The Dubai Investments Park Wastewater Treatment plant in the United Arab Emirates faced challenges in their oxidation ditch due to filamentous sludge bulking, resulting in poor sludge settling in the secondary clarifier. Supplemental aeration was needed to eliminate the filamentous sludge bulking.
The oxidation ditch is treating an average of 2.64 MGD (10,000 m3/day) of wastewater, composed of seventy percent municipal and thirty percent industrial waste streams. High organic loads, summer heat and low dissolved oxygen levels were likely the culprits of the filamentous sludge bulking.
Water Matrix Technologies FZE of Dubai partnered with Aeration Industries International to provide a sludge bulking solution by providing two 30hp (22.4kW) Aire-O2 Triton® process aerators/mixers to assist the existing supplemental high-speed surface aerators.
The Tritons were able to drive additional oxygen to the lower levels of the oxidation ditch, depriving the filamentous bacteria of low oxygen concentrations and nearly eliminating the filamentous sludge bulking. This also resulted in a high suspension of solids throughout
the tank, temperature destratification and greatly increased dissolved oxygen.
Despite summertime temperatures as high as 36°C, the plant has been treating an influent BOD of 500mg/l down to <10mg/l and influent ammonia levels of 30mg/l down to <1.0mg/l. The plants total capacity was expanded to 8.19 MGD (31,000 m3/day) with plans to expand to 21.1 MGD (80,000 m3/day) over the next thirty years. The completed project will serve more than 37.1 acres (150,000m2) municipal and industrial residents.
The water conservation features of the plant include effluent reuse for irrigation and district cooling makeup water. The treated water can be used to irrigate approximately 150,000m2 of dry land. With Dubai’s heat, water reuse is crucial.