Vortex FlowTM, by IPEX Inc., a solution for odorants from sewerage systems

Vortex Flow Insert   It is well known that wastewaters accumulation at the bottom of sewer drop structures may be a source of odor emissions in urban environments. H2S and other odorants are released from stagnant waters containing organic matter in solution. In addition, H2S damages concrete and metal structures, increasing maintenance costs of sewer and manholes for municipalities.

Current liquid phase odour control methods include injection of various chemicals such as ferrous sulphate, calcium nitrate or hydrogen peroxide into the sewage flow. Ozonization is another way of controlling odour in the stream.

The Vortex Flow Insert is a specially engineered drop structure that uses the kinetic energy of falling wastewater to eliminate odour discharges from municipal manholes and pumping stations.

Incoming sewage is accelerated to supercritical flow conditions in the upper vortex form that has an increased slope. As the flow is accelerated, it flows around a swirl of decreasing radius, thus generating a centrifugal force.

The sewage flow proceeds to a much smaller diameter drop pipe, where it continues to spin and drop at the same time. This creates a whirlpool effect, forming an air core down the centre of the drop pipe.

This whirlpool or vortex effect creates a slightly lower pressure in the air core, creating a down draft that draws odorous gases down to the bottom of the manhole. The H2S and other gases are entrained back into the sewage in the specially designed energy dissipating pool.

Because of the vigorous aeration and mixing that occurs in the energy dissipating pool, the dissolved oxygen content of the sewage is drastically increased, thus oxidizing the H2S gas.

According to the Maker, for the Vortex Flow Insert to be effective, a drop depth of at least one metre is required; however, a drop of three metres or more is considered optimal.

While the Vortex Flow Insert typically has a lower capital cost than most chemical injection systems, the real savings come when considering the annual chemical costs. Based on a flow of around 4 000 m3/day, with a concentration of 5 mg/l of dissolved sulphide, annual chemical costs could range between €23 000 and €30 000 annually (Richard St-Aubin, Environmental Science & Engineering - September 2003).

In areas where the total drop may be less than adequate for complete odour attenuation, the Vortex Flow Insert can work in tandem with traditional chemical injection to reduce chemical costs.

More information here.

 

 

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Carlos Nietzsche Diaz Jimenez's Avatar

Carlos Nietzsche Diaz Jimenez

Carlos is the editor-chief of olores.org and has been in the odour world since 2001. Since then, Carlos has attended over 90 conferences in odour management, both national and international and authored a few papers on the subject. He has also organized a few international meetings and courses. Carlos owns a small company named Ambiente et Odora (AEO). He spends his free time with his wife and his twins, Laura and Daniel, and of course, writing on olores.org.

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