Questions You Should Know about water well machine

25 Mar.,2024

 

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These important steps include siting, drilling and pump testing the well. Even though following the recommendations in this page will not guarantee all the clean water you may need or desire to have, it will greatly increase your chances of having a clean, reliable, productive well which is able to meet your needs.

Siting

Groundwater exploration is not a hit or miss (or random) proposition. Excess rainwater percolates into the soil and rock beneath the earth's surface accumulating in zones of saturation called aquifers. A well is a hole drilled into the aquifer from which a small portion of the groundwater can be pumped to the surface for man's use. It is true that any well penetrating an aquifer will yield water but the amount of water produced from a randomly sited well may be very small. Such low producing wells often provide adequate water for domestic or farmstead uses. If a well is to provide irrigation water a more highly productive well will usually be needed.

Scientific methods have been developed for locating wells where they will penetrate into zones of fractured rock buried beneath the soil surface. Wells located on a fractured rock zone will produce much larger quantities of water than wells drilled into zones where the rock is not fractured. Finding the fractured rock zones, or better yet, finding the intersection of two fractured rock zones can be a time consuming and expensive procedure. Only geologists and engineers with training in aerial photo interpretation and hydrogeology are qualified to locate wells by the fracture-trace technique. If a high producing well is desired, however, the consultants fee for siting the well is worth the extra benefit.

In addition to the siting considerations discussed above which pertain to finding adequate water, wells should be located at least 50 feet from sewers and septic tanks; at least 100 feet from pastures, on-lot sewage system absorption fields, cesspools and barnyards; and at least 25 feet from a silo. Areas where groundwater comes to within 10 feet of the soil surface should also be avoided.

Drilling

Drilling a well is more than boring a hole into the earth. A finished well will consist of a borehole cut into the aquifer at a diameter large enough to accept the well casing (see Fig. 1) which will receive the pump. The decision on how large the pump must be to meet your intended demand must, therefore, be made before drilling starts. Table 1 relates the necessary well casing size to the size of pump needed to pump various quantities of water. For instance, a 6-inch casing will receive pumps which can pump up to 100 gallons per minute (gpm). If you desire to pump more than 100 gpm an 8-inch casing will be needed which will dictate at least a 10-inch borehole. Your well driller will actually make these decisions, but he must know your needs.


Figure 1. Well components.

The borehole itself can be drilled using any one of several types of drill rigs including impact, rotary, or various combinations. After the borehole has been drilled into or through the water bearing aquifer, the well screen should be installed in the producing zone. The zones above the producing aquifer must be cased to prevent cave-ins, and the annulus between the borehole and casing must be filled with grout to keep surface contaminates from entering the well.

Table 1. Well casing and borehole diameter for desired pumping rate. Borehole size
(inches)Casing size
(inches)Pumping rate
(gpm) 6 4 less than 20 8 6 20 to 100 10 8 75 to 175 12 10 150 to 400 14 12 350 to 600 20 16 600 to 1300 24 20 1300 to 1800 28 24 1800 to 3000

Development

Developing a well is the process of clearing the well of fines left by the drilling operation, and flushing these fine particles out of the gravel and aquifer between the well screen and the first few feet of the aquifer.

Development is accomplished by surge pumping, bailing or any operation which will force water through the development zone at high velocities. Developing a well is the responsibility of the well driller. Properly developed wells will yield more water than poorly developed wells.

With the well in place, the question remains "How much water can be pumped from the well on a sustained basis?" The sustained pump rate is determined by the aquifer rocks ability to move water toward the well under the influence of gravity while the well is being pumped. To determine the sustained pumping capacity of a well a pump test must be performed on the well. The pump test should be completed by the well drilling contractor as part of the contract to drill the well. The desire for a pump test must be made clear to the driller before drilling begins, since some drillers are not able to do pump testing. Be sure to use a driller who can complete the work including a pump test.

Pump Testing

With the well in place, the question remains "How much water can be pumped from the well on a sustained basis?" The sustained pump rate is dependent upon the aquifers ability to move water toward the well under the influence of gravity while the well is being pumped. To determine the sustained pumping capacity of a well a pump test must be performed on the well. The pump test should be completed by the contractor as part of the well drilling contract. The desire for a pump test must be made clear to the driller before drilling begins because some drillers are not able to do the pump testing. Be sure to use a driller who can complete all drilling work including the pump test.

Several types of pump tests have been developed, but all are designed to establish the long term equilibrium rate at which water will flow towards and enter the well. The simplest, most straightforward pump test is to place a pump in the well, after the development phase is complete, and pump water from the well at a constant rate. The discharged water must be dumped some distance from the well so it can not recirculate back into the well during the pump test. The pump rate should be great enough to stress the well, but not so great as to cause the well to be pumped dry. During the pump test, the water level in the well must be measured and recorded at regular intervals starting at the time pumping begins and continuing until pumping stops. Pumping should continue for at least 24 hours (without interruption) or until the water level in the well remains at the same elevation for three consecutive half-hour readings.

Figure 2 is a schematic of the water levels within the geologic structure while a pump is drawing water from a well. The cone of depression is produced when water is removed from the well bore by the pump, causing the water level in the well to drop. This drop in the well water level means the water surrounding the well is at a higher elevation and the gravitational water in the rock begins to flow into the well bore. As this continues, the distance between the original water table and the water level in the well, or drawdown, increases forming a large cone of depression. At some point, the drawdown reaches a point of equilibrium, where the water flows to the well at the same rate as it is being pumped from the well. This equilibrium usually occurs after 24 to 48 hours of continuous pumping at a constant flowrate.


Figure 2. Well hydraulics.

The capacity of a well can be estimated by first determining the specific capacity of the well. Specific capacity Sc of a well is the pump rate, Q in gallons per minute during the pump test, divided by the drawdown, s (in feet) after 24 hours or at equilibrium. In other words, the specific capacity is the flowrate per foot of drawdown.

Sc = Q(gpm)/s(ft)

Knowing the depth of the well and where the permanent pump will be placed, the maximum permissible depth to water in the well can be taken to be 10 feet above the permanent pump intake location. The difference in elevation between the original water table and the maximum permissible depth to water is the maximum drawdown, Smax. The maximum sustainable discharge for the well is then the specific capacity times the maximum drawdown.

Qmax = Sc (Smax)

After the pump test is completed, you will have developed knowledge about how much water the well can be expected to produce. You are now ready to proceed with your irrigation design.

The water treatment industry is in the forefront of treating drinking water that is both a health hazard and a nuisance to the household. Home water treatment service and supply companies and products promise to deliver drinking water that is safe and contaminant free. Purchasers need to sift through advertising claims and technical data to select the appropriate treatment method.

The first step in choosing a water treatment device is to have your water tested for contaminants and characteristics you suspect are causing a problem. Most people are alerted to potential problems due to objectionable taste, odor, color, or presence of sediments and staining. Rely on independent water tests conducted by a state certified lab to identify and evaluate specific contaminants.

If the water test indicates that you have a problem, installation of a treatment system may be necessary to remedy it. Be aware that water treatment equipment has tradeoffs:

  • There is routine maintenance.
  • Some systems may need to be periodically back-flushed, which will increase the wastewater load to your septic system.
  • The treatment may remove one contaminant, but add something else to your water. For example, an ion exchange system installed to remove iron and manganese, may add sodium to your drinking water, causing a potential problem for people with high blood pressure or on sodium restricted diets.

Do your research and be a good consumer when shopping for water treatment equipment. The following are questions you can ask a water treatment professional or the water well contractor who installed the well to determine the type of system needed. Background information follows many of the questions. The extent to which the manufacturer or distributor is willing to provide answers can assist the consumer in making an informed choice.

1. What exactly does the water analysis performed by the treatment professional show? Are health hazards indicated? Should more testing be done?

Many water treatment companies provide free in-home water testing as part of their services. Not all contaminants can be evaluated this way. For example, many man-made chemicals, which have been associated with serious health problems, must be analyzed in a laboratory with sophisticated equipment. The consumer must be wary of companies that claim their home analyses determine more than basic water quality constituents such as hardness, pH, iron, and sulfur. Ideally, you should verify in-home tests with a water test conducted by a state certified laboratory.

Once you’ve accurately determined what contaminants and characteristics your drinking water has, the level detected will dictate the type of treatment system, if any, is most effective. Factors to consider include whether the water presents a health hazard and how the levels detected compare to Federal and/or State Drinking Water Quality Standards. Refer to the fact sheets about specific contaminants or characteristics that may be present in your drinking water. Additional information can be found on Internet sites such as the Environmental Protection Agency’s Office of Groundwater and Drinking Water

2. How long has the company been in business, and is there a list of referrals the consumer can contact?

Make sure the company is reputable and established. Ask the company for referrals and contact the referrals to find out customer satisfaction.

3. Have the product and the manufacturer been rated by NSF International or another third party organization? Was the product tested for the specific contaminant in question, and over the advertised life of the treatment device under household conditions (tap water, actual flow rates, and pressures)?

NSF, International is a non-profit organization whose function is to set performance standards for water treatment equipment and evaluate test results of treatment devices to determine if claims are realistic. Products that have been tested and certified by NSF and meet their minimum requirements are entitled to display the NSF listing mark on the products or in advertising literature. Manufacturers and models that meet the applicable standard are included in a listing published twice a year. NSF has developed standards for the following types of treatment units.

ANSI/NSF 42: Drinking Water Treatment Units - Aesthetic Effects ANSI/NSF 44: Cation Exchange Water Softeners ANSI/NSF 53: Drinking Water Treatment Units - Health Effects ANSI/NSF 55: Ultraviolet Microbiological Water Treatment Systems ANSI/NSF 58: Reverse Osmosis Drinking Water Treatment Systems ANSI/NSF 62: Drinking Water Distillation Systems

Ask the sales representative which standards the product meets. Also, ask for test results showing removal of the specific contaminant(s) you need or want to remove. Tests by third party organizations (those neutral to and trusted by all interests served) should provide extra confidence.

4. Is a second opinion on treatment procedures and equipment necessary?

Consider a second opinion on recommended water treatment equipment. Check with at least one additional dealer to see what treatment procedure and equipment is recommended, and ask questions. Compare at least two brands, and consult other references.

5. How can I tell whether the dealer knows the home water treatment business?

The Water Quality Association (WQA) is an organization of manufacturers, distributors, and dealers that sets minimum acceptable levels of knowledge for water treatment businesses, sales and equipment installers. Ask if the dealer is a member of WQA and if any employees are WQA-certified water specialists, sale representatives, or installers.

WQA is a voluntary organization, so nonmembers are not implied to be less competent. However, persons who have attended training sessions and taken tests to demonstrate their knowledge should know their business. The Association’s web page is www.wqa.org.

6. Does the water quality problem require whole-house treatment or will a single-tap device be adequate?

Depending on the type of contaminant and its concentration, you may need to treat all the water entering the house or only the water used for drinking and cooking. If the contaminant is only a problem when you drink it, such as lead, you may only need point-of-use (POU) treatment. POU treatment devices are typically installed at the kitchen faucet to treat water for drinking and cooking. However, if the contaminant is also hazardous when you get it on your skin or inhale it, for example, a volatile organic compound or radon, you will need to treat all the water entering the house, point-of-entry (POE). POE treatment devices are typically installed in the basement after the water pressure tank. Many treatment units are available in both POU and POE models, including granular activated carbon filters, reverse osmosis, and microfiltration units.

7. Will the unit produce enough treated water daily to accommodate household usage?

The consumer must be certain that enough treated water will be produced for everyday use. For example, distillation units produce 3- 12 gallons of treated water daily depending on the model. In addition, the maximum flow rate of the treatment device should be sufficient for the peak home use rate. Consider installing a flow water meter to help determine what the peak home water use is.

8. What are the total purchase price and expected maintenance costs of the device? Will the company selling the device install it and service it? Will there be a fee for labor? Can the consumer perform maintenance tasks or must the water treatment professional be involved?

The consumer must watch for hidden costs such as separate installation fees, monthly maintenance fees, or equipment rental fees. Additionally, the disposal of waste materials, such as spent cartridges from activated carbon units and used filters, can add to the cost of water treatment and should be figured into the purchase price. You may be able to install some treatment devices on your own. Ask the dealer for all costs involved in the installation and maintenance of the treatment system.

9. What are the service intervals and the costs involved with this equipment?

Regardless of whether you or your dealer provides the service, there is a cost. Filter cartridges must be changed, materials added as needed, and the water tested regularly to be sure things are working properly. Unserviced equipment may contribute to increased levels of some contaminants. Find out what supplies and equipment are needed, and the expected costs. Determine how often a filter membrane, ultraviolet light, or media will need to be changed and who is responsible for doing this. Ask the dealer if there are any other water quality conditions, like pH or sediments that can affect the effectiveness of the treatment system.

10. Will the unit substantially increase electrical usage in the home?

The cost of treated water in the home will vary depending upon the cost of electricity and the amount of energy required to operate the treatment unit. Ask about average monthly electrical use for the system you are interested in purchasing.

11. Is there an alarm or indicator light on the device to alert the consumer of a malfunction?

Many units have backup systems or shutoff valve functions to prevent consumption of untreated water.

12. Will the manufacturer include in the purchase price follow-up water testing to ensure the equipment is working properly after a month or two?

Testing the water a month after the equipment is installed will assure the homeowner that the unit is accomplishing the intended treatment. Have the test completed at a state certified laboratory. Additionally, water used for outside purposes should not have to be treated. This will provide you with a raw water tap, which can be periodically tested to compare the effectiveness of your treatment system. Water test results from the raw water tap will also help you to assess changes in your water quality.

13. What is the expected lifetime of the product? What is the length of the warranty period and what does the warranty cover?

The warranty may cover only certain parts of a device. The consumer should be aware of the warranty conditions.

14. What potential secondary effects will the treatment unit have on your water quality?

The consumer should be aware that some water treatment equipment works by adding something to your drinking water to remedy the problem at hand. For example, some water softening units will replace the iron removed from the water with sodium.

Quick Reference to Water Treatment Devices

These guidelines are for individuals planning to consult a water treatment industry representative. It must be emphasized that treatment can be for aesthetic as well as health factors. If drinking water poses a health risk, the consumer should consider the cost of purchasing bottled water or tying into a public water system, if available, as an alternative to treatment.

Water Treatment Devices for Common Contaminants and Undesirable Minerals Contaminant and Minerals         Treatment Devices           UV Light Ion Exchange Mechanical Filter Activated Carbon Activated Alumina Reverse Osmosis Distillation Aeration Chlorination Bacteria and Viruses ♦               ♦ Taste and Odor       ♦   ♦ ♦     Lead   ♦   ♦ ♦ ♦ ♦     Nitrate   ♦       ♦ ♦     Chlorine, Trihalomethanes       ♦           Radon       ♦       ♦   Hardness   ♦               VOCs and other Organics       ♦       ♦   Pesticides, PCBs       ♦     ♦     Iron and Manganese   ♦       ♦     ♦ Sulfate   ♦       ♦ ♦     Giardia and Crytosporidium Cysts     ♦     ♦ ♦     Sediment, Turbidity     ♦             Total Dissolved Solids           ♦ ♦     Aluminum           ♦ ♦     Arsenic         ♦ ♦ ♦     Barium   ♦       ♦ ♦     Cadmium   ♦       ♦ ♦     Chloride           ♦ ♦     Chromium           ♦ ♦     Copper           ♦ ♦     Fluoride          ♦ ♦ ♦     Mercury           ♦ ♦     Radium   ♦       ♦ ♦     Selenium         ♦ ♦ ♦     Silver           ♦ ♦     Zinc           ♦ ♦    

Adapted from Citizen’s Guide to Home Drinking Water Treatment Devices, Commonwealth of Pennsylvania Department of Environmental Protection, Bureau of Water Standards and Facility Regulation, P.O. Box 8467, Harrisburg, Pa 17105-8467. 10/2005

Advantages and Disadvantages of Home Water Treatment Devices Device and Cost Advantage Disadvantage

Activated Carbon Filter:

Point-of-Use activated carbon filters cost between $100 and $500. Replacement filters cost $30 to $50.

Point-of-Entry treatment devices cost between $750 and $1,500. Replacement filters cost $300 to $500.

Effective at removing a wide range of organic contaminants such as VOCs and pesticides.

Carbon block and precoat designs have been validated as effective for lead reduction.

Often effective for reducing taste and odor problems.

Does not use electricity or generate wastewater.

Not effective at removing inorganic materials such as hardness, iron, nitrate or fluoride.

Bacteria growth may occur in the carbon filter if not maintained properly.

May require post-disinfection.

Reverse Osmosis:

Under the sink devices including a mechanical prefilter and an activated carbon post filter cost $500 to $1,500. Replacement membranes cost $50 to $150.

Can remove a wide variety of inorganic and organic contaminants including lead, nitrate and sodium.

Normal household water pressure provides good performance.

Uses from three to five gallons of water for each gallon produced.

Some membranes are damaged by chlorine.

Ion Exchange:

From $500 to $1200 depending on the resin and type of equipment. Cation exchange resins cost less than Anion exchange resins.

Cation Exchange Units

Effective for removing minerals such as hardness, barium, radium, nitrate, sulfate, calcium and magnesium. Effective for removing iron (if concentrations do not exceed 1 mg/L).

Anion Exchange Units

Effective for removing nitrates, bicarbonate, selenium and sulfate.

Removes one type of ion replacing it with another, i.e. sodium replaces with iron.

Requires backwashing and regeneration (usually with sodium chloride or potassium chloride).

Microfiltration:

Use-device mechanical particulate filters typically cost between $50 and $200 Filter replacements cost $20 to $60.

Effective for removing suspended particles such as rust, dirt and sediment. Filters tested and approved for Giardia and Cryptosporidium cysts are available. Not effective for removing dissolved contaminants such as lead, nitrate, VOCs, etc.

Distillation:

Between $150 and $700 for a countertop model.

Removes the greatest variety of contaminants.

Uses approximately three kilowatts of electricity per gallon of water.

Water-cooled units waste a considerable amount of water.

Will require frequent cleaning, especially where the water is hard.

Removal of minerals may leave bland taste to the water.

Process is slow.

Aeration:

Between $3,000 and $4,500.

Effective for removing radon and volatile organic chemicals.

Expensive to purchase and install.

Requires secondary pumping and pressurization.

Ultraviolet Light:

Between $300 and $700.

Effective for destroying bacteria and Giardia and Cryptosporidium cysts. Not effective for virus removal.

Activated Alumina:

Same as Activated Carbon.

Effective for removal of arsenic, fluoride and lead. Does not use electricity and does not waste water. Will usually not remove minerals other than those listed.

Chlorination:

Between $800 and $1,500.

Only effective way of dealing with large amounts of iron, hydrogen sulfide and colloidal iron.

It is an excellent disinfectant.

Requires handling and storage of hazardous chemicals.

Requires time to insure that chemicals are mixed properly and available when needed.

Adapted from Citizen’s Guide to Home Drinking Water Treatment Devices, Commonwealth of Pennsylvania Department of Environmental Protection, Bureau of Water Standards and Facility Regulation, P.O. Box 8467, Harrisburg, Pa 17105-8467. 10/2005

Summary

The purchase of water treatment equipment is a decision that must be carefully considered. Whether the purchase is being made to improve the aesthetic characteristics of the water or to address health considerations, many factors must be determined. You may want to keep a logbook, allowing you to keep track of all maintenance and repairs on your treatment system. The following are some key steps in selecting equipment:

  1. Correctly identify the problem to be addressed using appropriate tests performed by state certified laboratories. Also, inquire about the history of the groundwater in your neighborhood to help determine if any water quality problems exists. If so, test your drinking water for these contaminants.
  2. Identify options for correcting the problem.
  3. Decide whether whole house (point-of-entry) or single-tap (point-of-use) treatment is needed.
  4. Determine if the system will treat enough water to meet for your needs.
  5. Select a reputable dealer.
  6. Obtain second opinions.
  7. Check to see if proposed equipment has been tested or validated by independent organizations such as NFS International or the Water Quality Association.
  8. Talk with others who are using the same equipment you may purchase.
  9. Be sure to know all the costs of the equipment: purchase price, installation, operating, and routine required maintenance.
  10. Understand what maintenance will be required and who will be responsible for doing it.
  11. Understand how to determine if the equipment is operating satisfactorily.
  12. Determine the expected life of the equipment and components.
  13. Understand any warranty provided with the equipment.

Resources

Center for Agriculture Food and the Environment

This fact sheet is one in a series on drinking water wells, testing, protection, common contaminants, and home water treatment methods available on-line
and Cape Cod Cooperative Extension: 508-375-6699
http://www.capecodextension.org

MA Dept. of Environmental Protection, Division of Environmental Analysis
Offers assistance, information on testing and state certified laboratories: 617-292-5770
For a listing of MassDEP certified private laboratories in Massachusetts

U.S. Environmental Protection Agency, New England Office
Information and Education on where drinking water comes from; drinking water testing and national laws; and how to prevent contamination

US Environmental Protection Agency

For a complete list of primary and secondary drinking water standards

MA Department of Conservation and Recreation, Division of Water Supply Protection
Maintains listing of registered well drillers, information on well location and construction: 617-626-1409, 

NSF International

The NSF International has tested and certified treatment systems since 1965. For information on water treatment systems: 800-NSF-MARK

Water Quality Association

The Water Quality Association is a not-for-profit international trade association representing the household, commercial, industrial, and small community water treatment industry.

Questions You Should Know about water well machine

Questions to Ask When Purchasing Home Water Treatment Equipment

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