The homeowners having the septic system installed saved $10,000 because they questioned their engineers work and decided to install an Eliminite denitrification system rather than one from the "Big Guys."
This is significant because the total installed cost of the entire system (Building sewer, primary tank, Eliminite treatment unit, drainfield, pumps, control panel and labor) was about $21,000. This is a huge savings.
The two systems, Eliminite and "Big Guys", are regulatory equivalents meaning in the eyes of DEQ they are equal. However, I have years of data comparing the effluent from the two systems showing Eliminite has far superior nitrogen removal results.
So why is the other system so expensive? My opinion is that they have, with the assistance of your state and local health department, enjoyed a near monopoly.
In Maryland, the agency charged with permitting these system actually lowered the standard to accommodate a system that they had previously approved but could not meet the original standard for which it was permitted.
Generally, these systems are approved for installation by providing ONE data point, NSF testing. The problem is once the system has passed NSF's fantasy test, the state agencies don't bother exploring REAL WORD numbers from the installed systems and it is a well know fact, though only spoken in dark corners of empty rooms, that certified systems generally do not meet real world nitrogen standards. Hence the shenanigans in Maryland. (The certification is pricey...it would cost a company in the neighborhood of $150,000 to complete the 6 month test. Who pays for this? You do.)
In Rhode Island it is reported that residential denitrification systems cost $35,000 to $45,000. http://www.thewesterlysun.com/news/shoreline-building-hurt-by-dem-rule/article_227ed8b8-0955-11e1-9058-001cc4c03286.html
Here is a breakdown of the types of systems installed in Charlstown, RI taken from: http://www.charlestownri.org/index.asp?Type=B_BASIC&SEC=%7B57BE787A-1F23-406A-906B-4FBC5BCACF34%7D&DE=%7BA376CA24-20CF-48FA-B83B-5FC3F0F62459%7D
Monopoly? You decide. I can tell you that based on the pie chart, Eliminite would provide dramatically lower effluent nitrogen numbers than the vast majority (90%+) of the systems being installed (I can't speak to every system listed because I am surprised anyone even uses them any more) and cost thousands less.
This means that Rhode Island would see an immediate reduction in the cost of residential denitrification systems of about....you guessed it $10,000 to $25,000.
That is real money in the homeowners pocket and less nitrogen in the environment.
Oh..and for the record, Montana's water is better.