Can someone please list what the possible environmental issues are with water washing as far as used water discharge into the environment? Have there ever been any tests done to quantify any undesirable stuff in the waste water?
Here's some results we had run (at a third party lab) from a commercial plant back in 2006 that were above reportable limits:
Biochemical Oxygen Demand, 5 day 82400 mg/L
Total Suspended Solids 1330 mg/L
Phosphorus 61.7 mg/L
Hope this helps,
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The Trouts, thanks for the info, but I'm not sure how to interpret it? Can u help?
The reportable levels in the US state the commercial plant was located was as follows:
Biochemical Oxygen Demand, 5 day 2000 mg/L
Total Suspended Solids 50 mg/L
Phosphorus 5 mg/L
As you can see, typical biodiesel wash water can greatly exceed the allowable discharge levels for BOD and TSS - this is primarily due to the soaps, glycerine, and residual biodiesel in the wash water.
So it comes down to scale. When you take a shower, you are putting similar levels of BOD into the wastewater stream. Commercial entities are regulated differently than residences - so if you are planning a commercial venture, best to work with your local authority.
Also, pre-treatment (acidulation and recovery of FFA's followed by pH balancing is not hard and is done by commercial plants who still water wash.
Hope this helps a bit.
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Basically most communities suffer from acid rain so adding a bit of alkaline wash water to the sewer system from your little operation won't amount to anything. Yes, it uses up tons of oxygen and once your water reaches the sewage treatment plant it will take a lot more aeration to compost it. I could be wrong but that's my take on it.
If you're worried empty it into a 55gal plastic drum first, get an electronic pH meter, neutralize with any acid such as vinegar, sulfuric, etc.
Over 15000L of B100 produced. Burns in 01' F250 7.3L, 06' Jetta TDI, 02' Jetta TDI. Biopro190 owner since Oct2014.
Seriously? 1.33 grams of solids in a liter? What the heck did they test? Something doesn't smell right with that. Either that's a number derived from an untreated waste stream emanating directly from a poorly operating wash system or someone intentionally grabbed the worst thing they could find to send in.
Dealing with city waste water departments is a nightmare in both politics and technical expectations.
I designed a waste treatment plant about a decade ago that was built to remove heavy metals from a 20,000 gpd stream. We adjusted the pH down and added coagulant, then brought the pH up and added a flocculant, then down again just a little to bring it into the middle of the specs the city gave us.
Here's the kicker.. Our primary heavy metal was zinc and the city (Detroit) set our limits at 1.3 mg/L of zinc or an hourly spike of 2.6 mg/L. And get this.. the city water potable supply that everyone drinks, and the same stuff we use for process water, was allowed to contain up to 5mg/liter! WTF??? So technically, if you turned on the drinking fountain or flushed the toilet, the wasted water could be over our daily and hourly limit!
That is how screwed up it can get.
I hope I am not speaking out of turn here, but this is how I see it.
You are probably not the only one who wants to use the stream as a sewer.
If everyone who wanted to use this stream as a sewer was allowed to add huge amounts of solids to it...WTF???
No, you're not out of turn at all.. your perspective is the most correct one as I see it.. but that's not the point I was trying to make.
Technically, if we flush the toilet, we could be over our discharge limit.. Do they really expect every industrial building to install a fecal matter waste treatment system also? It all ends up in the same pipe.
The way the spec is written, we would have to spend money on treatment chemicals just to discharge the water they are supplying us with even if we didn't use it.
This sample was untreated wash water. We were sending our wash water and glycerin to an anaerobic digester at the time, and this was part of a characterization study on the effluents from the process. This material was not going into the municipal waste water system.
I posted this objective, third party data to answer the OP's question:
That may explain why it doesn't "smell right". The sample had residual methanol (no recovery was done) and all the soaps (no acidulation and FFA recovery). This sample would be representative of what untreated wash water would look like.
Hope this helps.
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Are soaps considered solids? If not, what solids would you anticipate being in there that could add up to over a gram?