Don't waste sewage – it is a valuable resource

by Michael Smith

The way we treat sewage needs to undergo a revolution on the same scale as we have seen attitudes change to household rubbish and industrial waste.

This was, basically, the core message of an event hosted by consultants Aqua Enviro in January 2009.

While the value of most other resources is widely recognized now, in the UK and elsewhere, we tend to have a devil-may-care attitude to water consumption in the UK, perhaps in part due to the climate.

The current wastewater treatment regime does almost exactly what it says on the tin - it wastes water.

Aqua Enviro's Dr Nigel Horan told delegates at the event that while technology may have moved on, there has been no real change in the way we look at sewage for generations.

We need to look at sewage as a resource, rather than a waste product to be simply got rid of, he said.

He said that the the system of treating our sewerage was put in place in Victorian times and had a function - to get solids off the street because people were dropping down dead from diseases.

The very thought of the way sewerage was disposed and treated before that just makes one cringe, if not more. No wonder we were having diseases run rampant in Britain.

"We've done that quite effectively but we've not had much in the way of innovation for the past hundred years."

He argued that water companies were not just throwing money away, they were paying to throw money away.

More water metering, widespread use of sludge in energy-from-waste generation and the extraction of marketable chemicals would all help realize the true value of wastewater, he said.

A case in point is phosphorus, he said, a chemical found in abundance in raw effluent with a market demand is on the doorstep.

"Fertilizer manufacturers in this country can only meet about 40% of the demand each year because they don't have the phosphorous," he said.

"There's enough phosphorous in wastewater to meet the whole of the demand."

The industry needs transforming, he said, and we need to tap into the resources that are currently being horribly wasted.

Another thing that no one seems to talk about is the fact that sewerage contains methane as a gas and that this could be extracted to heat homes and businesses and to run electricity generating plants, ideally on a local level.

Currently, at most, if not indeed all, wastewater treatment plants methane is flared off and a most valuable resource is being wasted. Instead it could be used to power a local power plant.

Such suggestions in Britain, though, would, no doubt, bring out the NIMBY brigade again and nothing like that could ever be implemented, which is rather sad.

When we are talking about methane, the sewerage gas, the self-same gas is also being released by all landfill sites and in the UK in most cases this is being vented off or flared off and it is not utilized yet again.

Are we going to learn some day?

© M Smith (Veshengro), January 2009
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