Proper preventive maintenance for onsite treatment systems is necessary to protect groundwater resources and reduce public health impacts. Luckily, experience has shown that the technologies are sound and usually require little in the way of preventive maintenance.
Onsite systems, such as aerobic treatment units or packed-bed media filters, have been engineered and proven to work worldwide in a variety of harsh conditions. Where problems occur, they are typically not with the primary treatment system; rather, the problems lie with the rules and regulations (where they exist), the design and installation of the system, or inadequate operator skill.
Rules and regulations
Maintenance of alternative treatment systems must be made mandatory. For instance, the Virginia Department of Health (VDH) estimates that there are more than 65,000 alternative onsite systems in Virginia, but a maintenance company operating in 33 of the state’s 95 counties services less than 2% of that number.
While most cluster and commercial systems are required to have a licensed wastewater operator, until recently, no such requirement for single-family treatment plants and small-flow units — less than 3800 L/d (1000 gal/d) — existed. Recently VDH has imposed some mandatory maintenance requirements. This is a step in the right direction.
Now, VDH requires periodic laboratory sampling of biochemical oxygen demand and total suspended solids to confirm secondary and advanced secondary treatment systems are meeting their performance requirements. Additionally, reporting to the local health department is required following each scheduled maintenance visit and alarm response.
Engineering and design
Systems should be designed for maintenance. Engineers and designers should specify watertight tanks with watertight risers on all tank openings, as well as match components so that they are compatible with the primary or secondary treatment system. Mixing and matching manufactured and pre-engineered components leads to problems.
Designers should avail themselves of opportunities to simplify operation and maintenance (O&M) associated with their designs. For example, a manufacturer may already have a control panel that will operate its packed-bed media filter, as well as the drip-dispersal field. Combining these operations could eliminate having to install a second control panel or additional components from a second manufacturer to disperse the treated effluent safely and properly. Additionally, specifying a high-head turbine pump for a drip-dispersal field versus an open-faced centrifugal pump can make a world of difference to a service provider.
Installations should be performed in a way that will simplify future maintenance, wherever possible. For example, a pump discharge line should extend up into the riser so that it is easily accessible from the ground surface. Float “trees” — the plastic pipe assemblies to which the floats are attached — should be used instead of attaching float sensors to the pump discharge line. Attaching the float to the discharge line can lead to the need to remove the entire pump in the case of a sensor failure.
Control panels should be installed so that the bottom of the panel is a minimum of 914 mm (36 in.) above finished grade.
All wiring should be run inside conduit, and appropriately rated electrical splice boxes should be used where required. Plastic risers are more desirable for water tightness than concrete risers. Spending some extra time at installation on using the appropriate materials, making certain that tanks and risers are watertight, and making everything accessible can save the property owner/builder money in the future.
Education, certification, and licensing
When units are designed and installed properly, the major problem is the lack of understanding or knowledge of how and why these high-end wastewater treatment plants work and how use and abuse can “upset” them. Manufacturers may spend no more than 2 or 3 hours on “training” sessions for the designers, installers, and operators. Typically, these sessions are little more than sales pitches for the equipment. Many have very little educational content.
To help solve this problem, the Consortium of Institutes for Decentralized Wastewater Training (CIDWT) has developed a glossary of terms and a national O&M training course. This 2- or 3-day training program teaches the O&M basics. The course addresses how and why a treatment system works. Topics range from the primary septic tank to secondary and advanced treatment systems to disinfection and effluent dispersal. Detailed checklists that were developed by professionals from the onsite industry assist students with performing basic maintenance.
Additionally, Virginia now mandates licenses for onsite wastewater system professionals in addition to the maintenance and reporting requirements mentioned above. Virginia used the CIDWT program as one of the reference materials for its new licensing program.
Licensing professionals equals professional accountability. In the past, if the designer, installer, or operator made a gross error, he seldom was held fully accountable. Sometimes, he had to cover costs for part of or all of a repair to the system, but there was nowhere for a customer to file a formal complaint or any records kept of past problems.
To obtain a license in Virginia, an applicant must document experience; give written references; pass a written test to prove general knowledge, skills and abilities; and maintain a minimum of 20 educational contact hours every 2 years. A Virginia license gives the holder permission to operate any alternative treatment system up to 37,850 L/d (10,000 gal/d).
Operators also should obtain manufacturer certification and training in the particular treatment system they install and/or operate. The state does not require individual manufacturer certifications; however, the Virginia Department of Professional and Occupational Regulation acknowledges that should a state-licensed operator err and a notice of violation be issued, holding manufacturer-awarded certifications will aid in the operator’s defense. Conversely, lack of certifications may aid in the operator’s demise. There are now civil penalties and fines that may be assessed against a licensed professional, as well as a paper trail to reveal the good and bad performers.
Licensing onsite system professionals has a side benefit: It opens the door for competition — lots of it. Manufacturers can no longer restrict a territory to one or two chosen service providers, designers, or installers. Therefore, property owners can shop around.
Licensing also should help stabilize the price of service and improve the quality of service. The operator who is not responsive to his client’s alarm events or questions is going to lose that client. The installer who repeatedly cuts corners on the installation is now going to be called back by the operator to repair problems. No operator is going to want to take on a system that has installation problems. The systems should be designed and installed properly, and now there will be a concerned and knowledgeable person looking over the designer’s and installer’s shoulders to ensure that things go according to plan.
Still, homeowners must be educated, then educated, and then educated some more. These systems are not pretty. Installed properly, there are multiple access risers and control panels sticking out of the ground. Builders and homeowners want to hide the treatment system components under decks and behind foliage, making them inaccessible for maintenance.
Homeowners and builders also should identify the right system for the home. Home amenities, such as a whirlpool bathtub or a super-soaker shower suite, will affect the operation of the treatment system. Onsite systems can accommodate devices with large surges of water only if the system is initially designed using larger primary tanks and perhaps flow equalization to slowly introduce the flow to the treatment system. All of this may cost more money up front but will save money for the client in the long term.
Homeowners also must understand what can and cannot go down the drain. Things such as pouring paint into an onsite system, either during initial home construction or later, can damage attached growth treatment media and require immediate attention or replacement of the media and other components.
Maintaining toilet fixtures in proper working order also is extremely important. About 80% of alarm events received by the aforementioned Virginia maintenance company are due to a toilet fixture staying in the open position and flooding the treatment system.
A properly designed, installed, and maintained treatment system should be able to last the life of the residence and cost the owner no more in maintenance fees than being on a municipal sewer system.
Trapper Davis is founder and owner of Coastal Plains Environmental Group (New Kent, Va.), which specializes in the maintenance of alternative onsite wastewater disposal systems.
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