Thursday, June 1, 2017

Problems with Well Water-Iron and low pH

As part of my volunteer work as a VAMWON volunteer often get calls and email for help. Also, the blog seems to generate questions, too. I received the following inquiry by email:

We have been dealing with water issues for some time (10 years) and I think I have my hands wrapped around things. It would take a while to go into all the details but, basically we have a low pH, high iron, magnesium, and flow rate of 7 gallons per minute.  Originally, we had a water softener and acid neutralizer that did not seem to solve the problems. I installed a Chem feeder with soda ash and chlorine followed by an iron filer. My issue is that I believe my pipes have continued iron in them? First thing in the morning when I turn on the water, the water is actually very clean and then within a gallon, when the water starts flowing, it gets a bit brownish. Not as bad as before, but discolored. Makes me think that particles start to come off of the pipes. Does that sound right?  

A Chem-feed is a brand of diaphram pump used for feeding a controlled amount of chemicals, in this case chlorine and soda ash into a system. Soda ash is used to treat low pH and chlorine can very effectively treat high levels of iron as well as many other things. (I really love chlorine as a treatment option because of its versatility).

Low levels or iron can be treated with a water softener, but water with a low pH tends to be soft and combining an acid neutralizer with is really just a system to make the water hard and a water softener usually does not give good results. Chlorine treatment should be followed by a filter to remove the precipate and a carbon filter to remove excess chlorine. I had several questions.. Do he have a holding tank to assure an adequate contact time for the chlorine? How big is your pressure tank (it is possible to use the pressure tank in lieu of a holding tank to increase contact time if the treatment is installed ahead of the pressure tank) What concentration of chlorine was he using? What was the natural level of iron? After treatment what is the pH and chlorine level? What is the pipe material of construction?  What is the iron and manganese concentration after treatment?

To solve any water problem properly, you need to fully understand your natural water chemistry and the chemistry after treatment and when you are experiencing breakthrough. In this case the appearance of iron after some flow suggests breakthrough. Very high iron levels without adequate contact time for the chlorine could have this effect. I suspected that he was using his pressure tank instead of a contact tank and the first gallons had had adequate treatment after sitting overnight. However, other things could be going on.  I needed more information and facts to be any help. I sent my questions.

Iron 3.65 ppm
ph 6.7
manganese 0.1
TDS 52 ppm
Iron bacteria noted in sample

Lab testing did note "yellow color removed by 0.45micron filtration."I have a 15 gallon Chem- feeder.  Added soda ash until PH was 8 right before iron filter, and 4 cups of bleach.  Very trace chlorine on test strip right before filter.  Small pressure tank.  No contact tank, no other bacteria noted.
Filter installed after chem feeder "removes iron, rust, sulfur, manganese, dirt, turbidity, tastes, odors and even chlorine", per manufacture.  Backwashes overnight. The pipes are copper and cpvc mix.
 Some of the pipes were removed because of damage and the pipes removed at time of installation were lined with orange residue.  I don't not have a high concentration on test Iron strip from sink taps.  
 Was thinking maybe the residue is washing away, causing the water to be brownish?   The color is faint and mostly notable in a white styrofoam cup.  

The pH of water is a measure of the acidity or alkalinity. The pH is a logarithmic scale from 0 – 14 with 1 being very acidic and 14 very alkaline. Drinking water should be between 6.5 and 7.5. For reference and to put this into perspective, coffee has a pH of around 5 and salt water has a pH of around 98. Corrosive water, sometimes also called aggressive water is typically water with a low pH. (Alkaline water can also be corrosive.) However, his water is naturally within the normal range. It does not really need any treatment.

Low pH water can corrode metal plumbing fixtures causing lead and copper to leach into the water and causing pitting and leaks in the plumbing system. However, there is no reason to think that kind of corrosion was taking place here. The presence of lead or copper in water is most commonly leaching from the plumbing system rather than the groundwater. Acidic water is easily treated using an acid neutralizing filter. Typically these neutralizing filters use a granular marble, calcium carbonate or lime. If the water is very acidic or there are other problems to be addressed a mixing tank using soda ash, sodium carbonate or sodium hydroxide can be used. Acid neutralizing filters will increase the hardness of the water because of the addition of calcium carbonate. The sodium based systems will increase the salt content in the water.

Iron and manganese are naturally occurring elements commonly found in groundwater in this part of the country. At naturally occurring levels iron and manganese do not present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing and discolored water. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) less than 1/10 of the level in his water. This level of iron is easily detected by taste, smell or appearance. In addition, some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a well, water system and any treatment systems. These organisms change the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and water treatment equipment accumulate in pipes and hot water heaters.

Multiple problems can be addressed with a single treatment train. You can increase the pH by injecting soda ash, and add chlorine to oxidize the iron in a single operation. However, it appears that iron and iron bacteria are his only problems. A holding tank may be necessary, to allow the chlorine enough time to do its work in iron removal. Adding retention time always improves efficiency, and with some treatments can be essential to do the job. While filters are necessary to remove the “precipitated” contaminant (iron in this case), or to remove an injected chemical and its by-products after it has done its work. Excess chlorine is often removed using a carbon filter. If the water has adequate contact time, an oxidizing filter should not be necessary. It appears that he is using the Chem-feed to unnecessarily raise the pH and the iron filter to remove iron. He should be using the Chem-feed to control iron using chlorine.

The concentration of chlorine he is using (if he is even using it constantly), may not be adequate or the chlorine could be shaking loose the build-up in the pipe as he suggested (it could also be iron bacteria), or the treatment train is not properly set up for the level of iron. It is possible that he is using the iron filter to remove the iron and it just can’t do the job. To properly solve the problem I would first attempt to “blow it” out of the pipes and the well by using a very heavy chlorine shock and overnight hold. Then flush the system. This is effectively what public water systems do every spring to clear out their pipes.

After chlorine treating and flushing the system, next try adjusting the treatment system to more effectively control the iron and forget the pH. The Chem-feed should be constantly feeding chlorine and then followed by filtration to remove precipate and chlorine. If that fails, get a holding tank to increase the contact time with chlorine and adjust the treatment system accordingly. He will need to chlorine shock the well with about 600-800 ppm chlorine solution and then run the solution into the house and let it sit 16-24 hours in the pipes and hot water heater without using water. Do not flush out the well into the house or you will have to pump the septic tank (that much chlorine will cause a die-out in the septic system) and drain the hot water heater. For details on how to do this read my posts on Iron Bacteria and Chlorine Shocking My Well about two years ago. He does not have low pH and does not need to continue treating that problem.

He got back to me with some more questions:
  1. I was cautioned that shocking the well could cause sediment that could harm the pump.  Would you agree?
  2. Hot water heater - I have heard of changing the anode rod?  and poring a cup of bleach into the hot water heater? Then flushing it.  
  3. How do you feel about using IronOut in chem feeder for a one time flush of the pipes.
  4. If after flush with no success, would you recommend a contact tank or just a much larger pressure tank.  (I heard large pressure tank helpful for well pump life).
I still can't figure out why sometimes (last night), water was completely crystal clear, then a few hours later not.  Chem feeder is about 1/4 full at this point.  Thinking of adding 4 cups of bleach, and flushing pipes again.

IronOut is an acid in a solvent base. DO NOT EVER PUT IT IN YOUR DRINKING WATER pipes. It contains Sodium hydrosulfite which has a probable oral lethal dose (human) 0.5-5 g/kg of body weight. Because of rapid oxidation to sulfates, sulfites are well tolerated until large doses are reached; then violent colic and diarrhea, circulatory disturbances, central nervous depression, and death are described. It is best not to have human consumption to be safe.

In the commercial and public water supply sector it has been accepted for decades that the appropriate maintenance treatment for a well is to acid or chlorine treat to eliminate encrustation and buildup. Only in the past five to ten years so has this knowledge migrated to the private well sector. University extension departments now accept that as a water well ages, the rate at which water may be pumped (commonly referred to as the well yield, flow or performance) tends to decrease. Now Penn State Extension states that “often, reduced well yield over time can be related to changes in the water well itself including:
  • Incrustation from mineral deposits
  • Bio-fouling by the growth of microorganisms especially iron bacteria. This is also likely to kill your pump.
  • Physical plugging of "aquifer" (the saturated layer of sand, gravel, or rock through which water is transmitted) by sediment
  • Sand pumping
  • Well screen or casing corrosion
  • Pump damage”
They go on to state that the two most common methods to rehabilitate a water well are: chemicals to dissolve the incrusting materials from the well including acids and chlorine; and physically cleaning the well. Physical methods include using a brush attached to a drilling rig, high pressure jetting, hydro fracturing, and well surging. Chemical treatment usually dissolves the encrustations and extends pump function. I suppose it is possible that pump could catch a pebble or rock shaken loose and be damaged, but so can a pump you leave alone. These days regularly treating a well with chlorine is the recommended strategy to extend the life of a well and equipment. See well maintenance tips from Penn State University Extension, University of Minnesota Extension, University of Arizona etc. Pouring 4 cups of chlorine into a Chem-feed system is entirely inadequate to do the job.

Proper disinfection of the well and plumbing system using 600-800 parts per million chlorine includes the hot water heater. (Don’t forget to turn it off-you do not want hot chlorine water.) Anode rods are typically magnesium and should not have any impact or involvement in a rust problem. Hydrogen sulfide a different story. Leave it be.

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