The treatment and disposal of waste waters from dairies and milk products factories.

  • Great Britain. Water Pollution Research Board
Date:
1941
Catalogue details

Licence: Public Domain Mark

Credit: The treatment and disposal of waste waters from dairies and milk products factories. Source: Wellcome Collection.

    24/162 (page 14)
    These observations were made at a time when the depot was not working at full capacity. At rush periods the difference in the period of drainage allowed for different churns might be expected to be even greater. As a first step in reducing the quantity of milk lost it is clearly of importance that churns should be removed from the drainage rack in the same order as that in which they are placed on it, so as to provide approximately the same period of drainage for each churn. The figures given in Table XI show that if loss of milk from splashing were entirely avoided, and if the period of drainage of churns were increased to the optimum value, there would remain a loss of about 15-5 gallons of milk per day from the depot investigated, when 17,000 gallons of milk were being received daily. This loss is equivalent to about 0-09 per cent of the milk handled, and probably represents the minimum loss which could be attained under the most efficient conditions of working. Substantial reductions can usually be made in the volume and polluting character of waste waters discharged from cheese factories. It is important that cheese vats should not be filled too full and should not be stirred so ‘vigorously that liquid is splashed on to the floor. After the removal of whey from the vats, they should first be washed with small quantities of water which should then be added to the whole whey. Subsequent washings with larger quantities of water would then contain much less polluting matter. Large quantities of whey frequently enter the waste waters when cheese vats are emptied, since the usual type of drain-cock for emptying the vats allows liquid to be splashed over the floor of the cheese room, from which it is subsequently removed with the floor washings. This wastage can be avoided by using a more efficient type of drain-cock, and in some factories removable guards or shields placed round the cocks to, prevent splashing have reduced the loss. A considerable amount of whey is often lost from the cheese presses. This loss can be prevented by the installation of collecting tanks at the outlet of the presses. In butter factories losses of buttermilk can be reduced by first washing out the butter churns with a small quantity of water. These washings can be added to the whole buttermilk, which is evaporated to dryness or used for feeding livestock. In most milk depots and milk products factories, the total loss of milk and of products and by-products is made up of a number of relatively small losses from the different parts of the plant: These losses can usually be reduced by simple modifications in the design and by constant attention in the operation of the plant. By this means not only can direct savings be made in the depot or factory, but the size and cost of construction and operation of the plant required for the treatment of the waste waters can be greatly reduced. . CHAPTER IV, LABORATORY EXPERIMENTS ON METHODS OF TREATMENT OF WASTE WATERS TREATMENT BY FERMENTATION Wo. waters from dairies and from factories manufacturing milk products are discharged almost entirely during the daytime. In any system of continuous treatment of the waste waters it will therefore usually be necessary to store part of the liquid for a period of at least 12 hours, in order to get greater uniformity in the flow to the treatment plant. During this