Seamless Integration of Regulatory Strategy and Project Execution
On-Site Soil Evaluations and Wastewater System Design
EPA and OSHA Compliance Evaluation
OSHA Voluntary Protection Program
Industrial Wastewater, Stormwater, and Pollution
On-Site Soil Evaluations and Wastewater System Design
Onsite Sewage Disposal Systems in Virginia
In Virginia, approximately one third of all homes are served by onsite sewage disposal systems. The Environmental Protection Agency has identified pollution from old, failing, and outdated systems as one of the largest sources of groundwater contamination in the US. In response, states have strengthened their onsite sewage regulations to protect public health. Many of these changes have resulted in the requirement for alternative or advanced onsite systems in areas where conventional septic systems were once allowed.
Regulations and Professional Requirements
States now require more stringent controls on companies that design systems and evaluate sites. Virginia’s Authorized Onsite Soil Evaluator (AOSE) program was introduced to facilitate the proper design of onsite wastewater systems. An AOSE is an environmental professional with experience and training in evaluating sites for onsite sewage disposal. AOSEs are also required to complete Virginia Department of Health testing to ensure their competence in performing soil evaluations and designing onsite systems.
Critical Items in Soil Evaluations:
- Depth of Seasonal Water Table:
A standoff or separation distance from the bottom of the onsite system to a seasonal water table is crucial for protecting groundwater. This standoff allows the natural organisms in the unsaturated soil to quickly outcompete and kill off the harmful pathogens found in the sewage. The standoff varies from system to system, generally decreasing as the level of treatment provided by the system increases.
- Texture of Soil:
The heavier the texture of the soil, the larger the absorption field needs to be for any given flow. For example, a system for a four-bedroom house located in heavy clay will be larger than a system for the same house located in very sandy soil.
- Sanitary Survey:
This survey is critical to determine if the horizontal separation distances required by Virginia’s 2000 Sewage Handling and Disposal Regulations and 1992 Private Well Regulations can be maintained. Both sets of regulations contain the required horizontal setbacks from onsite systems and other sources of contamination (e.g., underground storage tanks) to all types of wells. It is important to ensure that a septic system is not placed too close to a well or vice versa.
