Before defining or choosing a type of valve for any application it is very important that the fluid is fully understood and what its function will be, therefore, let's study a little about Wastewater, better known as Sewage.

Wastewater basically contains organic and mineral material in solution and suspension, as well as high amounts of bacteria and other pathogenic and non-pathogenic organisms.

Other products may be improperly disposed and flushed into the wastewater network, such as oakum, pacifiers and other child-related materials, feminine hygiene items such as absorbents, or even toxic industrial products, used condoms and etc.

Anaerobic decomposing wastewater produces gases that, in enclosed spaces, such as pipes or stations, can be concentrated in dangerous levels, requiring the use of special equipment and rescue teams.

Hydrogen sulfide is the main responsible gas for the typical smell of anaerobically decomposed sewage, being the most dangerous gas present is methane, for being explosive, having already cause  the death of some sanitation companies workers.

Residual water contains as its main feature, the presence of solids, an important or perhaps one of the main points that define the Valve type to be used in its containment.

The risk factors presented contraindicate the use of Butterfly Valves, Gate Valves (Registers) and Clasar Retention, since their operations are seriously impaired when there is  the presence of solids in the fluid of interest, such as: Clogging, Blocking and Locking, which does not allow the correct triggering, wear, damage to Seats and plugs.  

For that matter, respecting the main feature of Waste Water, Knife Gate Valves stand out, since its concept is that of a Guillotine, to cut the fluid in question and also present Full Passage, which allows perfect fluidity of the processes and its solids.

To complement this gain, FKB developed Knife Gate Valves focused on this sector, aiming to further improve its performance, with some technical details that complete its operation and durability.

Stainless Steel Coated Passage which protects the Cast Iron body, Non-toxic EPDM Seat, which does not contaminate the fluid in question, UHMW (Ultra High Molecular Density Polyethylene) Scraper, to scrape and clean the Knife, ensuring longer working life for Gaskets (Top Seal).

In addition to this brief explanation, a comparison between Knife Gate Valves x Bi Eccentric Butterfly Valves and Knife Gate Valves x Gate Valves is also available on our website.