The concept of an onsite training center began in North Carolina. The North Carolina folks have done a great job of developing a 'hands-on' training center. On December 3, 2003, onsite program managers from seven Southeastern states met in Raleigh, NC and received a tour of the site hosted by Mike Hoover. These photos show some of the highlights of the site visit and by no means cover all the stations or training concepts this site contains.
There is quite a variety of septic tank designs used in NC. The training center shows a variety of concrete and plastic tanks. Most are about half buried so you can get a good look at the whole tank.
North Carolina requires the use of an outlet screen (aka "filter") and there are quite a few varieties to choose from.
ATU's are used in NC to pretreat effluent before release into soil. NC does not have a general NPDES permit for stream discharge.
Peat filters are also used in NC and the Puraflo (foreground) and Ecoflo (left background) are shown here. Normally both are buried or filled.
This is a close-up of the outside of Premier Tech's Ecoflo. It is normally buried so only the manhole (top center of the unit) is above ground.
Here are two Puraflo units and a sampling chamber manufactured by Bord na Mona. These units are normally filled or buried up to their lid.
One of the nice aspects (and by no means the only one) of a training center is being able to see products side-by-side. Here are a variety of manifold distribution devices that are used in pressure dosed systems to split effluent flows evenly among multiple absorption areas.
Here's a close-up of one "pre-engineered" manifold manufactured for onsite systems. These manifolds are all connected to a pump and clean water source and can be demonstrated in operation.
Here's yet another manifold. This one shows a clear flexible hose that is left in place and used to measure head pressure during routine inspections. Over time pressure can change as components wear or become clogged with solids. This is a good way to monitor performance over time.
Steven Berkowitz (NC) demonstrates how the manifold head pressure is monitored and adjusted while Jimmy Coles (AL) keeps a safe distance away. Apparently he has experienced Steven's demonstrations in the past. Note the flow in the 4" corrugated pipe in the background. This system is essentially an enhanced flow system as described in Virginia's regulations.
Here's the definitive answer regarding how far water (or sewage) moves down the pipe in an enhanced flow system. When the pipe is covered by gravel in an actual installation this isn't possible to see but it has led to a few good debates over the years.
This is an example of two trenches can be laid out precisely on contour. It isn't what you'd expect but the Training Center has a level and transit that you can use to convince yourself that these trenches are exactly on contour.
Another interesting part of the NC training site is a station where a variety of trench systems are installed side-by-side so you can visualize what they look like installed and compare one to the other. This is a conventional gravel trench system with 4" corrugated pipe.
This is a chamber system similar to those used in Virginia under the substituted system policy (GMP #116).
This is a large diameter pipe system.
This is an example of a system that uses expanded polystyrene for aggregate.
Low pressure technology began in NC. Here's how they do it now. The 1.25" PVC pipe is installed in a 4" corrugated pipe sleeve and the holes in the pressurized pipe are pointed up. When the pipe becomes clogged and cannot be cleaned, the sleeve provides ample room to allow the PVC pipe to be removed and a new pipe installed. Pointing the holes up prevents a hole from being obstructed by gravel or a pipe corrugation. Their experience really shows.
This is a panel-block system. It consists of a special cinder block like material laid up as shown and bedded in sand. Septic tank effluent is applied inside the pipe. Information provided at the site indicated that effluent is treated to approximately sandfilter quality by the time it enters the soil.
This is an above grade cross section of a sandfilter showing the pressure distribution piping, gravel, sand media, gravel underdrains and the effluent collection pipe.
This is where it all starts - where sewage is generated. Here Mr. Steinbeck discusses the merits of water saving toilets and explains the history of low water use toilets. The demo site can be set up to show the volume difference between a flush of each toilet.