On September 28, 2009 the Virginia Department of Health published their proposed Alternative Onsite Septic System, AOSS, regulations for public comment. For single family homes the regulations require that these systems are installed with conservative horizontal set backs, are operated and maintained by a licensed operator, grab samples taken by a licensed operator at either once a year or every five years (there is an inconsistency in the proposed regulations) and analyzed by an EPA certified laboratory, and an operating manual and records need to be maintained on site.
While I think the sampling requirement which is expensive does not provide additional protection to the environment and the operating manual requirement is inappropriate, the operation and maintenance of the system by a qualified and trained individual is reasonable. (Whether that individual needs to be licensed by the Board for Waterworks and Wastewater Works Operators and Onsite Sewage System Professionals at the Department of Professional and Occupational Regulation (DPOR) as a professional operator is for another time.) The truth is people do not seem to be able take appropriate responsibility for their septic systems. One method to deal with this problem is to eliminate all but the most basic systems in the most geologically favorable locations (reduce percolation rate tolerances and design the systems as conservatively as possible). The other method is to regulate, control and track. Establish system performance and monitoring and maintenance requirements, establish a tracking system and operating permits for compliance monitoring, and establish fines and enforce the program as the current regulations propose. Some version of these proposed regulations will go into effect in the near future. So, Virginia has chosen the control and track approach.
Let’s look at how requiring operation and maintenance might protect public health and the environment. A real world example would be a geologically unfavorable groundwater rich location. The small development where I live is located within the northeast quadrant of the Culpeper basin in Prince William County. The soil (if you want to call it that) consists of an interbedded sequence of sedimentary and basaltic rocks created around 200 million years ago probably by volcanic action. The rocks of the Culpeper basin are highly fractured and overlain by a thin cover of overburden. The lack of overburden is a challenge to gardens and limits natural protection to the aquifer. The sedimentary rocks are highly productive aquifers, but also subject to fractures that allow contaminants to move swiftly and easily through the system and easily reach depth in the groundwater aquifer.
Groundwater flows under ambient pressure from Bull Run Mountain towards Bull Run, the river. Thus, groundwater flows west to east. The soils in our neighborhood are described by the USGS as Balls Bluff Siltstone with a gravel, sand and clay type bedding plane. (That is the technical name for the flat plane, edged orange red rocks that are everywhere you put a shovel.) In the siltstone bedding plane, the fractures within the rock run predominately north south. Thus while ground water flows generally speaking west to east, water or a contaminant that catches a fracture will carry the contaminant to drinking water depth in a north south pattern. Contaminants can enter the groundwater at these fractures and zigzag through the neighborhood. The neighborhood is bound to the south by a river and the area is bound to the east by a river. There are also natural ponds, a manmade pond, and seasonal creeks. The rivers serve as hydraulic breaks. There is no natural attenuation in a fractured system. Any malfunctioning septic system, improper disposal, or spill on any property has the potential to impact the drinking water well of other residents to the south, southeast or east.
The new alternative septic regulations would require me and all my neighbors to properly operate and maintain their septic systems. Hopefully, preventing the neighbor’s septic system from contaminating the drinking water wells in the neighborhood. (I already have a operation and maintenance contract and my septic alarms to an automatic dialer to the maintenance company and my e-mail.) A cracked septic tank, malfunctioning system, improper management of stables, dumping of chemicals down the drain or in the yard, all have the potential to impact large sections of the neighborhood and need to be diligently guarded against by all residents. The need to negotiate the best rates for AOSS contracts may offer the opportunity for the HOA to create a buying group and educate neighbors. This could serve to protect all our drinking water. That remains to be seen; in the meantime I will be testing my water twice a year.
Very informative, and a clear explanation of the importance of groundwater protection.
ReplyDeleteThe Culpeper Basin is not the only geologically sensitive area of the state. Karst terrain, area underlain by fractured limestone are also prone to groundwater contamination, as well as transport of contaminants long distances from their source. Shallow groundwater areas throughout the state have unique issues, as do crystaline bedrock in the Blue Ridge also often overlain by thin soil mantels, and underlain by fracture trace (a fine name since they may be discernable as a trace across the landscape). The coal fields and ridge and valley to the west also have challenges with roots in geological phenomenon. Anywhere we see springs we also have the distinct possibility of back contamination of the aquifer.
The difficulty is this; to adopt a Code which conserves the resources is difficult without the ability to tailor the requirements to differing conditions of population density, ecological sensitivity, technology, economy and political will. The risks are not all from septage, nor are the greatest risks from secondary effluent. The current proposals ask for such low nitrate effluent that the off the shelf ATU's can not meet the standard, and therefore consumers wishing to reduce site impact will have to bear the cost of custom engineering, or go conventional (STE). Unless the regulations are linked to the technology, and economy we will backslide. In truth the cost of a peat filter or recirculating sand filter could be reasonable to the average consumer, and the benefit of reducing the organic loading is considerable. But I'll say it again, why are we regulating secondary effluent at a higher level than STE?
Does the Commonwealth have the political will to handle these questions. What if the science points to residential lawn care as the primary contributor of Nitrates to the aquifers?
Why is there so little environmental science being applied to the questions, and how could the budget cuts which laid off the geologists, contract soil scientists and other relevant personnel reverse the losses and begin to feed data back to the policy makers and politicians that should be considering these issues?
Thanks for handling an issue that should receive wider coverage. Your points are well taken, I've always appreciated an engineer's perspective.