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Waste water discharge from washing?

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June 30, 2013, 10:16 AM
PD.Vancouver
Waste water discharge from washing?
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?
Thanks. P
June 30, 2013, 10:51 AM
The Trouts
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,

Bob


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June 30, 2013, 12:01 PM
PD.Vancouver
The Trouts, thanks for the info, but I'm not sure how to interpret it? Can u help?
P
July 01, 2013, 04:22 AM
The Trouts
Sure.

From wikipedia:

http://en.wikipedia.org/wiki/B...d#Typical_BOD_values

quote:
Typical BOD values

Most pristine rivers will have a 5-day carbonaceous BOD below 1 mg/L. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L. Municipal sewage that is efficiently treated by a three-stage process would have a value of about 20 mg/L or less. Untreated sewage varies, but averages around 600 mg/L in Europe and as low as 200 mg/L in the U.S., or where there is severe groundwater or surface water Infiltration/Inflow. (The generally lower values in the U.S. derive from the much greater water use per capita than in other parts of the world.)



http://en.wikipedia.org/wiki/Total_suspended_solids

quote:
Total suspended solids


Total suspended solids is a water quality measurement usually abbreviated TSS. It is listed as a conventional pollutant in the U.S. Clean Water Act.[1] This parameter was at one time called non-filterable residue (NFR), a term that refers to the identical measurement: the dry-weight of particles trapped by a filter, typically of a specified pore size. However, the term "non-filterable" suffered from an odd (for science) condition of usage: in some circles (Oceanography, for example) "filterable" meant the material retained on a filter, so non-filterable would be the water and particulates that passed through the filter. In other disciplines (Chemistry and Microbiology for examples) and dictionary definitions, "filterable" means just the opposite: the material passed by a filter, usually called "Total dissolved solids" or TDS. Thus in chemistry the non-filterable solids are the retained material called the residue.



http://en.wikipedia.org/wiki/C...d#Phosphorus_removal

quote:
Phosphorus removal

Phosphorus occurs naturally in both organic and inorganic forms. The analytical measure of biologically available orthophosphates is referred to as soluble reactive phosphorus (SR-P). Dissolved organic phosphorus and insoluble forms of organic and inorganic phosphorus are generally not biologically available until transformed into soluble inorganic forms.[11]
In freshwater aquatic ecosystems phosphorus is typically the major limiting nutrient. Under undisturbed natural conditions, phosphorus is in short supply. The natural scarcity of phosphorus is demonstrated by the explosive growth of algae in water receiving heavy discharges of phosphorus-rich wastes. Because phosphorus does not have an atmospheric component, unlike nitrogen, the phosphorus cycle can be characterized as closed. The removal and storage of phosphorus from wastewater can only occur within the constructed wetland itself.


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.

Bob


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September 03, 2013, 01:39 AM
westvandude
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.
October 08, 2013, 01:27 AM
Murphy
quote:
Originally posted by The Trouts:
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,

Bob


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.


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October 08, 2013, 02:43 AM
Jerri
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???

quote:
Originally posted by Murphy:
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???

October 08, 2013, 09:46 AM
Murphy
quote:
Originally posted by Jerri:
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???

quote:
Originally posted by Murphy:
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???


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.


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October 09, 2013, 03:56 AM
The Trouts
quote:


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.



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:
quote:


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?


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.

Bob


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October 09, 2013, 12:13 PM
Murphy
Are soaps considered solids? If not, what solids would you anticipate being in there that could add up to over a gram?


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