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Experiences with the Deep‐shaft Process at Tilbury
Author(s) -
IRWIN R. A.,
BRIGNAL W. J.,
BISS M. A.
Publication year - 1989
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/j.1747-6593.1989.tb01525.x
Subject(s) - effluent , biochemical oxygen demand , environmental science , activated sludge , aeration , waste management , engineering , sewage treatment , environmental engineering , chemical oxygen demand
The deep‐shaft activated‐sludge process, which was originally developed for single‐cell protein production by ICI 1 , has been successfully applied to the treatment of high‐strength domestic and industrial waste water. The process exploits the hydrostatic pressure generated at the bottom of a column of liquid to enhance the transfer of oxygen to a rapidly‐circulating mixed liquor. About forty deep‐shaft plants are in operation worldwide of which four have been built in the UK. The latest of these treats a mixed industrial and domestic waste water at Anglian Water Authority's sewage‐treatment works at Tilbury. At a dry‐weather flow of 30 Ml/d, this is the largest deep‐shaft plant in the world. The paper gives a description of this works and some performance data obtained during a 3‐month monitoring period following plant commissioning. The results show that the BOD and suspended solids loads were extremely variable and exceeded the design capacity of the works by approximately 40% during the month of July. Despite this, the effluent quality remained within consent limits with a 95 percentile BOD of 83 mg/1 (consent limit: 120 mg/1 BOD). The computerized aeration control system was not functional during the trial period; nevertheless, considerable potential energy savings were indicated. During a one‐week period, an average of 41 000 kg BOD were removed daily at a mean oxygenation efficiency of 2.5 kg BOD removed/kWh.