Singapore

In Singapore, the Public Utilities Board (PUB) services the entire population of 4.8 million people.

PUB is Singapore’s national water and wastewater utility and is a statutory board of the Ministry of the Environment and Water Resources.

PUB also oversees the NEWater system, which converts used water into potable water. The first NEWater plant was completed in 2000, and today there are four plants throughout Singapore to supply 30 per cent of the country’s drinking supply.

The board uses a number of trenchless technologies, such as pipe bursting and spiral-wound lining in sewer rehabilitation work as they continue to maintain the 3,400 km of gravity sewers, 220 km of pumping mains and 130 pumping installations of the sewer reticulation system.

PUB has also used trenchless methods to reline some 600 km of public sewers and private drain lines under their sewer rehabilitation program. Techniques used include cure-in-place piping (CIPP), spiral-wound lining and fold-and-form technology.

The ongoing sewer rehabilitation program, in the current phase 2009–2014, will see the refurbishment of more than 1,000 km of this network. Much of this work will be undertaken using microtunnelling.

Hong Kong

In Hong Kong, the Water Supplies Department (WSD) is the sole water utility.

The WSD is responsible for collecting, storing, purifying and distributing potable water to consumers, and also provides seawater for flushing toilets. It is the sole water utility in Hong Kong, and serves 99.9 per cent of the national population of seven million people.

In 2000, the department started the 15-year Mains Rehabilitation and Replacement Program, which will see approximately 3,000 km of water mains rehabilitated or replaced.

A substantial portion of the mains were laid more than 30 years ago and are approaching the end of their service life, becoming increasingly difficult and costly to maintain.

The project will be relying on the use of trenchless methods such as pipe ramming, pipe jacking, horizontal directional drilling (HDD), close fit lining, CIPP and pipe bursting.

Work is progressing at a rate of approximately 30 km of water mains being replaced or rehabilitated every month.

The WSD predicts that by the end of the works, the anticipated number of pipe failures per year will be decreased from 24,970, recorded in 2000, to 15,000 by 2015.

Japan

In Japan, most water utilities are small in size and are established by municipalities on a self-sufficient basis.

Approximately 124 million people use tap water in Japan, and most of the remaining people use their own wells or unregulated small-scale water supply services.

At the end of 2007, there were 16,978 water supply systems in Japan. On top of that, there were 102 bulk water supply businesses, which provide treated water to water supply businesses.

While water utilities serve the population on a small scale based on municipalities, the Ministry of Health, Labour and Welfare (MHLW) is responsible for maintaining the quality of drinking supply in Japan. Water utilities must also follow the requirements outlined in the Waterworks Act 1957.

MHLW gives a licence to water utilities that service populations greater than 50,000. Smaller water utilities must obtain a licence from prefectural governments.

The Japan Water Works Association (JWWA), established in 1932, is responsible for improving public health by enhancing the development of water supply. The association conducts research on water supply management, conducts inspections and quality certification of water supply equipment and provides registration services for quality management systems.

The total length of water mains in Japan was 262,183 km in 1975. This figure grew to 610,066 km in 2007.

After 1945, Japan experienced a boom of underground infrastructure construction. As Japanese cities have now had sewer networks of lengths longer than 7,000 km in place for over 50 years, renewal is essential.

The former Japan Society for Trenchless Technology (JSTT) Executive Secretary said, “In 2005, the sum total of construction using the rehabilitation method was 380 km, and the grand total of pipes renovated from 1996 to 2001 has reached 3,000 km.

“Utilising the trenchless technique minimises the need for traffic control, since it doesn’t require a large space to dig the road,” he said.

In Japan, many trenchless techniques are being developed and put into practice, such as CIPP, relining, pipe-eating and pipe-bursting.