From the point of view of the towns and cities called upon to handle the sewage, the Grossmann process holds out many inducements. It complies with the demands of sanitation because it precipitates no nuisance. It is the most hygienic process yet evolved for the disposal of sewage sludge. The revenue derived from the sale of the by-products--manure and grease--is such as to render the operation of the plant not only self-supporting but money-making. As a rule the sewage works of the average town represent a sink in more senses than one, more especially when it becomes incumbent to resort to the tipping, dumping or other disposal of the enormous accumulations of the sludge. But signs of awakening are apparent. The Oldham plant has been investigated by Corporations and other authorities, not only of this country but from other parts of the world, who have been satisfied as to its commercial practicability. With the restoration of normal trading conditions it is anticipated that the process will become more extensively adopted, especially as during the past five years ceaseless effort has been devoted to the perfection of details to assure the establishment of the process upon a firm commercial basis. CHAPTER XIX HOUSE-BUILDING WITH WASTES Of the many problems of the day demanding prompt settlement, none, perhaps, is so vital to the welfare of the community as the provision of increased housing accommodation. The issue is by no means confined to Great Britain; it is incidental more or less to every country. Such a state of affairs is not surprising, seeing that building operations, at least in the domestic sense, have been reduced to a condition of comparative stagnation for five years. Even those countries which were not drawn into the actual fighting arena have been unable to carry out housing schemes to meet the needs of their growing populations owing, primarily, to the dearth of the necessary materials and the enhanced labour charges. So far as Britain is concerned the outlook is decidedly disquieting. It is estimated that at least 1,000,000 houses are required to meet the needs of the population. As a first instalment it is proposed to complete forthwith 300,000 houses, but, here again, experience is proving it to be far easier to adumbrate such comprehensive schemes on paper than to carry them into expeditious effect. Questions of cost have arisen. This constitutes the vital factor, because obviously it is folly to build houses for people who cannot afford to live in them. And the limit in the upward tendency has by no means been attained.