BUBBLE TROUBLE ON TAP (Jul, 1962)
BUBBLE TROUBLE ON TAP
By Volta Torrey
We use 320 billion gallons of water a day but by 1970 pollutants may cut our ration NOT LONG AGO, a woman in Long Island, N.Y., was filling a cooking pot with water from her kitchen tap. Suddenly the pot foamed over with crisp, white suds.
These suds, she knew, were caused by synthetic detergents that had drifted over from neighborhood septic tanks and were adulterating her well. Since the sudsy water is distasteful, she uses tap water only for cooking and washing. She buys drinking water in bottles in another town for herself and her family.
Some months earlier, another housewife found that detergents were corroding metal parts in her automatic washing machine.
This corrosion of parts, and sudsing of tap water, are among the first signs a community has that something is happening to its water supply. This something is so widespread that some washer manufacturers are finding it necessary to forestall corrosion by using plastic or stainless steel parts. Automatic garbage disposers have been affected, too. While a heavy stream of cold water usually will flush the stuff out, one maker now puts a polypropylene lining into his disposers to cut servicing costs.
These annoying occurrences in homes and to appliances, however, are only signs of a grave crisis in store for our water supply by 1970, if something is not done. This crisis is developing, say experts, because we have to reuse our water more rapidly as our population grows. Many of our facilities for restoring water to reusable purity are not up to the job, and, for another reason, we have not yet learned to deal with many beneficial chemical inventions such as detergents which, unfortunately, can cause harm when disposed as waste into our water supply.
In many areas, the fight, at least for the present, seems lost as suds come billowing out of streams that once were pure, or flow out of control into a neighborhood’s wells.
The basic problem is that synthetic detergents (syndets) defy both nature’s and man’s standard methods of purifying water.
Soap, the kind your mother used, was made from animal fats on which bacteria and other micro-organisms fed and thrived. Soap’s molecules consist largely of long chains of carbon atoms with hydrogen atoms attached to them. After soap goes down the drain with waste water and into cesspools, sewage-treatment plants or surface streams, the bacteria destroys the chains of molecules and effectively disposes of the waste.
Synthetic detergents were invented during World War I, because Germany’s supply of soap was cut off. Dr. Fritz Gunther devised a detergent that could be made from coal tar. But it and other detergents that have since come on the market are not considered good eating by the bacteria and micro-organisms which thrive on animal-fat soaps. And because the syndets are not eaten by bacteria, they tend to remain in the water system and escape destruction by standard water purification techniques.
Syndets have long chains of carbon atoms with hydrogen atoms attached and, in addition, they often have a benzene ring hooked to an atom of carbon. It is this ring which makes it more difficult for the micro-organisms to break up the stuff after it has been consigned to the sewage-treatment plant.
This was not a serious problem 25 years ago when there were few detergent manufacturers. Today there are more than 250 in the U.S. alone, and detergents outsell soaps two to one. Housewives like syndets because they lift and disperse many kinds of dirt liable to be found on dishes, in clothing or other things washed with water. Detergents lower surface tension and make things soluble that ordinarily are not. When water is hard, as in many parts of the Middle West, natural soaps tend to leave a “bathtub ring.” Synthetic detergents create suds and work better than natural soaps in such water.
According to the U.S. Public Health Service, four billion pounds of syndets are produced each year and each pound ends up as waste in water.
Manufacturers use an inexpensive product of crude oil and many of their detergents also contain the foam-maker, alkyl-benzene sulfonate, or ABS. This is the stuff that is creating mounds of slippery foam in some city sewage treatment plants, and by its foaming presence, is revealing the extent of the pollution problem.
ABS is not the only fly in the otherwise beneficial detergent ointment, however. Some types of detergent also carry phosphate compounds that promote the growth of scum and other unattractive by-products. ABS, however, attracts attention because very small concentrations of it—a few pounds per million gallons—will make water foam. Consequently ABS is easily detected and serves as the tattletale which has put the experts on guard.
If a town puts syndets into a river near the headwaters, it can carry some of them to the next town downstream. This town’s water may not be affected seriously, but when it adds syndets to the river in its waste, the third town may get too many in its water.
This cycle may be repeated from five to ten times along the river and towns near the river’s mouth may receive waste overburdened with syndets.
We apparently can consume such small concentrations of ABS as have been put in our water so far, without becoming ill. But the consequences of continued consumption of such water for long periods of time are not yet known. It is probable, however, that water containing enough ABS to be harmful is likely to be so unattractive that we would object to drinking it.
ABS, though, isn’t the only chemical that may be harmful. A standard reference book, used by filtration engineers, states that a wide range of chemicals goes into the complex compositions we know as synthetic detergents. Any one of these individual chemicals may be an irritant. The book further points out that the early synthetics touched off a large number of cases of contact dermatitis. Although considerable progress has been made in removing the irritants, the incidence of dermatitis of the hands is considerably higher than* it was before the synthetics took over the market.
A postscript to this information is added by Edward J. Zimmer, director of Chicago’s Plumbing Testing Laboratory: “If it’s rough on the tough hides of hands, what do you think it does to the delicate interior plumbing of the human being?”
Syndets also can get into ground as well as surface water and they may remain there undetected until they are so concentrated that costly removal methods or new sources of water are needed. In one Long Island, N. Y., development that has four to five homes per acre, syndets recently were found to have penetrated a third of the wells. In other suburban communities even deepening the wells has failed to yield water free of syndets.
What can be done to remove ABS from water? One way to do the job is to run water through activated carbon. This is an added expense, but authorities at the Department of Health, Nassau County, N. Y., where the technique has been tried, urge further study of its use both with water from private wells and in large water-treatment plants.
Foam fractionation is another possible way of combating syndet contamination. This process has been known for years, but was not considered seriously in connection with water pollution until recently.
In foam fractionation, a gas (usually air) is put into the polluted water to create a stream of rising bubbles. Since the chemicals usually flock to points where air and water meet, they cluster around these bubbles and ride them to the surface. The resulting foam then can be skimmed off like the head on a glass of beer.
In small-scale tests, researchers of the Esso Company have demonstrated that 90 percent of the detergents can be removed from sewage-plant affluent this way. The U.S. Department of Health, Education and Welfare has contracted for further study of this technique.
The federal government also is supporting studies of possible dumping places for troublesome chemicals and investigations of ways of making discarded materials useful again. Businessmen have become concerned, too, and both university and industrial laboratories are tackling the pollution problem’s many aspects. The Midwestern Research Institute in Kansas City, for example, is seeking more fundamental knowledge of the washing process by using a vibrating jet method to study the surface tension at the surface of freshly formed detergent solution.
Prof. Rolf Eliassen, Stanford University, has challenged the chemical inventors to come up with a solution to the problem their products have created. “It should not be difficult,” he says, “for the chemical industry to develop a different series of compounds, and produce some which could be broken down by bacteria and still be relatively inexpensive.”
Detergents that bacteria can destroy after they’ve been used can now be made from sugar-based materials. These are said to be biologically soft detergents, and efforts are under way in many laboratories to develop soft detergents that can be competitive in cost and popularity with the hard ones.
Hard detergents still could be used in coastal communities where waste water is discharged into the sea, and soft detergents where that water must soon be used again in some other community. People with soft water might also be encouraged to go back to using soap.
Finding ways to change or oust the pollutants is a problem that is not restricted to American’s back yards. The problem is a worldwide one that has already arisen in England, West Germany and Russia.
Manufacturers have cooperated with government authorities in England to place only certain kinds of detergent on sale in some areas, and in West Germany legislative action has been taken. Even the Russians have not yet claimed to have invented a solution. Their public health journal, Hygiene and Sanitation, reports that new combinations of sewage and waste are causing so much pollution in the U.S.S.R. that it constitutes a threat to the “entire national economy.,, The U.S. Public Health Service has set a limit on the detergent level permissible in the water of interstate carriers. Few water supplies have syndet levels anywhere near that maximum now, but more public awareness of the problem, research, and engineering know-how is needed to stop the suds from rising.
“The problem has not yet been solved,” says Dr. James M. Symons of the Massachusetts Institute of Technology’s Civil and Sanitary Engineering Department, “but I have every confidence that an intensive research effort will bring an adequate solution within the next few years.”
There are signs already that research on the problem is paying off. For example, Continental Oil Company recently announced that it is building a $10,000,000 plant to turn our “straight-chain” industrial alcohols from petroleum. These new alcohols are expected to be used in detergents. Because they are much simpler in chemical composition than existing compounds, they probably will be much easier to “break down” at the time they have done their job and must be destroyed.
The detergent manufacturers themselves, for 10 years, have been working toward a solution of the problem (though they deny that the problem, basically, is one of detergents). The Soap and Detergent Association, in a statement to Popular Mechanics says: “First of all, the residues of detergents, as present in waste water, have been shown to be nontoxic. While they may be a cause of froth in some situations, they are not a cause of taste and odor; but rather are indicators of concurrent, invisible sewage pollution which causes such taste and odor.
“In areas of high population density, there is agreement that no lasting solution to this problem exists short of public water and sewer services. In modern sewage-treatment plants, the present surface-active material in detergents is broken down as much as 50 to 70 percent; it’s not indestructible, but is one of a number of persistent or ‘refractory’ organic wastes, all of which must be dealt with in such treatment in the future.
“Today, research is proceeding along two lines: Companies in our industry are seeking individual product improvements which will increase their amenability to treatment while maintaining cleaning efficiency and low cost. At the same time, the U. S. Public Health Service and others are seeking improvement of treatment processes which will deal successfully with all the new and persistent waste material.”
That’s the problem, to date. And a bubbling, seething problem it is, for it will affect the palatability—and safety—of your drinking water.
Your shirts may be whiter these days, because the syndets are highly efficient at wiping away dirt. But the syndets themselves are stubbornly refusing to vanish.