Info

a One quart contains 135 ordinary teaspoonfuls of water.

bLet stand 30 min before using. To dechlorinate, use sodium thiosulfate in same proportion as chlorine. One jigger = 1-1/2 liquid oz. Chlorine dosage is approximately 5-6mg/l. (1 liquid oz = 615 drops.) Make sure chlorine solution or powder is fresh; check by making residual chlorine test. Double amount for turbid or colored water.

a One quart contains 135 ordinary teaspoonfuls of water.

bLet stand 30 min before using. To dechlorinate, use sodium thiosulfate in same proportion as chlorine. One jigger = 1-1/2 liquid oz. Chlorine dosage is approximately 5-6mg/l. (1 liquid oz = 615 drops.) Make sure chlorine solution or powder is fresh; check by making residual chlorine test. Double amount for turbid or colored water.

Chlorine-containing tablets suitable for use on camping, hunting, hiking, and fishing trips are available at most drugstores. The tablets contain 4.6 grains of chlorine; they deteriorate with age. Since chloramines are slow-acting disinfectants, the treated water should be allowed to stand at least 60 minutes before being used. Iodine tablets (Globaline) and halazone tablets are also available at most sporting goods stores and drugstores. Check the expiration date.

Homemade chlorinators may be constructed for continuous emergency treatment of a water supply where a relatively large volume of water is needed. Such units require constant observation and supervision as they are not dependable. Figures 2.23 and 2.24 show several arrangements for adding hypochlorite solution. In some parts of the country, it may be possible to have a commercial hypochlorinator delivered and installed within a very short time. Some health departments have a hypochlorinator available for emergency use. Communicate with the local or state health department for assistance and advice relative to the manufacturers of approved hypochlorinators. Simple erosion-type chlorinators can also be purchased or improvised for very small places. A daily report should

FIGURE 2.23 Homemade emergency hypochlorinators. To make chlorine solution, mix 4 pt of 5 percent hypochlorite to 5 gal of water.

FIGURE 2.24 Emergency chlorination for fire supply, under health department supervision, for pumping into a hydrant on the distribution system, if necessary. Data for preparation and feed of chlorine solution: The asterisk denotes that the paste should be made in a jar. Add water and mix; let settle for a few minutes; then pour into carboy or other container and make up to 5 gal. Discard white deposit; it has no value. Dosage is 5 mg/l chlorine. Double solution strength if necessary to provide residual of 4 to 5 mg/l.

FIGURE 2.24 Emergency chlorination for fire supply, under health department supervision, for pumping into a hydrant on the distribution system, if necessary. Data for preparation and feed of chlorine solution: The asterisk denotes that the paste should be made in a jar. Add water and mix; let settle for a few minutes; then pour into carboy or other container and make up to 5 gal. Discard white deposit; it has no value. Dosage is 5 mg/l chlorine. Double solution strength if necessary to provide residual of 4 to 5 mg/l.

be kept showing the gallons of water treated, the amount of chlorine solution used, and the results of hourly residual chlorine tests.

Iodine

Eight drops of 2 percent tincture of iodine may be used to disinfect 1 quart of clear water (8 mg/l dose). Allow the water to stand at least 30 minutes before it is used. (Bromine can also be used to disinfect water, although its use has been restricted to the disinfection of swimming pool water.) Studies of the usefulness of elemental iodine show it to be a good disinfectant over a pH range of 3 to 8, even in the presence of contamination.206 Combined amines are not formed to use up the iodine. A dosage of 5 to 10 mg/l, with an average of 8 mg/l for most waters, is effective against enteric bacteria, Giardia and amoebic cysts, cercariae, leptospira, and viruses within 30 minutes. Tablets that can treat about 1 quart of water may be obtained from the National Supply Service, Boy Scouts of America, large camping supply centers, drugstores, and the Army, in emergency. These tablets dissolve in less than 1 minute and are stable for extended periods of time. They are known as iodine water purification tablets, of which Globaline, or tetraglycine hydroperiodide, is preferred. They contain 8.0mg of active iodine per tablet. The treated water is acceptable. Iodine is toxic. It should be reserved for emergency use only.207

Filtration in an Emergency

Portable pressure filters are available for the treatment of polluted water. These units can produce acceptable water, provided they are carefully operated by trained personnel. Preparation of the untreated water by settling, prechlorina-tion, coagulation, and sedimentation may be necessary, depending on the type and degree of pollution in the raw water. Pressure filters contain special sand, crushed anthracite coal, or diatomaceous earth. Diatomite filtration, or slow sand filtration, should be used where diseases such as amebic dysentery, giardiasis, ascariasis, schistosomiasis, or paragonimiasis are prevalent, in addition, of course, to chlorination.

Slow sand filters (consisting of barrels or drums) may be improvised in an emergency. Their principles are given in Figure 2.2 and Table 2.2. It is most important to control the rate of filtration so as not to exceed 50 gpd/ft2 of filter area and to chlorinate each batch of water filtered, as shown in Table 2.19, in order to obtain reliable results.

Bottled, Packaged, and Bulk Water

The bottled water industry has shown a large growth in many parts of the world because of public demand for a more palatable and "pure" water. It is not uncommon to find a wide selection of waters from various sources in the United States and Europe and in supermarkets and small grocery stores in almost all parts of the world. A major bottler in France was reported to have a capacity of 800 million bottles per year. The 1989 production in the United States was estimated at 1,384.4 million gallons per year.208 There were an estimated 700 water-bottling plants in the United States in 1972.209 In addition, self-service water vending machines that dispense water into an individual's container are available.* Per-capita consumption increased from 5.2 gallons in 1985 to 6.2 gallons in 1989, with a 1989 sales value of $2.375 billion, compared to $1.5

* Water vending maching sanitary design details are given in ref. 211.

billion in 1985 and $275 million in 1975.210 The demand for bottled water is of course minimized where a safe, attractive, and palatable public water supply is provided.

In an emergency, it is sometimes possible to obtain bottled, packaged, or tank-truck water from an approved source that is properly handled and distributed. Such water should meet the federal and state drinking water standards as to source, protection, and microbiological, chemical, radiological, and physical quality. Water that is transported in tank trucks from an approved source should be batch chlorinated at the filling point as an added precaution. The tank truck, hoses, fittings, and connections should, of course, be thoroughly cleaned and disinfected (not less than 100mg/l chlorine solution) before being placed in service. Detergents and steam are sometimes needed, particularly to remove gross pollution, followed by thorough rinsing with potable water and disinfection. Only tank trucks with a dedicated use for hauling potable water should be used. Each tank of water should be dosed with chlorine at the rate of 1 to 2 mg/l and so as to yield a free chlorine residual of not less than 0.5mg/l. See Table 2.19.

Milk pasteurization plants and beverage bottling plants have much of the basic equipment needed to package water in paper, plastic, or glass containers. Contamination that can be introduced in processing (filtration through sand and carbon filters) and in packaging (pipelines, storage tanks, fillers) should be counteracted by germicidal treatment of the water just prior to bottling. In any case, the source of water, equipment used, and operational practices must meet recognized standards.

Bottled water should meet EPA and state water quality standards for drinking water and comply with FDA regulations and industry standards for the processing and bottling of drinking water.212 Many states also have detailed regulations or codes including water quality standards. The National Sanitation Foundation also has guidelines and makes plant inspections. The FDA microbiological quality standards are 9 of 10 samples less than 2.2 coliforms per 100 ml, with no sample showing 9.2 or more by the multiple-tube fermentation method, and the arithmetic mean of all samples should be not greater than 1 per 100 ml with not more than one having 4.0 or more coliform organisms by the membrane filter method.212 The standard plate count of the bottled water at the retail outlet should be less than 500 per 100 per milliliter. The FDA considers bottled water a "food" and regulates its purity.* Mineral water is exempt; its definition is vague. Mineral water has been defined as bottled water containing at least 500 ppm dissolved solids and originating entirely underground. Nevertheless, mineral waters should meet the physical, microbiological, and radiological standards for drinking water. Bottled water should also be free of Pseudomonas aeruginosa.

Bottled water may be labeled natural water (no change), natural sparkling water (carbon dioxide added), spring water (groundwater), purified water (demineralized), mineral water (assumed 500 ppm or greater total dissolved solids), seltzer water (carbonated tap water), and club soda (carbonated with salt

*Other standards refer to turbidity, color, odor, chemical quality, fluoride, and radiological quality.

and minerals added). Up to 0.02 percent caffeine and 0.5 percent alcohol by weight may be added to natural sparkling water, club soda, seltzer, and soda water, according to the FDA.214

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

Get My Free Ebook


Post a comment