Mixing Zone Analysis for Coastal Wastewater Discharge
Publication: Journal of Environmental Engineering
Volume 123, Issue 12
Abstract
A case study of the conceptual design and mixing zone analysis for an ocean outfall to discharge a dense wastewater is summarized. The recommended diffuser consists of upwardly inclined nozzles that discharge the effluent as high-velocity jets resulting in high dilution. Mixing by oceanic diffusion increases the dilution further as the wastefield is transported to the edge of the mixing zone. Local currents are highly variable, resulting in intermittent transport of the wastefield to any location. This is analyzed by computing the spatial variation of the “visitation frequency,” and the minimum and harmonic average dilutions of the wastefield. The visitation frequency decreases quickly and the average dilution increases rapidly with distance from the diffuser, indicating that any environmental effects of the discharge will be confined to a small area. Maximum and average values of chemical concentration at the mixing zone boundary were computed to assess compliance with acute and chronic water quality criteria. It was concluded that all requirements of the California Ocean Plan and other international standards would be met.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Allen, H. E. (1993). “The significance of trace metal speciation for water, sediment and soil quality criteria and standards.”Science of the Total Environment, Suppl., 23–45
2.
Brenner, S. (1993). “Circulation and hydrography of Haifa Bay: Final report.”IOLR Rep. H37/93, Israel Oceanographic and Limnological Research Ltd., Haifa, Israel.
3.
Brooks, N. H. (1960). “Diffusion of sewage effluent in an ocean current.”Proc., 1st Int. Conf. on Waste Disposal in the Marine Environment, Univ. of California.
4.
Csanady, G. T. (1973). Turbulent diffusion in the environment. D. Reidel Publishing Co., Boston, Mass.
5.
Csanady, G. T.(1983). “Dispersal by randomly varying currents.”J. of Fluid Mech., 132, 375–394.
6.
Davies, P. H. (1976). “The need to establish heavy metal standards on the basis of dissolved metals.”Toxicity to biota of metal forms in natural water, R. W. Andrew, P. V Hodson, and D. E. Konasewich, eds., Duluth, Minn., Oct. 7–8, 1975.
7.
Jirka, G. (1994). U.S. EPA Mixing Model Workshop, Univ. of Portland, Oreg., May 2–4.
8.
Koh, R. C. Y.(1988). “Shoreline impact from ocean waste discharges.”J. Hydr. Engrg., ASCE, 114(4), 361–376.
9.
Pincince, A. B., and List, E. J.(1973). “Disposal of brine into an estuary.”J. Water Pollution Control Federation, 45(11), 2335–2344.
10.
Roberts, P. J. W. (1990). “Outfall design considerations.”The sea, ocean engineering science, B. Le Mehaute and D. M. Hanes, eds., Wiley Interscience, New York.
11.
Roberts, P. J. W. (1995). “Design report for the sea outfall and diffuser for discharge of Haifa chemical's waste into the sea.” School of Civ. Engrg., Georgia Inst. of Tech., Atlanta, Ga.
12.
Roberts, P. J. W., Ferrier, A., and Daveiro, G.(1997). “Mixing in inclined dense jets.”J. Hydr. Engrg., ASCE, 123(8), 693–699.
13.
Roberts, P. J. W., and Toms, G.(1987). “Inclined dense jets in a flowing current.”J. Hydr. Engrg., ASCE, 113(3), 323–341.
14.
Tahal Consulting Engineers. (1992). “Disposal of acid wastes to the sea. General planning report.” Tahal Consulting Engrs., Ltd., Tel Aviv, Israel.
15.
U.S. EPA. (1993). “Office of water policy and technical guidance on interpretation and implementation of aquatic metals criteria.” U.S. EPA, Office of Water, Washington, D.C.
16.
Zeitoun, M. A., Reid, R. O., McHilhenny, W. F., and Mitchell, T. M. (1972). “Model studies of outfall systems for desalination plants. III: Numerical simulations and design considerations.”Res. and Devel. Progress Rep. No. 804, Office of Saline Water, U.S. Dept. of Interior, Washington, D.C.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 123 • Issue 12 • December 1997
Pages: 1244 - 1250
Copyright
Copyright © 1997 American Society of Civil Engineers.
History
Published online: Dec 1, 1997
Published in print: Dec 1997
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.