Today's post is part one of the EPA report summary

According to the U.S. Environmental Protection Agency (EPA), “the management of onsite systems plays an important role in the ongoing restoration of the Chesapeake Bay.” The EPA released a document providing recommended models for onsite systems. This document, A Model Program for Onsite System Management in the Chesapeake Bay Watershed November 2012, is important to our line of work and will thus be summarized on this blog.

To begin with, the EPA acknowledges that ‘Bay restoration programs have been ongoing for some time but still do not meet applicable water quality standards.’ As a response to these quality standards, “the Chesapeake Bay Total Maximum Daily Load (TMDL) issued by the EPA, is designed to accelerate the actions needed to limit pollution inputs and restore the Bay (EPA, 2010c). The TMDL is a historic and comprehensive “pollution diet” set at the level necessary to clean up the Chesapeake Bay and its tidal tributaries. The TMDL identifies a 25% reduction in nitrogen inputs to the Bay and a maximum nitrogen load to the Bay of 185.9 million pounds per year.

The report notes that, “to support the development of the TMDL, states in the Bay watershed developed Watershed Implementation Plans (WIPs) detailing the actions they would take to reduce nitrogen, phosphorus, and sediment inputs to the Bay. The WIPs evaluate a range of opportunities to reduce nutrient inputs to the Bay, including reductions from agriculture sources, point source discharges such as municipal wastewater treatment facilities, stormwater discharges, and onsite wastewater disposal systems . . .” For information regarding PA’s WIP, click here!

The EPA reports that, “onsite wastewater systems (also called septic systems or decentralized systems) contribute approximately six percent of the overall nitrogen load to the Bay” (EPA, 2010c). This percentage designates the negative effect that septic systems have on the bay. The good news though is that “nitrogen discharges from onsite systems can be mitigated through advanced technologies and improved design, installation, and management practices” and “a variety of technologies exist that provide this level of treatment, and the available technologies and their performance are expected to increase over time.” (EPA 2010a, Rich, 2005).

“States looking to reduce the nitrogen impacts from onsite systems are encouraged to establish a performance-based approach involving use of these alternative treatment systems. The level of treatment specified should depend on the extent of nitrogen reduction that is needed to meet the goals within a state’s WIP.” Below is a table produced by the EPA that provides states with a recommended nitrogen treatment approach.

Table EX-1: Summary of Recommended Onsite System Nitrogen Treatment Approach

Horizontal Distance from the Bay or a tributary1

Recommended Nitrogen Treatment

0 – 100 feet

No discharge of onsite system effluent

100 – 200 feet

5 mg/L for total nitrogen

200 – 1,000 feet

10 mg/L for total nitrogen

Beyond 1,000 feet

20 mg/for total nitrogen

The horizontal distance, or setback, extends from the dispersal system to the ordinary high water mark of the Chesapeake Bay, or the tidal portion of any tributary to the Bay.

“To properly manage nitrogen treatment systems, state and local authorities should implement specific requirements guiding their siting, design, construction, and operation and maintenance (O&M) oversight.”

 Stay tuned for the second half of this summary which deals with some EPA management models for onsite septic systems.