Sewage Disposal at Rio De Janeiro.
Writing from Rio de Janeiro a correspondent of The Sanitary Record gives some interesting details regarding the disposal of sewage in that city:
The Rio Improvements Company is responsible for the proper disposition of the entire sewage of the city. This company, an English one, received its charter, or concession, from the Brazilian government so far back as the year 1857, but it was 1862 before the various works were built and operations were begun. The principal function of the company is to control and utilize the entire sewage of the city, subject only to the supervision of the government inspector, and it is under heavy penalties should it neglect its duties or cause an avoidable nuisance. For this work it is paid an annual subsidy by the government, and to every new house that is built it has to make the drains to the main sewer. The company also either supplies the sanitary fittings to the house or sees that those placed in it arc of suitable character, and not likely to cause offense or danger to the inmates. The company has six pumping stations in different parts of the city, all abutting upon the bay, with wharves, on which are unloaded all its appliances and materials.
The mode of treatment of the sewage is as follows: The sewage from a certain district is brought in a main to its station; here, as it enters the company’s premises, it is treated with a mixture of lime, sulphate of alumina and charcoal; it then passes on to precipitating tanks of the usual character, and, after precipitation has been effected and the effluent been allowed to travel through a series of narrow canals, it is discharged into the bay inodorous and of a standard of purity which is said to be much higher than required by the Rivers Pollution Committee in England.
The residuum is dried and burnt twice. The first burning gives back a lime, which the company either uses for its own purposes or sells if there is an excess. The second burning reduces it to a hard clinker; this is ground, and makes as good a cement as the best Portland. In Brazil manure is not required, but as nearly every house is faced with cement, there is an enormous demand for the article; hence, by utilizing the sewage in this manner, the company obtains a valuable marketable commodity.
“I must say,” remarks the writer, “I was much astonished at finding in this much-abused place so perfect a system of sewage disposal so admirably carried out without nuisance to the inhabitants. I was, however, surprised to hear how little some of the leading inhabitants knew of the manner in which their sewage was disposed of, some of them believing that it was discharged into the bay in its normal condition. I mentioned this to Mr. Benest, the managing director, who smilingly replied: ‘From what I have shown you, you must see that the sewage is too valuable an article for us to throw away if we can avoid it, but you shall see and judge for yourself.’ He then explained to me that in time of excessive rains, owing to the flat surface of the city, the storm water (which goes into the sewers) would soon cause an inundation if it were not allowed to escape, consequently arrangements have to be made for its disposal at each station. In such cases it is necessary for a time to open a sluice instead of attempting to pump it into the tanks, and allow the whole to run into the bay. But whenever it is found to be necessary to do this, the fact has to be immediately notified to the government inspector, who visits the station, and when the penstock is closed, writes down the day and date on which it was opened and signs the document. It is then affixed in such a manner that the penstock cannot be lifted without destroying the notice, and the government seal is affixed to it.”