Influence of Temperature on Treatment Efficiency of Constructed Wetlands

An existing free-water-surface constructed wetland system at the Auburn University Poultry Science Unit wasused to evaluate the effects of water temperature on the treatment of poultry lagoon effluent. Each wetland consisted of twocells in series. One series was planted with an approximate 10% fill of Sagittaria lancifolia. A second series containedPhragmites australis and Scirpus spp. with an approximate 5% fill of plants. A third series was unvegetated and acted as acontrol. Wastewater samples were collected approximately every 12 days at the influent and effluent of each cell andanalyzed for TKN, ammonia, nitrate, BOD5, COD, total phosphorus, orthophosphorus, and potassium. Water temperaturewas measured using thermographs placed at the midpoint of each cell with temperature readings being taken each hour fromJuly 1995 until June 1996. The percent removal of each wastewater pollutant from each series was compared to the averagewater temperature over the sampling period (every 12 days) to determine what effect, if any, temperature had on treatment.For most cases, temperature was not found to significantly affect treatment of poultry wastewater. Treatment efficiency(percent removal) was significantly correlated to temperature in one series for ammonia, one series for nitrate, one series fortotal phosphorus and one series for orthophosphorus. Mass removal was not correlated to temperature in any of the casesstudied.