Re: “Dumping sewage is not sustainable,” letter, May 30.
Forty-four years ago, or half my life, I was given the task of assessing an application for a permit to discharge raw sewage through a long outfall discharging at a depth of 60 metres.
The application had been prepared on behalf of the Capital Regional District by a firm of consulting engineers led by Merv Stewart, who had a doctorate in engineering. A land-based plant would have diluted the waste 10-fold, but initially the long outfall was going to dilute it 200-fold before it began to disperse. Later, a British royal commission deduced that where conditions were suitable, long outfalls “could be environmentally preferable” to secondary treatment. A committee set up to advise the U.S. Congress, led by the director of the Scripps Oceanographic Institute, rejected the notion that discharges to the sea should have secondary treatment, “the evidence to the contrary being overwhelming.”
The long outfalls have been providing better treatment than a land-based plant would have done and still do so. They also provide much better control of pathogens.
J.E. (Ted) Dew-Jones, P.Eng.
Victoria
