Steven G. Wright, Rance T. Shields, H.J. Thung 1
Three subsurface flow constructed wetland systems, also known as rock-reed filters, were built in 1990-1991 to serve the towns of Binger, Maysville, and Colbert, respectively. The facilities were designed and constructed in accordance with the subsurface flow constructed wetlands design criteria used in the state of Louisiana. After the systems were put in operation in early 1991, initial test results indicated the systems were producing acceptable effluent quality. Within six months the performance of the facilities began to deteriorate. Ponding, septic conditions, and unacceptable effluent quality were among the major problems. As various corrective measures failed to improve the performance of the treatment facilities, the USEPA determined the wastewater treatment plants failed to meet design performance standards. Comprehensive Performance Evaluations at each of the facilities concluded the failure was not due to third party negligence or error but rather to the degree of complexity of interrelated biological, physical-chemical, hydrological and hydraulic factors, and insufficient information concerning optimum site specific design criteria.
