Through primary treatment of acid wastewater, polymerizing iron sulphate of sewage cleaning anents is prepared.

Those researchers, led by Wajih Naqvi and Victor Smetacek, created a bloom of phytoplankton by fertilising an area of 300 square kilometres with six tonnes of iron sulphate, which dissolves in water.

The iron-sulphate system at Lampoldshausen, meanwhile, is capable of treating 4, 500 litres of waste water in an hour or two.