A special type of machine has been evolved whereby the tops and bottoms of the bright recovered tins can be cut off. The resultant cylinder is then cut through on either side of the original seam, and the sheet pressed out to form a flat plate. The eliminated joint, of course, is set on one side to be treated for the recovery of the solder, while the small pieces of tin find their way to the scrap-metal bin. The sheets of bright tin which are thus recovered, and which are quite equal to new tin-plate, command a ready sale, because they can be restamped into smaller flat tins for packing boot polishes and similar commodities extensively retailed in this form. The process is simple, rapid, and can be made profitable.
Rusted tins require to be treated in a different manner. Some corporations merely crush them flat to facilitate and to cheapen transport, selling them in bulk to firms who specialize in the handling of such product. However, it is a matter for investigation, when such tins are recoverable from the garbage in appreciable quantities, as to whether it would not prove more remunerative to the local authorities to deal with the tins themselves. A furnace is required to burn off the tin-dirt and to recover the solder. The tin itself, representing about 1 per cent., is lost, although there are processes in operation for its reclamation. The receptacles may then be crushed and baled into billets for which an hydraulic press is necessary. A plant capable of making a bale measuring 24 × 14 × 6 inches is well-adapted to this duty. The solder is in demand, while the plate is worth from £3—$15—upwards per ton as scrap metal. At this figure the local authorities would undoubtedly find it far more profitable to incur the extra expense and labour involved to prepare the billets rather than to dispose of the tins in their crude form. When the quantity is heavy direct sale to the steel-works is possible and the middleman’s profit diverted to the benefit of the ratepayers.
Paper should also be baled for reasons of transport. Either hand or power appliances may be used, but unless the quantity likely to be handled is pronounced, the hand-operated machine will be found adequate for the task. Of course, it must be admitted that, to-day, prices for the recovered materials rule somewhat high. Consequently it may be averred by critics that, whereas such auxiliaries might be perfectly justifiable under conditions such as now prevail, they would fail to show an equally satisfactory result in normal circumstances.
But it must not be forgotten that prices are steadily rising all round. Accepted raw materials are costing more, labour is more expensive, and the tendency in both directions is still in the ascendant. But even should prices and costs droop, it must not be forgotten that such a movement would be attended by the utilization of greater quantities of the articles concerned. They would be recoverable from the garbage in greater volume, and then it would be possible to keep the plants running to their full capacities for no heavier operative or overhead costs. Consequently, in the long run the disposal of enhanced quantities of tins, either as “bright” or scrap, at a lower figure, would probably prove more profitable in the aggregate than treating a limited supply, such as obtains under stringent economic conditions, at a high figure.
How does a recovery plant of the foregoing description work out in practice? This is the vital question. Upon this point it is possible to advance some interesting figures. An investigation of the domestic refuse problem as it affects the country as a whole has revealed the circumstance of the contents of the dust-bin being tolerably consistent, whether it be drawn from a residential or manufacturing town, from the East-end or from the West-end, from the city or from the suburb. On the basis of the analysis set forth elsewhere in this chapter, and taking for our illustration a metropolitan suburb having a population of 85,000 souls contributing 100 tons of refuse a day, the possible recovery of by-products comes out as follows:—
| Material. | Tons per Day. | Price per Ton. | Total Value. | ||
|---|---|---|---|---|---|
| Fertilizer prepared from fine dust and pulverized debris from washer and picking belt | £ s. d. | $ | £ s. d. | $ | |
| 65 | 0 1 0 | 0.25 | 3 5 0 | 16.25 | |
| Cinders | 25 | 0 10 0 | 2.50 | 12 10 0 | 62.50 |
| Tins and metal | 2 | 4 0 0 | 20.00 | 8 0 0 | 40.00 |
| Paper (unsorted, dirty) | 1 | 7 0 0 | 35.00 | 7 0 0 | 35.00 |
| Rags | 0·5 | 15 0 0 | 75.00 | 7 10 0 | 37.50 |
| Glass | 0·5 | 2 0 0 | 10.00 | 1 0 0 | 5.00 |
| Gross total per day | £39 5 0 | $196.25 | |||
The foregoing figures may be accepted as moderate. Thus the cinders, with a heating value equal to five-sevenths of that of good steam coal, are priced at 10s.—$2.50—per ton. But, as experience has proved, they readily command 14s.—$3.50—per ton, providing, in their washed condition, a first-class, clean, cheap and economical fuel for the poorer classes of the community. At 10s.—$2.50—per ton they are equal to coal costing 14s.—$3.50—per ton, at which price such fuel is absolutely impossible to-day. Even coke cannot be purchased at double the figure. In other words, by buying washed cinders at the prices quoted the purchaser is receiving a fuel equal, if not superior, to contemporary household coal costing 35s. to 50s.—$7 to $10—per ton.
Again, the tins are assessed at a low scrap-metal value. Probably 50 per cent. of the tins rescued from the dust-bin to-day coincide with the term “bright,” and thus would pay to turn into tin-plate. The quotation for this material ignores the value of the solder, as well as that ruling for other metals, such as brass and copper, and of which far more is recovered from the ash-barrel than may be popularly imagined. The figure given, moreover, represents the official price, but since the removal of control scrap-metal has recorded higher quotations. So far as the other materials are concerned the prices may be taken as representative.
On the above showing of £39 5s.—$196.25—per day the plant gives a gross return, in round figures, of £235—$1,175—for a six-day week, or £11,775—$58,875—for a 300-day year. Allowing £5,000—$25,000—a liberal figure—for the annual operation of the plant, the sum of £6,775—$33,875—remains—the net return from the realization of some of the utilitarian material recovered from the dust-bins into which 85,000 people throw what they consider to be useless during the course of the year. Truly may it be said that the average member of the public has but little, if any, idea of the wealth he allows to slip through his hands as a result of carelessness or lack of knowledge. Again, when it is reflected that, for the most part, the whole of such potential wealth as this has been permitted to vanish in smoke, or if incombustible to be kicked from pillar to post, we certainly cannot complain when accused of deplorable extravagance.
So far as the capital expenditure of a plant, such as is set forth above, is concerned, this may be set down at £1,000 to £1,500—$5,000 to $7,500. If for such a paltry expenditure a net revenue of £6,775—$33,875—can be secured during the course of the year, surely the moment has arrived when we ought to put our civic and municipal houses in order. Granting that prices to-day are abnormal, and reducing the net return by 50 per cent., even at £3,387—$16,935—per annum, which may be taken as a safe assumption, a plant of this description is able to pay its way within a short time after its installation, after making even the most liberal allowances for capital charges, interest, and depreciation.