cars. O n the other hand, public works projects which are judged to contribute to the “common good” are paid out of general tax funds. A particularly interesting situation exists in the power industry, where cooling facilities add to the cost of electricity but rates are controlled by public utilities commissions. Max N. Edwards Assistant Secretary U S . Department of the Interior Warhington, D.C. 20240 Dual water supplies
DEAR S I R : Urban water resource development is becoming ;I matter of increasing national importance. In a reportreleased in January to the Office of Water Resources Research-the ASCE Urban Water Resources Research Program ( Harvard University) finds that the national investment need over the next 10-15 years will total well over S IO0 billion for municipal water facilities alone. To back u p this national investment need, which is mostly nonfederal, the Federal Government will spend approximately $149 million in fiscal year 1969 on water resources research, ranging from artificial rainmaking to soil conservation practices, advanced waste treatment, desalting, public health aspects, and planning research. It is important, therefore, to use every possible forum to point out problems. and to discuss approaches. solutions. and alternatives. 1. therefore, welcome Daniel A. Okun’s article. “The Hierarchy of Water Quality” (ES&T. September 1968, page 672). particularly if the dual water supply systems he advocates for cities of the future will lead to cleaner water for all uses. I have a n agg i n g s usp i c i on that 0kun ‘s ar guments might be used as an excuse to further pollute our already beleaguered rivers and estuaries when these are not used for drinking water supplies. For example. Okun says, “Dual systems would reduce the requirement for wastewater treatment because the receiving streams would not be a source of drinking water.” Other as some water uses, however-such oyster harvesting, fish propagation. and swimming-may require a quality of water as high as or higher, in some Mays. than drinking water supplies. These uses-protected by state and federal water quality standards-must
Write for Bulletin #132 ’Wa‘ste Disposal Systems”.
Circle No. 28 on Readers’ Service Card
Volume 3, Number 3, March 1969 197
DO YOU HAVE ANV OF THE FOlUlWlNG WASTE DlSPOSAl PROBLEMS? Synthetic Rubber Wastes Thermal Setting Plastics Oil Sludges and Heavy Hydrocarbons Butyric Acid Ammonium Sulfate Mercaptans Hydrogen Sulfide Chlorinated Hydrocarbons Sulfur Slurry Nitriles
Hydrogen Cyanide Spent Sulfuric Acid Carbon Monoxide Cyanates Carbonyl Sulfide Coal Dust Tars Contaminated Water Alcohol Filter Cake
A THERMAl OXD I ZIER I K IS FROM JOHN ZN THE SOlUTlON FOR YOU The John Zink Co. can design and build a thermal oxidizing system to cope with virtually any waste problem, whether the pollutant is gas, liquid or solid. The John Zink Co., a major supplier of burners and other equipment for the process industry for almost 40 years, has a waste disposal division with its own engineering staff and research facilities. The company produces complete systems that will dispose of any waste material that can be oxidized or dissociated by heat. Virtually all thermal oxidizers can be equipped with heat recovery systems. There are John Zink thermal oxidizing systems in operation around the world. If you have a waste disposal problem, give us the details and we will give you the solution. Write for our comprehensive catalog on pollution control products.
JOHN ZN I K COMPANY -
- ~
_
Post Office Box 7388
~
_
Tulsa, Oklahoma
Phone RI 7-1 371
Circle No. 39 on Readers’ Service Card
198 Environmental Science & Technology
(AC 91 8)
be supported by a high degree of waste treatment, even with dual water supply systems. Furthermore, it is becoming clearer every day that the problem of waste disposal is directly related to water supply. So. I would like to amplify the concept in Prof. Okun’s paper, which deals primarily with water supply, by pointing out potentials of a dual waste water system. Such a system would separate high BOD wastes from toilets and garbage disposals from the low BOD wastes (from dishwashers, clothewashers, and showers). Dual systems in which pneumatic toilets are installed and air pressure is used to transport the toilet wastes into a closed tank now are in operation. at least experimentally, in Sweden, Israel, and other countries. The toilet wastes are contained in a small volume of water which makes them cheaper to move. pump, and treat. Not insignificantly. the system conserves water, too. This is critical with our clean water demands expected to double in the next two decades. If ocean outfalls are used. then the problem of fresh water losses to the sea is significantly reduced. Nontoilet waste water could probably be treated more cheaply, and the reconditioned water recycled and reused in Okun’s dual water supply system. Or the rejuvenated waste water could be reused for a variety of other industrial, agricultural, or recreational purposes, preventing further water pollution at the same time. Finally, a dual waste system also may simplify the urban storm runoff problem, since the pathogens are almost entirely concentrated in the separated sanitary wastes. Dual systems, both for water supply and waste disposal, have the great advantage of making more options available. There are disadvantages. of course. Initially, there may be some psychological resistance against them by the public. Then. as in all dual systems, there is the additional cost of installation; but. as Okun aptly points out, as much new city will be built by the year 2000 as exists today. We must do better in these new cities than we have done in the past. Dual systems offer one promising approach in water resource management. S. Fred Singer Deputy Assistant Secretary U S . Department of the Interior Washington, D.C. 20402
