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The 21st century has been called "the century of water," with water shortages made worse by global warming. Around 1.1 billion of the world's approximately 6.5 billion people (as of 2006) do not have access to safe drinking water.
Some 2.4 billion people have to live without proper sanitation, including wastewater and sewage treatment. Regions lacking adequate sanitation also suffer from serious water contamination problems.
Thus, water treatment technologies will soon be critical for global environmental conservation.
World Water Stress in 2025
Water stress refers to the ratio of water demand to renewable water resources.
When this ratio tops 40 percent, it is said to be high. According to Vital Water Graphics (United Nations Environment Programme), four billion people are expected to face high water stress by 2025.
Ratio of People with Access to Good Sanitation (2004)
Source: Health indices, The State of the World's Children 2008 (UNICEF)
We contribute to global environmental conservation by offering water treatment systems and technologies for treating tap water and sewage, industrial wastewater and ship ballast water.for a safe and reliable water supply, the base of human existence.
|Sewage treatment Industrial wastewater treatment||Technology using microorganisms to efficiently remove nitrogen from sewage and industrial wastewater|
|Sewage reclamation and recycling Industrial water reclamation and recycling||Water treatment technology combining membrane separations and biological treatments|
|Ship ballast water purification||Water treatment technology combining flocculation and magnetic separation that avoids the use of disinfectants and protects marine environments|
Professor, Institute of Industrial Science
The University of Tokyo
Pressure from population growth, economic development, urban concentration and climate change are squeezing world water supply and demand ever more tightly. This is less due to water shortages in arid areas than due to the lack of a social infrastructure for a stable supply. The Hitachi Group and other companies can contribute to solving the world's water problems in many ways, including creating the social mechanisms for maintaining a healthy water cycle and teaching skilful water use that minimizes water pollution, as well as the transfer of water treatment technologies and the supply of funds. Supporting access to water promotes good health, hygiene, and food production as well as energy, transportation, and education. This underpins sustained economic growth in the developing world and world stability; it also substantially contributes to Japan's national interests.
China's urbanization has gone hand in hand with severe water pollution. A prime example is TaiHu Lake, an area in the Yangtze River Delta known for its scenic beauty. Large amounts of blue-green algae now bloom there every summer, causing a strong odor in the tap water of coastal regions fed by the lake. This is thought to be due to nitrogen and other substances in domestic and industrial wastewater flowing into rivers, lakes, and marshes, causing eutrophication (when too many nutrients cause excess growth of plants and organisms).
To address this problem, we are looking to deploy a unique nitrogen removal system using immobilized microorganisms trapped in polymer gel cubes.
Gel containing highly
The most common sewage treatment method is the activated sludge process, where air bubbles are fed into a bioreactor, using the action of microorganisms for water purification. While this is an effective way to break down organic matter, it cannot completely remove contaminants such as nitrogen. With entrapped immobilized microorganism technology, microorganisms that can remove nitrogen are trapped in a polymer gel shaped into 3-mm cubic pellets. Injecting the pellets into the bioreactor substantially boosts the nitrogen removal rate. PEGASUS, a nitrogen removal system jointly developed with the Japan Sewage Works Agency, uses this technology. It is already performing well in sewage in Japan and private-sector industrial wastewater treatments.
To deploy this new technology in China, it was vital to use actual wastewater to verify the technology and win over the government and major design institutes that determine sewage plant specifications. We have demonstrated the effectiveness of entrapped immobilized microorganisms through joint research with a number of Chinese universities.
In conjunction with the Shanghai Jiao Tong University, under a joint research project, we set up a pilot plant for tests at a brewery in Guangdong Province. These tests produced good results and proved the effectiveness on wastewater containing high concentrations of ammonia. We also undertook on-site verification in sewage plants in cities in the TaiHu Lake area. In our research with Nanjing University, we made an on-campus evaluation of entrapped immobilized microorganisms and also performed demonstration experiments at sewage plants.
We have also developed a system for water recycling and reuse in regions with serious water shortages. The PERSEUS system produces treated water suitable for reuse with a membrane bioreactor where a membrane is submerged in a bioreactor for solid-liquid separation.
A PERSEUS system installed
at a construction workers'
housing complex in Dubai
processes wastewater for
about 1,500 people.
The PERSEUS system is already in commercial use. Units began operating in 2007, for example, in Dubai in the United Arab Emirates, a city that is attracting attention for its large-scale urban development. In September 2008, a new company was set up with local investors to gather domestic city wastewater in tank trucks for advanced treatment using the PERSEUS system, where the treated water is sold for use in industry, toilets, irrigation and plantations.
At the same time, given that many areas with serious water shortages are in the developing world, increasing the market penetration of water recycling technologies will require a significant lowering of costs. We are jointly researching how to do this with leading universities around the world that have special technologies. In Singapore, which has the NEWater Plan for recycling wastewater as a drinking water resource, we have begun working with Nanyang Technological University to apply the university's eading-edge technologies to develop a system that is driven by a small amount of energy. We are also collaborating with China's Sichuan University to create a low-cost hollow fiber membrane that combines the university's polymer material and spinning technologies with our membrane treatment technologies.
(Published in July 2009)
Presenting Hitachi's activities aimed at monozukuri in harmony with the environment, such as environmentally conscious products, eco-examples at offices and plants, and employees' activities.