»
Wastewater Management
High strength and ability to resist saltwater corrosion made Outokumpu Forta LDX 2404 duplex stainless steel the ideal material for the sluice gates at the at the Gårda Dämme in Gothenburg , Sweden . Photo : Outokumpu .
in existing infrastructure , 316L is now standard in nearly all modern upgrades and new-builds . A significant growing market is district heating pipes , where stainless is applied in both in the primary circuit connecting the power station to the substations and the secondary circuits within the buildings . The duplex family of stainless steels play an indispensable role in more demanding applications . The modes of use can be divided into two types of service : handling corrosive or erosive substances such as wastewater of saltwater ; and providing lightness and strength in floodgates . Desalination , a chemical process , requires various duplex and superduplex grades . The most demanding environments , combining heat , high pressure and corrosion , are found in the energy-intensive MED and MSF plants , especially at the brine water intake stage . Depending on specific factors , superduplex type 2507 , lean duplex LDX 2101 , superaustenitic 254 SMO and austenitic 316L all come into play . Duplex grades are also used in wastewater treatment processes , where high strength and resistance to erosion and corrosion are required . A recent example of its use in Barhale ’ s work for Thames Water on sewerage in East London , where duplex was applied on wastewater pipes . Another application requiring duplex is floodwater management . Municipalities are turning more and more to these grades for floodgates , where not only resistance to saline corrosion but also a favourable strength-to-weight ratio are required . Projects include : Tammerkoski rapids , Tampere , Finland ( completed in 2012 ). The wooden floodgates had to be replaced , and at first carbon steel was envisaged . But in the end
Water and the Olympics
As part of the preparations for the Olympics in Paris this summer , 1.4 billion euros were spent on a massive clean-up of the long-polluted river Seine . This allowed some of the swimming races to be held in the river . ( However , some of the participating athletes were taken ill and hospitalized .) A huge water overflow and storage basin was built in the area round the Gare Austerlitz in the heart of Paris . With a capacity of 20 Olympic swimming pools ( 50,000 cu m ), it captures and stores dirty water and redirects it towards a treatment plant where it is cleaned before being released into the river . This prevents untreated water from overwhelming the treatment facilities and polluting the Seine . Other newly built facilities include a water treatment plant in Champigny-sur-Marne , east of Paris . A floating swimming pool with gym , “ Annette K ”, was also built for the Olympics . The suspended pool , resembling a ship ’ s hull , was built of wood , glass and stainless steel . Italy ’ s Myrtha Pools also installed two modular stainless-steel swimming pools at La Defense Arena , for the swimming and water polo events . The pools use 47 tonnes of the Italian company ’ s stainless-steel components . Because swimming pool water is chlorinated and warm , type 316L is standard in items such as piping , attachments and rails .
Public or private ?
Should water be treated or distributed in the public or the private sector ? When I was growing up in the UK the 1950s , water was free ( or covered by local taxes ) and unmetred , and it came from a publicly owned water authority . Then the water service was privatized , but the profit motive was held in check by EU legislation protecting the environment . When the UK left the EU , the water companies were free of this constraint , and sewage discharge increased to scandalous proportions as companies chose to please their shareholders rather than act in the public interest . Water privatization can be good , as competition can stimulate innovation . However , there should be a robust and strictly enforced regulatory regime to protect the public interest .
Outokumpu ’ s Forta LDX 2101 lean duplex grade was applied in the main structural parts of the gates . Gårda Dämme , Gothenburg , Sweden . In 2013 , Outokumpu supplied its Forta LDX 2404 lean duplex grade to replace wooden gates . The coastal city is built on islands intersected by canals , and flooding is a great risk . The new gates help to protect its inhabitants at a time of rising sea levels . Mont St Michel , France . The sea was encroaching on this historic landmark , making access more difficult . That is , until a flood barrier was elected . Industeel supplied 36 tonnes of 2205 duplex plate as cladding for the gates ’ coated carbon-steel frame . The valves were almost made from duplex grade 2205 . Victoriaslussen project , Stockholm , Sweden . This lock is located at Lake Mälaren right in the city centre , an area prone to floods . Apart from flood protection , the gates prevent brackish water from contaminating the drinking water . As part of the extensive Slussen project , new duplex sluice gates in duplex 2205 were built . They will be larger and stronger , capable of releasing more water than their wooden predecessors . The gates were inaugurated in 2022 . Kamihirai Flood Gate , Tokyo , Japan . This is a crucial structure in Tokyo ’ s flood defence system . Originally built in carbon steel in the 1970s , the carbon-steel slide gates were recently replaced with ones in duplex stainless steel . It was decided that using a conventional austenitic grade would significantly increase the weight and pose a risk to the structure . Therefore a lean grade , NSSC ’ s SUS323L , was used . Another factor that weighed in the selection of a strong material was the need for protection against earthquakes .
42 Heat Exchanger World October 2024 www . heat-exchanger-world . com