drinking water quality concerns and water vending machines.
S. Congress set up a Scientific Advisory Committee in 1978 to advise the United States. S.
Environmental Protection Bureau (EPA)
The congressional committee on environmental affairs classifies contaminants in drinking water as a serious risk to human health (4).
Recently, the Ministry of Health\'s survey of hundreds of residents in a county in the Midwest found that consumers listed the quality of drinking water as the second most important factor in various environmental health problems after solid waste treatment (5).
Although often exaggerated in media reports, evidence of the actual and potential risks of contaminated drinking water to human health remains widespread.
These risks include an expanding range of microbial, chemical and radioactive contaminants.
This article reviews some contemporary concerns about the quality of drinking water and the development of water vending machines that can be seen as a response to the public\'s negative perception of the quality of our tap water.
This article also discusses the treatment methods currently provided by the vending machine and describes the national certification plan for its design and construction.
Microbial concerns, while improved water purification methods and more comprehensive monitoring have significantly reduced the number of cases of water-borne diseases in the United States, regular outbreaks, sometimes dramatic, it continues to happen in public and private systems.
In fact, it is reported that there are 291 outbreaks of water-borne diseases in the United States. S.
1981 to 1990 (3).
In a water-borne outbreak, the most common pathogen is the lamella giatti, a whip flag native that destroys the microfluff lining of the upper large intestine (6, 7). Fifty-
During the period from 1965 to 5%, 1985 of the Jia Di sucking disease epidemic occurred in the community water supply system, which is usually due to inadequate disinfection, although turbidity and coliform concentration are usually within the prescribed range7).
The concern about water-based dust absorption is serious to the EPA\'s promulgation of surface water treatment rules (SWTR)
In 1989, under the authorization of the amendment to the 1986 Safe Drinking Water Act.
The rule requires the use of a public water system for surface water for treatment to reach 99.
A decrease of 9% in Jia Di\'s sac (8).
The Environmental Protection Agency also recommends that the population served by these systems be at no more than 1 risk per 10,000 persons per year for infection with GIAD (8).
While it is expected that this policy will further reduce the risk of jadirasi, Lechevalier, Norton and Lee (9)
It has been proved theoretically and empirically that SWTR will not ensure that the treated water does not have a GIAD cyst and does not exceed the EPA target.
It is also interesting that at least one recent epidemiology study has shown that more than a third of the reported cases of water-borne intestinal diseases may be due to drinking water that meets the applicable drinking water standards (10).
Another current microbial problem in drinking water is cryptospores, a newly discovered human parasite that causes cryptospores disease.
It is reported that the water-borne disease broke out in public water supply systems in the United States and the United Kingdom (3, 11).
The most recent incident occurred in Milwaukee, Wisconsin, in April 1993, with an estimated 300,000 people ill (12).
This outbreak immediately prompted the proposed legislation to establish more than one
A multi-billion-dollar revolving fund that allows countries to issue loans for the construction or improvement of water treatment plants (12).
This is just a sign of the impact of water quality issues on Congress.
If a patient with AIDS or someone else in the immune suppression system is infected with cryptospores, cryptospores infection is particularly serious because there is no effective drug for the treatment of the disease (3).
Just like GIAD, lechewalier, Norton and Lee (9)
It has been shown that compliance with SWTR does not necessarily ensure that the treated water does not have a cryptospore yolk sac.
Other contemporary microbial health issues in drinking water include legion, virus, and E. Coli
E. Coli, bleeding type 0157: H7, can cause bloody diarrhea and potentially fatal hemolysis-
Urine poisoning syndrome (3).
As noted above, despite recent progress in water treatment and regulation, microbial contamination of drinking water remains a serious public health risk (13).
The number of chemicals involved in inorganic and organic chemicals regulated or proposed under the Safe Drinking Water Act has more than doubled in recent years (14, 15).
It includes various volatile organic chemicals such as vinyl chloride and four chlorine carbon;
Synthetic organic chemicals, including many pesticides and herbicides;
As well as trace metals and other organic substances such as asbestos and nitrate.
Two more open chemical concerns about drinking water include lead contamination and the formation of potentially toxic disinfectionproducts (DBPs).
Lead is a cumulative poison, and the physical burden of lead is getting lower and lower, which is related to potential severe neurological effects in young children, including decreased learning ability and behavioral changes (16).
Recent news reports say that there is a clear prevalence of lead pollution in public water supplies above the Environmental Protection Agency\'s 15 ppb level of action, which increases public concerns about this important public health hazard (17).
Lead contamination in the supply of drinking water is usually caused by a pipe connection between the water supply pipe and the home or a lead loss in the home pipe itself (18).
For these reasons, 1986 the Safe Drinking Water Amendment prohibits the use of lead pipes, solder and flux in pipes connected to public water supply systems (19).
\"Lead-free\" as defined in the act means no more than 0.
2% of lead in welding and melting, and no more than 8% of lead in pipes and fittings (19).
Most of the serious lead pollution problems seem to be related to highly corrosive waters, especially when the water is allocated to old houses with lead pipes, or to relatively new houses with lead pipes connecting copper pipes --based solder (18).
Contact time is another important variable (20)
, Those with potential lead contamination in the water system are often advised to rinse the water pipes before drinking, especially when the water has not been in operation for several hours, or to seek additional treatment or alternative sources of drinking water.
Methane three (THMs)
Such as methyl chloride and methyl bromide, the formation is mainly caused by the reaction of chlorine and nature
Their cancer has been studied.
Production potential in the past 20 years (21).
In fact, these and associated organic substances found in the chlorine drinking water may cause a threat to cancer, at least in part because the original Safe Drinking Water Act was passed in 1974 (22, 14).
And DBPs chloride-
Cancer connections are still considered uncertain and concerns about DBPs will increase as alternative disinfectants continue to be tested and used for drinking water supply.
According to the American Association of Water Engineering: \"The issue of DPBs, many of which are still unknown, its toxicology is basically unknown and, more complex, the risk of these contaminants being weighed against water-based microorganisms, these contaminants may flourish if disinfection is reduced.
This risk assessment is hampered by insufficient data ,\"(23, p. 43).
Radioactive contaminants in drinking water are usually produced by natural leaching.
Radionuclides in geological structures enter the supply of groundwater. Radium-
For example, 226 and 228 are relatively common in deep water in the southeastern United States. S.
New England, Texas, Iowa, Illinois, Utah and Idaho (24).
The main health problem with the intake of RA is bone cancer based on the study of the RA dial painter (25).
RA is also a risk factor for leukemia, although the level of risk at low levels in drinking water is controversial (25).
Recently, the US Environmental Protection Agency has put forward the standard of less limit.
Drinking water 226, 228 (15)
Some people think it is more economical than public health considerations.
According to the Safe Drinking Water Act, radon is also the subject of the proposed regulation (15)
, Although there is some dispute about the reasons behind the proposed maximum pollutant level of 300 piC/L (3).
From the point of view of some consumer advocacy groups, radioactive excess in any form of drinking water is a serious public health problem, and anecdotal data seem to indicate that in areas where excessive standards are detected, many consumers have changed their drinking habits.
Consumer concerns about the health impact of the demand for tap water alternatives on contaminants in drinking water only partially explain the increased consumer demand for bottled water, intravenous drinking water and residential water treatment units.
Consumers are also concerned about the aesthetic quality of their water, especially aspects related to taste, smell and appearance (26, 27).
These factors, coupled with media exaggeration and aggressive marketing, began to explain the development and growth of the industry that produces alternatives to tap water.
The automatic water sales industry is a good example.
According to the Beverage Marketing Company (BMC)
In the June 1991 edition of bottled water in the United States, sales of automatic water sales increased by 60% from 1988 to 1990 to $57,100,000.
BMC estimates that sustained growth averaged 8% to 1991 per year
95 and 7% per year thereafter.
According to Soost (28)
Compared with bottled water, the vending machine provides a significant advantage for retail stores.
These include reduced demand for ordering, storing and storing space for valuable shelves, large volumes and low margins
Produce bottled water and increase profit margins. Soost (28)
Consumer demand for water supply due to cost savings (
The price of Ven water is usually 50% to 60% lower than bottled water)
, Relative convenience, perceived quality of the product, attention to health, and enhanced environmental awareness (
Customers can reuse their containers, thus reducing the potential waste that can be generated by bottled water containers).
The Hispanic and Asian populations have the highest demand for perfume (26)
Especially in a warm climate like California, Arizona and Florida.
Surprisingly, the vending machine is not a new phenomenon.
215 B early. C.
Get the sacrifice water from the desktop dispenser (29).
However, in 1908, more than 2,000 years later, another \"vending machine\" appeared at the scene.
This time, consumers bought a small separate paper cup from the dispenser and filled it with drinking water from the adjacent reservoir.
This is the invention of the \"Dixie cup\" and the manufacturer does not think it will be sold unless the customer is able to use it (29).
However, it was not until 1976 that the first practical vending machine was designed and put into use, and it was not until the beginning of 1980 that the vending machine became a viable industry.
Nowadays, there are three basic installation methods for automatic vending machines. Most are self-
Independent floor model located inside or in front of grocery store, convenience store or other retail store.
Some vending machines are installed on the counter, usually adjacent to soft drinks, coffee and other beverage distribution equipment.
Recently, some water vending machines are being designed to handle components located in remote areas of the facility (
Often storage room)
, While a smaller distribution unit is located on the counter in the store sales area.
In terms of water treatment, most water vending machines provide purification at or above the first level. Filtration-
As shown in figure 3, only the machine provides the most basic level of processing.
These machines are basically designed to reduce the taste, smell and turbidity of the water source, which should come from the approved water system.
Other machines may contain additional handling devices to reduce the high concentration of the total dissolved solids (TDS)
To achieve a more delicious level or to produce \"pure water\", must have a TDS concentration of not more than 10 ppm, among other requirements (30).
Many vending machines offer a variety of water options on the same machine (e. g. , filtered-
Only water and pure water).
Depending on the quality of the water source, the vending machine can start the treatment process with a mechanical filter to remove sediment and residue.
The following is usually activated carbon filtration, usually the second mechanical filter to remove the carbon powder extracted from the carbon filter. This so-
The so-called \"pre-filter\" process that includes these or other filtering steps typically uses a filter with a media aperture ranging from 1 to 20 microns.
Activated carbon filtration can effectively absorb a variety of organic compounds, including organic compounds that can bring flavor, smell and color to water supply, or organic compounds that may cause cancer, such as THMs or other volatile organic compounds (31).
The carbon medium may be block or granular, and the longer the contact time, the greater the treatment effect.
When the carbon adsorption capacity is exhausted, the filter or regeneration medium must be replaced.
The carbon filter is also used to remove or reduce chlorine, otherwise it will damage the reverse osmosis (RO)membranes (31).
The RO process usually follows pre-filtration in the processing sequence that requires TDS reduction, receiving the feed water at one end of the semi-permeable membrane pressure.
Water-based Ben passes through the membrane one drop.
When water passes through the membrane, contaminants (
Dissolved and suspended solids)
Being left in the \"reject\" water, it is possible to return to the RO membrane for further treatment or, more often, discharge into the drainage system.
Reverse osmosis system is effective in reducing TDS;
Metals such as arsenic, cadmium, copper, lead and sodium; nitrates; asbestos; radium; Giardia cysts; and bacteria (31, 24).
The effectiveness of the membrane depends on several factors, including its age, the type of contaminants, and the concentration of solids in the feed water.
If the vending machine produces \"purified\" water, RO-treated drinking water can further reduce TDS to a level of no more than 10 ppm by removing the ion tank.
The machine that uses RO treatment will have an internal storage tank as the RO film takes quite a long time to produce the reduced TDS water.
The tank can be pressurized or non-pressurized. pressurized.
Disinfection is the last step in the processing, before the water is allocated to the customer\'s container.
Disinfection in vending machines is usually done by exposing water to ultraviolet light (UV)radiation.
UV lamp is similar to fluorescent lamp except that it uses low-
UV wavelength required for pressure mercury vapor generation (254 nanometers).
Since most materials do not transmit UV rays efficiently, a special quartz glass is used to encapsulate the lamp.
Quartz glass allows about 93% of the emitted UV rays to enter the water (32).
When exposed to ultraviolet rays, microorganisms are destroyed because ultraviolet rays disrupt their DNA structure and interfere with cell reproduction (32).
Radiation dose, exposure time and water quality are only a few factors that must be considered in effective sterilization treatment (32).
Usually, 13,000 microwatts-
Seconds with a wavelength of 254 nm per square centimeter are enough to be effectively disinfected in the automatic vending machine (30).
Some vending machines use ozone as a means of disinfection.
In this process, ozone is injected into the water before it is allocated.
Ozone concentration 0.
The International Bottled Water Association recommends the use of 5 ppm to ensure effective sterilization.
Unlike ultraviolet rays, ozone causes cell cracking (33).
A potential limitation of ozone disinfection is that it can smell drinking water. Since the half-
However, the lifetime of ozone is very short (
Usually less than 30 minutes)
This should not be considered a major issue.
With the popularity of vending machines in the United States, some quality control measures are essential.
While local and national health authorities have the primary responsibility to develop and implement minimum public health and safety standards for the installation, operation and maintenance of on-site vending machines, it also seems important to have a national standard for their design and construction.
Fortunately, there is such a standard.
National Association of automatic commodity sales in 1957 (NAMA)
Build automatic sales Health-
Council of Industry (AMHIC)
As an independent advisory group
Health members of AMHIC represent professional associations and local, state and federal regulators, and their industry members represent vending machine operators and manufacturers.
The council\'s initial task was to establish a voluntary program to assess food and beverage vending machines as defined in the United StatesS.
The regulations on public health services and the code automatically sell food and drinks.
Due to its activities, the Council established the NAMA standard for hygienic design and construction of food and beverage vending machines, which came into effect on 1961.
Ten revisions occurred between 1966 and 1990 (30)
Including the addition of a section on the standard vending machine in 1984.
When the vending machine meets the standard requirements, the \"compliance letter\" identifying the machine by manufacturer, model, product type, special qualification and certification date is issued by an independent public health consultant conducting the assessment.
Re-evaluation is carried out every year to ensure that the machine continues to be manufactured according to standards.
Many regulators rely on the NAMA assessment program to identify machines manufactured in accordance with the public health standards accepted by the state.
States such as California, Ohio and Georgia require all food and beverage vending machines (including vending machines) to carry the NAMA Service logo, which indicates compliance with the standard.
In 1992, 22 manufacturers of water vending machines participated in the voluntary NAMA certification program.
The NAMA standard defines the water vending machine as \"water-
Connected Vending machines designed for the distribution of drinking water, purified water and/or other aquatic products. \" (30, p. 4).
Drinking water as defined by NAMA is \"drinking water that is disinfected and treated by an automatic vending machine to reduce or remove turbidity, odor and odor\"tastes. \" (30, p. 2).
Pure water is defined as \"by distillation, ion-
Exchange, reverse osmosis or other processes. \" (30, p. 3).
In all cases, the NAMA requires the vending machine to be connected only to the approved water supply system.
In addition, the drinking water machine must meet all applicable requirements of EPA primary drinking water standards and EPA\'s recommended secondary guidelines, while the purified water machine must meet the US standardsS. Pharmacopoeia (30).
Several examples of many of the requirements for vending machines under the NAMA standard highlight the full nature of this voluntary certification program: 1. Filtration-
Only machines must be designed to connect to drinking water systems containing 500 ppm or less TDS, as these machines do not reduce TDS concentration and the TDS requirement is 500 ppm according to the secondary drinking water guidelines. 2.
Unless the vending machine is equipped with an inlet air gap, it must contain a vacuum circuit breaker, a pressure relief zone device, a double check valve, or other effective anti-reflux device upstream from the first processing part, to reduce the possibility of return or return to approved water sources. 3.
The strength of the UV lamp used for disinfection must be designed for automatic or manual monitoring to ensure that it is not less than the pre-
Established standard for 13,000 microwatt
A few seconds per square centimeter at a wavelength of 254 nm.
If UV rays are missing, burnt out, broken or below the required dose, the machine must be designed to invalidate the vend mechanism. 4.
Water vending machine cabinets, vending machine tables and interiors must be designed and built to facilitate daily cleaning and maintenance and to minimize the entry or collection of moisture, dust or carriers. 5. All water-
Contact with parts, surfaces and media, including recommended alternatives, must comply with FDA standards (
21 CFR, part 170-
Food Additives Amendment 189)
, Or is generally considered safe (GRAS)
This is provided in 21 CFR Part 182. 6.
When process water is collected inside the machine to discharge to an external drain, the discharge point of the processing unit must be at least 2 inch above the edge of the reserved container.
In addition, the scrap line on the machine must be air-gapped. 7.
Sensors and/or controllers must be provided that, in the event that any process or function failure causes the water quality to be lower than claimed, these sensors and/or controllers will invalidate the machine (e. g.
, Pure water)
Or overflow of waste containers.
Machine disinfection is not required if automatic recovery or switching mode is used to re-process poor quality water. 8.
Performance test data must be provided to show the processing effectiveness of all water treatment equipment under the proposed operating specification. 9.
Each machine must be accompanied by a copy of the printed hygiene and repair procedures, at least the machine installation procedures must be included; step-by-
Step description of In-
Clean and hygienic places;
Recommended schedule for repair and replacement of components with limited effectiveness;
A guide to troubleshoot water quality problems;
Appropriate control settings to maintain the quality of the product water;
And a recommended schedule for testing the conductivity, taste, smell, turbidity and microbial quality of the product. 10.
In order to facilitate cleaning under and around the vending machine, cabinets must be installed on legs, casters, etc.
Easily moved by one person or permanently sealed on the floor or counter. 11.
There must be self-protection for the automatic sales desk
Closing the door or panel, unless the stage is designed with a mechanism that makes the dispensing nozzle inaccessible when the machine does not have a vending machine, minimizes vector access to the machine. 12.
Product water for representative machines in production must be sampled annually to ensure compliance with applicable water quality standards and to demonstrate the effectiveness of the machine handling process.
The Chicago National Association of automatic sales or the standards themselves provide a more detailed description of these and other NAMA requirements for the vending machine (30).
Summary and conclusion on quality of drinking water in USAS.
Power was provided to the industry involved in the development of water alternatives.
The vending machine is a good example.
For some consumers, the water provided by the vending machine is an attractive alternative to residential tap water, which may be considered objectionable for aesthetic or other reasons.
From a public health perspective, when the vending machines are connected to the approved drinking water supply system and when they are properly designed, manufactured, installed, water treatment and delivery and service should be considered acceptable.
Certification programs like NAMA provided with local and state public health inspection programs will greatly help ensure that the vending machines provide what they claim-
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