Challenge

Mushrif Trading and Contracting Company of Kuwait City is installing a high-performance nutrient removal system to handle 180,000 cubic meters per day (m³/day) average to 270,000 m³/day peak flow at the Kubd wastewater treatment plant (WWTP) outside of the Kuwaiti capital. The solution is based on a biological process optimization program from Siemens Water Technologies that will help the WWTP meet required effluent levels to produce reuse-quality water for irrigation and landscaping purposes. The integrative program evaluates effluent requirements, land availability and specific cost factors such as energy use, labor, and disposal.

After reviewing merits of the plant design and operating results from a similar installation in South Carolina, USA, Mushrif and end-user, Kuwait’s Ministry of Public Works, were convinced Siemens’ total solution-based approach would best meet the plant’s needs. It’s an alternative to the originally specified conventional MLE (Modified Ludzack Ettinger) nitrogen removal process that consisted of an anaerobic selector, anoxic zone and fine-bubble aeration for nitrification, scraper clarification, and sand filtration/disc filtration.

Solution

The Kubd WWTP's design includes:

• Four VertiCel® vertical loop reactor aeration systems – each consisting of an aerated-anoxic tank followed by an aerobic tank – in two parallel operating trains for a reduction in footprint and a 30% reduction in power cost.
• Six 46m high-performance Envirex® clarifiers instead of the original 10 units, for a reduction in footprint.
• Eight Forty-X™ filters with a pleated media design and 24 discs apiece that capture more solids in a smaller footprint for power and construction savings and improved effluent quality.
• Floating surface aerators for aerobic digestion and an odor control system with reduced chemical usage for improved operational costs.

Results

Compared to its conventional counterpart, Siemens’ solution provides superior process design and performance, a smaller footprint, less energy consumption, and compact tertiary filtration.

With 80% of the process equipment from Siemens, including the sludge handling system, the different processes used in the design offer additional advantages in that they're designed to enhance one another. For instance, each clarifier combines the advantages of a Siemens' Rim-Flo® peripheral feed, peripheral takeoff clarifier with the Tow-Bro® unitube sludge removal system into a single high-performing activated sludge final clarifier.

The Kubd wastewater treatment plant will be commissioned in 2011. Siemens also has provided an overall warranty for the biological process to guarantee the plant meets required effluent quality levels.

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