Septic System Design

[RIP - VTEnviro]

I'm guessing that a lot of the folks on this board have designed a septic system before. I'm talking your typical stone and gravel trenches with a septic tank and a d-box. Pretty basic engineering.

Basic enough that in my state, you don't need to be a PE to sign off on a system for a single family house and some other small applications. You just need to pass an exam with a written and field component and you are considered a "certified designer." This makes sense, as there are a lot of rural areas here with no municipal sewer, and you don't really need a full blown engineering study to put in a leachfield. If you are a PE however, the testing requirement is waived and you are allowed to design anything, including mound systems, dosing, etc. that the 'designers' are not allowed to do.

Compare this to New Hampshire, which also has a subsurface designer certification program. I had some downtime recently and looked into it. Regardless of your PE licensure, you still need to take a day long written exam, plus a field component on another day. And it's only offered twice a year. No waivers. I couldn't believe it.

A licensed engineer, and you can't do a single family leachfield?!? That's messed up. We had to farm out a job recently on a project since neither my boss or I are certified.

Do any other states have this stupid rule or is NH the only one?

 

[MA_PE]

I had some first-hand experience with the NHDES regarding there "approval" process for septic design. I walked away with the understanding that it is a political racket and despite what the rules say they do whatever it is they want to.

I was complaining about a system a neighbor commissioned which was put in very close to a vacation property (admittedly and old, rouch-looking camp). The f'n neighbor/the designer/ and the installer made no effort to contact the owner of the adjacent property (my family). The new system had been "approved" by DES. Well my comparison of the submitted and approved drawing to the regulations revealed at LEAST a half a dozen problem including some outright lies in the drawing notes.

My gripe was specifically related to an existing well in close proximity to the newly approved and installed system. When I spoke with the NHDES reviewer he actually threatened me with an audit of the exisitng system at my family's vacation property, because he claimed it was "not approved". Probably, not so coincidentially, my family used the same "certified" installer and we paid for a permit which wasn't on file at the DES. I had good communication with the NHDES legal person buyt this subsurface reviewer was quite the piece of work.

I won't bore you with the rest of the story but suffice it to say that they excavated and moved the edge of the system back ~10ft. Not my goal, but they clearly didn't have a leg to stand on, and I know the designer didn't even get a warning for submitting drawings that had some significant violations to the regulations. Likely, because he's a big fish in the little town.

 

[RIP - VTEnviro]

^ Nice, when's the eb.com retreat to your cabin?

 

[Guest]

In Florida you can become a Registered Sanitarian through the Dept of Health.

I am not sure how the Dept of Health picked up the duties of regulating domestic septic tanks but IMHO the septic tanks in FL will soon be the single largest contribors to Non-Point Source Pollution as development continues to grow unchecked. :2cents:

I haven't heard any stories, but then again I really don't deal much with septic tanks unless somebody was discharging illegal (hazardous) substances into them creating soil and/or groundwater contamination issues.

JR

 

[MA_PE]

^ Nice, when's the eb.com retreat to your cabin?

of course you'd have to "do your business" in the woods. :happy:

 

[Dleg]

I'm the septic system regulations guy over here (as well as the stormwater guy, the solid waste guy, the .... get the picture?)

Our current regulations date from the '80s and are extremely basic. I plan to come up with entirely new ones maybe next year, if I make it that long. Anyone is allowed to design & install a septic system for a single family residence. To make that less of a problem than it was, I developed standard drawings and a sizing spreadsheet that homeowners can use, with our help, to get a set of construction drawings to their contractor of choice. Our staff then inspect the construction at about 5 or 6 points during construction, and personally verify setback distances.

The big problem is that it's a "prescriptive" regulation system - meaning it tells you exactly how to design the system. That's a big problem because a septic system should be designed by someone who understands ssptic system design, and most importantly: soils. Prior to my employment, people were just building the prescribed system everywhere, usually directly into limestone. In other words, no soil. Which means no treatment. On top of that, our subdivision rules were based purely on politics with no regard to wastewater loading, in a place that relies solely on groundwater for its water supply, so we have a development density of around 5 homes per acre. It was only this year (2007) that we started seeing the nitrate levels in our groundwater exceed the maximum contaminant level for nitrate. Now everyone is screaming "how did this happen?" Duh.

I think the real reason most states are requiring at least some level of additional education and certification for septic system designers is because of the soils and "site evaluation" knowledge you must have to responsibly design a system, and to know when a tradition septic system won't work, and what other type of system would be more appropriate. And VT - I know as well as you do that we aren't tested at all on that knowledge for the PE exam. I don't personally know if Civil Engineers are tested on it, but I doubt it since the enviro exam covers the same wastewater/water resources subjects.

But I will agree with you that it's ridiculous to require people to attend a training workshop, and then to only offer it twice per year. (But it sounds awfully similar to becoming licensed as a PE, doesn't it? Is that any more fair?). Personally, I think it is entirely acceptable to provide study materials on-line and allow people to self-study, and to come in and take a test by appointment at any time they choose. However, there needs to be some field component as well, and scheduling that is more difficult.

MA_PE: it sounds like you just had the bad luck to run into a real asshole, and possibly a corrupt asshole as well.

 

[RIP - VTEnviro]

In New York, where I started my career, septic systems are done on a county by county basis by that county's Dept of Health. And the design HAS to be done by a PE.

The thing I've noted about New England, or at least VT and NH where I work, is that everything is either town or state based. The county has no jurisdiction over anything and really doesn't have much government function.

I agree that soil ID is most important for a septic system, but you also run into the fact that 10 different engineers will log a test pit 10 different ways and not be wrong.

This also relates well with my rant the you need to be a PE to design something, but it's reviewed by some technician with half your quals.

 

[Dleg]

^ That reminds me of my own rant. When I started work here, the engineers in the community were all happy that there would finally be an engineer reviewing their plans. They all knew me from my private sector work for a local A&E firm. Then they got pissed off anyway when I started noting problems with their plans, and blamed it on me not being a PE. So now I am a PE. Now I am told that I am just "anti business". I can't win. So I now focus on training. That sems to be working the best.

My rant is therefore: A PE license is not a magic wand. You don't gain the actual ability to do everything you're licensed to do overnight. You still need to work just as hard at learning new things as you did before you got the PE.

One thing to perhaps give those "technicians" credit for is that they probably deal with ALL the complaints regarding failed septic systems in the area. They may not be engineers and may not even understand septic design and the codes themselves, but they probably have good intentions, and just want to see a system built that will work. From a regulator's point of view, their ass is covered if you follow the rules in your design. That's usually all they care about, in my opinion.

 

[DVINNY]

I am working on a project here that is a first in the state, and the Public Service Commission here has formed a task force to look at this project and the type of regulations that need to be in place to do these across the state.

It involves individual on-site systems mixed with cluster systems, all under one management entity.

The 'clusters' that I've designed all have individual septic tanks with small diameter collection pipes taking the effluent to a common grinder pump station that lifts it to one D-box and into a community drain field made up of chambers. This state allows for a 40% reduction in square footage of field if a chamber system is used vs. a stone based trench line.

There reasoning is that some places have bad soil conditions and/or too small of areas for a proper field, and there may be a great area for a drain field just a few hundred yards away.

The houses that do have an individual system will have it 'taken over' by the utility and inspected on a constant basis, and the tank emptied every three years regardless of need.

This will help keep fields from failing due to miss-use.

 

[MA_PE]

You guys ever work with a STEP system? (Sewerage Treatment Effluent Pumping) The idea is each residence has its own sealed "septic tank" actuall a holding tank where baterial action breaks down the solids and then the effluent is pumped to common force mains to be treated at a treatment plant. we had a big job ~15 years ago in FL where the tanks were made of fiberglass and were of pretty "crappy" (yes pun is intended) design and construction and they started collapsing left/right very shortly after installation. We looked at it from a structural view and didn't have anytihing to do with system operation. there were about 1500 of these tanks involved. People weren't happy.

 

[Guest]

It involves individual on-site systems mixed with cluster systems, all under one management entity.The 'clusters' that I've designed all have individual septic tanks with small diameter collection pipes taking the effluent to a common grinder pump station that lifts it to one D-box and into a community drain field made up of chambers. This state allows for a 40% reduction in square footage of field if a chamber system is used vs. a stone based trench line.

Won't that make this project a CLUSTER !@#$% ?? :Locolaugh: :Locolaugh:

The houses that do have an individual system will have it 'taken over' by the utility and inspected on a constant basis, and the tank emptied every three years regardless of need. This will help keep fields from failing due to miss-use.

That is an interesting concept because obviously the primary issue with residential on-site treatment of wastewater is the loss of efficiency due to not keeping the system maintained. Thinking out-loud, I am wondering what authority the State is citing to impose these requirements on private property owners. One could view those requirements as a takings issue unless there was some sort of standing agreement or contractual obligation whereby the private property owners agree to the maintenance requirements.

Aside from some of the legal entanglements it sounds like a good idea! Shitty septic tank systems (yeah pun intended) are beginning to lead to poor water quality in Florida and in fact have started contributing to the INCREASED nutrient loading in what used to be fairly pristine waterbodies.

Oh well .. this state is going to hell in a handbasket. What's a few added colonies of fecal coliforms?? :Locolaugh: :Locolaugh:

JR

 

[DVINNY]

MA PE,

I was involved in that type of system before, and the treatment plant just treated the 'grey water', in this system I'm talking about now, there is no treatment plant as part of the system, the grey water is dispersed through ground injection, and the septic tanks are pumped out regularly by a contractor, (honeydipper, who then takes it to a plant for treatment)

 

[Dleg]

MA_PE - we looked at a STEP system as an alternative to conventional gravity collection for one village where we are planning to put in a collection and treatment system. Every home already has a concrete septic tank, so we thought it was worth checking out. However, once we really got down into the details, it only saved a small amount of capital costs because the condition of the tanks was unknown just enough to justify building a new tank for every home. Then, there was the huge hassle of having to pump out 3,000 septic tanks every three years, and not to mention the grinder pumps that would be required in more than half of them. We ultimately decided that it was better to go with conventional gravity sewer, looking at long term operational considerations.

I think it has its place, though. That place might be in more affluent areas, say lakeside communities where water quality is very important, but soils or depth to water table is not optimal, where development density is low (say a total of 100 homes per system) and homeowners are affluent and responsible enough to support the maintenance costs. I've seen some very glowing case studies of where it has been successful. I just don't think it will work in every community.

DVINNY - I think that type of system is pretty good, but depending on just how good the soils are at the community drainfield, I would seriously consider looking into some further treatment than septic tanks only. Something like a recirculating sand filter can provide excellent treatment, even knocking down the nitrates, and that might make up for worries I (or any other state regulator) would have about the concentrated loading of pollutants at that one point. Or even a subsurface flow wetland - decent treatment and very little operation and maintenance required.