NZ firm makes bio-diesel from sewage

A New Zealand company has successfully turned sewage into modern-day gold.

Marlborough-based Aquaflow Bionomic yesterday announced it had produced its first sample of bio-diesel fuel from algae in sewage ponds.

It is believed to be the world's first commercial production of bio-diesel from "wild" algae outside the laboratory - and the company expects to be producing at the rate of at least one million litres of the fuel each year from Blenheim by April.

To date, algae-derived fuel has only been tested under controlled conditions with specially grown algae crops, said spokesman Barrie Leay.

Aquaflow's algae, however, were derived from excess pond discharge from the Marlborough District Council's sewage treatment works. Algae take most chemicals out of sewage, but having too many of them taints the water and produces a foul smell.

Creating fuel from the algae removes the problem while producing useful clean water, said Mr Leay. The clean water can then be used for stock food, irrigation and, if treated properly, for human consumption.

Mr Leay said the process could also benefit dairy farmers and food processors as the algae also thrive in those industries' waste streams.

And unlike some bio-fuel sources which require crops to be specially grown - using more land, fuel, chemicals and fertilisers - the algae already exist extensively.

To get the fuel, the algae are processed into a pulp before lipid oils are extracted to be turned into bio-diesel.