY (USA); Onondaga County Dept. of Drainage and Sanitation, Syracuse, NY (USA); Syracuse Univ., NY (USA). Dept. of Civil Engineering; O'Brien and Gere Engineers, Inc., Syracuse, NY (USA)
• Sponsoring Organization: NYSERDA; New York State Energy Research and Development Authority, Albany, NY (USA)
• OSTI ID: 5738014
• Report Number(s): NYSERDA-90-20; ON: TI91012246
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
59 BASIC BIOLOGICAL SCIENCES
ANAEROBIC DIGESTION
OPTIMIZATION
BIOREACTORS
PERFORMANCE
SLUDGES
COST
ECONOMICS
METHANE
PRESSURE EFFECTS
PROGRESS REPORT
WASTE MANAGEMENT
ALKANES
BIOCONVERSION
DIGESTION
DOCUMENT TYPES
HYDROCARBONS
MANAGEMENT
ORGANIC COMPOUNDS
PROCESSING
WASTE PROCESSING
320604* - Energy Conservation
Consumption
& Utilization- Municipalities & Community Systems- Municipal Waste Management- (1980-)
550500 - Metabolism