DDW-2024-011327

Sand Hollow Well #2 Rehabilitation,
Proposed Chemical Addition Instructions

Step 1: Brushing and Swabbing followed by bailing to remove
as much physical material from the well as possible.
After doing a physical brush and or swab to remove as much physical debris as
possible, bail all debris and sand from the bottom and find the original bottom of the well. Step 2: – Day 1, Chemical cleaning with acid descaler
Goal: Targeted application of a chemical mixture and volume of chemistry is
added with dual swab into screened intervals. The blend of chemistry is
NSF/ANSI Standard 60 Certified. We’ll do the following Acid Descaling and Biofilm removal Solution mix for a total treatment volume of 8778 gallons.
i. 6898 gallons of drinking water.
ii. 30 gallons Bonderite 103, NPF iii. 1700 gallons of 35% hydrochloric acid, iv. 145 gallons of KlearWell 186 BioMin Dispersant v. 5 gallons of KlearWell NIS Surfactant
vi. Mix ingredients thoroughly in preparation to add to well
a. Inject Acid Descaling Solution into Well: i. Starting at the standing water level, use a dual swab tool to force
acid descaling solution into the well.
ii. Inject approximately 157 gallons of acid descaling solution into each 10 feet section of the 560 feet of well screens. Note: it is more important to get all the chemistry in the well than spending the initial swab time per 10-foot section of the screens. It needs 48
hours to work its magic.
iii. Swab each 10 feet section of well casing for 5 to 10 minutes or as time allows. iv. When all the chemistry is installed, begin swabbing the well from the bottom up with high mechanical force until leaving for the day.
Step 3, Day 2: Continued Cleaning with descaler:
b. Swab, develop and agitate the well as much as possible. Allow Acid Solution to stay in the well for up to 48 Hours. Note: some swabbing and development with the chemistry can be very beneficial. Swab, develop and agitate the well as much as possible for the next 48 hours
Step 4: Preparation for Neutralizing and Disposal of
Initial Acid Descaling Chemicals:
Using the dual swab method, start evacuating the chemicals form the well
while monitoring the pH of the solution
a. Neutralize chemicals to a neutral pH of 6.5 to 7.5. The well pump-out discharge should be collected in a Baker tank in which the
neutralization reaction can be carried out. As the pH is raised toward neutral or
the accepted pH range for discharge, most acid solutions will precipitate up to 50% of the dissolved solids coming from the well Calculation of the neutralizing chemistry with soda ash is not as easy as it should
be since the pH and the amount of water to be discharged is usually unknown.
This is a chart showing the potential neutralization requirements based on the amount of acid used and the pH of the discharge water. The actual process will require the use of a pH meter or pH paper in order to
adjust the amount of soda ash so discharge to the environment is maintained
within acceptable limits. We’ll do the following;
1. Fill the baker tank to about 90% capacity with the discharge from the well.
2. Measure the pH of the water
3. Calculate the pounds of acid used in the cleaning procedure. 4. Using the chart on the next page, estimate the pounds of soda ash needed.
5. Add the necessary soda ash as we are filling the Baker tank.
6. Check the pH of the neutralized water and if it is in the range of 6.5 to 7.5 it can safely be disposed of.

Step 5: Final Chlorine Disinfection:

After complete removal of the acid peroxide mix and debris such that the effluent chemistry’s pH is consistently 6.5 or above, the addition of a pH enhanced chlorine solution is started with development and sufficient soak time of 12 to 24 hours.
a. Prepare Disinfection Solution: The step calls for a 275 PPM free chlorine residual using about 3 times the 7994 standing water volume of the well which is 20,000 gallons of total disinfection applied into the well. Since our frac tanks hold up to 20,000 gallons we can mix the chemicals in one batch.
b. combining the following into each of three tanks:
i. 19,919 gallons of water ii. 37 gallons of KlearWell 440 Chlorine Enhancer. iii. 44 gallons of 12.5% liquid chlorine. iv. Mix ingredients thoroughly in preparation to add to well
c. Chlorine Application to the Well: i. Starting at the standing water level of 135 feet, use a dual swab tool to force the chlorine solution into the well.
ii. Inject approximately 357 gallons of chlorine solution into each 10
feet section of well screens and casing. iii. Swab each 10 feet section of well casing for 5 minutes. iv. When all the chlorine disinfection chemistry is installed, begin swabbing the well from the bottom up with high mechanical force
until leaving for the day. Next Day, Chlorine Disinfection Solution Removal and Neutralization:
a. If possible, run the swab through the well one more time to mix and help re-
suspend any sediments or precipitation. b. Chlorine Neutralization: Pump the chlorinated water to the surface in a large tank where it will be mixed with powdered sodium thiosulfate or KlearWell
486 ChlorStop for neutralization. Chlorine neutralization is accomplished
by a form of reducing chemistry. The amount of neutralizing chemical needed to neutralize chlorine is related to the chlorine residual of the water pumped from the well. Since chlorine residuals may be greatly reduced during swabbing, it may not require much neutralizing chemistry. A little goes a long way. It will take
approximately 1.5 pounds of sodium thiosulfate or KW-486 per 1000 gallons of
water with a chlorine residual of 250 mg/L to neutralize it to zero. Use 0.3 pounds per 1000 gallons to neutralize water with 50mg/L chlorine residual.

Safety Requirements
Water and Wash Stations Have water available for emergency eyewash and shower if spills occur.
A contingency plan should be developed should the source of clean treatment water become unavailable. Flammability and Combustion In unique cases, acids and biocides can produce flammable gasses. Geological conditions could release flammable / explosive gasses into the well head. The well head should be considered a flammable and explosive environment and appropriate signage should be placed at the well head. Ventilation Maintaining adequate ventilation is mandatory at all times. REQUIRED READING FOR ALL ONSITE PERSONNEL There can be a variety of gaseous vapors that collect and concentrate in a well, including methane, hydrogen sulfide from bacteriological waste and gas pockets within the earth. Our
position needs to be that there are too many variables to make any preconceived assumptions. The gaseous state of any material is the most volatile and poses a safety risk. The well, though a water source, should always be considered a volatile environment where the
utmost safety considerations should be in place. Flammability
KlearWell 101 or HCl, Hydrochloric Acid - 22 be’ - 35% Contact with metals may evolve flammable hydrogen gas. Fire Hazard – Negligible. Hazardous Combustion Products - Hydrogen Chloride, Chlorine, Hydrogen Gas Conditions to Avoid – Will react with metals forming flammable hydrogen gas. Ensure that adequate neutralizer (soda ash or sodium bicarbonate) and eyewash stations and safety showers are close to the workstation location. Recommended Equipment A. Old rusty metal parts are going to get clean. Be sure all connections are secure, tight, and in
good order. If threads of corroded metal are holding it in place, it is likely the rust will be removed and it will come apart. B. Stainless steel #416, cheap metal, pot metal, low grade aluminum, galvanized piping and low
grade metals as a whole can be degraded. A copper penny is not copper; it is 97.5% zinc and 2.5% copper. Zinc is water and acid soluble. C. Pump Connectors, fittings etc. – use poly or non 416 stainless.
D. Tremie Pipes – use poly or non 416 stainless, do not use galvanized. E. If it’s rusty and pitted you are likely to get leaks. F. CAREFULLY AND GRADUALLY ADD PRODUCTS DOWN-HOLE. MAJOR CHEMICAL REACTIONS CAN GENERATE THE RELEASE OF CARBON DIOXIDE AND PRESSURE. Signage Recommended Personal Protective Equipment Eye Protection: Wear chemical safety goggles with a face shield to protect against eye and skin contact when appropriate. Provide an emergency eye wash fountain and quick drench shower in the immediate work area. Skin and Body Protection: Wear chemical resistant clothing and rubber boots when potential for
contact with the material exists. Always place pants legs over boots.
Hand Protection: Wear appropriate chemical resistant gloves. Consult a glove supplier for assistance in selecting an appropriate chemical resistant glove. Protective Material Types: Nitrile,
Neoprene, Butyl rubber, Polyvinyl chloride (PVC), Responder®, Trellchem® ,HPS, Tychem® Respiratory Protection: A NIOSH approved full face respirator equipped with acid gas cartridges (appropriate for hydrogen chloride) may be permissible when symptoms have been observed. Consult the Safety Data Sheet for all products for proper safety attire Summary and Disclaimer: The above methods of cleaning and disinfection represent the state of the art in well rehabilitation and chemicals, patterned after many years of research and trials using various methods and chemicals. In most cases well efficiency and production are improved, however the chance remains that the corrosion and plugging in the well may be hard to reverse. Studies have shown the best method used to keep wells healthy is to apply maintenance cleaning on a regular
basis. By doing so, the debris in the well is soft and easily removed, thus preserving the integrity of the metal casing. Widdison Well Services Inc. cannot assume the responsibility of failure to return the well back to
its original production or that the well casing is still in its original intact condition. The inhibited
acids and chemicals will remove scale and iron oxides and will not attack bare metal. Any
damage to the well casing that might be observed will have already occurred due to the effects of
many years of corrosion.