Effluvia dependent—
1. On the accumulation of filth on or about business premises, or on its removal in an offensive condition.
2. On a generally filthy condition of the interior of buildings and premises and utensils generally.
3. On an improper mode of disposal of offensive refuse, liquid or otherwise.
4. On insufficient or careless arrangements in reception of offensive materials of the trade, or in removal of offensive products.
5. On an improper mode of storing offensive materials or products.
6. On the escape of offensive gases or vapours given off during some part of the trade processes.
It is evident that under the first two headings the proper remedy is cleanliness. Filth should be removed in impervious covered vessels, at regular intervals. Structural arrangements should be made, which will facilitate cleansing operations. Solid refuse should, as far as possible, be separated from liquid refuse, as thus putrefaction is retarded.
Under the last head important remedies are applicable. In many cases a careful selection of the materials of manufacture will form an effective remedy. Thus much of the nuisance connected with soap or candle works arises from the putrid condition of the fat collected from butchers and marine store dealers, and might be obviated by more regular and more frequent collection of the materials of manufacture. The offensive vapours arising during processes of manufacture may be intercepted before reaching the external air, and so treated that they lose their obnoxious character. Various methods of interception are adopted, according to the processes involved. Occasionally it is necessary to have the air of the entire workshop drawn by means of artificial ventilation in a special direction; usually the interception of air from special chambers suffices. When thus collected, the offensive air may be dealt with by (1) passing it through water or some other liquid capable of absorbing the offensive materials; or (2) passing it through some powder with which it has chemical affinity; or (3) if its offensive materials are capable of condensation by cold, passing them through an appropriate condensing apparatus; or (4) if the evolved matters are organic in nature, conducting them through a fire. (5) Occasionally it is sufficient to discharge the offensive gases into the air from a high chimney; and this always produces a mitigation of nuisance, as compared with discharge at a low level.
It is usually found that the adoption of one or other of these methods is directly or indirectly profitable to the offender.