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Discuss connecting ejector (pressurized) to secondary / gravity main line in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

ohnoflood

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5
question about connecting an ejector pump to the sewer, where there is no existing conditioned structure that gravity-feeds:

We have a lot that will be built in a couple years. Lot is sloped, with road and sewer main nearest to the up-hill lot line. The house will built in that corner, and high enough to gravity feed to the main. For the next several years & through construction, we're living in a yurt, placed on the opposite (downhill) edge to be out of construction's way.

The yurt needs a toilet, but it is much too low to gravity feed directly to the sewer. We're familiar with ejector toilets, using one for a basement bath in another property - but that house has its own bathrooms above grade (meaning existing gravity connection to sewer, in a conditioned space, requisite venting etc). Obiously the fixtures flowing to the ejector require their own venting to code, as well.

What are our options to connect to the sewer exclusively from a pressurized / non-gravity line? Can we accomplish this withOUT a (conditioned) structure high enough to gravity feed, housing the vent stack and junction for the ejector's pressurized effluent pipe?

Many thanks!
 

oz-plumber

Esteemed
Plumber
Messages
3,045
From the sounds of your situation, it may be cheaper to install a septic tank for the interim period of time.

A black water pump system is a very expensive option.
The Pumps aren't cheap and the (not sure where you are located) local requirements for setting up a black water system are
very strict.

You will most likely require 2 pumps ( duty & standby ), alarm systems, concrete pit with fixed steel cover, point for connection of vacuum truck incase both pumps fail or backlog of black water due to power failure.

Costs were @ 50k mark $AU.

I would go with septic tank
 

ohnoflood

Messages
5

rpm

Esteemed
Plumber
Messages
12,639
Look at the Sanifos range which claim to pump up hill over a distance.
 

ohnoflood

Messages
5
Look at the Sanifos range which claim to pump up hill over a distance.
yes - see my previous link; it's to an ejector (SanifLow brand no less :) )

the issue is that the saniflow needs an existing sewer stack to Wye into.

And that's my question: is there any way to get around having a separate conditioned structure, just to house the connection (and vent) to the 4" sewer line. This is basically a "throw away" shack I'd have to permit, build, and heat ... really hoping to avoid it.
 

rpm

Esteemed
Plumber
Messages
12,639
If you look at the pump curve of the model in your link it will not pump up a hill over any distance which the Sanifos range of pumps will therefore it doesnt pump into a stack and can connect to a manhole at ground level connected to the sewer.
 

ohnoflood

Messages
5
If you look at the pump curve of the model in your link it will not pump up a hill over any distance which the Sanifos range of pumps will therefore it doesnt pump into a stack and can connect to a manhole at ground level connected to the sewer.
Thanks for your reply. Could you elaborate on the what the plumbing requirements are for the below-grade "manhole" junction? For context, i have read section 7 of the UPC (I only have 2009 in hand); section 710.12-13 speaks to ejectors/macerators specifically, but doesn't cover anything beyond "manufacturer directions" ... I can't find in the code where it deals with coupling a (pressurized) residential ejector line with the (gravity) sewer.

of particular concern is the vent inside the manhole ('red' below, center)- is this just "open air" where the pressurized line 'dumps' into a "receiving tank" that has a manhole-style cover? If that's the case, what's the right name for this tank with a 4" sewer connection & iron manhole cover?

It seems plausible to me (but I am hoping for expert confirmation - because I may not have found or interpreted the relevant code) that this could be as below, but please correct me:
You don't have permission to view attachments. Attachments are hidden.


for reference, this is rise and run is WELL within the Saniflow spec:
You don't have permission to view attachments. Attachments are hidden.
 

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rpm

Esteemed
Plumber
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12,639
For which model is that rise and run spec sheet?
Problem I have is that I know Saniflo release some models in the USA that we dont see here in the UK. I can try and get a contact for you in your state from Saniflo UK if that will help you.
 

ohnoflood

Messages
5
For which model is that rise and run spec sheet?
Problem I have is that I know Saniflo release some models in the USA that we dont see here in the UK. I can try and get a contact for you in your state from Saniflo UK if that will help you.
SaniGrind Pro
https://www.saniflo.com/us/module/attachment123/attachment?id=77 (page 2)

although note there are several other products with equal/better performance and a different (below-floor) form factor that we're also considering, such as SANICUBIC 1 – Pre-assembled grinding simplex system – SANIFLO - https://www.saniflo.com/us/installing-a-lift-station/105-sanicubic-1.html

Thanks!
 

rpm

Esteemed
Plumber
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12,639
Aha, we dont get the Sanigrind here but that is pretty impressive specs, we do have the cubics (1 & 2) here but when I left Saniflo there was problems wit the PCB`s and motors but that was a few years ago so I hope the problems have been overcome by now.
You could contact Saniflo. usa
 
S

SanifloConfusion

I need to flush uphill, about 6' vertical over 120 feet horizontal, then another 6' vertical to be able to drop into the septic input.
Saniflow insists I can't pump uphill on the slope, must first pump straight up 12', then use gravity to traverse the 120' horizontal.

How does the pump, pumping against a given head pressure, know whether it is pumping straight up or on an angle following terrain?
 

rpm

Esteemed
Plumber
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12,639
What Saniflo UK actually say is if there is a rise in the discharge pipe then it must be at the start of the run and only one rise is permitable. (Or words to that effect).

What you are expecting is outside of what the average sani can do however thinking outside of the box for a minute have you considered using two pumps.
 
S

SanifloConfusion

I spoke to one of their techs today, and he said the Sanicubic 1 can handle this application. He said the 1HP motor in that unit has considerably more torque than the 1HP motor in the Sanibest Pro units.

Kind of reading between the lines, it sounds like their published specs might be somewhat optimistic when applied to real-life situations, and perhaps should say "or" rather than "and/or" when giving the rise/run numbers.

I didn't press him on how the pump performance would be different between identical head pressures from an angled vs. a vertical pipe installation.

I also corresponded with Zoeller, and the tech there said their Qwik Jon Premier might handle this, with a 1/2 HP pump.

I'm looking further into that possibility with him.
 

rpm

Esteemed
Plumber
Messages
12,639
Are you also in the states as the original poster was?

I can promise you a an ex Saniflo UK guy that the published specs are not optimistic and the and/or relates to how the discharge pipe is run.

The two motors you refer to are totally different as are the pumps and share no common parts and here in the UK one is rated t 1100w and the other is 1500w so neither are 1hp motors.
 
S

SanifloConfusion

Yes, I am in the US, (Hawaii).

Thank you for the pump info. I just recently realized this type of system might be something I can use, so have a lot to learn, still.

I took some more precise measurements yesterday, and this is what I have...

From the new toilet, next to a barn/workshop (I think of it as an outhouse with plumbing), there is an upslope run, with about a 4' (1.2 m) rise over a horizontal distance of 115' (35 m).

At the top of that upslope, it needs an additional vertical rise of 5' (1.5 m).

That's a total rise of 9' (2.7 m), consisting of 4' (1.2 m) on the gradual upslope, plus 5' (1.5 m), vertical at the top of the slope.

From there, it's a gravity run of 48' (14.6 m) with a 1.5' (.5 m) drop into the septic pipe.

That's the physics part.

I have been cautioned about using a grinder to feed a septic system, due to the reduced solid sizes resulting from the grinder and the longer time required for the finer solids to settle out.

I found this article, which addresses the topic:


Our septic tank is 1000 gallons, currently used by just two of us. We average probably 50 gallons inflow into the tank, per day, and maybe as much as 100 on a heavy usage day (our washing machine uses 13 gallons per load, two people flush maybe 6 times a day with low-flush toilets), and maybe six 20 gallon showers per week

According to the article, the spec for the Hydraulic Retention Rate is 4 days, and our HRT is currently greater than 10 days.

Our 10-15 day HRT seems to me to provide adequate capacity to handle a grinder that will flush perhaps 3 to 5 times on a busy day, and likely 1-2 times a day, on average.

No other fixtures will be connected to the grinder.

Your feedback on the physics and the biology of this proposed usage will be much appreciated.

Aloha.
 

rpm

Esteemed
Plumber
Messages
12,639
Hi and thanks for the link which was interesting, the problem we have living in different countries is that the regs (laws) and equipment are not always the same even if they are from the same manufacture.

Perhaps best if you log on that web site in the link, say where you are and outline what you want to do there but I would look towards a lifting station rather than a domestic style pumping system.

Good luck with the project.
 
S

SanifloConfusion

I'm a licensed General Contractor here, so I have a working knowledge of the local codes, and ready access to the Building Department and its inspectors.

I'm much more interested in learning how the laws of physics and biology/chemistry apply to this type of installation.

The pump's output is fed into a pipe for delivery elsewhere, and the total head presented by that pipe can be calculated using the pipe's size, length, number and degree of turns and elevation lift.

It's still unclear to me why a pump would be required to pump against one component of the total head (the lift) before pumping against the other components of the total head.

What principles of physics would support that requirement?

For the biology/chemistry part, it seems clear that pumped, macerated sewage has finer particles that require a longer dwell time in a septic tank to settle out. The answer to the question of "How much longer?" does not seem to be impossible to find an answer to. I think the article I linked will lead me toward a good answer.

Other solutions would include installing a holding tank below the proposed toilet location, and having it pumped periodically. Or pumping up to my septic, and having the septic tank pumped periodically.

Eventually, the city will install sewer lines to connect me to their sewage treatment plant, which is, maddeningly, only about 1-1/4 miles away, and all downhill from here.
 

rpm

Esteemed
Plumber
Messages
12,639
The pump's output is fed into a pipe for delivery elsewhere, and the total head presented by that pipe can be calculated using the pipe's size, length, number and degree of turns and elevation lift.

It's still unclear to me why a pump would be required to pump against one component of the total head (the lift) before pumping against the other components of the total head.

What principles of physics would support that requirement?
You might want to join the Grunfos acadamy or even better the Chesterton pump web site to learn why there are different designs of pumps and selection is so important.
 

oz-plumber

Esteemed
Plumber
Messages
3,045
As Plumbers, we are persons who install components 'fit for purpose'

We assess jobs and source equipment that is suitable for the specific job.
We rely on manufacturers specifications for installation of products.

If we have queries on specifics of what a product can or can't do, we contact the manufacturer.

We have no access, or knowledge, about what their products can, or can't do, outside their recommended installation instructions.

If you have an issue outside the manufacturers specification, it would be beneficial to contact the manufacture and get them to supply you with the information required to have their product installed.

Even better, get them to design and warrant a system that suits your purpose.

You would be far better off having a manufacturers designed system installed than a 'guesswork' system installed by a plumber.

Plenty of Plumbers are capable of designing and installing a variety of products, but don't have access to manufacturers 'in-house' design criteria.

If you have something outside the common design specifications of a product, get the manufacturers of the product to help you.
 

Reply to connecting ejector (pressurized) to secondary / gravity main line in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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