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One in three people worldwide live without access to clean drinking water . Even major cities with established utilities are projected to fall short of demand for potable water . One of these cities is Shenzhen : China ’ s first freetrade zone and unofficial innovation capital . An ambitious plan specifies molybdenumcontaining Type
316 stainless steel distribution systems as a solution to water loss .
By Fabio Ries , IMOA
About IMOA Reproduced with the kind permission of the International Molybdenum Association ( IMOA ). IMOA is a non-profit trade association representing the majority of molybdenum industry worldwide . For information , visit www . imoa . info
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In 1980 , Shenzhen was a sleepy fishing village of a few thousand . One taxi pulling a wooden cart served the whole town . Today , it ’ s a bustling city of 17.5 million people and an innovation and tech hub , indispensable to the global supply chain . Shenzhen ’ s location on China ’ s southern coast , adjoining Hong Kong , made it the ideal testing ground for the export-driven economic model that defines the modern era . Shenzhen sees the growing reliance on its strained water resources not as a hurdle , but as a catalyst for better infrastructure . The city unveiled targets for improved water resources by 2025 , even promising a clean drink from the tap – a first for modern China . Type 316 stainless steel secondary water supply systems are being implemented across Shenzhen to minimize wastage of this most precious resource . With support from the central government , it is expected that other municipalities will emulate Shenzhen ’ s plan and reduce leakage throughout the country . Secondary water systems
Secondary water supply systems transport water from the mainline under the street to the tap in multi-story buildings . These systems began to proliferate in China during the late 1980s and early 1990s . It was the first time high-rise apartment communities with indoor plumbing were built for ordinary city dwellers , and these facilities soon became symbols of the new prosperity . The typical secondary water supply system starts with the “ snap tap ”. Water is directed from the main through this snap tap into a secondary pipe and then to a tank for buffer storage . In higher buildings , pressure is added through pumps , regulated by frequency inverters to adjust to variable flow rates , which guarantees reliable supply with maximum energy efficiency .
Troubled waters
In China , secondary water systems were made traditionally with galvanized steel , ductile iron or plastic , which all suffer leakage problems . The World Bank estimates global water demand will exceed supply by 40 % in less than 10 years . Yet , approximately 25 % to 30 % of the world ’ s treated drinking water supply is wasted through leakage . Some regions lose well over half of their water during distribution . It ’ s not just water that ’ s wasted – the resources used to treat , store and transport it are also squandered . But most importantly , this loss creates a risk for water shortages , es-
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For valves , pumps and meters , the use of type 316L stainless steel is not yet mandatory but strongly recommended . Photo courtesy of Zhengtong
pecially during droughts , which are increasing due to climate change . Most leakage occurs in the final leg of distribution , in the “ service lines ” , underground pipes that carry water from the mainline to the meter at individual residences and businesses . Installing stainless steel service lines is associated with dramatic reductions in both leakage rates and repair cases , saving cities like Tokyo valuable water resources as well as billions of dollars over the life of the system . China is home to almost 20 % of the world ’ s population , but only to 7 % of its freshwater resources . Water is unevenly distributed : the north and west are parched while the south swells with seasonal heavy rains . Severe pollution , which makes over 60 % of ground water and 25 % of rivers and lakes unfit for human contact , does not help . 20 % of China ’ s fresh water is unfit even for industrial or
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