Table #2 needs a small change – The last raw of this table - CHANGE FROM 0” to <12” TO <12”. The reason for this change is that the designers (mainly Professional Engineers) must have freedom to design system below limiting features and <12” is a more clear indication of that freedom than what is currently proposed.
Comment #8
Section 12 VAC5-613-90 – DELETE Items “C.1” “C.3”, and “C.5”; as they impose unnecessary restrictions on responsible professionals (designer, installer, and RME) for offering wastewater services using AOSS and there is no scientific basis for these requirements.
Comment #9
Section 12 VAC5-613-90 - While I applaud the Department efforts to consider Nitrogen Mass Loading as requirement for AOSS, I suggest that Table 3 be DELETED. This table takes away designers ability properly account for soil treatment for total nitrogen reduction. I also suggest that you DELETE the Part D of this section and instead add the following language – “D. All AOSS in the Chesapeake Bay Watershed shall be designed such that the mass loading of total nitrogen does not exceed 10 lb/year/acre at the project area boundary and groundwater concentration of total nitrogen does not exceed 3 mg/l.” Otherwise, small rural communities would greatly suffer unnecessary cost over-run for both capital and operational of large AOSS.
We now have a design tool that allows designers to determine what level of nitrogen treatment can be achieved in soil and based on that level the designer can then determine what should be the end-of-pipe total nitrogen level needs to be for a given project. I suggest that you incorporate this design tool in the Regulation.
Reference for the Design Tool is “Quantitative Tools to Determine the Expected Performance of Wastewater Soil Treatment Units, Guidance Manual; 2010, Water Environment Research Foundation, Project # DEC1R06” and the entire tool kit (Excel spreadsheet and the manual) can downloaded at no cost from www.werf.org I suggest that you incorporate this reference into the Section 12VAC5-613-90-D of the proposed regulation as a design tool (similar to what is done in Section 12 VAC5-613-40 G related to use of the Field Book for Describing and Sampling Soils.)
The regulations should also add language that would allow the Designer to propose another tool that is science based and is published in some form of technical literature.
