Kuwait wastewater plant opts for Siemens nutrient removal system

Warrendale, Pennsylvania - Siemens Water Technologies has won a contract to provide a new nutrient removal system, called BioFlowsheet+ Solutions, for the 180-mld Kubd wastewater treatment plant (WWTP) at Kuwait City. The plant will be commissioned in 2010 under a Euro5.2-million deal with Kuwaiti contractor Mushrif Trading and Contracting Co.

The installation at the Kubd plant will comprise four VertiCel systems in two parallel operating trains, six 46m clarifiers and eight Forty-X disc filters. The system was an alternative to the originally specified conventional MLE (Modified Ludzack Ettinger) process that consisted of an anaerobic selector, anoxic zone and fine-bubble aeration for nitrification, scraper clarification, and sand filtration/disc filtration.

BioFlowsheet+ Solutions integrates several WWTP operations including biological, solids separation, solids treatment and controls to meet the needs of most wastewater treatment applications. The system evaluates effluent requirements, land availability and specific cost factors such as energy use, labour, and disposal and, claims Siemens, offers better process design and performance, a smaller footprint and less energy consumption than conventional systems.

The project marks the largest VertiCel system and Forty-X disc filter orders to date, said Siemens, which will also provide an overall process warranty for the biological process to guarantee the plant meets required effluent quality levels. The VertiCel activated sludge process consists of reactors in series, with vertical loop reactor tanks followed by fine-bubble reactor tanks.

The process employs anoxic tanks, mixed and aerated with mechanical aerators, followed by fine-bubble reactors maintained in an aerobic state. The VertiCel process requires less installed and operating power than conventional fine-bubble aeration processes through the use of optimised aerator selection and stratified dissolved oxygen levels.

Siemens’ Envirex clarifiers use only six secondary clarifiers - compared to 10 conventional clarifiers - resulting in substantial savings in civil, piping and erection costs. Each clarifier combines a Rim-Flo peripheral feed, peripheral takeoff clarifier with special sludge removal technology into a single high-performing activated sludge final clarifier.

The Rim-Flo requires 50% less surface area than a conventional clarifier, while the fully assembled Forty-X disc filters will be delivered to the Kubd plant for installation in a small footprint concrete tank, compared to conventional sand filtration that would require a large gallery of piping, backwash pumps, and blowers, said Siemens.