ADDRESSES. sives," which, when properly used, will minimize the danger from this source. In this connection, efforts have been made to devise a laboratory method to test the inflammable character of samples of coal dust, and to classify them according to their inflammability. This method is based on determining the amount of combustion which takes place when clouds of dust of the same density are ignited under the same conditions, the amount of combustion being determined by the pressure developed within the explosion vessel. In this way it is possible to obtain results on any one sample of coal dust which agree to 3-5 per cent. of the total pressure developed. By varying the temperature of the platinum coil, used as the source of ignition, it is also possible to study the change in the amount of combustion taking place when the source of ignition varies. The result has been to show that when a highly inflammable dust is under investigation, the pressure developed soon reaches a maximum, and an increase of the temperature of the coil causes but little increase in the pressure developed, indicating that the combustion has propagated throughout practically the whole cloud of dust. With a slightly inflammable coal dust the pressure developed continues to increase with increasing temperature of the coil over the whole range of temperature a t which it is practicable to operate. One of the proposed means of lessening the inflammable character of coal dust is to ad'd a noninflammable dust. The laboratory method used to investigate the inflammability of coal dust has been extended to various percentages of coal dust and finely ground shale in order to determine to what extent the combustion is limited by the presence of the inert dust. The experiments indicate that a marked diminution of pressure is not obtained until about 2 5 per cent. of inert dust is added, the pressure then falling off rapidly with a further increase in the amount of shale dust added. This investigation is in charge of Dr. J. C. W. Frazer.
______
DISPOSAL OF STARCH FACTORY WASTES.' B y T. B. WAGNER.
When your esteemed President asked me, about two months ago, to read a paper before this meeting, I accepted his invitation with much hesitation, not only because of pressure of business, but particularly because I do not consider myself well qualified to speak on such subjects as come up before your Association. While I desire to make my remarks as brief as possible, I believe that I shall have to go back into the history of the industry of corn products, to give you a better understanding of the subject under discussion. In the early stages of the corn products industry, that is, primarily the manufacture of corn starch, dating back fifty years or more, the manufacturers concerned themselves solely with the starch contained in the corn; the other constituents of the corn were t o them of no concern. These constituents are, the
* An address delivered before the Lake Michigan Water Commission, Chicago. December 1 7 . 1910
99
outer hull of the corn-the so-called bran-the gluten located immediately underneath it, and finally, the germ of the kernel itself. When you consider that corn contains approximately I O per cent. of nitrogenous matter, you will note that in a small factory consuming only about one thousand bushels of corn a day, this ingredient alone would amount t o approximately 5600 pounds per day. The bran forms about the same percentage of the corn and there would be a like waste from this source. However, there are no starch factories operating on so small a scale to-day, the smallest consuming about five thousand bushels a day, whereas the larger factories, which usually produce not only starch but glucose and sugars as well, grind about twenty-five thousand bushels a day. Our Argo factory represents the latest achievement in the corn products industry and its grind, a year from now, will approximate fifty thousand bushels a day. I give you these figures so that you may fully appreciate the importance of the recovery of the by-products. If these by-products were not recovered, our industry could not exist, not only for financial reasons, but particularly because the waste of the by-products would lead to intolerable conditions from a sanitary point of view. Our industry has made remarkable progress. At the time the above conditions prevailed, that is, when starch factories did not recover any by-products, the total recovery of the corn did not amount to more than 5 0 per cent. ; that is to say, all that a manufacturer produced from a bushel of corn weighing 56 pounds were about 28 pounds of commercial starch, part of the starch and all other ingredients of the corn going to waste. With the introduction of the recovery of the byproducts, this yield was, of course, greatly increased until it finally reached about 9 2 per cent. Only about ten years ago this was considered a good showing for any starch or glucose factory. With the construction of modern plants and the introduction of modern machinery, and through the closest attention of the operating men to the smallest details of the process, it was possible to increase this yield to 95 per cent., which as recently as four years ago, was considered a most excellent result. Since then, the yield has been further increased so t h a t the new standard is 98 per cent., although we have had months where some of our factories recovered as much as 9 9 1 / ~ per cent. You will note from this that the trade waste from a modern starch or glucose factory cannot be considerable, expressed in per cent., yet it reaches large proportions when applied t o the corn consumed. Mr. Sjostrom will give you the exact figures as to the amount of this waste. When we undertook to treat our trade waste a t our Waukegan factory, it was not done for the purpose of recovering this waste, but our efforts were the result of an action taken by a number of residents of the town of Lake Forest, located on Lake Michigan, eight miles south of Waukegan. These parties claimed that our trade waste was Earried in the waters of Lake Michigan and while in transit became putrefied and created obnoxious odors which made life very un-
I00
T H E JOURNAL OF I N D L'STRIAL A N D ENGINEERIXG C H E M I S T R Y .
Feb.,
pleasant for them. They brought an action in the We do not claim that we have solved the problem Federal Courts, for the purpose of having the Warner of the proper treatment of trade waste from starch Sugar Refining Company (the predecessor of the Corn and glucose factories, but we believe that me have Products Refining Company) either instal the necessary gone as far as we can go with the present knowledge apparatus and process to remedy the trouble, or of the subject. I think we are the first ones, so f a r cease operating the factory. The principal factor as our industry is concerned, who have ever underin producing the trouble was the steep-water; that is, taken to treat waste waters on so large a sca.le as is the water in which the corn is soaked and which being done a t Waukegan. The undertaking was contains by far the largest amount of the soluble not a small one and involved a very large expenditure ingredients of the corn. At the time the suit was of money. I do not believe that a mechanical o r brought this steep-water amounted to 2 0 0 , 0 0 0 chemical treatment will ever yield a trade waste gallons a day. While this suit was pending, free from objections. The ultimate solution must the Corn Products Company succeeded the Warner come from within the factories; that is to say,we shall Sugar Refining Company, and the first step it keep on devising ways and means of recovering in took was to instal the necessary evaporating ap- the factory all the soluble matter still discharged paratus to recover this water in the same fashion as in our waste waters, and while it may take years t D is the practice in its other factories. This relieved accomplish this end, I believe that eventually we shall the situation very much. Upon investigation, h o w - be successful. CORN PRODUCTS CO.. CHICAGO. ever, we found that the remaining waste was discharged into the lake immediately a t the shore and that there was no means of diluting this trade waste, which m-as TREATMENT OF WASTE WATER FROM A STARCH AND, GLUCOSE FACTORY.' carried in concentrated form, so to speak, southward BY OTTO A SJOSTROM. toward Lake Forest. We, therefore, laid a new The waste water from a starch and glucose plant is, ser~,erpipe, about thirty inches in diameter, and carried it into the lake a distance of two thousand composed Of effluents from different departments of In 'peaking Of the components Of the feet; a t this point the lake is about fourteen feet deep, the and it stands to that with the current usually discharge through the main Sewer we distinguish existing in Lake Michigan, tve secured an between condenser-water, , gluten cones overflowa great imwater, starch cones overflow-water, and feedpress-. dilution of these waste waters, provement was made in this way, the conditions still water' ' Of these the condenser-water represents by far the remained unsatisfactory. This was because the waste m,aters contained a not inconsiderable amount of sus- largest amount but can be left out of consideration in pended matter which cannot be recovered or isolated this connection, as it does not contain any products by filter presses or other means usually employed for from the manufacture' It happens occasionally, of course, that the vacuum pans entrain soluble solids such purpose. Mechanical means being unsuccessful, SO that some sugar is lost with the condenser-water. our only hope lay in a chemical treatment, the governing thought being that if ~~e employed a precipitant, As this is a serious but avoidable loss, due to irregu1arit)i of the machinery, a close watch is always such as lime, this finely suspended matter might be thrown down together with the precipitate formed kept on this water and whenever tests indicate traces by the action of the lime. The results obtained in of sugar steps are immediately taken t o remedy the experiments conducted on a small scale were so trouble. The different names of the other effluents do not complete and surprising as to tempt one t o consider this theory an inspired one. It is remarkable how indicate that the composition of the solid matter is different. A short outline of the method of manucompletely this suspended matter is thrown down facture Of the nature give a better and how quick]y the precipitate settles to the bottom, of the waste. Filter pressas being out of the question, the Success of The is first steeped f o r time with this scheme depended upon the rapidity mith which this slightly acidulated mith sulphurous acid. hi^ sof-form and how the supernatant tens the corn thoroughly and prepares it for grinding. precipitate water was. The tests mere carried out in a large tank The is first ground and through mawith cone-shaped bottom, holding about 2 8,000 chines for removing the germ. I t is then ground gallons of water. The results were highly satisfactory; s,er!. fine in stone mills. The so-called mill slop immediately after the addition of the lime the precipi- issuing from the mills is run Over shakers and reels in to the bottom and the supernatant water order to separate the starch and gluten from the hulls. tate -4 series Of tests Were The hulls are washed to make this operation complete, Was as dearas spring Water. then made with the treated water, with the particular The starch milk is run Over the so-called tables, where. view of ascertaining how quickiy the dissolved oxygen the starch settles. The gluten is lighter and remains would oxidize the organic matter. The large amount suspended in the water which tails Over the end of of dissolved oxygen in Lake Michigan water and the the tables. This gluten milk is then run into setenormous dilution secured by our method of discharge tlers, which built with a conical bottom, The brought about this fesult if: a very satisfactory man- operation of settling is continuous. The bulk of the, ner' not any further into the Of this 1 Corn Products Refining Co.'s P l a n t at !Taukegan. Ill. An address process, as Mr.Sjostrom Ivi1l deal with that in his read before L a k e Michigan Water Commission, Chicago, December, 1910. I
