Subsurface Drip Dispersal Following Lagoon Treatment–a Case for Optimizing Environmental Protection.

The need to manage human waste has traditionally been driven by a desire to protect human health.  Expectations have increased over time to achieve better protection, including the environment.  Many older facilities have undergone a series of upgrades over time, most of which seek to achieve a higher level of protection.  Bullards Beach State Park on the Pacific Coast of Oregon is a good example of this progression.  The purpose of this presentation is to provide an overview of its wastewater treatment history and a bit more detail about the most recent upgrades.

Bullards Beach State Park consists of 192 campsites and was constructed in 1965.  The initial wastewater treatment system consisted of an activated sludge package plant with spray irrigation on about 1.1 acres.  A two-cell facultative lagoon system was installed in 1988 and the package plant was decommissioned.  Lagoon effluent continued to be irrigated to the same site.  The park receives an average of 60 inches of precipitation per year.  The lagoon system was not designed large enough to operate in a strict winter holding-summer irrigation pattern.

The requirements from the Oregon Department of Environmental Quality (DEQ) for spray irrigation changed after the lagoons were constructed to restrict irrigation to the growing season and limited to the water and nutrient needs of a crop.  Subsurface dispersal is allowed year round and an innovative approach was developed to minimize the potential impact to human health and the environment while optimizing existing infrastructure and site features.