Our slow sand filter trial with secondary effluent from a local wastewater treatment plant is coming towards the end. Joseph is maintaining them for a further few weeks to monitor coliform removal and nutrient cycling. He’s been back-washing Manz biofilters and also cleaning our conventional slow sand filters here:
There’s a really healthy biofilm growing in the filters now; there’s excellent coliform removal, lots of protozoa and interesting nutrient cycling. Our next tasks are around analysing DNA and RNA extracts to determine community structure; potential metabolic functions; and gene expression.
We were also sampling today from the River Corrib for Octavi’s slow sand filters (SSFs), which he will feed with river water. His focus is on the mechanisms of coliform removal by SSF biofilms, as well as the persistence of environmental strains of E. coli in the filters – and whether these more successfully evade removal by, for example, protozoan grazing. We’ll work with Dr Florence Abram and Dr Conor O’Byrne on this question.
More updates soon.