SEWERAGE OF A SEASIDE TOWN, 775 



Dr. Arthur Angell, the County Analyst for Hampsliire, 

 speaks thus of it : — 



" Ferozone contains a large proportion of ferrous iron saUs, and 

 for that reason alone cannot tail to be a powerful chemical dis- 

 infcictant ; further than this, however, it contains salts of alumina 

 and of magnesia, both of whicli assist as decolorants and 

 precipitants. The remaining part of ferozone is made up 

 principally of very finely divided porous magnetic oxide of iron, 

 and this serves both as a further oxidising agent and as a weight- 

 ing material, which accelerates the subsidence of the suspended 

 matter, and keeps the sludge down as it accumulates at the 

 bottom of the tank. 



"The insoluble portion of the ferozone is composed of finely- 

 powdered polarite — a newly-invented material, to which the 

 filter-beds containing it owe their very remarkable oxidising 

 powei-s ; this powder, therefore, keeps the sludge sweet during 

 subsequent disposal, either by pressing or drying, or by both ; and 

 thus a part of the process, which is so offensive at sewage works 

 where lime forms one of the ingredients used, is carried on without 

 committing a nuisance." 



I have seen ferozone used in several places, and always 

 with satisfactory results. At Southampton, a seaside town 

 with over 60,000 inhabitants, it is used for the treatment of 

 the greater part of the sewage in the following manner : — 



On the Town Quay, close by the Town Pier, in a publicly 

 frequented place, there are built two covered precipitating 

 tanks or reservoirs, each of which is cajmble of holding more 

 than 360,000 gallons of sewage, and which are used alter- 

 nately, — the two together being large enough for treating 

 the whole sewage of the town. They are at the outlet of a 

 main sewer ; and upon this main sewer, at about 50 yards 

 before it arrives at the tanks, is an ordinary man-hole in the 

 street, and close by is a small cottage used as a store for the 

 ferozone. In this store the ferozone is slightly moistened 

 with water, to whicli a little sulphuric acid is added, — the 

 dosage being one pound of acid to the hundred-weight of the 

 precipitate. In the man-hole a perforated box is slung down 

 into the sewer, so that the bottom of it is always in the stream 

 of sewage. The ferozone is sent into the box by means of a 

 shoot from the top of the man-hole, three charges a day 

 being sufficient. The quantity used is not quite 9 cwt. to a 

 million gallons, costing at Southampton about sixteen shil- 

 lings. The perforations in the box are so arranged as to 

 allow the varying quantity of sewage to wash out the proper 

 quantity of the precipitant, 



