A process for the treatment of minewater or other waste waters integrating existing treatment processes in a modular sealed system wherein the improved treatment system can make use of a positive head of water, either via siphon or conducted flow to displace pumping costs involved in water treatment. The improved process can to be located underground, as it is both modular and intensified, reducing the physical size of the treatment plant and increasing its flexibility. The improved process has a lower capital cost and reduced operating costs.