at Crossness and Salford, will give you on the blackboard a rough sketch
of the above trial plant.

The Salford tanks are admirably adapted to the application of the
electrical or in fact any process of precipitation. They are 12 in
number, and it is proposed to take two end tanks for the electrical
channels, in which the iron electrodes would be placed.

The total I.H.P. required for treating the whole of the Salford and
Pendleton sewage, taken at 10,000,000 gallons per 24 hours, is
calculated at 400 I.H.P., based on the actual work done during the
trial. The electrical plant would consist of four engines and dynamos,
any three of which could do the whole work, and three boilers, each of
200 I.H.P.

The total cost of plant, including alterations, is estimated at £16,000,
to which must be added the cost of about 5,000 tons of iron
plates--ordinary cast iron--at say £4 per ton. These plates would last
for several years.

If filtration were required, there would be an extra expenditure for
this, but it will be remarked that as the treated sewage is practically
purified when it leaves the electrical channels, these filters would be
only required for complete clarification, which for most places would
not be a necessity.

The filtering material used could be gradually prepared from the sludge
obtained after electrical treatment, unless it could be more profitably
sold as a manure, and I am not a believer in the value of sewage sludge
in large quantities. This sludge, a waste product, is converted into