Water Resources Research Act Program

Details for Project ID 2016AL177B

Onsite Wastewater Management in Hale and Wilcox Counties: Failing Septic Systems, Direct Discharge by "Straight Pipes" and Microbial Source Tracking

Institute: Alabama
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $21,980 Total Non-Federal Funds: $43,964

Principal Investigators: Mark Elliott, Kevin White

Abstract: In the Black Belt region, low-permeability soils and other factors, including poverty, make onsite wastewater management challenging. Black Belt soil and geology make over half of the area unsuitable for conventional septic systems (He et al., 2011). In addition to failing septic systems, many in the rural Black Belt directly discharge sewage from the home, usually to a nearby wooded area or ditch through a so-called straight pipe. The prevalence of straight pipes and failing septic systems in rural areas with impermeable soil is well-known by health department workers and other stakeholders. However, while the problem has been acknowledged by EPA (EPA Region 4, 2002) and others, little data is available on the magnitude of these problems. We are aware of only two studies to quantify the fraction of homes with straight pipes: one in Madison County, NC (Baldwin, 2000) and the other a study in Bibb County, AL (White and Jones, 2006) conducted by three of the investigators on this proposal. These rural, southern counties had 15-17% of households with straight pipe discharge, rates of direct discharge that are frankly shocking for the United States in the 21st Century. While the impacts of these raw sewage discharges on our rivers and ecosystems are undoubtedly substantial, the greatest concern is the large number of waterborne pathogens released and the threat to human health. Based on the number of straight pipes in Bibb County, the volume of raw sewage and the number of human pathogens released into Bibb County can be estimated. We estimate that in Bibb County, households with straight pipes account for over 60,000 gallons of raw sewage discharged per day; that is over 22 million gallons of raw sewage per year. To put these volumes into context, wastewater plant spills of 5,000 gallons or less typically make newspaper and television headlines in Alabama (Reed, 2015). While these spills from wastewater treatment plants are regrettable, they are generally infrequent and are greatly exceeded in volume by straight pipe discharges occurring every day in just one county. Based on typical pathogen concentrations in sewage (Payment and Locas, 2011; Robertson et al., 2006), straight pipes in Bibb County discharge billions of infectious pathogens per day. Estimated pathogen loads of only a few of the hundreds of waterborne human pathogens: >1 billion enteric viruses, >1 billion Giardia cysts, and >300 million Cryptosporidium oocysts discharged from straight pipes onto the ground surface or into streams of Bibb County alone every day. It is important for regulators to understand that the absence of E. coli in Alabama surface water samples does not guarantee their safety when these environmentally robust pathogens are being discharged in such high quantities. Failing septic systems, like straight pipes, also expose Alabama residents to harmful pathogens. When a septic system fails hydraulically and sewage surfaces into the yard, children and household pets are frequently exposed. Household pets track pathogens back into the home, exposing the residents. Children are exposed directly when they play in and around what looks to them like a puddle, or when removing toys and balls that have accidentally fallen into puddles of sewage. Although there is not enough information to quantify the pathogen load or risk from failing septic systems, the vicinity of these pathogens to the home and the potential for exposure of particularly children are especially troubling. Even more troubling is the fact that local stakeholders agree that the sanitation conditions in Black Belt counties are likely far worse than in Bibb County.