Hot Water: Menace and Resource

Abstract

Thermal electric plants discharge 50 trillion gallons of heated water each year into United States waterways, some cases with devastating effects, says Dr. J. I. Bregman, Deputy Assistant Secretary of the Interior for water pollution control. By 1980, he predicts, the figure will double, giving rise to intolerable increase in thermal pollution if corrective steps are not taken. Growth of electric power is so rapid, says Wilfred E. Johnson, a member of the Atomic Energy Commission, that more than half of all the country's freshwater runoff will be needed for cooling by 1990, and in some heavily populated areas, 100 percent. thermal plants are a major and growing problem. To compete with conventional plants, they tend to be larger, and require more coolant. Also, they discharge most of their waste heat in the coolant, whereas gas-, coalor oil-fired plants send a good deal up the stack. In Portland, Ore., R. F. Poston, regional director of the Federal Water Pollution Control Administration, says: Nuclear power development presents the greatest single threat to the fisheries -and to the environment-that we face in the Pacific Northwest in the next few years. In the East, Senator Joseph D. Tydings (D-Md.), member of the Senate Subcommittee on Air and Water Pollution, says: power generation poses an immense risk of destruction of the marine life in Chesapeake Bay and on the Potomac. Many state fish and game departments have blamed the hot water for fish kills. In Lake Michigan, temperature increase and its handmaiden, oxygen starvation, are major suspects in last summer's deaths of hundreds of millions of alewives, the worst fish kill in U.S. history (SN: 2/17, p. 159). Rising temperatures diminish water's capacity to retain dissolved oxygen and simultaneously foster growth of oxygendemanding bacteria and algae. Also, dissolved oxygen is needed by bacteria to decay waste matter, so a decrease in oxygen has the same effect as introducing another oxygen-consuming waste. Furthermore, heat intensifies the action of chemical pollutants. There are techniques for dissipating heat. But beginning to emerge now is another, more attractive possibility: the heat could be a valuable industrial side product. * Hot discharges from Potomac Electric Power Co. at Dickerson, Md., kept several miles of the Potomac from freezing in the winter of 1960-61 when the rest of the river was frozen over for weeks. The technique might be applied to navigable waters. * It has been suggested that manatees be imported into Chesapeake Bay, to winter in warm discharges and earn their keep by controlling growth of unwanted aquatic vegetation. * Offshore hot discharges may attract fish by creating the flora and fauna they feed on. Near Los Angeles, warm water from steam plants reaches half a mile to sea, creating a winter haven for many fish that once swam south for the winter, and a boon for fishermen. * Waste heat may prevent frost damage to orchards, or extend the growing season of crops that bring premium prices on an early market. In one $3.7 million experiment, normal temperature