Determining the Effectiveness of On-site Septic Systems foe the Removal of VirusesAuthors: George R. Heufelder M.S. R.S.
In 1995, the Commonwealth of Massachusetts made significant changes to its regulations governing onsite septic systems to reflect advancements in the knowledge base of onsite wastewater treatment. While these changes reflect many of the advances in our understanding of the treatment for certain constituents, much was still not understood about the role of standard septic tank-leach fields in the treatment for pathogens, notably viruses. The need for this type of understanding was amplified when the state allowed the use of innovative/alternative (I/A) septic systems, which under certain approvals were allowed to compensate for certain deficiencies that an applicant might present (i.e. less distance to groundwater or less available soil absorption system area). While the efficacy of I/A for treatment of certain constituents was widely accepted, questions arose as to whether the “credits” granted to I/A technology were appropriate in light of the present knowledge base regarding pathogens. The purpose of this study was to determine the efficiency of standard septic systems for the removal of viruses and compare this performance with selected I/A technology. The study further endeavored to place the findings in context of recent literature and make recommendations for maximizing virus removal from onsite septic systems.
Results from our study were presented in many forums including two journals, four national meetings, two regional meetings, and two annual meetings of the Massachusetts Environmental Health Association. Copies of all presented/published papers are supplied herein. Although there is considerable research still to be conducted, this grant has allowed us to serve as a valuable resource to DEP and Boards of Health for issues regarding pathogens. Our research corroborates the decision by DEP to require pressure dosing of leachfields where I/A technologies receive “credits” for leachfield size or reductions to groundwater. A review of the literature along with concurring research under this grant compelled certain recommendations that are included in this report. The findings of this study will also be incorporated into revisions of training materials yet to be compiled and including the Department’s “Self-Pace Course in Title 5” for local Boards of Health.