Siemens Water Technologies will supply a nine-piece odor control system at the 250,000 m³/d North Jeddah Sewage Treatment Plant (STP), Saudi Arabia. As the STP is located next to the King Abdullah Aziz Airport in Jeddah, the Ministry of Water and Electricity requested that odor control equipment be installed, the company said in a statement on Friday. Valued at more than $2 million, the system will consist of three different technologies located at five areas throughout the plant. Once completed by year's end, this will be one of the largest odor control installations in the Kingdom. The ministry selected Siemens for its odor control experience and number of installations in the Kingdom. Siemens is one of the few bidding companies that were able to provide a multitude of odor control solutions, including a combination of biological, chemical, and activated carbon. Siemens will also guarantee the overall system's efficiency. Two two-stage bio-trickling filters will remove the bulk of hydrogen sulfide (H2S) in the aerated grit chambers and bio-phosphorus tanks, followed by a LO/PRO two-stage chemical scrubber to reduce overall odors. A three-stage chemical scrubber will remove 99.9% of H2S and other odors in the sludge thickener and tanks area. Three additional scrubbers will be installed in the sludge dewatering building to treat ammonia and amines, H2S, and organic sulfur compounds in three separate stages. A ZABOCS biofiltration unit installed in the return and excess sludge pumping station will remove H2S and various other odorous compounds. A single-stage packed tower chemical scrubber in the aeration tanks rounds out the system, treating a high volume of air and a range of odors and concentrations in a small footprint.