The accumulation, transport, and processing of sewage results in the generation of harmful gases and odors. Chemical scrubbing is a gas scrubbing method in which the contaminants are removed from the gas stream. During this process, the gas stream passes through a packed structure with a large wet surface area. The wet area enables contact between the gas and the scrubbing chemicals and allows for the removal of contaminants from the gas stream. Due to the high H2S concentration in the foul air, we are here to help you out with a two-stage chemical scrubber system with a total capacity of 300,000 m³/hour. The system has four trains that can individually treat a flow of 75000 m³/hour. Each of the trains holds a stainless steel fan connected to a suction manifold for air extraction from the different locations inside the pumping station. Each fan is provided with a pressure transmitter and flow sensor for controlling the flow by VFD.
The fan blows away the air firstly into a chemical scrubbing tower which is operated with an aqueous caustic liquid. In the scrubber, the air is brought into intensive contact with the liquid for allowing H2S, mercaptans, etc to pass to the liquid phase and to bind to the caustic. Around 95 to 98% of the H2S is removed in the first step. For doing so, the water is circulated over a packing material by a spraying system at the top of the vessel. The packing material combines a low-pressure drop with a high specific surface for ensuring good contact between the gas phase and water phase. Both the recirculation pumps and the dosing pumps are provided as duty. With the help of the PH-measurement and the H2S sensors which are available before and after each scrubber vessel, the consumption of chemicals is carefully monitored. The scrubber is fitted with a mist eliminator to prevent droplets from passing to the next treatment step. As a polishing step, a second chemical scrubbing tower is operated with an aqueous solution of caustic and bleach. The recirculation liquid is carefully monitored by pH and ORP measurement for ensuring an odor-free exhaust and minimal chemical consumption. The second scrubber is also fitted with a mist eliminator to avoid droplets to escape through the stack.
Due to the performant design of the odor control unit, the system can handle very high H2S concentrations. During peak periods, the chemical scrubbers handle H2S concentrations up to 500 ppm and reduce this to odor-free air while keeping the chemical consumption low by the combination of precise PLC-monitoring, adequate recirculation, and selection of proper packing material. The chemical dosing tanks are located inside a cooled building to avoid the decomposition of the bleach under high temperatures.
Dutco Tennant LLC supplies a premium range of Chemical Scrubbers which offers optimum performance at each step and can boost up the performance of your wastewater plants and give access to clean water.