Harvey H. Harper

Removal of contaminants in highway runoff flowing through swales

Abstract Simulated highway runoff was pumped over a well established grassy swale at Maitland Interchange and a newly constructed swale at EPCOT Interchange, near Orlando, Florida to investigate mass transport and removal efficiencies for nutrients and heavy metal concentrations under controlled environments. Dissolved metal concentrations, particularly those existing in ionic species, were better removed than phosphorus and nitrogen. Nutrient concentrations in highway runoff flowing over roadside swales may increase. However percent mass removal of all pollutants were found to be higher than concentration removal due to infiltration.

Heavy metal accumulation and transport through detention ponds receiving highway runoff

Sediment accumulations and associated heavy metal concentrations into retention/detention ponds receiving highway runoff from several ponds and metal concentrations in various sediment layers were analyzed to determine the extent of vertical migration. Extraction of heavy metals had been evaluated using various solutions including the United States Environmental Protection Agency Toxicity Characteristics Leaching Procedures (TCLP). Also, sediments were incubated under various conditions of redox potential and pH to investigate the effects of changes in sediment conditions on the stability of metal-sediment associations.

Fate of heavy metals in stormwater runoff from highway bridges

Abstract Pollutants associated with runoff water from highway bridges located in Central Florida, USA, were characterized and quantified. These pollutants are directly discharged through scupper drains to adjacent water bodies and floodplains or detained in ponds before being released to lakes and streams. Runoff water contains heavy metals such as lead, zinc, copper, chromium, iron, nickel and cadmium which concentrate in adjacent soils and biota. It appears that soil systems are efficient in removing heavy metals from highway bridge runoff. It is suggested that bridge drainage be directed towards retention/detention ponds or floodplains and direct drainage of bridges in water bodies beneath them should be avoided as much as possible. This paper summarizes several studies conducted by the University of Central Florida for the Florida Department of Transportation and the Federal Highway Administration, U.S.A.

TREATMENT EFFICIENCIES FOR RESIDENTIAL STORMWATER RUNOFF IN A HARDWOOD WETLAND

ABSTRACT The fate of nutrients and heavy metals contained in storm-water runoff was investigated in a 3 ha hardwood wetland near Orlando, Fla. The wetland receives stormwater runoff from a large residential community through a small shallow canal and provides treatment prior to discharge to Hidden Lake. Field investigations begun in 1984 were divided into the following tasks: (1) assessing the quantity of nutrients and heavy metals entering the wetland by stormwater runoff, (2) attenuation of the pollutants during travel through the wetland, (3) monitoring movement of nutrients and heavy metals in ground water, and (4) accumulation of nutrients and heavy metals in the sediments of the wetland. During continuous flow, the wetland system was found to be very effective in removing heavy metals but less effective in removing nutrients. Heavy metals appear to be tightly bound into the upper sediment layers. Treatment of runoff by infiltration through wetland soils resulted in good removal of nutrients as well ...

FATE OF HEAVY METALS IN STORMWATER MANAGEMENT SYSTEMS

ABSTRACT The State of Florida requires that stormwater originating within a new project or development be managed and treated within the boundaries of the development to protect surface waters. Retention and exfiltration systems are the most common management practices. Theoretically these provide complete removal efficiency up to the design capacity since none of the stormwater reaches the receiving water body by direct inflow. The fate of various pollutants once entering these systems is not known, particularly whether heavy metals remain in them locked tightly by a chemical or physical association or slowly disperse outward over a much larger area to other water bodies. Investigations on an 8-year-old stormwater retention facility (1.5 ha) in Orlando, Fla., to define movement of heavy metals into and out of the basin seek to answer these questions. Stormwater runoff has been collected and analyzed from the input pipe for approximately 1 year. In addition, both wet and dry bulk precipitation are being c...