Soil chemistry and phosphorus retention capcacity of North Carolina costal plain swamps receiving sewage effluent
We analyzed the soil chemical properties and P sorption potentials of three North Carolina coastal plain swamps to (1) characterize their soil chemistries, (2) analyze both short- and long-term effects of wastewater addition on soil chemistry, (3) determine their P sorption capacities and the relationship between P sorption and soil chemistry, and (4) develop a predictive index to evaluate the P sorption potentials of other coastal plain swamps. At Brown Marsh Swamp, soils were analyzed both before and after the initiation of wastewater discharge. At Cashie Swamp, which has been receiving wastewater additions for approximately 30 years, soils were collected both above and below the discharge point. Soils from nearby non-impacted Wahtom Swamp were analyzed for comparison. It is concluded that maximum utilization of wetlands for phosphate removal from wastewater with minimum ecosystem impact can only be achieved under conditions which maximize retention time and the effective surface area of the wetland, and minimize the average impact per unit area. This could be achieved by adding acidified wastewater using a well-designed diffusion system, rather than as a point discharge.
