The whole of the output from the Oldham sewage works, which, owing to the process of concentration, is really limited, notwithstanding the volume of crude sewage handled, is readily absorbed by farmers. Disposal was entrusted to a firm to act as the selling agents for the Corporation. Owing to the number of repeat orders received, year after year, this house declares that it could easily place 20,000 tons of the fertilizer, were it forthcoming, without increasing its present staff of travellers. While the outbreak of hostilities militated against the expansion of the process, although many other Corporations have expressed their readiness to introduce the process into their respective sewage works, the past five years have not been allowed to represent dead time. Improvement upon improvement has been incorporated with the object of securing still higher efficiency. In this direction the inventor has made many distinct progressive strides. The one objection levied against the process was the heavy expense incurred in regard to fuel charges for drying the sludge, and these costs naturally have become accentuated by the 200 to 300 per cent. rise in the price of coal. But in this direction it is now possible to record noticeable reductions. As a result of experiment the inventor has evolved a new method for settling the sludge. He found that, by adding a very slight amount of sulphuric acid--about 1 part to 1,000--to the sludge coming from the settling tanks, the usual settling process is completely reversed. Instead of the sludge settling to the bottom, the addition of the acid causes it to rise to the surface, and in a much more concentrated form. The water settles to the bottom in a clearer condition and can be drawn off. By further settling and draining this top layer--virtually a thick scum--a sludge can be obtained carrying about 30 per cent. solid matter, and therefore as a less volume of water needs to be evaporated a considerable saving in the consumption of fuel and cost of drying is achieved.