WASTEWATER TREATMENT BY OVERLAND FLOW
A. Ray Abernathy, Professor
Environmental Systems Engineering Department
Clemson University
Clemson, S.C. 29631
INTRODUCTION
The U.S. Environmental Protection Agency in 1976 funded both construction and monitoring of
an overland flow treatment facility at Easley, S.C. The project was completed in December 1981 after
three years of operation. The overland flow facility was designed to treat 95 cubic meters (25,000
gallons) per day of comminuted raw sewage and 284 cubic meters (75,000 gallons) per day of
facultative lagoon effluent. The wastewater flow included approximately 38 cubic meters (10,000
gallons) per day of process wastewater from a textile mill. This was primarily wastewater from desiz-
ing textile materials which had been sized with starch or polyvinyl alcohol. No apparent problems
resulted from this process wastewater.
The Easley Combined Utility System was the owner and operator of the system, and the Environmental Systems Engineering Department of Clemson University provided assistance with proposal
and report preparation, conceptual design, project supervision, and performance monitoring. The
design criteria were developed from published reports on the Paris, Texas facility of the Campbell
Soup Company [1,2], reports on the experimental system at Ada, Oklahoma [3,4], and the system at
Pauls Valley, Oklahoma [5].
OBJECTIVES
The purpose of the Easley project was to evaluate overland flow for treating municipal wastewater
in a region of high rainfall, mild climate, and relatively low soil permeability. Detailed objectives were
to: (1) Design and construct overland flow systems to treat 95 cubic meters (25,000 gallons) per day of
comminuted raw sewage and 284 cubic meters (75,000 gallons) per day of facultative lagoon effluent;
(2) Evaluate system performance with respect to removal of BOD5, suspended solids, nitrogen and
phosphorus from the applied wastewater; (3) Increase knowledge of the criteria for designing and
operating overland flow systems; and (4) Evaluate the potential for groundwater pollution or nuisance
problems.
PROJECT DESIGN
The site chosen for the project was adjacent to an existing 3.6 hectare (nine acre) lagoon already
treating the 378 cubic meters (100,000 gallons) per day of wastewater collected within that drainage
basin of the Easley service area. The Combined Utility System purchased 8.1 hectares (30 acres) of
suitable land which was crossed by the sewer line to the lagoon. Figure 1 shows the layout of the project and the relative locations of the lagoon, the sewer line, overland flow plots, collection channels,
chlorination facility, and receiving stream.
Plots
All plots were graded to a four percent slope by motor grader. All final grading and seeding operations were done across the slope. Three plots 34 meters (110 feet) wide by 50 meters (165 feet) long
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