Replacing Peat media in Puraflo and Eco-Flo Systems

It is estimated that about a third of homes in Virginia have septic systems. There are many different types of septic system designs. The most common type used for single family homes is still the traditional septic system that consists of a single chamber septic tank that flows by gravity to a drain/leach field. However, due to regulatory changes, continued growth in housing Alternative Onsite Sewage Systems (AOSS) have become popular.

A typical AOSS in Virginia consist of a septic tank, treatment unit, pump chamber, conveyance line, distribution system, and an absorption field (trenches, pad, drip tubing, etc.). However, the exact set of components that make up the system are site and system specific. AOSSs allow homes to be built on land that “does not perk”- can neither pass the standard percolation test nor support a traditional septic system.

To protects public health, the waters of the state and the environment AOSS are regulated in Virginia under 12VAC5-613-140. This regulation requires all AOSS are designed, meet minimum performance standards and will be properly maintained and inspected at least once a year with newer systems required to be sampled regularly. The full text of the regulations can be read at this link.

These non-conventional septic systems include: aerobic tank or ATU’s, peat filter systems, coir filter systems, single and recirculation sand filters, mound systems, drip dispersal, spray and low pressure dispersal. Manufacturers of these systems have gotten their systems approved in the commonwealth so that they can be bought off the shelf. These systems include but are not limited to: Advantex, Clearstream, Puraflo, EcoFlo, EZ Treat, Fujiclean, Microfast Norweco, Bio Coir. All of these systems are approved for use in Virginia, but may not be optimal for all sites and are also expensive to build, maintain and replace.All of these systems are approved foruse in Virginia, but may not be optimal for all sites and are also expensive tobuild, maintain and replace.

None of these AOSS systems is ideal, but I’ve always liked the simplicity of the peat filter systems and the peat is a phenomenal media for absorption. The peat media filter system is a traditional septic tank with peat filtration system instead of a leach field. The filtration system is the aerobic portion of the treatment and is located in tanks which are filled with peat moss over a gravel base. The filtered septic tank effluent is collected in the pump tank. A timed dosing system pumps the effluent through an inlet manifold located at the base of the treatment modules. An orifice plate is located inside the top of each inlet manifold which allows the flows to be split equally and fed simultaneously to each biofilter module or modules. (The number of modules is based on the size or type of the system-the number of bedrooms is how these systems get sized.) The inlet manifold is connected to the base of the biofilter module and is fed upwards to a rectangular distribution grid located 6 inches below the top of lid. The effluent percolates laterally and vertically through the depth of the peat fiber treatment media and emerges as a clear, innocuous liquid from the base of the system. The treated effluent is then collected and dispersed. New systems are installed with a sample port.

from EcoFlo

From Anua

The peat is an excellent media for allowing the natural secondary treatment of the sewage waste to take place: Absorption and filtration of any impurities chemical adsorption, and microbial assimilation. As a result, these systems are typically capable of removing 90% or more of the polluted mater (characterized as BOD, SS, Coli forms and E. Coli). The life of these systems varies by manufacturer and origin of the peat. For Puraflo systems, peat moss replacement is recommended around every 14 years. For Ecoflo systems they recommend that the peat should be replaced approximately every 7 years. These number assume that the system is properly used and maintained (or less with improper use). The required annual inspection of the system will determine when to replace the peat, and when to pump the tanks.

The problem is that the peat used in these systems came from Canada, Ireland, or other overseas location (depending on if you have a Puraflo or Ecoflo), and extraction and removal of the peat can impact natural ecosystems of those locations. Peat is a limited natural resource and as such expensive. Recently, the cost of replacing the peat media is $2,250-$3,010  per module for the Puraflo system (depending on the number of modules) and $5,200-$6,000 for the Ecoflo system. This pricing includes disposal of the existing peat and labor, but does not include the pump-out of the tanks which is necessary. This has gone up significantly since I last checked pricing. The Puraflo prices are down somewhat since the end of the pandemic. Ecoflo pricing went up during the pandemic and have stayed up.

There is another option. Puraflo has a new media, coir, coconut fiber. While Anua has a Bio-Coir system that is generally approved in Virginia, you can also use a coir media as a direct substitute for peat. Unfortunately, since this substitution of media has not been generally approved, it would require five rounds of 180 day sampling to prove it’s functioning, new spray nozzles and an engineer’s stamp on the design. (see the VHD memo.)(see the VHD memo.)

 The costs to change the media would be about the same as the costs for replacing the peat listed above, the first time. Though coir, which is coconut fiber, is low-cost and a renewable resource that gets consumed over time, the change from peat media includes disposal of the existing peat and changing of the spray nozzles to the ones designed specifically for the coir. Going forward the system would only require the addition of coir as needed, but that is a long term cost savings and many do not keep their homes long enough to benefit. Coir is a by-product of coconut harvesting and is a renewable resource.

The AOSS market in Virginia is dynamic. Things change and it is likely that steps that need to be taken to replace peat media with coir will evolve and become simpler. However,  for now though costs are still high.