Nearly 5,400 units connected to Nizwa sewage plant

MUSCAT: Since its establishment in 2002, Haya Water is working hard to implement the largest number of wastewater projects using state-of-the-art wastewater treatment technologies in all governorates except Dhofar.
Due to its pioneering role in the field of wastewater, the government has assigned Haya Water with the establishment, development, management and maintenance of the wastewater facilities in the regional governorates that were once managed by the Ministry of Regional Municipalities and Water Resources in 44 wilayats with varying population densities. The management of the wastewater assets was transferred from the Ministry to Haya in several stages. In March 2016, the assets of Nizwa Sewage Treatment Plant (STP) was transferred from the Ministry of Regional Municipalities and Water Resources to Haya Water.
Saud bin Nasser al Shedani, Senior Manager of Operations and Maintenance in the Regional Governorates at Haya Water, said that the number of housing units and government and commercial establishments that are connected to the wastewater network is more than 5,391 units.
As for the wastewater treatment phases at Nizwa STP, Al Shehadi emphasised that the treatment process is a triple treatment. It starts with the primary treatment, which aims at depositing the largest amount of organic matter and the suspended solids that are contained in the liquid wastes. This includes the use of mechanical filters to get rid of floating solid materials, such as cans, cloths and wood, as well as the removal of gravel, sand and suspended solids using primary deposition to protect the STP equipment.
It is then followed by secondary treatment, the purpose of which is the oxidation of organic matter or its transformation into liquid wastes that are not deposited in the primary sedimentation tanks by air bacteria. This includes ventilation process using mechanical surface ventilations or through air pressure using air blowers to increase the oxygen required for this process, as well as the deposition of sludge and solids by using final sedimentation tanks, sludge concentration and disposal by converting it into easy-to-pack and transport materials by using pressure filters.
Finally, the third phase aims to purify the water from suspended solids and increase the process of water oxidation by using sand filters and adding chlorine to sterilise the water that is discharged outside the STP.
Al Shedani added that one of the most important achievements of Haya Water in Nizwa, after receiving the STP, is stopping yellow wastewater tankers from dumping wastewater and oil in the lake located in Wadi Kalbouh. This was considered one of the most important challenges that existed for several years and was a cause of concern for all residents of the area. Haya has coordinated with various government authorities to overcome all existing issues by receiving all yellow wastewater tankers coming from various wilayats of the Governorate of Al Dakhiliyah. Moreover, the company installed an additional device to remove and dispose oil.
The company has repaired 15 inspection chambers that were leaking out of underground water, which was itself a problem at Nizwa STP. The STP used to receive large amounts of excess water, which affects the quality of the treated wastewater, especially during rainy days.
Haya Water has also completed the implementation of the supply and installation of a sludge separator, which enhances the efficiency of the treatment process at Nizwa STP. — ONA