Modern drainage and wastewater treatment systems in the world

(Baonghean.vn) - Drainage and wastewater treatment systems are increasingly playing an indispensable role in modern cities. In the world, along with urban development, drainage and wastewater treatment are important issues that have been focused on very early.

1. Singapore

A network of canals and sewers was established extensively in Singapore.

Singapore is recognized as a global pioneer in water treatment technology and has established a water management agency since 1972 called the Singapore Water Board (PUB).

Previously, Singaporeans relied on water from three reservoirs and imported it mainly from neighboring Malaysia. But today, Singapore collects rainwater through an 8,000-km network of pipes that feed 17 reservoirs, and also recovers used water from a system of drainage tunnels 60m below ground.

The canal system with more than 40 canals and drainage ditches with a total length of 1,000 km along with an 8,000 km long sewer network has helped Singapore deal with flooding caused by high tides and heavy rains in recent years.

Interestingly, Singapore’s extensive network of canals and aqueducts was the result of public health initiatives. In the early 20th century, rampant malaria led the colonial government to build a drainage system that prevented Anopheles mosquitoes from breeding in stagnant water.

Since 1973, the government has spent about US$2 billion on building canals and drainage systems.

2. Japan

A giant underground drainage system in Japan, consisting of 59 reinforced concrete columns, each column can support 500 tons of ceiling weight.

Japan is known as a country that is often affected by natural disasters, including earthquakes and typhoons. For this reason, combined with limited land area, Japan has built a giant underground drainage system in the suburbs of Tokyo. This system is the largest underground drainage project in the world and took 17 years to complete.

According to the description, the system consists of 5 large cylindrical shafts, about 70m high, about 30m in diameter, wide enough to hold a space shuttle. All of these shafts are connected by a curved tunnel, 10m in diameter, 6.3km long.

At the end of the system, the water is stored in a giant pressure control tank, which reduces the pressure of the water flowing, as well as controlling the flow in case a pump fails. The tank is larger than a football field, measuring 177m long, 78m wide and about 22m underground.

After the system went into operation in August 2008, a torrential rainstorm hit the area. At that time, it helped drain 12,000,000m3 of water into the Edo River, equivalent to the amount of water that would fill 25,000 standard 25m swimming pools.

3. United Kingdom

Thames Barrier water protection system.

A serious flood occurred in London in 1953, when the North Sea overflowed into the Thames River, causing more than 300 deaths and serious economic damage. After that terrible flood, the British Government decided to build the Thames Barrier system in Woolwich to protect the 125km wide central London area.²from flooding. The project was completed in 1984 and cost £535 million.

The Thames Barrier spans 520m across the river. The north bank is Silvertown in Newham and the south bank is New Charlton in Greenwich. The barrier consists of six directional gates, four of which are 61m wide and two of which are 30m wide. There are also four smaller, non-directional gates, located between the nine concrete piers and two abutments.

Since its inauguration until July 2014, the Thames Barrier has been closed a total of 174 times to prevent flooding. Notably, on November 9, 2007 alone, the Thames Barrier was closed twice due to a major storm in the North Sea, comparable to the storm in 1953. In addition, it is also raised monthly to test its operational capabilities.

4. America

Sewer system in Michigan, USA.

Most of the first sewer systems in the United States before 1948 were built as combined sewers (which carried stormwater and wastewater). The water was discharged into rivers, lakes, and oceans without treatment. The reason for using combined systems was to save on construction costs. The first large-scale sewer systems in the United States were built in Chicago and Brooklyn in the late 1850s.

In the late 19th century, very few sewage treatment facilities were built. In the early years of the 20th century, in the interest of public health, many cities chose to build separate sewer and wastewater treatment systems.

The U.S. sewer infrastructure includes 1.2 million miles of sewer lines (both sewer and combined sewer systems), wastewater pumping stations, and 16,024 publicly owned wastewater treatment plants. Additionally, at least 17% of Americans have on-site sanitation systems such as septic tanks.

Wastewater treatment plants serve 189.7 million people and treat 32.1 billion gallons per day. There are 9,388 secondary treatment facilities and 4,428 advanced water treatment facilities.

5. Australia

A wastewater treatment plant in Australia.

Another country with an advanced sewerage and wastewater treatment system is Australia. Its sewerage system processes over 320,000 million liters of wastewater each year, enough to fill 128,000 Olympic-sized swimming pools.

Wastewater from bathrooms, toilets, kitchens and laundry rooms flows into the sewerage system through a network of underground pipes. In Melbourne, wastewater from manufacturing businesses is called commercial waste.

Businesses need permission from water retailers to discharge commercial waste, and sewer systems contain more pollutants than domestic waste. Commercial wastewater can contain chemicals, metals, and cleaning agents that can increase environmental risks and increase treatment costs.

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