Cleaning by Squeegeeing
The squeegee method is used on smooth pavements. Batteries of two and three squeegees are usually preceded by sprinklers, which use as much water as possible without flooding the pavement, while the squeegees use just enough water to create a wash. The idea of sprinkling the pavement is to soften the surface and enable the squeegee to cleanse the street of slime as well as coarser material. Squeegees are followed by men who sweep up windrows of dirt into piles and a sufficient number of carts follow to remove the dirt. In New York where no sprinkling cart is used they average 50,000 square yards per machine per day with the use of 200 gallons of water per one thousand square yards. In Washington with a sprinkling cart they get about 80,000 square yards per machine per day.
Parlin says that squeegeeing produces very effective results with a limited use of water on smooth pavements in good repair.
Very believes that squeegee machines have their value, and if the sprinkler cart is used in advance better results are obtained.
In Milwaukee machines are in constant operation on smooth surface pavements. In certain sections where streets are exceptionally wide, three machines are used in staggered formation and necessitate but one and one-half complete trips over a street to perfect cleaning. They are routed in such a manner that little idle travel is necessary and filling plugs are specified to prevent empty haul to any great extent. The same system is applied to territories where only two machines can be operated, except that four return trips are necessary to complete the work. In no wise are operators allowed to confine their work within a given block unless conditions prevent, but must continue until tanks are emptied, which usually occurs at end of second block. Two laborers are employed with these machines to keep gutters free from dirt and obstructing the water from flowing to the catch basins.
The average area cleaned in one year was 377,712 square yards at a cost of $96.35 per day or 25.5 cents per 1,000 square yards. Of the total yardage of pavement in the city 1,105,324 square yards are free from car tracks and subject to squeegee process. Some are squeegeed twice a week while others are cleaned but once and each have the additional service of White Wings and sprinkler.
The Milwaukee Bureau of Municipal Research gives the cost of squeegeeing as follows:
| Cost of machine | $1,250.00 | |
| Fixed charges | ||
| Depreciation and repairs at 10% on machine | $111.00 | |
| Depreciation & repairs at 50% on roller | 70.00 | |
| Interest at 4½% | 56.25 | 237.25 |
| Maintenance: | ||
| Painting (each season) | 20.00 | |
| Hose and coupling (each season) | 15.00 | 35.00 |
| Season cost, $272.25 | ||
| 150 days operation, cost per day | 1.815 | |
| Operation: | ||
| Team hire per day | 5.00 | |
| One sweeper at $2 | 2.00 | |
| Water at 6¢ per 1,000 gal | .82 | |
| Cost per machine per day | $9.635 |
Manufacturers have placed on the market a modern motor driven squeegee said to be efficient and economical to a city with large area of smooth pavement. The capacity of this tank is increased to 750 gallons (an increase of 200 gallons over horse-drawn machine), which will permit a large area to be cleaned uninterrupted by constant filling, and reduce the lost time at hydrants. There are two sets of sprays, one directly in front of machine and one directly in front of squeegee. Back of the first spray or sprinkler head is a set of two brushes to loosen any hardened matter that might not be subjected to the squeegee process. By using this machine, the employment of laborers to continue the flow of water to catch basins is unnecessary, as the discharge of water is sufficient to remove any slight particles that are removed by the horse drawn equipment. At the end of the season, the machine can be dismantled and a box attached to make it available for other purposes. The cost of operating this style is estimated by the Milwaukee Bureau to be as follows:
| Cost of machine | $4,000.00 | ||||
| Depreciation and repairs at 25% on machine (one-half chargeable to street cleaning) | $481.25 | ||||
| Interest investment 4½% (one-half chargeable to street cleaning) | 90.00 | ||||
| One roller per season | 85.00 | ||||
| Maintenance: | 656.25 | ||||
| Hose, couplings, 4 tires depreciation at 50% | |||||
| Replacement of two brushes | 69.00 | ||||
| Season cost | 725.75 | ||||
| 150 days operation on street cleaning | $4.84 | ||||
| Operation: | |||||
| 1 sweeper per day | $2.00 | ||||
| 1 chauffeur per day | 3.00 | ||||
| Gas and oil | 1.82 | ||||
| Water at 6¢ per gal. | 1.60 | ||||
| 8.42 | |||||
| Daily cost | 13.26 | ||||
| Average square yards cleaned per day, 80,000 | |||||
| Cost square yards, 16.5¢ | |||||
| Assessment for foot front based on a street 30 feet wide and cleaned fifty times a season would be $1.37. | |||||
This cost data shows motor driven squeegees will perform twice the amount of work as horse drawn at a reduced unit cost. The difference in operating cost of two types would be:
| Horse drawn, average cost per 1,000 square yards | 25.5¢ |
| Motor driven, average cost per 1,000 square yards | 16.5¢ |
Whinery says that while it is true that flushing methods, if thoroughly used, do carry the removed dust into the sewers or drains, which is regarded by many objectionable and to clog the pipes, this might happen where the whole of the street dirt, coarse and fine, is thus carried together into the sewers. He does not know of any instances where actual trouble has resulted. The practise of cleaning the streets wholly by squeegeeing or flushing is not, however, to be recommended, he believes, if for no other reason than that it would be impracticable to do the work several times each day and thus prevent the formation and flying of dust. The danger of clogging the sewers by flushing dust only into them is, he thinks, very remote, as the quantity of the dust remaining after proper coarse cleaning is small. Careful determination by the New York Commission on Street Cleaning and Waste Disposal showed that on smooth pavements cleaned by the patrol system the accumulation of dust in 48 hours after the street has been washed either by hard rains or by flushing, does not exceed five per cent. or six per cent. of the total daily quantity of street dirt, though on rough stone block pavement it may be much larger. This quantity is so small that its disposal through the sewers could hardly cause serious trouble. In fact, the large volume of water used tends rather to flush and clean out the sewers.
In a paper read before the American Society of Municipal Improvements, Mr. Parlin summarizes as follows the results of a study made by him to determine the economy of the various types of flushing equipment: “Hose flushing on small areas was the most economical method; that up to 40,000 square yards, the horse drawn equipment was next in economy; that from 40,000 square yards to 90,000 square yards the hose was about as economical as the automobile; that from 90,000 square yards to 120,000 square yards automobile was supreme, and for daily schedule areas of over 120,000 square yards the automobile and street car equipment give nearly the same economy.”
The street washing equipment of the future will probably be a combination affair. This has been used in Europe for several years. New York City is now developing combination equipment.
The ideal system of street cleaning would, therefore, be efficient patrol or hand cleaning through the day or during a longer period if the volume of travel in the evening requires it, and thorough scrubbing with squeegees or washing with water under pressure by flushing machines or hose at night as often as may be necessary.
Although the automobile equipment has not been in use long, experience has shown that it is both efficient and economical, particularly in the larger cities.