make its technology available to quali fied companies under licensing or other suitable agreements." Union Carbide can supply limited quantities of cable from inventory. Mr. Humphrey stresses that sodium cable is still considerably cheaper than other insulated underground cables for transmitting electric power. In prac tice, it has proven technically sound and has not met a serious problem in acceptance by installation crews. The fact is, however, that uninsu lated overhead electric transmission is cheaper than underground cables. The economics will likely remain this way unless insulation or underground transmission becomes required by, law. Sodium's major current use (more than 80%) is in making lead anti knock additives for gasoline. This market lies under a legislative cloud that casts major uncertainty on most of sodium (C&EN, Feb. 16, page 13). So far this year, tetraethyflead and other additives have performed strongly in spite of talked-up actions against lead additives in Washington. For sodium cable, the market is in suspension until more utilities feel as did American Electric Power Service when it installed the cable in a resi dential development in southern Vir ginia nearly two years ago. Confirm ing the cost advantage, AEPS went on to state, "and underground distri bution, with no visible poles or wires, is part of keeping America beautiful."
SODIUM:
Cable Shelved Sodium is soft, silver, lightweight, highly conductive, highly reductive— and commercially quite volatile. Slated for a boom just five years ago, the metal now finds its major markets in considerable doubt. A new blow hits sodium as Union Carbide discon tinues its Nacon Corp., the sole U.S. producer of sodium cable. Sodium cable has been a highly promising and potentially sizable out let for the metal, which comes to more than 325 million pounds per year in total U.S. production. Nacon vice president L. E. Humphrey states that the company had put sodium cable in 90 installations at 63 utilities throughout the world. This is more than 500,000 conductor feet of cable at voltages from 600 to 34,500 volts. But Nacon is being liquidated. For the reason, Mr. Humphrey says, that "although the field evaluation program has been veiy successful, Na con Corp. has not received sufficient support in the form of commercial or ders to permit it to continue in busi ness under present economic condi tions." For the future, Mr. Humphrey feels that with further experience in sodium cable by the power industry, perhaps "sufficient demand will develop to war rant resumption of manufacture. To fulfill this need, Union Carbide will
r
Pesticide output turned downward in 1969 1200
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1000
C .Ο
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800
finn I960
1961
1962
1963
1964
1965
1966
1967
1968
1969
Source: U.S. Tariff Commission
After years of uninterrupted growth, production of pesticides slipped 7.4% last year to 1.1 billion pounds, according to a just-released report by the U.S. Tariff Commission. Sales (at the manufacturers' level) were also down, amounting to 929 million pounds, valued at $851 million, compared to 960 million pounds, valued at $849 million, in 1968. The major reason for the decline was a reduc tion of inventory levels by many manufacturers, a move made necessary by, as one producer puts it, "our lousy forecasting." Demand for pesticides, which grew 1 0 % or more per year in the mid-1960's, has slowed. Last year it probably was up only 4 to 5 % over 1968. Many producers were simply too optimistic in their projections for growth, particularly for herbicides.
SEWAGE:
S02 Should Help Engineers who operate modern sew age treatment plants are constantly faced with the problem of how to get rid of activated sludge, the residue that results from treatment of sewage by aerobic bacteria. This activated sludge usually contains less than 5% solids. And being for the most part a colloidal suspension of microbial cellu lar material, thickening is a difficult and lengthy procedure. Sulfur dioxide may provide an an swer to the problem, Federal Water Quality Administration's Dr. Robert B. Dean told attendees at the 5th Interna tional Water Pollution Research Con ference in San Francisco. The novel FWQA-developed process, which has been tested out in the laboratories of Foster D. Snell, Inc., involves heating the activated sludge with steam at 30 p.s.i. for half an hour in the presence of 0.5% S0 2 . The result is a drastic reduction in filtration time and in the amount of water retained by the filter cake. Moreover, the clear filtrate, when concentrated to a molasseslike syrup, has nutritional value and could be used as animal feed supplement. S0 2 likely plays a dual role in the process, theorizes Dr. Robert J. Bouthilet, a consultant who worked on the process while at the Snell labs. On the one hand, it seems to speed the alteration in the physical nature of the particles to a form more easily filtera ble, a change that steam treatment alone promotes more slowly. In addi tion, S0 2 as sulfurous acid hydrolyzes polysaccharides and proteins in the sewage and increases the efficiency of food utilization of the mixture. This latter effect may reflect the ability of S0 2 to protect the essential amino acids from degradation. Dr. Dean, who is chief of the ulti mate disposal research program, a unit of FWQA's advanced waste treatment research laboratory in Cincinnati, Ohio, presents preliminary cost esti mates for batch-lot production of or ganic molasses from activated sludge filtrate. Digestion of 25,000 pounds of solids in stainless steel tanks would amount to $160. Subsequent evapora tion would add on another $245, bringing the total cost of the operation to $405, or 0.015 cent per pound. Currently, various types of molasses sell for between 2 and 5 cents per pound as animal feed fortifier, he notes. The new sewage-treating proc ess thus opens up a profit opportunity that would go far in helping a muni cipality defray the cost of sewage dis posal. He points out that the cost es timates don't take into account addi tional savings resulting from improve ment in speedingfiltrationand drying. AUG. 10, 1970 C & E N 15
