AL , 1876. with an equal weight of carbonised shale powder. The THE CHEMICAL NEWS. powerful odour of the fresh fæces was rapidly destroyed, VOL. XXXIV. No. 878. RESEARCHES ON THE CHEMICAL TREAT By J. J. COLEMAN, F.C.S., Assoc. Inst. Eng. Scot. PRESENT methods of dealing chemically with sewage resolve themselves into, first, treatment with lime; secondly, treatment with metaliic oxides or salts; and, thirdly, treatment with carbon. In reference to the lime process chemists are familiar with the literature upon the subject. The second method, viz., the use of a metallic oxide or salt has certain advantages when the precipitant can be obtained cheaply and the sewage to be dealt with is largely contaminated with refuse from dye-works, as is the case at Leeds and Coventry. Subsulphate of alumina has been used in such cases. The third method of dealing with sewage, viz., by the agency of carbon, appears to me to be most generally useful, for whilst possessing the power of abstracting noxious matter from the sewage in at least as great a ratio as any chemical that can be used, the carbonaceous deposits are not liable to subsequent noxious decomposition, and the manurial value of the mud is not interfered with. In practice carbon is used in processes such as the A B C, where alum is an essential part of the system. The efficiency of carbon for these purposes is doubtless dependent upon its being in a fine state of division, and in practice a cheap form of carbon, suitable for deodorising, has not been by any means easy to get. Common coke, peat charcoal, carbonised street sweepings, and, as proposed by Mr. Stanford, carbonised excreta, have been proposed or actually used, but all these forms of charcoal require expensive and cumbrous plant in the form of retorts, and condensing arrangements for vapours evolved in the distillation, and involve a large consumption of fuel for carbonisation, so that I have never known of any kind of charcoal being obtainable under at least 10s. per ton prime cost, the market price being generally from 20s. to 60s. per ton. My attention has been directed to a waste product produced largely-in fact, to the extent of 500,000 or 600,000 tons annually in Scotland alone. I mean the carbonised shale after removal from the retorts of our mineral oil works. The quantity of fixed carbon it contains ranges about 10 per cent, and its state of division no doubt is similar to that contained in boneblack, the carbon in the former case being associated with silicates of alum, lime, and magnesia, and, in the la ter, with phosphates and carbonates of lime. An analysis of the mineral constituents shows the following composition, the material having been dried at 60° F. : I have made a number of experiments as to its power of deodorising. In the month of May, 1875, I prepared several mixtures of human fæces with the material. The fresh fæces were first diluted with half their weight of urine. A weighed portion of the mass was taken, and mixed * Read before the British Association, Glasgow Meeting (Section B.) the mixture became odourless, and I preserved samples in partially closed wide-mouthed bottles. During 10 days and at a temperature of 60° F. no fœtid or unpleasant smell was noticeable, and the mass being somewhat pasty I mixed it with more shale powder, so as to bring it to a pulverulent state suitable for sowing by hand as a manure, and the sample has been kept until this date without emitting the least smell of organic putrefaction. Subsequently to this and in the month of June, 1875, experiments were made with the object of comparing its action with that of bone and wood charcoal. The same mixture of fæces and urine was used. As the general result of these experiments it was found that whether animal charcoal or carbonised shale were used the proportion of one part of carbon to two of excrementitious matter was insufficient to prevent a slight putrefactive smell, after the lapse of two or three weeks, but that equal parts of excrementitious matter and carbon formed a permanently odourless mass, whether animal charcoal or carbonised oil shale were used. It appears therefore that for deodorising excreta carbonised oil shale requires to be used in the same proportion as excreta charcoal is recommended to be used by Mr. E. C. C. Stanford. Experiments were also made with urine alone, in the proportion of one part of carbonised shale powder to 4 of urine. The latter was gradually changed into a liquid smelling purely of ammonia and without the slightest putrefactive smell although it was kept some weeks. In order to make experiments with sewage the City Statute Labour Trust of Glasgow supplied sewage collected from the following points : I. Sandyfaulds Street, Caledonia Road; 2. Duke Street; 3. Great Hamilton Street; 4. Gloucester Street; 5. Sauchiehall Street. These samples were mixed so as to get a fair average, and coming from water-closet districts in dry weather, the smell was most offensive. It was divided into two portions. The first portion was agitated for ten minutes with finely divided bone-black in the proportion of 100 grains to the gallon, and the mixture was then thrown upon a funnel partially plugged with sponge, the liquid being collected. The second portion was agitated with a similar quantity of carbonised oil shale in the same proportion and manner. Both these filtrates came through deodorised, and have kept sweet to the present time. Examined some months afterwards after being kept in closely stoppered bottles, the unfiltered sample contained 4210 free ammonia in 100,000 parts, and the sample, filtered through the carbonised shale, contained 0.428 free ammonia. In regard to albuminoid ammonia the unfiltered sample contained 0333 part and the filtered sample o 285 part. In reference to the adaptability of the material for the drycloset system, the ease with which it can be reduced to a soft charcoally powder is a great recommendation. Since these laboratory experiments have been made they have been confirmed by experiments on a large scale, and more particularly with the refuse from the water-closets and surgical wards of the Glasgow Royal Infirmary—the excrementitious matter from which is about as repulsive as any that can be met with. It is semi-liquid in character, and an experiment conducted by the author in conjunction with the medical superintendent proved that on mixing about 2 cwts. of this material with the same weight of the carbonised shale, it was, in the course of a few minutes, completely deodorised. Experiments have been also made by the Sanitary Inspector of the City of Glasgow. His report to the Police Board, dated January of the present year, includes description of experiments made with about 7 tons of the ground material in three of the public privies of the city, and extending over a period of fifty-seven days. The Sanitary Inspector fully endorsed the conclusions arrived at by the author as to the powerful deodorising 126 Chemical Treatment of Town Excreta. { CHEMICAL NE s, effect of the substance, and strongly recommended its | solid matters to subside, and afterwards filtering the preregular use by the city authorities. Glasgow public conveniences are, however, most of them on Macfarlane's water-trough system, and the difficulty of adapting self-acting mechanical arrangements to them prevented the adoption of a dry method, as also the fact that a Royal Commission on the subject of dealing with Glasgow sewage was then sitting. In treating sewage with the material upward filtration might be resorted to, or the carbonised shale might be employed in constructing, upon the sandy foreshores of the river, filters to be eventually converted to soil, or the material could be used as an adjunct to earth intermittent filters, or as an ordinary filter, combined, if necessary, with depositing tanks. Perhaps the best plan of utilising it would be the latter, the material being ground to a fine powder, and poured into the main sewer about 100 yards from the outfall, so as to establish thorough mechanical agitation; the mixture could then be allowed to deposit in tanks, and the clear overflow filtered through a filter of the same material in a coarsely powdered or crushed state. It will be in the recollection of members of this Section that our distinguished past President, Sir John Hawkshaw, has been acting as Royal Commissioner appointed to inquire as to the purification of the River Clyde. The report of the Royal Commissioner, which deals with the whole valley of the Clyde, recommends, however, chemical processes or irrigation for some of the smaller towns of the valley only, and goes on to express an opinion that he can see no other course in dealing with the sewage of Glasgow than running it to the sea with engineering works, estimated to cost 2 millions sterling, and including a tunnel 30 or 40 miles long. The Royal Commissioner, however, appears conscious himself that chemical science may eventually solve the difficulty, for towards the close of his report he remarks these engineering/works would not be thrown away by improved methods of treatment at the outfall. If chemical science can suggest a means of lessening the enormous expenditure of two and a half millions Sir John appears to think necessary, I feel no doubt the Royal Commissioner would be gratified. The tunnel scheme is a suggestion: the absolute recommendations of the Royal Commissioner being statesmanlike proposals for organising a Board of Sanitary Commissioners for the Clyde Valley, with certain definite powers, leaving it with local townships to carry out any particular plan of purification that may be agreed upon and approved of by the central authority he proposes to create. Sir John Hawkshaw, in the course of his enquiry, investigated the chemical processes in use in other towns, and discussed with much care the problem of dealing with the sewage of the second city of the Empire, which amounts in dry weather to 48,000,000 gallons daily.* Whilst approving of dry-closet systems in regard to public works and in particular circumstances, the Royal Commissioner does not see how such a revolution can be effected in large towns as the abolition of water-closets. After dismissing irrigation as impracticable from want of suitable land, and a strong objection to making experiments with ratepayers' money in farming, the report enters into the discussion of chemical processes versus gravitation to the sea. The arguments Sir John uses, independently of any bearing they have on the author's proposals, are of interest generally in regard to the question of dealing with the sewage of any large city, and I may also add particularly to irrigationists, in respect to the dealing with the sewage mud, which it is impossible to deliver over square miles of land by the pipes employed in irrigation. The Royal Commissioner uses these words-" By the addition of suitable deodorising and precipitating agents, such as alum, clay, lime, and charcoal, then allowing the Bateman and Bazalgette's "Report," 1868. Sir John Hawkshaw's !! Report," 1876, pared liquid through prepared filters to be used inter- (1.) It is argued that, assuming the daily flow of Glas- (3.) That on information received from Mr. J. B. Lawes tons. (4.) That judging from the balance-sheets of the sewage works at Leeds the cost of dealing with Glasgow sewage chemically would be £80,000 per annum Now in respect to the first argument. Glasgow sewage was analysed by the Rivers Pollution Commissioners under the superintendence of Dr. Frankland in 1870 ("Riv. Poll. Com.," Fourth Report, p. 26). It contains, in round numbers, 142 parts of solids per 100,000, which is equal to about 100 grs. per gallon. Again, Dr. Hofmann, in his Report on London Sewage, estimates its average composition as 100 grs. solids per gallon. Glasgow sewage, owing to the plentiful rainfall and abundant water-supply from Loch Katrine, is weaker than that of other towns; so that it is impossible that 48,000,000 gallons per day of sewage could give more than 100,000 tons per annum of solids, supposing the effluent be discharged as pure as distilled water. From this quantity must be deducted the soluble saline constituents, reducing it, say, four-tenths, or to 60,000 tons; and there must be added the moisture contained in artificial manures, say 25 per cent, which gives us as the probable correct figure 80,000 tons as the annual probable quantity of solids separable from Glasgow sewage in the form of manure. That this figure is correct is confirmed by Prof Way'st report on the sewage of towns, which would bring out the quantity 91,000 tons. Mr. J. B. Lawes's estimates would bring out 89,000 tons according to the ratio of 2 to 3 lbs. solids per ton. Finally, the experiments of Mr. Keatest at Crossness showed that 142 tons of prepared manure was obtained from 11,672,751 gallons of London sewage; 61 tons representing the mud precipitated from the sewage. This would indicate 80,000 tons per annum for Glasgow sewage, which I assume to be correct in place of the 186,000 tons assumed by Sir John Hawkshaw. In regard to the next argument of the Royal Commis. sioner, that the solids would be more than doubled by the lime process, this is difficult to see, as lime is only added as a fraction of the solids. It may be correct as regards carbon processes, but even then the annual production of manure would be 160,000 to 200,000 tons instead of the 400,000 or 500,000 tons estimated by Sir John. In reference to the third argument that the manure could not be disposed of. If sewage mud be classed with artificial manures of several pounds value, which appears to be what Messrs. Lawes and Caird include in their figures of 700,000 or 800,000 tons annual consumption of the United Kingdom, then I agree with the Royal Commissioner. But this is not the case. Sewage mud manure has only a few shillings value, and should be compared with city street sweepings manure, of which the City of * Hofmann and Witt," Report on London Sewage ;" also "Corfield on Sewage," 179 to 184 inclusive. + See Reports of Sewage of Towns Commissioners." Glasgow alone dispose annually to farmers no less than 200,000 tons, at prices varying from 2s. to 2s. 6d. per ton.* The final argument of the Royal Commissioner is that a chemical process would cost Glasgow £80,000 per year, including interest upon capital and expenses, taking the experience of Leeds as a guide. This is founded upon the assumption that the cost of the process would be the same here as at Leeds, and, secondly, that the product is unsaleable. Judging from the experience of Leeds, the cost of chemicals required for dealing with Glasgow sewage would be 43,800 annually, equal to about 10s. per ton of sewage mud. Against this must be set the value of the manure. At the price of street-sweepings it would be £25,000, and at a little more than double the price would cover the costs of the process; whilst, on the other hand, the interest upon an expenditure of two and a half millions of money in engineering works would be £100,000 per annum. Before leaving this subject it may be remarked that experiments made in the neighbourhood of the metropolis have been on such a small scale that they are utterly useless in judging of the results which could be attained with the sewage of a large city. This is noticeable in reading reports of the costs of manipulation, and more particularly the cost of drying sewage mud. Of course, large cities like Glasgow, near extensive coal-fields, have enormous advantages in cheap coals, but the evaporation of a given amount of water when heat is properly and continuously applied is subject to definite rules, and the results I have seen in printed statements of costs show such a grave departure from the results of engineering practice, that I should feel confident of much more successful results in the intelligent management of the sewage of extensive centres of population, such as are found in this city. described, peroxide of hydrogen, and camphoric acid (both of which may result from the action of water upon cam. phoric peroxide, CroH1404), acetic acid, camphor, and certain other less defined substances. The oil itself increases in specific gravity and contains after this treatment certain oxidised bodies, among which is a further quantity of this camphoric peroxide. I have been able to indicate the rate at which this oxidation takes place, and to investigate more fully the nature and uses of the solution I have described. And in doing so I have experimented with large earthenware vessels arranged in a series like so many Wolffe's bottles, each of about 20 gallons capacity. The oxidation proceeds very slowly at first, the rate being indicated by the estimation from hour to hour of the peroxide of hydrogen which is formed; but when once the oxidation has fairly set in, it proceeds more rapidly, with increasing production of peroxide of hydrogen and the other products, the amounts of which are Now, simply limited by that of the turpentine itself. assuming the operation to be started with a given quantity of turpentine in the presence of a given quantity of water at, we will say, 60° C., the turpentine begins slowly to oxidise and produce the bodies named, which then pass into solution, while the oil itself increases gradually in specific gravity, a phenomenon which is accompanied by a gradual rise in its boiling-point. Now, if no fresh turpentine be added to that already in operation there will come a time when the percentage of peroxide of hydrogen is at a maximum, and then if the blowing be continued after that time it slowly diminishes, in fact at about the same rate that it forms. If, on the other hand, the turpentine which is blown away as vapour be condensed and returned to the oxidiser, or what amounts to the same thing, if fresh turpentine be added the oxidation proceeds as rapidly as ever, while there is no limit to the amount of peroxide of hydrogen which is formed. It is remarkable that turpentine in the act of being oxidised is capable of imparting to fresh turpentine the same and equal facility to absorb oxygen. The slow rate at which the oxidation of fresh turpentine proceeds, and the greater rate attained after the molecules have undergone the change which induces a rapid oxidation is seen by the following figures which relate to an experi. ment conducted on some gallons of turpentine and water REPORT ON THE LIMITED OXIDATION OF By CHARLES T. KINGZETT, F.C.S., London A. Oxidation of Turpentine.-Since my last publication on terpenes and the products of their limited oxidation, I have had the opportunity of repeating the whole of my observations upon the aqueous solution that results when turpentine is oxidised by a current of air in the presence of water. This opportunity has been afforded me while experimenting upon no less than fifty gallons of turpentine; and while in no one particular have I to withdraw or alter any of my original statements, certain matters have come more strongly before my observation which are worthy of some notice. Before proceeding to summarise these it will be well to recapitulate the main products of the oxidation. My past researches, then, have established that turpentine yields when oxidised in the way I have The increase in the boiling-point of the oil as the oxidation proceeds is illustrated by the following determinations, which relate also to a different experiment. The turpentine used in this experiment boiled as indi "Reports of the Cleansing Committee of the Police Board of Glasgow." + Read before the British Association (Section B.), Glasgow Meeting.cated in column (1). 128 (1) Original Oil. 10 p. c. over at 157° C. Limited Oxidation of Essential Oils. In regard to these boiling-point determinations I should remark that in each case 100 c.c. were subjected to distillation in the way that is usual in these matters, and the temperature recorded after each ro c.c. was collected. It is necessary also to point out that the oil, although it has been oxidised in the presence of water, is yet so full of the organic peroxide I have discovered and described in my previous researches, that when it has once reached a temperature of 160° C or less, a violent effervescence sets in from the escape of oxygen, and much heat is eliminated, as indicated by the rise in the thermometer after the lamp has been removed. I shall conclude this part of my paper by stating that having been led by the value of the solution as an antiseptic and disinfectant to attempt the manufacture of it and the residual oil I have described, on a commercial scale, I have devoted a great deal of time to the study of those conditions which are calculated to lead to the most desirable results. In this attempt I have received much help from Mr. J. Brown, F.C.S., which I have the pleasure to acknowledge. For I have been so far successful as to obtain under certain conditions readily from an inconsiderable amount of turpentine, water, and air a solution containing such large quantities of peroxide of hydrogen and the other substances above named, as to qualify it for purposes and uses upon which I propose to dwell in Section B of my report. I find that a solution containing so much peroxide of hydrogen as to be capable of evolving from 1 litre either 1531 c.c. oxygen or 3062 c.c. oxygen, according as one or both molecules of oxygen (in H2O2) are affected, has all the properties which I propose to describe; but before doing this I must add that these properties are far from being entirely dependent upon the peroxide of hydrogen contained. They are related also to the camphoric acid and other constituents, for they are not seriously impaired by the total destruction of the peroxide of hydrogen. This I have substantiated in an experimental way, and shall now proceed to describe the experiments themselves. These I shall only preface by stating that a solution which contains 323 grains of {CHEMICAL NEWS, Sept. 1876. peroxide of hydrogen to the gallon also contains 367 grains of camphoric and acetic acids. But the percentage of each constituent and the strength of the whole mixture are matters to a great extent under control in the method of preparation. B. Antiseptic and Disinfecting Powers of the Solution.In studying the properties of the solution I have described I discovered that it possessed great power as an antiseptic and disinfectant, and I was led to investigate this matter somewhat fully, also to enquire into similar properties possessed by the known constituents of my solution, and in comparison with those of salicylic acid. In the experiments given at foot of page the solu tion employed was of that general strength I have indicated above, and contained 25 grms. H2O2 per litre. All these experiments were made during October and November, 1875. Those now to be given were made during June, July, and August, 1876. The antiseptic solution employed was not so strong as that used above. The only other alteration in each case was a slight darkening to brown in the colour of the albumin. But after each experiment the albumin had still its coagulable character and was not otherwise changed. After dipping in the same solution, brain matter also kept fresh for several days, whereas without such treatment, it stunk on the next day. Milk was also preserved for a much longer period than without, but not for so long a period as in the winter months. Beer was also thoroughly preserved for a number of days, as long as observed; so also was blood serum. Stinking water recovered and remained good with it for months. In conclusion I would only add that I have never examined seriously the influence of less percentages than those detailed, but there can be no doubt that much less quantities could be used in many cases with the same effects as those described. In fact this would be necessary with articles of food on account of the aromatic odour and peculiar taste of the solution. 5 c.c. neutralised by soda 10 c.c. neutral antiseptic = 5 per cent. Io c.c. antiseptic = 16 per cent. 10 c.c. antiseptic. 10 c.c. antiseptic cent. = 10 per 10 c.c. antiseptic: = 10 per cent. 10 c.c. antiseptic cent. = 6 per 10 G.c. antiseptic = 6 per cent. NEWS remains behind in the form of an insoluble amorphous white powder. From this the ammonium glyoxylate may be readily obtained by treatment with aqueous ammonia. Now, it is stated by Mr. Perkin that when this ammoniumsalt is evaporated in vacuo, the solution, although neutral at first, always becomes acid, and that without loss of ammonia, and ultimately yields a crystalline product having the same outward appearance and empirical formula as the soi-disant ammonium glyoxylate which Dr. Debus professes to have got by similar treatment, and an aqueous solution of which, he assures us, gave all the reactions of a genuine ammonium-salt. Mr. Perkin, on the other hand, was not slow in drawing attention to the fact that his crystalline powder, which I take to be a glyoxylamide with the formula— H2O2. Fo202,2F004-2H2Ne was very prone to assimilate water with reproduction of the original ammonium-salt,-a circumstance quite in keeping with his view of the matter. In weighing the arguments brought forward by these two distinguished London chemists, I cannot help believing in the identity of the crystalline powders obtained by Mr. Perkin and Dr. Debus, and that they possess the chemical constitution which my formula attributes to them. As regards the a formula which must not be confounded with that of the unexpected manifestations of acidity, &c., during the someric glyoxal,— H2O2. 2C2O2,2F00. The formation of this body is due to the splitting up of these bromacetates into the hydrates of their respective bases, and the subsequent transposition of the latter with the colligated formyl-chloride of the residual oxybromaceten, Fo2Br2,C2O2. When heated in the presence of water the aforesaid bromacetates will again produce the metallic bromides, but instead of glycolide we shall now obtain the water-salt of glycolic acid. Let us, in the next place, contemplate the effects of heat upon dry ammonium bromacetate in the presence of ammonia. The chief products of this reaction are found to be ammonium bromide and ẞ glycolamide or glycocoll, to which I assign the formula H2O2. H2O2. "When bromo process of evaporation, I may remark that a similar phe- Et2O2. 2(Et2O2). which implies that, in harmony with established facts, this body is endowed with the twofold character and functions of a feeble organic base and a feeble organic acid. In this metamorphosis we have again, in the first stage, the formation of ammonium bromide and glycolide; By this formula the compound before us is shown to be a but as regards the precise nature of the molecular changes triatomic ether-salt of glyoxylic acid, in which the acid attending the second stage of the process, and which are due to the substitutional action of ammonia on the newly2H; 2C2O5, as it exists in the water-salt, but the bibasic principal is no longer the monobasic oxyformic acid, formed glycolide, I am obliged to reserve my explanations carbonic acid, capable of saturating two molecules of for another opportunity. The same remark applies also ether base. Let us now imagine the replacement of one to the a glycolamide,of these two ether molecules by the molecule of basic water which is engendered during the conversion of the aforesaid oxyformic into carbonic acid, and it becomes identical with the well-known carbovinate of water,evident that the resulting compound, which I hold to be H2O2. Fo2O2,2F002-2H2N2, which derives its origin from the substitutional action of ammonia on the water-salt of glycolic acid. Let us now proceed to consider the effects of temperature upon the metallic dibromacetates. According to Mr. Perkin, when dibromacetate of silver is strongly heated it splits up into silver bromide and an insoluble powder, which is evidently bromo-glycolide, |