Shtang constucted the largest sludge treatment plant in the Middle-East. The plant treats sludge from the country's largest WWTP (400,000 m3/d).

The project entailed the construction of anaerobic digesters and pasteurization tanks that produce class A sludge and included piping, instumentation, electrical systems, control systems, HVAC, electromechanical equipment and much more. 

Shtang further enhanced the proejct's economic return by burning the methane gas emitted in the digestion process to produce heat and electricity in co-generators. This power plant, which uses sludge as its source of energy, is the largest of its kind in the world.