is not synonymous with pollution. Polhition is a condition created by improper disposal. Industry can dispose of its useless products either upon land, into the air, or in streams. When a plant disposes of its refuse prudently, only the management of that factory is concerned, but when the surroundin s are polluted with such wastes and the rights of others are affected, management cannot esca e liability, and the matter falls outside of its jurisdiction. ?%e plant can then be called upon by the authorities to abate the nwsance. x8PosAL
Dumps are convenient places for disposal when the substance is an inert solid which will not produce a malodorous condition. Such wsRtes must also not leach from the dumps into near-by streams or underground waters. Barren lands or depressions in the ground wrve W r a b l y for such disposal. Tailings from mining operations, ashes from power plants, and solid residues from smelters, steel qills, ceramic, and chemical operations are examples of residues that can be placed upon the land. Often i t is prudent to store solid wsate out of doors, or in the case of liquids to store them in reservoirs or tanka and then await an economical use for the material. The wisdom of such practice depends upon the probabilities of a practical solution of the waste problem. The j u d p e n t of the technical staff and the confidence of management in its chemists constitute the important yardstick. In the manufacture of acetylene from calcium carbide, hu e piles of the calcium hydroxide sludge which discharges from t f e reactors have been accumulated out of doors. I n many localities these sludges have foilnd rofitable applications. other acet lene plants are alert to possike uses for them. dynthetic pzenol produce enormous amounts of waste sodium sulfite. me operators have dried and stored this material in anticipation of an eventually profitable market. After the first World War, vast dump8 of nit.er cake had accumulated from the production of nitric acid for war pIants. These deposits were later purchased by the kraft pulp industry and used as a substitute for salt cake. Many such examples can be found where management is resourceful in attem ting to use its waste materials. An example of confPdence in the ultimate utilization of a byr d u c t chemical occurred in the acetone indust during the first orld War. The Allies were un re ared to %1 their requirements for acetone. Someone in t i e %Wish Admiralty remembered that a Manchester professor, C b i m Weizmann, had obtained acetone while experimenting with unusual bacteria in the fermentation of corn. Weizmann’s bacteria did not produce ethyl alcohol as did the better known t y es of bacteria. Weizmann was searchipg for a source of butyfalcohol to make butadiene for synthetic rubber. (It is interesting that this work of Weizmann was twenty years before the Germans announced Buna rubber.) But the Allies wanted acetone. Now they had a method based on the abundant raw material corn, but the rocesd yielded twice as much butyl alcohol as it did acetone. geveral plants were constructed quickly in the United States. What was t o be done with the butyl alcohol? Someone in authority had confidence in the chemists who told him that butyl alcohol could ber.ome a profitable by-product. Instead of burning the alcohol under boilei-8, which would have been convenient, large numbers of storage tanka were erected and tremendous quantities of butyl alcohol were accumulated. Many thought the plan foolhardy. Soon the publicity of this adventure reached the ears of chemists who were working vigorously to find a quick-drying lacquer for coating the canvas on airplane wings. With such a finish the production of airplanes could be stepped up materially. The butyl alcohol was found to be superior t o existing solvents.
From this cheap war surplus material came the first modern quick-drying cellulose lacquer, which was so effectively used later in automobile finishes.
When waste materials of an organic nature cannot be thrown onto dumps without creating a puisance, they are best burned under boileks or in an incinerator. The burning of great quantities of petroleum slud es by the refineries is a good example. Most refineries burn t&s refuse in open pits, but some of the laqer o atom have found it worth while to cotasruct specially d e s i g n s t e a m generators which utilize these high-sulfur hydrocarbon sludges as fuei. The huge ilea of sawdust produced by every sawmill continue to be a prob?em. Ten per cent of the fore& becomes sawdust before it becomes lumber. The furniture industry wastes 25% of its p~rchrtsedlumber in the form of sawdust. Usually this waste is burned in open ilea or in large operations under boilers for fuel. Technology is &ginning to find answers to the problem. With the tremendous demand for ethyl alcohol to meet the synthetic rubber program of the war, chemists have shown that alcohol can be produced economically from sawdust. America’s first full-size plant is now in production in Oregon. A yield of 50 to 55 gallons of ethyl alcohol per ton of sawdust is reported, and another product (lignin), which amounts t o 2 5 - 3 0 7 of the weight of the original sawdust, has become a robiem tor utilization. Without a use for lignin, the economics ofthe process is questionable for postwar operations. Spent gases from industry are usually urged directly into the air. Sometimes they create nuisances they are either corrosive, malodorous, or laden with fumes or small dust particles which are too small to settle out readily in the standard-hype duet collectors. Such ases can be corrected fore release to the atmosphere. In t f e case of corrosive gaaes%ey can be scrubbed with water or alkaline solutions. Malodorous gases can be proceased satisfactorily, but they usually do not yield a suflicient amount of the odorous substance to pay for the treatment. Necessity for correctin odor nuisances has to be found in the intangible benefit of o o f will in the community for the plant making the objectionaf odor. High-voltage electrical precipitators are used to recover finel divided dust particles from gases. Unfortunately such instalLtions have to be designed on the 4aa volume and not the dust loadin$, which makes the economics marginal in most cases. Installations on power-plant stack gases and also on the smelter stacks in the reclamation of pulp mill li uors have roved effective and advisable in communities w%ere dust a n i odors were troublesome.
Because
s+kLtcrstLecmd. A river is an efficient chemical and biological factory, since it purifies itself constantly. Ox gen dissolved in the surface waters is the purifying chermcal. $he bacteria within the water are the activatin agent. At 20’ C. and sea !evel, the solubility of oxygen in fresh water xs 9.2 parts per mlhon. When organic matter is present in the stream from natural or ekternal causes, the bacteria normally present in the water use the oxygen to digest the complex organic substances into simpler chemicab which are not injurious to fish and vegetable life. As the river moves along its c o m e it continually takes on more oxygen t o replace that consumed by this digestive proceas. Most streams can regenerate themselves within a few mil- of flow; but when (Continzlcd m pug6 106) organia matter such rn sewage or
industrial waste empties into the water, such a burden is added to tht! natural process that the oxygen content is lowered to, perhaps, 50% of normal, and a foul, putrid water condition is vreatod. In the early industrial period of our country, industries were small and the volume of process residues thrown into the streams were relatively low in respect to capacity to absorb the added burdm. Stream pollution was a rare situation. Now, however, huge plant8 place such an excessive load on the stream that the waters are seriously polluted in many places during its flow. Therefore the large enterprises have become the chief source of trouble. Public and indubtrial water supplies, fishing, recreation agriculture, power development projects, and navigation are ali concerned in an equitable division of rights in the use of water from a stream. On the other hand, it must always be kept in mind that industry is a vital part of our economy. It must be given au opportunity to continue. Until technological processes for utilization of the material are found or, failing that, a process for treating the waste to make it more receptive to the individual characteristic of the stream, i t is advisable that an existing plant use t,he stream as the final disposal medium for liquid wastes from municipality as well as industry. The elimination of industrial wastes from the streamb of this country is such an important problem from the standpoint of health, consewation, and public welfare that many states are taking legal steps to abate the nuisance. The subject is complicated, and many industries are alert to the need for finding a ractical and economical answer. The types of wastes are many, gut some basic unit processes for correcting the trouble already exist. These will be discussed in future articles. A convenient method for classifying the quality of surface waters and describing their condition has been proposed. Such a technique would serve as a means of describing streams during a survey and is not designed to indicate the desired quality of the waters. Four groups are proposed and additional standards for the first, three are given in Tabie I. CLASS1. Waters suitable for public water supplies with minimum treatment such as chlorination or disinfection and possibly filtration to remove turbidity. These are preferred for swimming and rerreational sites. CLASS2. Thib type can be treated by normal filter plant operation t o produce satisfactory water supplies. This 1s the normal classification of streams that receive surface runoff and distant pollution. They may he acceptable for swimming if the number of bacteria of the coliform group is low. They are suitable for healthy fish life. CLASS 3. These waters can be treated by advanced methods. They are not desirable as sources of public water supply because of taste-producing substances and low factor of bacterial safety. They are not considered safe for swimming and are not desirable for other recreational uses. They will support fish and other aquatic life, but the most desirable types of fish may be absent. CLASS4. Waters of this type are unsuitable for public or industrial supplies. They are not fit for swimming and will not support desirable aquatic life. ~~
FOR WATERSOF CLABSES 1, 2, AND 8 TABLEI. STANDARDS
STBEAM CONDITIOXS Appearance (oil, floating solids, scum, or debris exaeat from natural
CLASS 2'
CLASS1 None
None
20 desirable) Amount of color and turbidity 10 {desirable) which oan b e removed with normal equipment by standard practices
%day B.O.D.. p.p.ni. 1 .o Monthly average 2.0 Maximum obnervation Dissolved oxygen, P.P.m. Above 7 .On Monthly average 7.0" Minimum observation Coliform group, monthly geometric av. most probable No. per ml. 0.5 Swmming 0.6 Water s u p p l ~
PH
a
2.0
Upper layers of stratified lakes and poola.
106
Amount of color and turbidity which can be removed economically by advanred methods 4.0
4.0
6.0
8.6 5.0
5.5 4.0
10
Not approved
6.5-8.6 50
6.5-8.6
CLASB3 Moderate localireh
200
5.0-9.5
