Sir, – Septic tanks are generally doomed to failure. Why? Because on average a litre of effluent leaving the tank contains 100mg per litre of suspended solids. Allowing for a per capita consumption of 200 litres per day for a four-person household, this equates to 29.2kg a year of suspended solids. How long will the average percolation area remain viable having been exposed to this concentration and loading of solids? All the wastewater mentors and pundits have been remarkable by their absence in the current debate. It is painful at times to listen to the politicians grappling with the topic. Environmental scientists have a professional duty to enlighten the Dáil and set out the scientific facts. I cringed when I heard An Taoiseach Enda Kenny blame septic tanks for the contamination of Galway City’s water supply. Of course it was primarily caused by deficiencies in the Oughterard wastewater treatment plant. There has been a significant amount of research on septic tanks in Ireland. Will the authors please stand up! – Yours, etc,
Sir, – At €5 a throw, it’s almost tanks for nothing. – Yours, etc,