Septic Tanks, Drain Fields, and Certification

According to the United States Environmental Protection Agency (EPA) about 25 percent of the population relies on septic systems ( or Onsite Wastewater Treatment Systems, OWTS) to treat and dispose of household sanitary waste from toilets, sinks, washing machines and other household uses of water that needs to be disposed. This means that OWTS in the U.S. collect, treat, and release about four billion gallons of wastewater per day from an estimated 26 million homes (EPA). In addition, the number of onsite systems is increasing, with close to a million new systems being installed each year (EPA). These increasing numbers have led authorities to focus more than ever on OWTS and educate consumers and technicians and engineers alike about structurally-sound and operationally-effective OWTS. In the beginning, however, they had an uphill battle against the public’s overall negative attitude towards septic tank systems, their warped perspective that OWTS were only second-rate or temporary structures, and a fundamental rejection of their validity or necessity. These negative attitudes, perspectives, and rejections contributed to poorly designed, poorly constructed and inadequately maintained OWTS. Alarmed by the potential health hazards of improperly functioning systems, federal, state, and local governmental health officials have refocused their attention on rural wastewater disposal, especially given the billions of gallons of wastewater that, if not properly treated and disposed of, could cause major public health risks. Now they continually seek methods to improve the design and performance of OWTS.

Residential OWTS
Your standard single home OWTS is not that complex so with the right concern, they can be a very effective technology for people who do not live in cities or towns where there is a public sewer and water treatment plant, etc. Piping carries household toilet, sink, and other wastewater to a large septic tank, usually built underground. The typical OWTS is designed to let nature and gravity do most of the work. The wastewater, or effluent, is collected and temporarily held in the tank long enough so that as much of the solid waste settles to the bottom of the septic tank while fat, oil, and grease (FOG) rises to the top. In the middle, so to speak, is the remaining effluent which then flows out of the tank into a system of perforated piping situated a pre-determined distance from the home and/or well. While in the tank, bacteria has been continuously digesting the waste material and now, as the effluent seeps out of the holes in the piping which is laying in trenches underground, the effluent encounters more naturally present micro-organisms in the soil that continue to digest and break down the waste material. The area where the piping is and where the water seeps into the ground is called a leech field or drain field. When all is working as planned, nature simply takes its course and the effluent is filtered to the point that when it finally reaches the underground water table or river, lake, etc. it is deemed safe, or at least no longer toxic and deadly.
In the EPA’s 1997 Response to Congress it states: “these various types of decentralized wastewater treatment, if properly executed, can protect public health, preserve valuable water resources, and maintain economic vitality in a community…. adequately managed decentralized wastewater systems are a cost-effective and long-term option for meeting public health and water quality goals, particularly in less densely populated areas” (EPA, 1997). When designed, sited, installed, and maintained correctly OWTS provide a cost-effective way to treat and dispose of domestic wastewater for homes and communities without access to any public sewer systems. On the other hand, improperly used or operated septic systems can be a significant source of ground water contamination that can lead to waterborne disease outbreaks and other adverse health effects. To avoid any problems, the first thing to check for before someone has a septic tank system is the soil in the area where the system is to be built and placed.

Soil Testing Procedures
There are regulatory standards of soil testing before a septic system is installed, and requirements that toxins, pathogens, and chemicals like nitrogen do not enter the natural underground water table. The land where the proposed septic system and connected drain field will be must be soil tested to assure that it is healthy enough and the right density, etc., and that it could absorb the effluent without the effluent causing any environmental or health hazards. Standards vary state by state. So, for example, in the state of New York, at least one deep test pit and two percolation tests are required. “Percolation and deep hole tests must be performed in the area of the proposed absorption facility. Deep test hole(s) allows soil profile evaluation and depth measurements to any restrictive soil features identified.” Restrictive features may include water tables, bedrock, or layers of extremely slow or fast permeability. Percolation tests are performed to determine necessary leach field size and. to some extent. type of OWTS. Other site characteristics are recorded, including soil slope, dominant soil texture etc. These factors become increasingly important as housing density increases Local regulators, advised by soil scientists, may want to require or recommend that only particular OWTS be used based on these site characteristics. The most appropriate OWTS type is then chosen for the site (

Drain Field Failure
The EPA’s Onsite Wastewater Treatment Systems Manual (2002) defines system failure as “a condition where performance requirements are not met.” Septic Tank systems are relatively uncomplicated systems and as long as a properly sited and designed system is airtight and pumped when needed, an OWTS can last 20-30 years. So, when there is a failure, it is usually has something to do with the soil absorption system, the drain field. There are many causes related to drain field failure such as excessive rainfall, and tree roots interfering with the drain lines, or even from vehicles driving over the system and causing pipes to crack. However, the two most common causes are hydraulic and biological overloading. Hydraulic overloading occurs when too much water is sent to an under-designed system. Biological overloading is the result of too much organic matter in the effluent. Both of these are actually most likely caused by homeowners themselves. When designing a septic system, the determination of what capacity it should handle is usually based on the number of bedrooms (people) in the home, but this may not provide an accurate picture of the water uses of the inhabitants of the home and the subsequent flow generation in the system. Certain appliances, such as garbage disposals and dishwashers, can greatly change the quality of the wastewater sent to the system. These appliances send increased amount of solids to the system, possibly causing biologic overloading. Use these appliances in moderation, keeping in mind that a garbage disposal is not a waste receptacle. In addition, homeowners should avoid overloading the system with water. Instead of doing all of the laundry on a specified “laundry day,” the homeowner can stagger laundry loads throughout the week. Homeowners should not empty backyard pools or hot-tubs near or over the OWTS. They should also avoid discarding decay-resistant materials into the system such as grease, sanitary napkins, and other solids. Monitor tree roots if you can that are near or around your absorption system and lastly, homeowners should not use their drain field as a temporary parking lot. Given the ever-growing installation and use of OWTS, the public, and especially homeowners, should be educated on the nature of septic tank systems and how they work.

The education process does not stop at homeowners. The Liquid Waste Industry has responded well to the growing number of OWTS now in operation. Even though it may be the case that there are no federal standards or, in many cases, governmentally mandated state standards for the design, installation, and inspection of septic systems, that has not stopped many professional and upstanding companies that deal with OWTS to nevertheless go through thorough, formalized education and continuing education programs so they will be informed of the science and engineering involved in the design, installation, and inspection of OWTS. When hired to design or install an OWTS, companies in the liquid waste industry must apply for and follow a slew of permits and regulatory controls which ensure that the siting, the design, etc. of septic systems, including, drain field operations, are the right kind of sufficient capacity, and safe to the homeowners and to the public at large. So, despite the fact that there may be no federal or statewide licensing procedures that must be adopted or acquired, that has not stopped septic system and drain field designers, installers, and inspectors from nevertheless instituting standards, protocols, and minimum levels of education through professional organizations. This is why some consider many aspects of the liquid waste industry as being “self-regulated,” but the controls, standards, procedures, and level of education are no less stringent than if the government was setting the standards and education level. Almost every state has a professional organization—that is experts from the industry itself—that form to create the high engineering, science, professional, and ethical standards for their members working in the liquid waste industry. A good example of a privately-run certification granting organization is the PSMA.

In Pennsylvania there is the Pennsylvania Septage Management Association (PSMA). As Mark Mitman, Administrative Director of the PSMA, “Our mission” he says is “to protect PA’s citizens and our industry through sound management, proper maintenance, and environmentally conscious disposal of wastewater.” The PSMA accomplishes this by offering two levels of certification. They offer PSMA 101 Basic Inspector Courses and PSMA 102 Advanced Inspector Courses. PSMA 101 is for those technicians who are just starting out and do not yet have a comprehensive knowledge of septic systems, their safe design or sound installation processes. PSMA 102 is an advanced course that delves into the more scientific or engineering aspects of septic systems such as fluid dynamics, etc. This is mainly for the technician who has a good working knowledge of septic system design and installation, but wants to take it one step further and learn how to inspect any and all types of septic systems. “The PSMA was formed in 1986,” says Mr. Pitman, “in order to establish state-wide standards” for the installation and inspection of septic systems.” “Since the original standards were drafted,” he continues, “a PSMA Committee of our experts meets every three years to review the standards, which may include recent feedback from technicians in the field or new and innovative technologies geared toward what we do.”

High Technical and Ethical Standards
The PSMA also has a Code of Ethics that all members must take an oath to uphold and follow. The Preamble states that: The Pennsylvania Septage Management Association (PSMA) Board of Directors holds all members to a high ethical standard. PSMA wishes to remind all members to conduct business in a professional and ethical manner. PSMA believes in the importance of environmental protection and in complete compliance with all applicable laws, regulations and standards. The Board of Directors has, therefore, defined the ethical standards which its members must accept as a condition of membership. “As it says in our Mission Statement” Mitman tells us “the consumer is always at the forefront of our goals and motivations. It gives the new homeowner, or seasoned homeowner comfort to know that if a PSMA certified technician is installing, working on, or inspecting their septic system, they are in good hands. The consumer can be rest assured that our technicians have the highest technical skills and also the highest level of ethics and professionalism.” Being involved with the PSMA and working through its certification courses and programs also benefits the professional in the liquid waste industry. “There are unique opportunities for training” says Mitman, plus “being a member also helps you distinguish yourself from the competition that may not be PSMA-certified and consumers are more likely to hire a certified technician than a non-certified one. That’s what our research tells us.” If you are not yet a member of such an organization, look around your state and get in touch with its own state-wide certification-offering organization.

Story by Mark Joseph Manion

PIPELINE – Winter 2005; Vol.16,
No.1 National Environmental Services Center
EPA (1997)

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