To summarize what Tom said, while yes this is power plant wastewater, it is pumped from the ground into a pipe, ran next to another pipe of water to heat that water up, then dumped out into the blue lagoon. Alternatively, it is pumped from the ground then the water pressure and heat are used to spin a turbine for power. So while it was used in a power plant, it is still pumped from the ground then directly into the lagoon while never leaving that pipe or having anything else put into the pipe.,(reply>), its a geothermal reactor, theres no radiation involved or anything