Sir, – Cian Murtagh (June 13th) proposes large numbers of biodigesters as a means of dealing with nutrient problems in our lakes and waterways. Surely not. What we need is a mass adoption of the principle of “constructed wetlands”. These are a far more effective means of dealing with phosphate and nitrate run-off. They are also mass sequesters of carbon and can be then put against our carbon account. This technology has already been fully proven here in Ireland. What is lacking is the joined-up thinking needed to implement it on a grand scale. – Yours, etc,
NICHOLAS GRUBB,
Cappoquin,
Co Waterford.