An investigation of some factors affecting activated sludge population dynamics
Synthetic polymers are applied to many wastewater treatment plants to improve the settling characteristics of activated sludge, especially when the cause of the poor settleability is transient hydraulic overloading. After a few days polymer addition seems no longer necessary. However, many plants which only use synthetic polymers for a short period of time still face serious sludge settling problems immediately after the discontinuation of polymer addition. In the first part of this research, a study was conducted to investigate the reason for the poor settling of activated sludge after the addition of synthetic polymers is halted. The substrate utilization of Gram-positive and Gram-negative bacteria in two SBR (Sequencing Batch Reactor) activated sludges systems was investigated in the second part of this research. Crystal violet was applied to inhibit the Gram-positive bacteria in one of the SBR systems. The results were confirmed by testing under two different buffer intensity conditions. Nitrification characteristics in both systems and under different buffer intensity conditions were studied. The population structures of predominant microorganisms in each system under both buffer intensity conditions were also examined. Each species of bacteria displays different surface electrical potential due to the specific chemical structures on its cell surface. The zeta potential of activated sludge is always very high, therefore, extracellular polymers must be very important in the flocculation and the settleability of activated sludge. A study of the surface charge of microorganisms grown in pure culture as well as activated sludge was conducted in the third part of this research. The effects of monovalent (Na{sup +}) and divalent (Ca{sup +2}) cations on the zeta potential and settling velocity of activated sludge were demonstrated.
- Research Organization:
- Auburn Univ., AL (United States)
- OSTI ID:
- 5119354
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
POPULATION DYNAMICS
HAZARDOUS MATERIALS
BIODEGRADATION
WASTE WATER
DECONTAMINATION
BIOREACTORS
GENETIC VARIABILITY
GROWTH
POLYMERS
PRECIPITATION
SEWAGE SLUDGE
WASTE PROCESSING
BIOLOGICAL MATERIALS
BIOLOGICAL VARIABILITY
BIOLOGICAL WASTES
CHEMICAL REACTIONS
CLEANING
DECOMPOSITION
HYDROGEN COMPOUNDS
LIQUID WASTES
MANAGEMENT
MATERIALS
MICROORGANISMS
OXYGEN COMPOUNDS
PROCESSING
SEPARATION PROCESSES
SEWAGE
SLUDGES
WASTE MANAGEMENT
WASTES
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology