Substitute Aggregate Leach Field Proprietary products replace gravel with lightweight materials  The two proprietary products described replace the gravel in a conventional system with various lightweight materials. In the "EZFlow" product, recycled plastic is fabricated into grooved pellets that have a higher surface area per volume and a higher void to solid ratio than aggregate. In the Eljen In-Drain product, geotextile fabric with a high surface area is separated by plastic spacers to increase the leaching surface area.
See the article "On-Site Sewage Disposal Systems - Overview" for an overview that will help relate this technology to other options and to the overall system. In the EZFlow product, recycled polystyrene beads grooved to create a high surface area surround a 4" perforated PVC pipe in thicknesses from 1" to 4." The beads are held in place by a nylon netting. The Eljen In-Drain product uses a multi-layer composite bed of "egg-crate" plastic cores separating layers of geotextile fabric. It is formed into packages 3 feet wide, 4 feet long, and 7 inches high. 
Contractors and the local building department may be unfamiliar with these products. The Eljen product may be subject to clogging from biomat growth. Check with your local jurisdiction concerning the required field area, which may differ from the performance claims of the manufacturer. EZFlow is manufactured in North Carolina, Florida, Texas and Oregon. Eljen In-Drain is produced in Connecticut, with the 12 states in which it is approved scattered around the country. Availability will correlate with system approval by the state, as well as distance from a distributor.
Costs for leach fields are highly dependent upon the system sizing allowed for the product by the jurisdiction. The advantages of light weight, easy handling, and the use of recycled materials (in the case of the bead system) may override cost as primary considerations in choosing these systems.
Not Applicable
The EZFlow product is approved in 20 states, with approval pending in others. The Eljen product is approved in 12 states, with approvals pending in others. Sanitary engineers may not be familiar with the systems and may be reluctant to specify them. Each jurisdiction establishes its own rating for various system configurations.
Not Applicable
EZFlow piping can be laid in many configurations within a trench, but only certain arrangements may be rated by any given jurisdiction. The installation is covered with filter fabric after being set, and is then backfilled. The Eljen In-Drain is set directly on 6" of sand, a 4" perforated PVC pipe is placed down the middle of the bundles, and the installation is then covered with filter fabric and backfilled.
Not Applicable
For the EZFlow system, three parallel 10" or 12" diameter pipes in various configurations are rated by the State of Washington as having 2 to 3 sf of leaching surface per lineal foot of pipe. According to the manufacturer, a typical installation is about 3/4 the length of a conventional system. The EZFlow system uses recycled plastic in the beads. The Eljen product is variously rated over a very wide range in the 12 states that approve it, ranging from 5/8ths to 1/5th the size of a conventional system. The manufacturer claims that the layers of filter fabric within the bundles substitute for ground surface, allowing up to 10 square feet of functional biomat per lineal foot of product. In actual operation, this advantage is counteracted by the buildup of sediment on the fabric. Data from the field indicates that Eljen systems should not be downsized by the amount the company claims. | 
