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Active Contributor

Join Date: Jul 2017
Posts: 21

LOSS Tank Modifications

08/21/2017 10:54 AM

Hello,

here on campus, the plumbing for the pumping chambers of each of the 4 Step Systems in the Large On-Site Septic System (L.O.S.S.) is configured in such a way that some of the periodic maintenance we are obligated to perform is not practical, or even possible.

The L.O.S.S. was overhauled in 2006. During this process, new septic tanks and pumping chambers were added to the system and some of the old tanks were reused and updated. New pump vaults were installed in the pumping chambers of each of the Step Systems. These pump vaults are designed to be easily pulled up out of the tank for maintenance purposes. The septic pumps themselves, the filter screens and other components should be accessible for removal. However the contractors ran the pump discharge plumbing directly over the top of the removable pump vaults so that neither the vaults themselves nor the individual components can be removed without cutting the piping. This has prevented us from performing some of the basic periodic maintenance that we are required to perform. The filters for each of the pump vaults in the system have never been cleaned.

Also there are some septic tanks which have one of the covers buried without having a riser installed. As a result, some of the tanks can only be opened and inspected on one end. We perform periodic inspections of the system, which must include assessing the condition of the plumbing and baffles where it enters and leaves each tank, and also measuring levels of sludge and scum to determine when a tank is required to be pumped. In many cases we can only inspect one side of the tank, usually the outlet/clean side of the tank where there would be the least amount of build up. The inlet/dirty side, which is the most likely to have excessive build-up or other problems, is not accessible for inspection.

all that said, here is what I was thinking:

1.) Install new, larger risers for the 4 system pumping chambers to allow more room for plumbing. Modify the pump discharge plumbing so that the pump vault can be removed for maintenance. The permanently installed hard plumbing, including the pump discharge isolation valves, should be as close to the riser wall as possible and skirt around the perimeter of the riser wall. The goal is to be able to close the pump isolation valve, disconnect the pump flexible discharge hose at a union just upstream of the isolation valve, electrically unplug the pump, and then have the physical space available to be able to physically remove and reinstall the vault as needed for maintenance.

2.) Excavate all of the septic tank covers that are currently buried underground and install risers so that they can be accessed for inspection and maintenance

Any suggestions, comments, anything would be helpful, thank you in advance.

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Guru

Join Date: Mar 2007
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#1

Re: LOSS Tank Modifications

08/21/2017 4:44 PM

A diagram of existing system and one of proposed changes would be helpful....

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Guru

Join Date: Oct 2008
Posts: 39866
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#2

Re: LOSS Tank Modifications

08/22/2017 12:51 AM

Silly question: It took 11 years for this to 1. be discovered, 2. determine that remediation was required.

Either take the steps you have outlined and cross your fingers, or hire a consultant and let them incur the responsibility.

You are there, we are not.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
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#3

Re: LOSS Tank Modifications

08/22/2017 10:14 AM

"Do nothing" is not an option.

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Active Contributor

Join Date: Jul 2017
Posts: 21
#4
In reply to #3

Re: LOSS Tank Modifications

09/11/2017 12:02 PM

any suggestions would be great. thanks

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