Waste water testing detects Covid mainly from faecal matter

Something we've become increasingly reliant on during the course of the pandemic is waste water testing. It's pretty remarkable technology that's able to detect whether there is even a single Covid case in a community. As we're currently riding the crest of a new wave the virus, we thought it'd be worth touching base with one of the scientists behind the country's wastewater testing regime. Nathan Rarere asked ESR senior scientist Joanne Hewitt to talk me through how it works.