Optimization Studies of Anaerobic Expanded Bed Reactor Pretreatment of Domestic Wastewater

Theis, Thomas L.; Alderman, Bruce J.; Collins, Anthony G.; ,

Optimization Studies of Anaerobic Expanded Bed Reactor Pretreatment of Domestic Wastewater

by Thomas L. Theis, (M.ASCE), Clarkson Univ, Potsdam, NY, USA,
Bruce J. Alderman, Clarkson Univ, Potsdam, NY, USA,
Anthony G. Collins, (M.ASCE), Clarkson Univ, Potsdam, NY, USA,

Document Type: Proceeding Paper

Part of: Critical Issues in Water and Wastewater Treatment

Abstract:

In recent years the advent of the anaerobic expanded bed reactor (AEBR) has made possible the treatment of wastewaters of comparatively lower strength than have traditionally been treated by anaerobic means. However, regardless of any benefits presented by its use, the process must be shown to be cost effective relative to other options before it will gain acceptance. This study reports on the results of a series of optimization exercises in which the costs of the AEBR as an expansion alternative for organically overloaded treatment plants are compared with costs for more conventional remedies. The optimization model developed includes the unit processes of primary clarification, AEBR, trickling filtration, secondary clarification, activated sludge, gravity thickening, anaerobic digestion, and vacuum filtration. Any of these options may be included or discarded from the overall model in order to represent a given wastewater facility. Several constraint parameters were varied in order to determine the cases for which the AEBR would be the cost effective option. These were: primary effluent COD, hydraulic loading, temperature, cost of labor, cost of power, cost of sludge disposal, and amortization interest rate. Since the primary motivation for the study was to determine the viability of the AEBR as a pretreatment method for organically overloaded plants, the primary effluent COD was the main parameter of interest and was varied in multiples of its design value. Results indicated that the AEBR may be a cost effective alternative when the primary effluent COD is approximately 230 mg/L or above, depending on the type of plant (activated sludge or trickling filter) and other eternal factors.

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