bkarr
New Member
60 yr old house on a hill slope has a septic tank with a failed leach field (plumbed with orangeburg ). There is no room to dig another leach field and I can't get city permission to rebuild it, even if I did there are half a dozen large trees within 20-30 feet of it. So I've finally admitted I need to make a connection to sewage.
The nearest sewage connection I can make is a 300 foot run from the inlet of the septic tank and 70 vertical feet above the tank. I believe the connection is to an unpressurized line. 20 GPM should be sufficient to handle the 3 bedroom/ 2 bath house.
Due to the line length and volume I'm concerned a 24" dia basin will have too small a pump cycle volume should the check valve get fouled so I'm leaning toward a 36" dia basin. Something like the Liberty D3672 Duplex package. I haven't really found anything bad about Liberty pumps so I assume they are pretty decent. The flow rate with the 2 stage liberty pump should be about 30 GPM.
http://www.libertypumps.com/Products/Category/SubCategory/Product/?p=42&s=13&c=19
Although I think I need the large tank size, I'm not sure if I really need a duplex system or if a simplex system would be sufficient. Is the duplex system worth it? Are there any issues with fiberglass tanks for longevity that would steer me in a different direction?
Using 1.5" PVC the total head including dynamic head should be about 90-95 feet, with 2" line I should get more like 76 feet of head. Although the head is higher on the 1.5" line it seems preferable because it would ensure minimum flow velocities in the pipe and also reduce the total pipe volume that can drain back into the basin to 27 gallons (2" pipe would be about 50 gallons). Or would I be better off with 2" pipe because it would be easier to clean out if necessary? Because of the high head I'm assuming I'll need the two stage pumps. The flow rate should be around 30gpm with those pumps which I think is sufficient to meet minimum flow velocities in 2" pipe should I use it.
Should I put in normally closed gate valves that bypass the check valves so I can drain the line back into the tank if necessary for maintenance? Do I need more than 1 check valve? How many cleanouts along the way do I need to put in? I don't know yet if I will be allowed to use PVC for this or not yet (it's early days), or is there something better? steel? Should I use unions on the check valves so they can be serviced more easily?
The septic tank is in the front yard only about 6 ft from the house and open windows, and 10 ft from the front door. It was unvented, I'm assuming it vented back through the inlet line to one of the vent stacks on the house. Would that be sufficient venting for the basin or do I need to put in a vent on the basin. If I do have to vent the basin can I pipe it somewhere more remote from the front of the house? It seems easiest to put the pump basin where the septic tank is now because that's where the sewage pipe exits the house.
Another issue is that the 300 foot run to the sewer connection needs to go under a driveway on which vehicles are parked. Is this an issue with PVC pipe? If so can I run the PVC pipe inside a 3" steel pipe under the driveway? I will also need to run the electrical power for the pump under the driveway alongside the outflow pipe, any issues with that or special considerations? The outflow pipe will also cross over the incoming fresh water pipe to the house. Any issues with that?
I intend to do most of the trenching myself since it should be shallow enough not to need shoring. I'll assist a friend who is an electrician to do the electrical work. This whole project will be very expensive for me so I want to minimize costs where I can by doing as much of the work myself, but I also want to end up with a very reliable system I never have to mess with again(except for the rare pump or electrical work). I don't want to have to mess with the plumbing and basin again, but if I do I want to make it as easy as possible to clean them out and inspect/work on them. I'm certainly willing to hire a plumber to do the work that requires his expertise, but I'd like to know as much as possible going in so I can be sure things are being done right.
I know this is a lot but please point out anything I may have gotten wrong, suggestions of things I've forgotten, recommendations on materials, recommendations on what I should not attempt myself but hire experts for, etc. Anything to help reliability and easy of maintenance.
Thank you very much in advance.
Barrett
The nearest sewage connection I can make is a 300 foot run from the inlet of the septic tank and 70 vertical feet above the tank. I believe the connection is to an unpressurized line. 20 GPM should be sufficient to handle the 3 bedroom/ 2 bath house.
Due to the line length and volume I'm concerned a 24" dia basin will have too small a pump cycle volume should the check valve get fouled so I'm leaning toward a 36" dia basin. Something like the Liberty D3672 Duplex package. I haven't really found anything bad about Liberty pumps so I assume they are pretty decent. The flow rate with the 2 stage liberty pump should be about 30 GPM.
http://www.libertypumps.com/Products/Category/SubCategory/Product/?p=42&s=13&c=19
Although I think I need the large tank size, I'm not sure if I really need a duplex system or if a simplex system would be sufficient. Is the duplex system worth it? Are there any issues with fiberglass tanks for longevity that would steer me in a different direction?
Using 1.5" PVC the total head including dynamic head should be about 90-95 feet, with 2" line I should get more like 76 feet of head. Although the head is higher on the 1.5" line it seems preferable because it would ensure minimum flow velocities in the pipe and also reduce the total pipe volume that can drain back into the basin to 27 gallons (2" pipe would be about 50 gallons). Or would I be better off with 2" pipe because it would be easier to clean out if necessary? Because of the high head I'm assuming I'll need the two stage pumps. The flow rate should be around 30gpm with those pumps which I think is sufficient to meet minimum flow velocities in 2" pipe should I use it.
Should I put in normally closed gate valves that bypass the check valves so I can drain the line back into the tank if necessary for maintenance? Do I need more than 1 check valve? How many cleanouts along the way do I need to put in? I don't know yet if I will be allowed to use PVC for this or not yet (it's early days), or is there something better? steel? Should I use unions on the check valves so they can be serviced more easily?
The septic tank is in the front yard only about 6 ft from the house and open windows, and 10 ft from the front door. It was unvented, I'm assuming it vented back through the inlet line to one of the vent stacks on the house. Would that be sufficient venting for the basin or do I need to put in a vent on the basin. If I do have to vent the basin can I pipe it somewhere more remote from the front of the house? It seems easiest to put the pump basin where the septic tank is now because that's where the sewage pipe exits the house.
Another issue is that the 300 foot run to the sewer connection needs to go under a driveway on which vehicles are parked. Is this an issue with PVC pipe? If so can I run the PVC pipe inside a 3" steel pipe under the driveway? I will also need to run the electrical power for the pump under the driveway alongside the outflow pipe, any issues with that or special considerations? The outflow pipe will also cross over the incoming fresh water pipe to the house. Any issues with that?
I intend to do most of the trenching myself since it should be shallow enough not to need shoring. I'll assist a friend who is an electrician to do the electrical work. This whole project will be very expensive for me so I want to minimize costs where I can by doing as much of the work myself, but I also want to end up with a very reliable system I never have to mess with again(except for the rare pump or electrical work). I don't want to have to mess with the plumbing and basin again, but if I do I want to make it as easy as possible to clean them out and inspect/work on them. I'm certainly willing to hire a plumber to do the work that requires his expertise, but I'd like to know as much as possible going in so I can be sure things are being done right.
I know this is a lot but please point out anything I may have gotten wrong, suggestions of things I've forgotten, recommendations on materials, recommendations on what I should not attempt myself but hire experts for, etc. Anything to help reliability and easy of maintenance.
Thank you very much in advance.
Barrett