Never before have there been so many different chemicals in our world. The production of plastics, pesticides and not least pharmaceuticals has created a chemical cloud around us. An invisible threat of synthetic chemicals. And through various routes, many chemicals end up in the sea. No one yet knows what the effects will be – on us and other living things. But there are ways to reduce chemical leakage. New technologies are being developed to purify water flows. Deep Sea Reporter visits a cutting-edge wastewater treatment plant.