Marrakech takes the lead in sustainable development. Waterleau built and operates the city's state-of-the-art wastewater treatment plant and has completed the world's largest solar sludge treatment facility in partnership with Thermo-Systems. Each year 75.000 tons of digested sludge from the wastewater treatment facility will be turned by robots or electric moles in large greenhouses, increasing through vaporization, dry matter content from 22% up to 80%, driving down transport. The plant is the first in the region integration biogas production, water reuse as well as solar sludge drying.