Unfortunately the answer to both of your questions is "No".
All fixture discharging into a sewage ejector receptor Must Be vented in the usual manner as defined for DWV applications prior to discharging into the receiver. The only exception to this rule is in the case of certain fixtures such as dedicated up-flush toilets that have a built in sewage ejector system.
Sewage ejector pumps occupy a totally separate section of the code and the restrictions are firm. Technically speaking a sewage ejector pump should be more aptly called a "Lift Station" because the code requires a number of features in addition to the pump itself.
First of all, a sewage ejector pump MUST BE housed in an approved watertight enclosure that is equipped with a removable service access cover and a separate vent through the roof of the structure. This vent may not be combined with any other venting within the structure.
Sewage ejector pumps may or may not be equipped with a macerator however only pumps specifically manufactured for the purpose of a sewage ejector may be used. If the pump is not equipped with a macerator feature the pump must be capable of passing 2" diameter solids. By definition a macerator is a grinder feature that can reduce solids to slurry before passing through the pump.
Under the International Residential Code (IRC 3007.1) the minimum permissible discharge rate of a sewage ejector pump must be 1.9ft/sec, which is equal to 14.2gal/min.

Under the International Residential Code the gravity flow drain receiving the discharge from a sewage ejector pump must be sized at the rate of 1.5DFUs for each GPM of the pump.

This means the minimum DFU load of a sewage ejector pump would be 14.2gpm x 1.5DFU = 21.3DFUÂs.

Under the Uniform Plumbing code (UPC 710.3.1) the minimum permissible discharge rate of a sewage ejector pump must be 20gal/min.

Under the Uniform Plumbing code (UPC 710.5) the gravity flow drain receiving the discharge from a sewage ejector pump must be sized at the rate of 2 DFUÂs for each GPM of the pump.

Under the Uniform Plumbing code the minimum DFU load would be 20gpm x 2DFU = 40 DFUÂs.

When combining the discharge of a sewage ejector pump with an existing drain we must first determine the existing load on that said drain line, then add the DFU load of the pump to determine the combined aggregate load.

Under the IRC the maximum number of DFUÂs permitted on a 3" branch line is 20DFUÂs while the minimum output of a sewage ejector would be 21.3DFUÂs. Therefore the sewage ejector pump discharge itself would be greater than the total load permitted on a 3" branch line, never mind the pre-existing load on that line. A 3" Main drain or building sewer is rated for a maximum of 36DFU while the sewage ejector is rated at 21.3DFUÂs therefore the pre-existing load on the 3" main drain may not exceed 14.7DFUÂs. Now considering that a bathroom group is 6DFU, a kitchen is 3DFUÂs and a laundry is 3DFUÂs. If the house has more than one bathroom and a 3" main drain or sewer you would be required to increase the size of the main drain and sewer line to add a sewage ejector pump.

In your case your Main Drain and sewer are 4", which is rated for a maximum of 180DFUÂs so if you install a sewage ejector you will be required to connect it directly to the 4" main drain line.

While the UPC assigns slightly different DFU values to the lines and fixtures in the final analysis it works out the same way.

Thank you lazypup.

The shower vent: I understand that it will require a vent, as the drain pipe lenth is too long to be unvented. Can I use a 1.5 inch vent for the shower, and can I tie the shower vent to the existing 1.5 inch vent that serves the diswasher? Or does the dishwasher vent need to be increased to 2 inches to allow this connection?

The ejector basin and pump I plan to use are designed to handle bathroom wastes. The basin is air-tight and has 2 inch effluent and vent openings. I plan to use unions, a check valve and a ball valve on the dischage line, so that the basin cover can be removed to permit service.

I understand that the sewage ejector must discharge directly into the main house drain, which means that I will need to cut into the cast iron. Is there a best practice or rule regarding how high the ejector effluent drain line must be above the main house drain?

It would seem that the only way to get a dedicated 2 inch vent for the ejector is to open the kitchen wall above and run it up to the roof.

Send me an email and ask for the sewage ejector illustration. I will return you an illustration that shows all the code requirements

LazyPup@yahoo.com

lazypup, thanks for the diagram. This is helpful. I will try to post it.

Brewbear

In Re your question of the fixture venting.

Under the IRC every structure is required to have one "Main Vent" which must run undiminished in size from the house main drain through the roof. After that is achieved you may reduce the diameter of auxiliary vents to 1/2 the diameter of the line they serve providing no vent is less than 1-1/4". The IRC will also permit an unlimited number of AAV (air admittance Valves) commonly called Studor vents or cheater vents. If your under the IRC for the fixture vent you could use an 1-1/2" AAV.

The UPC does not require a Main Vent but instead it requires ALL VENTS must run through the roof. Vents may be reduced in size providing they meet the standard for the DFU load served by that vent. 1-1/4"= 1DFU, 1-1/2" 8DFU but may not be used to vent a watercloset, 2" = 24DFU's.

The fixture vent may be combined with other house vents providing the point of tie in is a minimum of 6" higher than the highest flood level rim of any fixture served by the existing vent.

The UPC will allow a maximum of one AAV per structure with the expressed consent of the local inspector.

lazypup, thanks again.

The vent has a dishwasher (2 DFU), kitchen sink w/ disposer (3 DFU) and the new shower (2 DFU), for a total of 7 DFU. At 7 DFUs, I assume the vent is adequate to serve the three fixtures.

Are these assumptions correct?

I'd rather not use an AAV.

You may be using your local code DFU values, if so you are correct but under the IRC & UPC you have a minor error.

Under both the IRC and UPC all three fixtures listed are rated at 2DFU's each for a total of 6DFU's.

in either case, if your under the IRC it doesn't matter and under the UPC an 1-1/2" line is rated for up to 8 DFU's so you may use an 1-1/2" vent. In fact, you could also install a lavatory bowl(1DFU) near your new shower.

The only consideration here is that the vent line from the shower in the basement must rise vertically until it is 6" higher than the flood level rim of the kitchen sink before you may make the tie in.

Also keep in mind that the horizontal offset must be pitched at 1/4" per foot downward away from the stack. This is to insure that any condensate moisture that might develop in that line would flow down towards the riser from the basement and on down to the drain line.

The DFU numbers I used came out of a book titled "The Complete Guide to Home Plumbing" by Black & Decker, copyright 2001. The book seems to make reference to the UPC.

My plan is to tie the vent line for the shower to the existing 1.5 inch diswasher vent line, which disappears up into the ceiling next to the drain from the kitchen sink. I am running under the assumption that the dishwasher vent ties into the vent stack for the kitchen sink the required 6 inches above the counter.

Good pointer on the vent pipe pitch.

Thankx again. I will try to post photos if I can.

Ok, I figured out the photo thing. This is what I am working with.

Here is the portion of the DWV plumbing for the kitchen. On the left, the 1.5 inch copper dishwasher drain. On the right, the 1.5 inch dishwasher vent above, and the 2 inch sink drain below. In the middle, the 2 inch kitchen stack.

Here is the 4 inch cast iron main drain.

I plan to remove the 1.5 by 4 by 4 inch wye fitting that serves the laundry washing machine, the short piece of pipe to the left of the wye, and some of the pipe on the next length of case to the left of that.

I will be re-installing PVC, from right to left: a 2 by 4 by 4 inch wye to serve the sewage ejector, followed by another 2 by 4 by 4 inch wye to serve the washing machine, followed by a 4 by 4 by 4 inch wye to serve as a new cleanout.

Note how the existing cast iron drain has a sag just before it goes through the wall. This has caused backups, which the existing cleanout is downstream of. The new cleanout will be to help in dealing with this problem.

Here is the illustration of the sewage ejector by laxypup.

Thanks lazypup !!