Drinking Water. Charles J. Devine, III, MD

Transcription

1 Drinking Water Charles J. Devine, III, MD

2 First Sanitation Law in Virginia Jamestown May 24, 1610 First attempt at maintaining a clean water supply Water Quality from a Historical Perspective At the turn of the 20th Century in America, Typhoid fever killed 36 out of 100,000 people In 1908, New Jersey began to use Chlorine as a primary disinfectant which helped to decrease deaths caused from drinking water Virginia Department of Health created

3 Background Federal Safe Drinking Water Act: In 1974 EPA promulgated National Primary Drinking Water Regulations which apply to public water systems Provided for State implementation (primacy) Act was amended in 1986 and 1996 strengthening and increasing regulatory requirements

4 Virginia Water Supply Law Title through Title Code of Virginia Title 32.1 of the Code of Virginia, and specifically and , provide that the State Board of Health has the duty to protect the public health and to ensure that ground water resources are not adversely affected by the construction and location of private wells. In order to discharge this duty, the board is empowered to supervise and regulate the construction and location of private wells within the Commonwealth. Virginia Private Well Regulations 12 VAC et seq. Private Well Regulations VDH Office of Drinking Water regulates Public Waterworks. August 16, 2012

5 Virginia Water Supply Law WATERWORKS REGULATIONS 12VAC et seq. "Waterworks" means a system that serves piped water for drinking or domestic use to (i) the public, (ii) at least 15 connections, or (iii) an average of 25 individuals for at least 60 days out of the year. The term "waterworks" shall include all structures, equipment and appurtenances used in the storage, collection, purification, treatment and distribution of pure water except the piping and fixtures inside the building where such water is delivered (see Article 2 ( et seq.) of Chapter 6 of Title 32.1 of the Code of Virginia). Some apparent waterworks are constructed to NOT fit the above definition and thus escape the regulations and associated expense of public systems. Wells and such systems that do not meet the above definition are private wells. Maintenance of private wells and assurance that the water is safe to consume is the responsibility of the owners.

6 Public Water Supply Requirements Public water systems must perform routine sampling to ensure quality Public water systems must have certified operators All systems must have infrastructure components approved - construction permits All systems are required to take corrective action if quality requirements are not met All system are required to notify customers if sampling indicates a problem with the quality of the water

7 Public Water System Requirements EPA establishes Maximum Contaminant Levels (MCLs) There are approximately 90 different contaminants that have MCLs and health effects established Samples are collected on a frequency determined by IDEM based on the contaminant, size and type of system, past detections, etc Samples must be analyzed by State certified laboratory

8 Public Water System Requirements VDH ODW ensures that systems meet the MCLs and that water is safe Performing Inspections Reviewing monitoring and compliance data Providing assistance to Ensuring public water systems correct deficiencies Implementing source water protection Making sure public is notified if there is problem Approving infrastructure components So, who makes sure that your water is safe with a private system? You do!

9 Managing the Risk If on a private water system: Homeowner has the responsibility to provide him/herself with safe drinking water We recommend testing twice a year Annually for bacteria, nitrates/nitrites, and any other contaminants of local concern. More frequently than once a year if there is a change in the taste, odor, or appearance of the well water, or if a problem occurs such as a broken well caps, leaks or loss of pressure, or a new contamination source appears. If family members or houseguests have recurrent incidents of gastrointestinal illness. If an infant is living in the home. If you wish to monitor the efficiency and performance of home water treatment equipment. Most wells do not require chemicals for treatment

10 Testing for Bacterial Contamination The safety of privately owned water supplies is the sole responsibility of the owner. Testing for bacterial contamination Water sample analyzed by certified laboratory Indicator organism: total coliform bacteria Relatively inexpensive and easy to detect Total coliform standard is zero or absent Positives reported as number of bacteria per volume of water Most coliform bacteria don t cause disease. Act as an indicator that other dangerous bacteria may be present Virginia Household Water Quality Program recommends yearly testing for total coliform bacteria

11 When to Test for Bacterial Contamination There is an infant or pregnant woman in the home Prior to purchasing a new home that is reliant on a private water supply A new well is constructed (required by Virginia law 12 VAC D) Flooding occurs near the well, spring, or cistern. Any person or animal becomes sick from a suspected waterborne disease. The water supply system, including indoor plumbing, has been disassembled for service or repairs.

12 Testing for Bacterial Contamination If the sample is positive for total coliform, ask the lab to test for fecal coliform bacteria (E. coli). This will indicate water contaminated with human or animal waste.

13 Contaminated water: What Next? Finding coliform bacteria means there is risk. Ask the lab testing your water to automatically test for E. coli If your sample is positive for total coliform bacteria. If positive for E coli, then Boil your water before drinking or Drink bottled water and Identify problems and address them Not all bacteria cause illness: nonpathogenic bacteria

14 Treating Bacterial Contamination Treatment can be applied at the water system level, or by the individual homeowner at the house. Certain approaches are not practical for system wide use.

15 Treating Bacterial Contamination One Time Disinfection Shock Chlorination Continuous Disinfection Continuous Chlorination Not effective for Giardia or Cryptosporidia Distillation Uses no chemicals May be expensive to operate Ultraviolet Light Ozonation

16 Shock Chlorination Not available to the individual home owner in a development like this. When required, should be done by your homeowner s contractor. Is temporary unless the source is corrected can be very effective Liquid Chlorine Bleach or calcium hypochlorite powder or tablets may be used Solution volume used is based on the total volume of water in the water supply system. Should be followed by bacterial retest in one or two weeks

17 Continuous Chlorination Used if attempts to control contamination do not eliminate bacteria from your system. Widely used Destroys bacteria within a reasonable contact time. Chlorine is readily available and low in cost. Organic matter and iron and manganese in the water may limit effectiveness Not effective against Giardia or Cryptosporidia High levels leave funny tastes or odors Requires regular maintenance

18 Drinking Water Treatment Technologies other than chemical Filtration Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis Distillation Ultraviolet (with pre-filtration -needs clear water) Water Softeners Point of Use v Point of Entry systems

19 Filtration Filtration is a physical process that occurs when liquids, gases, dissolved or suspended matter adhere to the surface of, or in the pores of, an absorbent medium. Filtration of contaminants depends highly on the amount of contaminant, size of the contaminant particle, and the charge of the contaminant particle. Depending on the household s water needs, pretreatment before filtration may include the addition of coagulants and powdered activated carbon, adjustments in ph or chlorine concentration levels, and other pretreatment processes in order to protect the filter s membrane surface.

20 How big is a micron? How about a nanometer? 1 micron is one millionth of a meter Symbol= μ or mu Bacteria are.2 to 3 microns in size 1 nanometer is one billionth of a meter This is 1000 times smaller than a micron

21 Microfiltration A microfiltration filter has a pore size of approximately 0.1 micron Microfiltration has a very high effectiveness in removing protozoa (for example, cryptosporidium, Giardia); Microfiltration has a moderate effectiveness in removing bacteria (Campylobacter, Salmonella, Shigella, E. coli) Microfiltration is not effective in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Microfiltration is not effective in removing chemicals.

22 Ultrafiltration An ultrafiltration filter has a pore size of approximately 0.01 micron. Ultrafiltration filters remove particles based on size, weight, and charge; Ultrafiltration has a very high effectiveness in removing protozoa (Cryptosporidium, Giardia); Ultrafiltration has a very high effectiveness in removing bacteria (Campylobacter, Salmonella, Shigella, E. coli); Ultrafiltration has a moderate effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Ultrafiltration has a low effectiveness in removing chemicals.

23 Nanofiltration A nanofiltration filter has a pore size of approximately micron; Nanofiltration filters remove particles based on size, weight, and charge; Nanofiltration has a very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia); Nanofiltration has a very high effectiveness in removing bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); Nanofiltration has a very high effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Nanofiltration has a moderate effectiveness in removing chemicals.

24 Reverse Osmosis Systems Reverse Osmosis Systems use a process that reverses the flow of water in a natural process of osmosis so that water passes from a more concentrated solution to a more dilute solution through a semi-permeable membrane. Pre- and post-filters are often incorporated along with the reverse osmosis membrane itself. May waste as much water as it purifies.

25 Reverse Osmosis Systems A reverse osmosis filter has a pore size of approximately micron. Reverse Osmosis Systems have a very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia); Reverse Osmosis Systems have a very high effectiveness in removing bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); Reverse Osmosis Systems have a very high effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Reverse Osmosis Systems will remove common chemical contaminants (metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead; may reduce arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate, and phosphorous.

26 Distillation Systems Distillation Systems use a process of heating water to the boiling point and then collecting the water vapor as it condenses, leaving many of the contaminants behind. Distillation Systems have a very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia); Distillation Systems have a very high effectiveness in removing bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); Distillation Systems have a very high effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Distillation Systems will remove common chemical contaminants, including arsenic, barium, cadmium, chromium, lead, nitrate, sodium, sulfate, and many organic chemicals.

27 Ultraviolet Treatment Systems (with pre-filtration) Ultraviolet Treatment with pre-filtration is a treatment process that uses ultraviolet light to disinfect water or reduce the amount of bacteria present. Ultraviolet Treatment Systems have a very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia); Ultraviolet Treatment Systems have a very high effectiveness in removing bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); Ultraviolet Treatment Systems have a high effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); Ultraviolet Treatment Systems are not effective in removing chemicals.

28 Water Softeners Do not protect against protozoa, bacteria, or viruses. Use ion exchange technology for chemical or ion removal to reduce the amount of hardness (calcium, magnesium) in the water Can also be designed to remove iron and manganese, heavy metals, some radioactivity, nitrates, arsenic, chromium, selenium, and sulfate.

29 Summary Bacterial contamination of well water can pose health risks A water test is the only way to evaluate if pathogenic organisms are present Safety for private water supplies is the responsibility of the owner(s) Proper maintenance is crucial If bacterial contamination is found, take steps to indentify and eliminate the source(s) of contamination and disinfect the system Several treatment options are available

30 Thank you For more information please see: