NFUS warning over use of human waste ‘poo cakes’

Arable: Whisky industry ‘could reject’ crops grown using the fertiliser

“Poo cakes” made out of human waste intended to be used as fertiliser have been poo-pooed by farmers who say it may see crops rejected by the whisky industry.

The unique idea was put forward to farmers as a cost-effective alternative to expensive artificial fertilisers.

Despite the human waste cakes costing only £2.45 per tonne, NFU Scotland (NFUS) has warned its members against using the “poo cakes”.

The union believes that crops grown using the thermal hydrolysis fertiliser, or TH cakes, could be rejected by the whisky industry.

Organic matter is removed from 165 tonnes of sludge processed at Scottish Water’s Seafield treatment site every day. It is then heated to a temperature of 165C in a pressure vessel to remove any bacteria and sterilise the product.

John Davidson, farm manager at Penicuik Estate in Midlothian, believes the TH cakes are better for the environment.

He said: “They are ex- tremely cost-effective and I’ve managed to cut my usage of artificial fertiliser by around 30%.

“It’s a very slow-release fertiliser whereas the artificial kind is an instant hit and doesn’t last as long and can also leach into water courses.”

But Ian Sands, NFUS combinable crops chairman, has warned farmers to be “cautious” about using “poo cakes”.

He said: “NFU Scotland would advise any of our members who are thinking of using thermal hydrolysis cakes as fertiliser for crops of any type to be cautious and consider whether its use is acceptable for current or future buyers of crops grown on their land.

“For going on 20 years, the Scotch Whisky industry has not accepted malting barley which has been grown on land which has ever had this kind of fertiliser used on it.

“This means that, despite any advantage of using thermal hydrolysis cakes or similar fertilisers, growers cannot afford to have part of their arable land deemed to be unusable for the production of malting barley or other crops,” added Mr Sands.

A spokesman for Veolia, which runs Seafield for Scottish Water, said the cakes are suitable for a wide range of agricultural uses and meet the “highest safety and quality standards”.

ALTERNATIVE: Farm manager at Penicuik Estate John Davidson, here with dog Peg, uses thermal hydrolysis cakes on the land as fertiliser