An actual replacement system designed & built by Pierson at a 4-BR, 2 1/2-bath residence in Southern Chester County during the summer of 2014 is described here, and there is an accompanying annotated slideshow which contains almost 300 images. The link to that slideshow is at bottom of this page.
This was a relatively sophisticated system as the soil did not perc-test well - test failed at 36" but passed at 60 inches. System design called for a sub-surface pressure-dosed sand-lined trenches system. Originally installed in 1980, the Chester County code at that time required a 1250-gallon tank with dual baffles. This 1980 installation was probably larger than required by code at that time - essentially the entire back yard of the 1-acre plot was septic drain field. The tank was routinely pumped every two years (more frequently than the township requirement). The house did have a water softening system installed in 1981, and during its flush cycle it dumped about 50 gallons of salt brine per week into the septic tank. This is probably why the system failed - the concrete baffles were attacked by the brine and they gave way, were found in the bottom of the tank upon the initial opening of the tank by Pierson. The lack of both inlet and outlet baffles of course allowed sludge to enter and contaminate the drain field, which in turn caused cessation of the efficient functioning of the system.
Due to the back yard field situation, the most cost-effective approach was determined to be: 1) install the field in the front yard, which required 2) the closing & sealing off of the deep well in the center of the front yard, and 3) connection to "city water" provided by Chester Water Authority, who had installed a main along the street running in front of the house. Pierson provided all the pre-connect work for this as well.
The well was closed & sealed and that work documented all in accordance with Chester County code by KL Madron Well Driller & Pump Installer Company, Avondale, PA (www.KLMadron.com). During the entire process, Pierson Environmental worked closely with the Chester County Health Department. Their inspector observed the perc testing and made routine visits to observe the work at various critical stages, as required by county code.
The code changed between 1980 and 2014 - for example, a dual-compartment quad-baffle tank was required in 2014, and a separate 500-gallon tank to house the pump was required - pump was needed as the front yard drain field was at a higher elevation than that of the actual septic tank in the back yard. Usage of the pump required installation within the house of a tank high-level alarm as well as a power-outage alarm. Needless to say, system design was a critical part of the process. The design dictated that best utilization of the available space was to use three varying runs of drain field piping in three separate trenches of varying lengths, and the number of 1/4" holes to be drilled in each piping run was specified, as was relative elevation for each.
The county inspector was very helpful in dealing with other code considerations, including proximity of the CWA water supply piping to the actual drain field piping, distance from street right-of-way to the field, and distance from field to the driveway. Also, the new drain field had to be a minimum of 100 feet from existing water wells. Pierson frequently works closely with the county inspectors, the importance of which cannot be overstated.
VIEW SLIDESHOW - the slideshow will open in a new browser tab - simply close the tab to navigate back to this page. It can be manually navigated if needed for more time on any image.