Alfred Stowell Jones

“ It is a common idea that working a sewage farm for profit, and for purification of the sewage, are two incompatible things, whereas, the good manager with sufficient working capital (double or more what would be enough for the same acreage in ordinary agriculture) and a good market for produce will attain the two together in due proportion in all ordinary seasons, when a fair allowance has been made him for the necessary sanitary work. ”

“ How extremely simple it all is!” was the remark of a recent visitor at a sewage farm—which encourages me to venture on publication of the most recent discussions on a “problem” complicated by engineers, chemists, bacteriologists and inventors of systems, who have raised clouds of dust through which it is difficult for ratepayers and district councillors to find their way to “the best practical and available means of sewage disposal.” ”

“ The possibility of further mischief by pathogenic micro-organisms on sewage farms is exceedingly remote, if it exists at all. Bearing these observations in mind, it is quite clear, therefore, that neither theoretical investigations, as available up to now, nor practical results, support the theory that pathogenic micro-organisms may do mischief on sewage farms, and one is forced to conclude that this possibility—if it exists at all—after systematic treatment on land is an exceedingly remote one.
Sewage farms reduce the quantity of final effluent. ”

“ When considering natural and artificial sewage treatment, it ought to be borne in mind that in the natural treatment we have to deal with one treatment only, and that, in order to bring the results obtained from artificial processes up to the same standard, the artificial treatment ought to be supplemented by a treatment for the removal of nitrates from the effluent, and another for the removal of pathogenic micro-organisms, which means one treatment in natural, as against three separate treatments in artificial purification. ”

“ With the return of life and the awakening of nature in spring—especially with the approach of higher temperatures and the formation of moisture—micro-organic activity once more makes itself felt all round. During the summer months it is exposed to some injurious influences such as the heating and drying up of the upper layers of the soil, but, still gradually increasing, micro-organisms reach the climax of their activity during the autumnal rains, to remain in this state until with the advent of the cold season their activity gradually declines again. ”

“ Now, it will not be denied that all agencies are natural ones, whether the process employed is a purely chemical one, a purely “bacterial” one, land treatment pure and simple, or a combination of these, and, at the present time no such [Pg 38] thing as an artificial agency is known; indeed, it is perhaps not too much to say that there cannot be such a thing as an artificial agency. Hence it is impossible to divide sewage purification methods in this respect by the agencies employed, and one is bound to fall back upon the way in which these agencies are employed. ”

“ Before any sewage scheme is conceived a very careful survey of the neighbourhood ought to be made by a person who knows the requisites of a site for sewage disposal, especially if land irrigation is intended, because natural advantages of site both for tanks, main carriers, roads, etc., may make all the difference in the world in expense and efficiency not only in first cost of works but also in their use afterwards. ”

“ It may seem idle to complain of boards and their employees showing little interest in the work of sewage disposal, but it is worse to pander to their failings by selling them automatic machines under the pretence that all the thought, and fertility of resource, required for efficient sanitary sewage disposal can be supplied by ingenious applications of hydraulics on the principle that sewage is a fluid, and, as such, will behave like clean water. ”

“ Of course, when the aerobic treatment is carried out on a bare level surface of cinders or coke growing only weeds, the lack of interest is very excusable, but in the natural system the growth of crops and contouring a sloping surface with carriers so that every part shall have its trickling water alternating with dry periods for cutting the crops or hoeing out weeds, should be a matter of constant interest to an agricultural worker, and, if he knows his business, good crops and purity of effluent must go together. ”

“ If more sewage is poured upon the land than the effluent drains can deal with—and here it may be well to bear in mind that on sewage farms in our climate on a broad average throughout the year about one-third of the total quantity is lost by evaporation—the excess will pass down between the drains from the evaporation to the passage zone, and if the flow of the sewage is not discontinued the downward movement in the passage zone may be continued until, after having traversed the capillary zone, the level of the subsoil water is reached. ”

“ Organically polluted soil retains more water than clean soil. This will explain why a polluted subsoil containing a large amount of organic substances will retain more water than the same soil in a clean condition.
The retentive power of a soil is due to its surface attractions. The retentive power of a soil is due to the surface attraction of its particles, and when the space between them is small, or when, in other words, the pores are small, this attractive power will be all the greater. ”

“ In adhering to land as the natural and best agent, I have had the support of the Local Government Board with that of many Royal Commissions, notably the one now sitting, and I have naturally chosen cases where suitable land was accessible when I desired to demonstrate the efficiency and simplicity with which the powers of Nature can be applied for the use and convenience of man. ”

“ The process of decomposition proceeds as a rule at a much quicker rate on the surface and in the upper layers of the soil, where, as already mentioned, the number of micro-organisms is greatest.
When carefully worked there is no time limit to the purifying powers of the soil. It has been maintained that the soil of sewage farms will after a while silt up and cease to purify sewage, but the results obtained with carefully managed farms clearly disprove this, and under these conditions there appears to be no limit as to time to the purifying power of soil. ”

“ At Wrexham, in North Wales, I had nineteen years’ management of about 150 acres of good land, with a mixed residential and manufacturing sewage of some 15,000 population, with large breweries and leather works. The owner of this land at the termination of lease asked so exorbitant a price for the improved freehold, that the corporation decided to sacrifice the sewage works on his land, and to carry out a scheme of mine for carrying the outfall sewer two miles further to a site of 200 acres, which they could acquire on reasonable terms in the year 1889. ”

“ The work in the septic tank is chiefly done by obligatory anaerobes.
[Pg 83] (c) Explanation of Process.—Although the processes taking place in septic tanks are at present but imperfectly understood, they may be said to be in the main due to anaerobic micro-organisms, i.e. due to such micro-organisms which carry on their life’s work in the absence of oxygen. They split up or peptonise the organic compounds in the absence of air, and the group of changes brought about by them has been termed “anaerobic fermentation” or “putrefaction.” ”

“ I have for many years advocated education of sewage farm managers and watermen, to be selected from the rapidly decreasing class of agricultural labourers by the tender of high wages, houses and good gardens, with other profit-sharing allowances which it will well pay sanitary authorities to hold out to their sewage employees. ”

“ It is easy to get up a case with expert evidence against any sewage scheme where the land-owners, clergy and others have no means of properly informing themselves, and have a prejudice against sewage which it is very difficult to overcome except by giving the utmost possible publicity to the truth. ”

“ Absorbing powers of filling material. The filling material retains in its upper layers the suspended matters, which it strains out of the sewage in a purely mechanical manner, much after the fashion of a screen, and when the bed is filled its absorbing powers come into play, which cause the removal of the dissolved matters out of the liquid and their retention on the surface of the particles. This latter process is probably a chemico-physical one assisted by the micro-organic life in the sewage.
Decomposition of organic substances by micro-organisms when bed is empty. ”

“ When now and again opinions are expressed, which seem directly opposed to each other, it must be borne in mind that here, as in other things human, unanimity of opinion, though much desired, is apparently unobtainable. ”

“ In addition to this it must be understood that, owing to the great losses by evaporation and by growing plants, which are continually at work on sewage farms, especially during the summer months, when, as a rule, the flow of water in the brook that takes the effluent is smallest, the quantity of the effluent from the natural treatment is probably only from one-half to one-third that resulting from the artificial treatment, which is a point of very great importance. ”

“ When town sewage is pumped through a long rising main, it can often be spread on the land in its really crude state, and if the soil is clay ploughed up to receive it the sludge is most beneficial to its texture. ”

“ Passing now to the aerobic stage of sewage purification we find it universally admitted, that a good loam resting on very porous sand or gravel, affords the best medium for work by the oxygen-loving nitrifying organisms [Pg 6] when they are supplied with constantly moving liquid sewage, and given intermittent periods for the aeration of the pores of the soil. ”

“ When a town has more land in proportion to its sewage, permanent pasture may take the place of Italian rye-grass, and, with proper precautions, a part of the permanent pasture may be grazed; but the saving of labour, thus supposed to result from letting animals bite and carry their food, is expended in making up, in a necessarily imperfect manner, the carriers trodden in by the cattle. ”

“ Soil best suited for sewage farms.
Whilst practically no soil is entirely useless for sewage farming, with the exception perhaps of peat, owing to the quantity of moisture it contains, a soil that combines great permeability for air with high retaining and absorbing powers—such as a loamy sand with fairly large grains—is probably the best. ”

“ The amount of oxygen necessary for bacterial activity is partly abstracted, and with extraordinary energy, from the atmospheric air in the pores of the filling material, and a portion of the substances formed, such as carbonic acid and nitrogen—in gas form—escape into the atmosphere, whilst the remaining portions are washed out of the bed with other products, such as nitric acid, by the effluent. ”