Darkroom Plumbing below sewer line.

Hi all,

I'm about to start setting up a community darkroom for BW, colour, and alt process printing. The premises i'll be using is below the sewer line, and I'm wondering if anyone has any advice or experience dealing with this.

There is currently a macerating pump (up-flush) toilet, with a single small sink patched into that. I don't know if it would be worth building a separate tank with an ejector pump for all the photo sinks.

I'd like to keep energy costs low, so if anyone has cost effective solutions to pumping waste water to the sewer, any advice would be appreciated. The sewer line is about 10 feet above floor level.

Thanks!

P

Wow - interesting problem that I have never encountered , will be interesting to hear solutions...

I do not see a reason for an additional pump, except for a possible corrosion issue with current pump. This could be overcome by adding a reservoir for dilution, which in case of an added ejector pump would be necessary anyway.

Options are:
- use the existing macerating pump with a new sink plumbed into the existing pump
- use the existing macerating pump, dumping the chemicals into the existing sink
- install a new pump and new sink
- dump into 5 gallon/20 liter buckets and either dump into the sink tied into the existing pump or hand carry the buckets above grade and dump into an above grade sink

Lowest financial cost is the 5 gallon buckets dumped into a sink above grade, which is not connected to the macerating pump. But there is a cost of human energy.

You don't need a macerating pump, a sump pump is fine if you're dealing with liquids... use a 55 gallon plastic drum of the proper grade.... got the space?

What will your maximum water flow be and how many gallons will you accumulate in the storage tank before you empty it?

Have you considered a 50 gallon ( or larger) storage tank with a pump controlled by a level switch? This way your wash water would dilute the used chemicals before they enter the sewage system. Don't forget to put back flow preventers in the piping so you don't get sewage and waste from the rest of the building coming up through your drains.

jvo said:

You don't need a macerating pump, a sump pump is fine if you're dealing with liquids... use a 55 gallon plastic drum of the proper grade.... got the space?

Click to expand...

He already has a macerating pump.

There's always the question of whether the existing pump and it's sump reservoir can handle the increased load.

Given the low cost of a sump pump (at least here in US), I'd go with a separate sump reservoir and pump to avoid any issues. Keep in mind that your sump reservoir has to be lower than your sink drain, so a half a 55 gal drum has the same capacity as a whole 55 gal drum (unless you've placed it on it's side).

Thank you all for your responses!

pinholer said:

What will your maximum water flow be and how many gallons will you accumulate in the storage tank before you empty it?

Have you considered a 50 gallon ( or larger) storage tank with a pump controlled by a level switch? This way your wash water would dilute the used chemicals before they enter the sewage system. Don't forget to put back flow preventers in the piping so you don't get sewage and waste from the rest of the building coming up through your drains.

Click to expand...

I think this is what I will end up going for. The water flow won't be much for the first 6 months, but once things are up and running, print washing alone will generate a reasonable amount.

mgb74 said:

There's always the question of whether the existing pump and it's sump reservoir can handle the increased load.

Given the low cost of a sump pump (at least here in US), I'd go with a separate sump reservoir and pump to avoid any issues. Keep in mind that your sump reservoir has to be lower than your sink drain, so a half a 55 gal drum has the same capacity as a whole 55 gal drum (unless you've placed it on it's side).

Click to expand...

I'll take that into consideration.

I have a similar need (darkroom in the basement about 8ft below sewer line, and I'm wondering how I could get running water down there), and figured a sump reservoir and sump pump would be the easiest way to go. The sump pump can be easily upgraded to support growing demand.

I have done this (sump pump/reservoir) a couple of times on darkroom builds where I had to run along a ceiling to reach the drain. One was 8 ft the other 12 ft. Worked perfectly, it's not expensive or difficult. One concern about your existing macerating pump would be the volume and duty cycle specs, a toilet gets a lot less use than a group darkroom running water constantly.

btaylor said:

I have done this (sump pump/reservoir) a couple of times on darkroom builds where I had to run along a ceiling to reach the drain. One was 8 ft the other 12 ft. Worked perfectly, it's not expensive or difficult. One concern about your existing macerating pump would be the volume and duty cycle specs, a toilet gets a lot less use than a group darkroom running water constantly.

Click to expand...

This is definitely the way I would go. Get the pipe up to the ceiling level then look for the easiest place to tie into the existing stack. If you are dealing with cast Iron It's still doable, but with old plumbing and piping maybe best to leave sleeping dogs keep sleeping If all you are pumping is wash water (absolutely no concentrated chemicals) in theory, you could pump it out the side of a building. Sumps for ground water routinely pump out of the house onto the ground.

You need a lift station, if you are going into a sewer line you will need a P-trap on the horizontal line at the ceiling and a sewer vacuum breaker (or run a vent line)

If you are dealing with plastic this is easy. I would keep the sump around 5-10 gallons. You could even "seal" the sump and vent it but as long as you don't fill it with bad stuff odor should be minimal. I used these "air admittance valves" on both my darkroom sinks, eliminates the need for a vent line. Everything works great. If you don't use AAV or a vent you may end up with sewer gas in the house
Best Regards, Mike