Specification of Thomas Stevens : treating sewage, &c.

  • Stevens, Thomas.
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: Specification of Thomas Stevens : treating sewage, &c. Source: Wellcome Collection.

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    2 A.D. 1875.—N° 2829. Provisional Specification. Stevens' Improvements in Treating Sewage, Sfc. precipitates the matters held in suspension in the .discharge liquid or sewage, leaving an effluent water. The compound or agent is placed in a contiguous cistern or hopper, and is allowed to fall regularly in a continuous stream through suitable connections or tubes into the pipe (or pipes), in which the discharge 5 water is conducted from the mill or other work to a settling tank (or tanks); the proportion admited being about two gallons of the agent or compound for every thousand gallons of discharge liquid, and as they flow on towards the settling tank they become thoroughly mixed and incorporated, and at the outflow end of the pipe a proportion of the 10 common agent, “milk of lime,” of about two gallons to every thousand gallons of discharge water is admitted, the whole passing through a small wheel in the pipe (which may actuate the stirrer or agitator in the lime cistern above) thoroughly amalgamating the several ingredients with the water as it flows into the first compartment of the tank. 15 The tanks are divided into three compartments by walls or divisions with sluices in them, and into the first compartment about 7/8ths (seven eighths) of the matter held in suspension in the water is deposited, and as the water rises to the top of the first division wall, it flows over into the second compartment in a thin stream, and therein deposits the 20 remaining matter held in suspension, and the water having next filled this compartment flowTs over the second division wall into the third compartment which it fills to the height of several feet, and then flows down through a vertical filter into a small chamber, and thence through pipes to the river. 25 The precipitated matter is pumped out at intervals by a chain pump and engine into another tank, and therein drained of any superfluous water remaining; and the precipitate or sludge is then mixed with a sufficient or desired quantity of the sulphate of lime to convert it into a valuable manure. 30 The foregoing process is quite sufficient for the purification of the usual discharge water from the washing engines of paper mills, but to treat and utilize all the water passing from the mill, such as the “coolings,” the “lees,” and the water from the “paper machine,” which hold chloride of lime in solution, it is desirable to add a small 35 proportion of sulphuric acid to the before mentioned purifying agent, but any poison it may contain after passing through the filter is destroyed by the common filtering medium,