Wednesday, November 2, 2016

liquid waste storage

This is the natural follow-up to my previous post on solid waste storage.

We tend to keep our liquid investigation-derived waste (IDW) in either 55-gallon drums, poly tanks, or gigantic frac tanks.

Drums for liquids are the same as drums for solids, as discussed earlier. They're easy to drive around and pump off if needed, but troublesome if you're dealing with more than a couple hundred gallons.

I usually prefer poly (plastic) tanks, which range up in size from 150 gallons or so (about the maximum that you can put in a full-size pickup) up to a couple thousand gallons. The poly tanks tend to be much easier to open/close (which you may do often if you're just filling them a couple of buckets at a time) but still hold enough water to be useful for larger jobs. Also, if you have mildly corrosive water or treatment chemicals, these hold up better than the steel drums. About my preferred size (225 gallon) example here from ebay:

If I have a very large water sampling job, or an intermediate-sized drilling job, I may go with a much larger poly tank (this from rain for rent):
I've used these quite a bit - they vary in size (this one is almost 5,000 gallons, so on the larger end). The taller ones get a bit precarious to climb up. They have a top cap you can easily spin to open/close, and they have discharge connections at the bottom so that they don't need to be entered to be cleaned - you just need to aim a power washer or steam cleaner at the sides and empty from the bottom. Staff who are doing heavy-duty water handling can also directly connect to the bottom rather than dragging a hose to the top.

But sometimes, you find yourself handling lots of water. After a certain point, you'll need a frac tank. The biggest standard tank is 21,000 gallons, and if you're going to be doing a lot of deep drilling or potentially exciting drilling (karst? faults?) and need to containerize the water for disposal, you may get a couple of these (from Adler):
Oh boy. Frac tanks. I have strong opinions about these. If you need them, you need them. But what a pain. They need, like, acres of space to be dropped off. You need to perform confined-space entry to clean them. And I'm always paranoid that some local troublemaker is going to go ahead and open the front porthole (halfway up the face on the right in the photo) when the thing is mostly full and we'll have A Big Problem. Although I will admit that if I need a nice "quasi-aerial" photograph of a busy environmental investigation, the top of a 21,000-gallon tank is the perfect place to stand.

I'm sure that my counterparts in the oil and gas biz think that my frac tanks are hilariously small (they think the same of the drill rigs I use), compared to the manmade lagoons that they might make for a fracking project. But this is as big as it gets for me, thank goodness. I have a hard enough time keeping them properly sealed and secured.

1 comment:

Anonymous said...

Can you elaborate a bit on why/when you need to clean the tanks? Is this before filling, during, or after? I would have thought something like a frac tank would have supplier-side cleaning as part of the deal, but I guess that's too much to hope for?

And if you're cleaning out the tanks after they're used, where does THAT waste water go?