We have recently had brought under our notice a system of water and
sewage purification which appears to possess several substantial
advantages. Chief among these are simplicity in construction and
operation, economy in first cost and working and efficiency in action.
This system is the invention of Messrs. Slack & Brownlow, of Canning
Works, Upper Medlock Street, Manchester, and the apparatus adopted in
carrying it out is here illustrated. It consists of an iron
cylindrical tank having inside a series of plates arranged in a spiral
direction around a fixed center, and sloping downward at a
considerable angle outward. The water to be purified and softened
flows through the large inlet tube to the bottom, mixing on its way
with the necessary chemicals, and entering the apparatus at the
bottom, rises to the top, passing spirally round the whole
circumference, and depositing on the plates all solids and impurities.
All that is needed in the way of attention, even when dealing with
sewage, or the most polluted waters, is stated to be the mixing in the
small tanks the necessary chemical reagents, at the commencement of
the working day; and at the close of the day the opening of the mud
cocks shown in our engraving, to remove the collected deposit upon the
plates. For the past six months this system has been in operation at a
dye works in Manchester, successfully purifying and softening the
foul waters of the river Medlock. It is stated that 84,000 gallons per
day can be easily purified by an apparatus 7 feet in diameter. The
chemicals used are chiefly lime, soda, and alumina, and the cost of
treatment is stated to vary from a farthing to twopence per 1,000
gallons, according to the degree of impurity of the water or sewage
treated.
The results of working at Manchester show that all the visible filth
is removed from the Medlock's inky waters, besides which the hardness
of the water is reduced to about 6° from a normal condition of about
30°. The effluent is fit for all the varied uses of a dye works, and
is stated to be perfectly capable of sustaining fish life. With
results such as these the system should have a promising future before
it in respect of sewage treatment, as well as the purification and
softening of water generally for industrial and manufacturing
purposes.--_Iron._
[Illustration: WATER SOFTENING AND PURIFYING APPARATUS.]
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