– Environmentally compatible wastewater treatment for one million inhabitants
– Energy-efficient system using biogas for power generation
In 2014, the Vienna-based VA TECH WABAG GmbH signed a contract with the main contractor, DNGO Contracting Saudi Company, for the design and supply of a municipal wastewater treatment plant with a capacity of 200,000 m3/d to Al Kharj, located near the capital Riyadh. The end customer is the National Water Company (NWC). Tertiary treatment technology will guarantee first class wastewater quality, while anaerobic sludge treatment with the conversion of biogas into electricity will enable the treatment plant to cover half its power requirements autonomously.
WABAG offers a comprehensive range of technologies and services and the Al Kharj contract, which involves a large-scale, municipal wastewater plant with anaerobic sludge treatment as part of an energy-efficient plant design, falls within the domain of the Group’s company in Vienna. Accordingly, apart from the most economic offer, the decisive factor in the allocation of the order to WABAG was provided by its excellent references in combination with proven competences and high-level of quality in execution.
At present, the Al Kharj Road WWTP (the name refers to the facility’s location on the road to Riyadh some 30km distant from the Saudi capital) incorporates two earlier project phases each involving a plant capacity of 100,000 m3/d for the treatment of the municipal wastewater from the northern districts of Riyadh and the town of Manfouha.
WABAG was already responsible for Phase 1, which became operational in 2007. The current Phase 3 will have a capacity of 200,000 m3/d and include proven mechanical/biological treatment based on the activated sludge process, as well as an additional filtration and disinfection step. This will guarantee first class wastewater quality and permit the use of the cleaned water for irrigation purposes at all times. Plant start-up is scheduled for autumn 2017.
Energy-efficient. Anaerobic sludge treatment with energy recovery.
As opposed to the expansion phases 1 and 2, the new plant will include anaerobic sludge treatment. Four digesters with a capacity of 7,250 m3 each will be used for the digestion of the sewage sludge produced during biological treatment. This will result in combustible biogas, which will be turned into electricity in a combined heat and power unit. Consequently, the treatment plant will be capable of generating half of its energy needs autonomously, which will not only cut operating costs, but also provide a major improvement in its CO2 balance.
WABAG has already completed a series of plants in Saudi Arabia. For example, the wastewater treatment plant in Al Kharj follows a reverse osmosis drinking water facility at the same location, as well as a large brackish water desalination plant with a capacity of up to 200,000 m3/d in Al Wasia. Furthermore, a modern industrial water recycling plant was commissioned for Al Kharj in 2014 and is currently undergoing completion.
Erik Göthlin, the VA TECH WABAG GmbH CEO, sees the new order as being: “A most attractive success for our Viennese company and an excellent new reference in the area of large wastewater treatment plants designed for long-term sustainability. We regard this contract receipt as confirmation of WABAG’s well-known reliability and consistent top quality standards.”