Septics, lagoons, and alternatives

One of the first steps we needed to perform was to have a percolation test done on our acreage to see whether we could install an underground septic system or had to use an above-ground lagoon.  Mike Rezac took the initiative to contact Lloyd Jakoubek at Raymond Contracting to get that test done.  It takes a couple weeks, so it's good to have that out of the way.  The results just came in, and we failed the test, meaning we have to go with either an engineered type system or a lagoon.

Here's the email we got regarding the perc test:

I completed the perc test on this lot and it did not pass, meaning a traditional septic system will not work.  You're either looking at a lagoon or an engineered type system.  I will put the perc test results & invoice in the mail tomorrow. 

There are various types of wastewater treatment systems that require an engineer's design.  These are costly ($18K and up), consist of mechanical components, and require regular maintenance.  (For comparison, a simple lagoon with fence costs about $5K and requires virtually no maintenance.) Below are links to information regarding a couple types of systems we are familiar with: 

Mound system:
http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=271 

Constructed wetland:
http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=269 

Recirculating sand filter:
http://www.toolbase.org/Technology-Inventory/Sitework/recirculating-sand-filters

We haven't called Lloyd to discuss the various options, but I did read up on it on the web pages he gave. Here's a summary. The mound system basically brings in a bunch of good dirt and piles it up on top of the bad dirt that failed the perc test. You still need to fence it off so that foot & vehicle traffic doesn't compact the new dirt, but at least you can landscape the mound however you like.

The constructed wetland uses a gravel pit to do the initial filtering, and that then feeds into a lagoon at the end of the line. Both the pit and the lagoon can be filled with water plants. Because the lagoon doesn't do most of the filtering, it's a lot cleaner and safe for animals to drink from. You still don't want to swim in it, though.

The recirculating sand filter is completely underground, much like a traditional septic system. It uses a submerged sand pit to filter the sewage, which is run through the filter multiple times. I'm guessing this is the most expensive option of the three, although it does allow the entire system to be hidden from view.

We definitely like the idea of not having a large, exposed lagoon taking up that much space in our back yard.  A lagoon must, by Nebraska law, be at least 50 feet from the nearest tree or the nearest property line, which really puts it in the middle of our yard.  Still, I'm not sure if it's worth an additional $13K  to change that.  We'll see how the budgets work out.

Have any of you ever dealt with an engineered treatment system?  How did it work out?  Please speak up in the comments below.