Water Resources Research Act Program

Details for Project ID 2019PA225B

Long-term water quality performance at a central pennsylvania constructed wetland designed to treat domestic sewage

Institute: Pennsylvania
Year Established: 2019 Start Date: 2019-05-31 End Date: 2020-05-30
Total Federal Funds: $19,444 Total Non-Federal Funds: $38,887

Principal Investigators: Robert D. Shannon

Abstract: Rural communities are often served by decentralized, on-site domestic waste treatment systems, many of which have failed due to placement in poorly drained or shallow soils, and development in rural areas is often hindered by these same soil limitations. This study proposes to investigate the long-term removal of nitrogen and phosphorus from a treatment wetland constructed over twenty years ago at a remotely located Camp and Conference Center in Centre County, PA. At the time it was designed and permitted by the PA DEP (1996), the system was considered experimental, so permit requirements for effluent water quality sampling were limited to monthly sampling of limited parameters during high use, summer periods. The system was originally designed as a no-discharge system due to its location in a high quality/exceptional value (HQ/EV) watershed. However, modifications during construction necessitated the promotion of additional infiltration capacity directly adjacent to the riparian zone of the HQ/EV stream. Detailed investigation of the treatment effectiveness in the first two years after construction (Shannon et al., 2000; Flite et al., 2001) indicated that the system components were effective at removing ninety to ninety five percent of the total nitrogen, and ninety-five to ninety-nine percent of the dissolved phosphorus load, entering the system. However, beyond this intensive sampling within several years of construction, little water quality data are available in the intervening 20 years to know if the treatment effectiveness of the system has been sustained. Therefore, the objectives of the proposed study are to 1) investigate nitrogen and phosphorus removal effectiveness within the various components of the treatment wetland system after 20+ years of operation, 2) compare current treatment effectiveness with previously published and unpublished water quality data from the system, 3) investigate water quality within the adjacent high quality/exceptional value stream, and 4) make recommendations to the state regulatory agency (PA Dept. of Environmental Protection) and the Camp and Conference Center to assure long-term waste treatment consistent with water quality standards. The proposed detailed investigation of the long-term performance of this system comes at a critical juncture. The PA DEP has expressed interest in knowing more about the long-term functioning and impacts due to 20 years of waste treatment and discharge in this remote HQ/EV watershed. Emphasis on nitrogen and phosphorus removal effectiveness for conventional and experimental treatment systems within the Chesapeake Bay watershed has received significant state support within the past few years, and the proposed study will provide additional timely guidance to private landowners, nonprofits, and state agencies on the longterm functioning of decentralized, domestic waste treatment systems.