TITLE:
Evaluation of Offshore Wastewater Outfall and Diffuser for Onondaga Lake, NY
AUTHORS:
Emmet M. Owens, Steven W. Effler, David A. Matthews, Anthony R. Prestigiacomo
KEYWORDS:
Mathematical Model; Outfall; Diffuser; Near Field Dilution; Eutrophication
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.5 No.9A,
September
9,
2013
ABSTRACT:
Outfall alternatives are evaluated for a municipal wastewater
treatment facility that discharges effluent at the shoreline of an
urban lake. Occurrence of plumes of poorly diluted effluent in adjoining
portions of the lake is described. Alternatives considered include outfalls
over a range of depth and various diffuser designs. Benefits and impacts on
lake stratification and dissolved oxygen are evaluated for an array of design
alternatives with a model which links a far field hydrothermal and transport
submodel with a near field buoyant plume submodel. Outfall design features are
described that: 1) reduce shoreline discharge of bypass flow of partially treated
wastewater during major runoff events; 2) eliminate plumes of poorly diluted effluent; and 3)
reduce loading of the effluent to the upper waters. A deep (10 to 14 m) outfall
with a multiport diffuser would reduce the loading of the facility’s effluent
to the upper waters by approximately 40%, without noteworthy impact on
stratification or dissolved oxygen.