Biological Treatment of Waste
Water from Synthetic Resin Manufacture
K. G. SINGLETON. Supervisor
Quality Control Laboratory
CTBA(A.R.L.) Limited
Duxford-Cambridge, England
INTRODUCTION
CIBA (A.R. L.) Limited of Duxford, in the county of Cambridgeshire, is the
largest producer of synthetic resin adhesives in the United Kingdom. From modest
beginnings as a research establishment in 1934, rapid post-war expansion took
place, resulting in a company which now manufactures (a) formalin, a basic raw
material, (b) aminoplasts, urea-formaldehyde and resins, used in chipboard, as
wood adhesives and for decorative laminates, (c) phenol-formaldehyde resins, for
adhesive work and plywood, (d) epoxy resins, usedfor example as surface coatings,
mouldings, electrical insulations and adhesives, and (e) textile auxiliary products,
for the treatment of natural and synthetic fibers. Products which do not fall into
one of the above categories are too numerous to warrant individual mention.
Before the boom in synthetic resins became a reality, it was apparent that
complete treatment of any water-borne waste produced in manufacture would have
to be undertaken, since the site was in a rural district remote from any existing
disposal plant. It was fortunate that the factory was to be located over an artesian
chalk basin capable of yielding an adequate supply of water. The presence of a
neighboring trout stream (the upper reaches of the River Cam) would eventually
provide a suitable outlet for purified waste water.
EARLY WORK
In order to investigate methods of effluent treatment prior to the introduction
of large scale resin production, Mr. T. Waldmeyer joined the staff in 1948. Experimental treatment of waste water containing formaldehyde by both chemical
and biological means was undertaken. Attempts at chemical treatment included
the addition of acids, alkalis, aluminum sulphate and ferric sulphate and the passing of the effluent through activated carbon. Although good clarification was obtained in some cases, negligible purification was achieved. The possibility of
injecting the clarified waste into deep boreholes was considered, but a trial indicated that there was a positive danger of polluting neighboring ground water supplies. In fact, there was already evidence that a waste-water soakaway on the
factory site had produced contamination by Cladothrix of the original 120 ft borehole.
Waldmeyer (1) concluded, after conducting investigations with activated
sludge, that purification by biological methods was feasible. He found that a pilot
plant based on the diffused air system tended to be more versatile than that operating by mechanical aeration and produced a 60 per cent reduction in permanganate value of the waste water, after addition of a small volume of domestic sewage.
The decision was taken, therefore, to adopt the diffused air activated sludge system
as a full-scale treatment process, and the first section was commissioned in 1951.
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