pH Test Kits and Wastewater Treatment

Larry Hinckley

Hall of Fame Member
pH Test Kits and Wastewater Treatment

By Larry Hinckley, Delco Cleaning Systems of Fort Worth
Fort Worth, Texas

On the average a mobile power wash contractor will generate in excess of 500 gallons of wastewater each day that he washes. As you can see the potential for polluting our Nation’s water resources is tremendous. As professionals and concerned citizens it is incumbent upon us to do everything within our power to preserve our natural resources. To this end I offer the following for your consideration.


pH (p ch ) a chemical symbol.
A measure of acidity or alkalinity of a solution numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity. The pH scale commonly in use ranges from 0 to 14.
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[ p(otential of) h(ydrogen).]

People in the mobile power wash industry use a pH test kit for measuring the alkalinity or acidity of their wastewater. This is done prior to the discharge of this water to a sanitary sewer system where such is allowed. If the water to be discharged is not within the limits established by the authorities it can be brought into range by adding acid to a high pH or soda ash to low pH waste water which was captured for proper disposal. The most commonly used pH test kit consists of a small roll of red litmus paper and a color/number scale. To test the solution in question you tear off a small strip of the litmus paper and dip one end of the solution. Using the color/number scale provided with your kit you compare the color of the litmus paper that you have dipped in your test solution to the color/number scale and the color/number that matches is the pH value of the solution.

Environmental Impact:

A pH range of 6.0 to 9.0 appears to provide protection for the life of freshwater fish and bottom dwelling invertebrates
The most significant environmental impact of pH involves synergistic effects. Synergy involves the combination of two or more substances, which produce effects greater than their sum.
Synergy has special significance when considering water and wastewater treatment. The steps involved in water and wastewater treatment require specific pH levels. In order for coagulation [a treatment process] to occur, pH and alkalinity must fall within a limited range.




Sewer Types
Before discharging wastewater to any type of sewer you should check with the local authorities to determine the extent of their requirements.
{One source where this information may be found is on the internet at www.municode.com}
There are basically three types of sewers, they are: Sanitary, Storm, and Combined. Most cities have a Sanitary and a Storm Sewer System. The Sanitary Sewer System is what your home sewer is hooked up to. This system of pipes goes to the sewer treatment plant or Public Owned Treatment Works (POTW). At the POTW the sewage is treated and discharged to lakes, rivers or streams. This is where your wash water needs to go for treatment before being discharged to lakes, rivers and streams.
The Storm Sewer is where the rainwater goes into gutters along the streets and roads. This water is generally discharged directly to lakes, rivers and streams without treatment. Because this water is not remediated before discharge into the environment you should not discharge your wash water to a storm sewer.
Some cities have a combined sewer system where the sanitary and storm sewers are one system and all of the sewage and storm water is treated at the POTW. In these areas the wash water can be discharged to the storm sewer. You will need to call the Sewer Department in each area where you are washing, to determine which system you are discharging to.
Most outside drains are storm sewers and most inside drains are sanitary sewer drains but not always. Be sure to know which is which. If your customer does not know call the Sanitary Sewer Department you are hooked to and they will come out and determine which sewer system each drain is hooked to. In many areas this service is free.
The capacity and capabilities of POTWS vary greatly and so do their discharge limits. Discharge limits are determined by many factors including: the size of the body of water they are discharging to such as a lake, river, stream or ocean, what they are discharging, and the amount they are discharging. The larger the bodies of water the more relaxed are the discharge limits. Because discharge limits and POTW treatment abilities vary, the amount of treatment wash water needs before being discharged to sanitary sewer will also vary from POTW to POTW.


Disposal of Wash Water to a Sanitary Sewer
Because the discharge limits from POTWS vary so greatly so must the quality of water being discharged to them. Some POTWS will accept wash water without any pretreatment or very little pretreatment, such as filtering out the sludge. Some POTWS for cosmetic cleaning require only filtering with a 200 micron dirt and sand filter or a carbon filter. What POTWS will want to know is how much wash water you will be discharging and what contaminates will be in the water. A water analysis is generally required, this can cost $200 to $400 however some POTWS will do this test for free. Some POTWS will accept the wash water without any analysis and require an analysis only if a problem arises.
A common method for dealing with wastewater discharge is to recover the wastewater and carry it to sand traps located at Truck Washes or Coin-op Car Washes. The problem with this is that most cities do not want you taking your wash water from the location where it was generated and disposing of it at another location. This is because if a problem arises there is not a clear path of whose fault it is. Most cities want the water discharged where it was generated in order to cover liability. If there is not a sand trap on location the wash water will probably have to be pretreated before being discharged to a sanitary sewer. Another problem is that there are no rules that clearly define the transportation of wash water from site to site. Sometimes the cities try to classify wash water haulers in the same category as sand trap (grit trap) services. But you are not cleaning out or hauling sand trap contaminates. And wash water almost always tests non-hazardous. Also the EPA considers wash water SPECIAL WASTE. This is a different category than sand trap containment. Caution: do not discharge to a sand trap without first getting written permission from the owner of the sand trap.
A misconception is that biodegradable soaps can be discharged to a Storm Sewer. Biodegradation takes time and biodegradable detergents may be quite toxic before they reach the stage where they are completely harmless. Also there is a problem with what the soap emulsifies, like oils, greases, fats, dirt, pesticides and insecticides. Also phosphates that are used in some detergents can cause some POTW problems. Phosphates cause a problem because they are good fertilizers and cause algae growth, which depletes the oxygen in the water killing the fish. And of course fish kills are very visible with dead fish floating on top of the water, which attracts TV cameras and this creates the type of publicity you do not need! In some areas phosphate free soaps are required.
Many POTWS will accept your waste directly. However, this creates an economic problem with Commercial Waste Disposal Facilities. They think you should bring your wash water to them. They see the POTWS as government organizations competing with them. They already have a professional association representing them, so it comes down to politics and political power. Basically, the Commercial Waste Disposal Facilities will pass your waste on to the POTWS and charge you a fee for this service.
In some areas Commercial Waste Disposal Facilities are your best economic alternative. Their yellow pages heading is: WASTE REDUCTION, DISPOSAL & RECYCLING SERVICE, INDUSTRIAL. Typical costs for wastewater discharge range from 5 cents to 70 cents per gallon.
You will need to check with each POTW you are discharging to for their discharge limits. Normally these discharge limits will fall within these ranges: pH--(5 to 6) to (10 to 12); Fats, Oils, and Greases (FOG) or Total Petroleum Hydrocarbons (TPH)--less than (100 to 400) milligrams per liter (mg/l); Total Suspended Solids (TSS)--less than 200 mg\l to no limit; Biochemical Oxygen Demand (BOD)--less than 200 mg/l to no limit; Chemical Oxygen Demand (COD)--less than 450 mg/l to no limit. Heavy Metals Limit Ranges are: Arsenic (As)--less than (0.05 to 0.1) mg/l; Barium (Ba)--less than 5.0 mg/l; Boron (B)--less than 3.0 mg/l; Cadmium (Cd)--less than (0.3 to 0.7) mg/l; Chromium (Cr)--less than 5.0 mg/l; Copper (Cu)--less than (3.0 to 4.5) mg/l; Lead (Pb)--less than (0.1 to 2.9) mg/l; Manganese (Mn)--less than 1.0 mg/l; Mercury (Hg)--less than (0.005 to 0.01) mg/l; Nickel (Ni)--less than (1.0 to 2.0) mg/l; Selenium (Se)--less than 0.4 mg/l; Silver (Ag)--less than (0.1 to 1.0) mg/l; and Zinc (Zn)--less than 5.0 mg/l. If your wash water is outside the sanitary sewer discharge limits, you may still be able to discharge to the sanitary sewer but have to pay a surcharge.
Some companies have gotten permits to discharge to Leech Fields, Septic Tanks, and Injection Wells. Recently the Health Departments in some areas have been going out and testing these sites. Depending on what is found the companies may be required to stop using these sites or remediate the discharge areas. The safest technique is to discharge to Sanitary Sewer wherever possible.
Most POTWS do not require any pretreatment of the Wash Water when discharging to the Sanitary Sewer through a Truck Wash or Car Wash Bay as these sand traps are designed to for this purpose.
Disposal of Wash Water to the Storm Sewer
Normally you should never dispose of wash water to a storm drain. However, there are common exceptions to this rule. They are: house washing of a home by the owner, vehicle washing at residences, and vehicle washing by charities. Municipalities will generally overlook these transgressions.
Some Cities are allowing cold water washing with no chemicals (other cities hot water washing with no chemicals where there is no oil and grease, dirt only) to go into the storm sewer if these areas contain no hydrocarbons, pesticides, insecticides, or antifreeze. Hot water washing is considered to be PROCESSED WATER because hot water will emulsify oil and greases. Cold water washing is considered no worse than a rain event. The oil and grease spots should be pre-cleaned with absorbent clay (kitty litter) and disposed of in the dumpster. Leaves, debris, and dirt should be cleaned up before washing so this contamination does not enter the storm sewer. Storm Sewer entrances should be screened to catch leaves and debris and the wash water should pass through an oil absorbent boom or pad to absorb the hydrocarbons. No oil sheen should be present after passing through the oil absorbent filter. The lack of chemicals can be compensated for, by using a zero degree rotating nozzle such as a Turbo Nozzle or a Rotomax Zero Degree Rotating Nozzle. Typical washing examples are: Vehicles on Dealer Lots (dust only), sidewalks, shopping malls, parking lots, buildings, and homes.
Some cities will allow building washing with acid cleaners if the acid is neutralized before entering the storm sewer. Typical neutralization is with baking soda (sodium bicarbonate), soda ash (sodium carbonate), or an alkaline detergent instead of a clear water rinse. In other cities the cleaning is done with cold water, no chemicals, and rotating zero degree nozzles.
The information offered in this article is intended to give you a springboard from which you can begin your search for information. This is not intended to be the final word on the subject. You should continue your search for information. “Knowledge is Power”.
 
No comment till I get to FT WORTH
 
Larry :) I thought you retired! You coming back to help us out?
 
Larry :) I thought you retired! You coming back to help us out?

I retired oficially in December. I am working part time for Delux. I will always be available to help my friends.
 
Great post Larry H.

I have had great and not so great experiences with Authority having Jurisdiction (AHJ) in my state and others for discharge to POTW, via piping of facility being cleaned.

Some issues included:

Wash water pH monitoring and adjustment, did not develop this

Wash water plan approval

To the AHJ's that say "we dont want this wash water, must be hauled off", i was quoted by haulers $0.60 to $0.70 per gallon, and a truck minimum of $400 to $500 for 4 hours from the time it leaves their yard, whether we used their vacuum to pick it up or not, after which ~$125 per hr
 
Hi Larry! Good to hear from you again!

Great article.

It might be interesting for you to know that two guys can clean a W#lmart front in less than 30 minutes at a total of 12 gallons per minute with no soap with high frequency. That generates less wastewater than a hot tub.

The wastewater generally has FAR less contaminants than a 3 minute rainstorm running off the parking lot.

Yet, because of misinformation W#lmart set out on a failed course of required reclaim that resulted in higher costs for no reason other than a false fear.

With that in mind why are we going off in another direction and pushing the potw when screened and gravity filtered water is allowed AND safe in the storm drains in most jurisdictions including the San Francisco Bay area?

And what ever happened to God's filter...the landscaping ..... which is acceptable in almost EVERY community?

Thanks Larry

Sent from my DROID RAZR using Tapatalk 2
 
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