MAXIMIZING TREATMENT CAPACITY WITH NATURAL SYSTEMS

Since 1982, Clayton County Water Authority (CWWA) has been operating two forested land application systems (LASs) in Clayton County, Georgia: The Shoal Creek and the E.L. Huie, Jr. LASs. The Shoal Creek LAS spans approximately 360 acres, and was designed to treat 1.1 million gallons per day (mgd). The Huie LAS consists of approximately 4,000, of which about 2,300 acres are irrigated. The Huie LAS site was designed with an application flow rate of 19.5 mgd.Over the last 18 years, the CWAA LASs have continued to meet State of Georgia surface water and groundwater quality standards; however, increased effluent flows as well as the challenge of maintaining large irrigation areas have prompted the need for LAS improvements. To address this need, CWWA has been investigating the feasibility of implementing natural treatment systems that involve a combination of two natural biologicalbased components: slow rate spray irrigation and constructed wetlands.This paper discusses the natural treatment systems operated by CCWA to maximize its wastewater treatment capacity in a cost-efficient, environmentally beneficial manner to meet increasing drinking water needs. Included are detailed discussions pertaining to CCWA's LASs and its wastewater treatment facilities; regulatory considerations and guidelines; environmental setting; site investigations; and treatment wetlands.