August 20, 1831: Birth of Eduard Suess; 1914: Disinfection of Sewage Plant Effluents

0820 eduard-suessAugust 20, 1831: Birth of Eduard Suess, Austrian geologist.
He developed the plan for a 69-mile (112-kilometre) aqueduct (completed 1873) that brought fresh water from the Alps to Vienna.

At the age of nineteen he published a short sketch of the geology of Carlsbad and its mineral waters… n 1862 he published an essay on the soils and water-supply of Vienna

In 1864, the Vienna City Council voted the construction of the First Vienna Spring Water Main, which to this day covers approximately 40 percent of Vienna’s water requirements. It was planned by the geologist and City Council member Eduard Suess and implemented under Mayor Cajetan Felder. The main was to safeguard adequate drinking water supply even for the suburbs and to improve its quality, thereby excluding any further health hazards for the population.

After a construction period of only three years, the First Vienna Spring Water Main was inaugurated on 24 October 1873 by Emperor Francis Joseph I concurrently with the Hochstrahlbrunnen Fountain in Schwarzenbergplatz. The pipeline is 120 kilometres long, cost 16 million Gulden to build and soon became a symbol of Vienna’s liberation from water shortages and dangers of epidemics. In residential buildings, the formerly used domestic wells were gradually replaced by communal water taps. In 1888, over 90 percent of residential buildings situated within Vienna’s (then) municipal territory were already connected to the new main.

0820 Disinfection of Sewage Plant effluentsAugust 20, 1914: Municipal Journal article. Operation of Sewage Disposal Plants—Disinfection. “Having determined upon the size of the dose, the next thing is to apply it to the sewage or effluent at a uniform rate. The best practice is to dissolve the required number of pounds in a given amount of water and feed the solution at a definite rate proportional to the flow of liquid to be disinfected. This is not so simple as one might at first suspect. Several things have to be looked out for. The commercial dry powder varies in strength and loses strength considerably when exposed to the air. There must be sufficient water to dissolve out the hypochlorite, and care must be used in mixing the solution. The solution is corrosive and acts on tanks, piping, valves, etc., and it also forms incrustations which cause frequent stoppages in pipes, valves and feeding devices.

Unless it is feasible to analyze each lot of bleach, it should be bought with the available chlorine specified by the dealer. As the material deteriorates upon opening, the contents of a whole container should be mixed at once if possible. In many plants, however, this cannot be done; in such cases the unused material must be kept tightly covered in a cool dry place. While the larger sized containers hold about 700 pounds, at a slight increase in price hypochlorite can be obtained in 350-pound or 100-pound drums, and in many cases the smaller sizes are to be preferred, both because of convenience in handling and to avoid the keeping of large quantities exposed to the atmosphere.

In the mixing of the bleach, the active hypochlorite is dissolved while the inert lime and other insoluble impurities remain. Usually the bleach is thoroughly mixed with a small amount of water into a paste or cream so as to break up the lumps, then more water is added and the whole transferred to the solution tank, and agitated until a thoroughly homogeneous solution is obtained.

As it is very important that the solution be of the same strength throughout, and as this mixing is a laborious process, a power mixer should always be installed except, perhaps, for very small quantities. After all the hypochlorite has been dissolved and the solution once properly stirred up, the strength remains the same throughout the tank.

In some plants the contents of a whole container of bleach are washed out into the solution tank by means, of a stream of water from a hose, and the whole agitated until a thorough solution is obtained. In the mixing, care must be used to get the material thoroughly broken up and agitated so that all the hypochlorite will be dissolved or else a considerable amount of material will be wasted. The writer has known of over fifty per cent waste, due to improper methods of mixing. He has suggested a mixer in the form of a mill or grinder, so that the bleach could be fed through and ground with a stream of water. This he believes would break up lumps and hasten the process.

One should not attempt to dissolve too much hypochlorite in a given amount of water. The solubility of bleach is only about five per cent, and a five per cent solution is difficult to obtain and difficult to handle. It is much better, when possible, to use a weaker solution, say two or three per cent. It is usually better to keep the solution the same strength by mixing the required number of pounds according to the strength of the dry powder, and to vary the dose by changing the feeding device. A rod should be laid off, showing the number of pounds to be used for different depths of water in the tank, from the top down, so that if all of the solution is not run out the rod will show immediately the number of pounds to be used for the amount of water necessary to fill up the tank.”

Commentary: This article was published about six years after the startup of the chloride of lime (calcium hypochlorite) feed system ordered by Dr. John L. Leal and built by George Warren Fuller at Boonton Reservoir—see schematic of Fuller’s chemical feed system below. The description of the chloride of lime feed system for sewage treatment plants (above) is very similar to the one shown below. The article is also quite honest about the many problems with using chloride of lime as a source of chlorine to disinfect water. None of these issues were brought to light during the optimistic testimony given by Leal and the other defendant witnesses at the second Jersey City trial. Over time, chloride of lime feed systems were replaced with pressurized systems feeding chlorine gas from storage tanks of liquid chlorine stored under pressure.



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