Water Supply and Wastewater Engineering

Water supply and wastewater drainage were among the public facilities designed by civil engineers to control environmental pollution and protect public health. The availability of water had always been a critical component of civilizations. Ancient Rome, had water supplied by nine different aqueducts up to 80 km (50 miles) long, with cross sections from 2 to 15 m (7 to 50 ft). The purpose of the aqueducts was to carry spring water, which was better to drink than Tiber River water.

As cities grew, the demand for water increased dramatically. During the eighteenth and nineteenth centuries the poorer residents of European cities lived under abominable conditions, with water supplies that were grossly polluted, expensive or nonexistent. In London the water supply was controlled by nine different private companies and water was sold to the public. People who could not afford to pay for water often begged or stole it. During epidemics of disease the privation was so great that many drank water from furrows and depressions in plowed fields. Droughts caused water supplies to be curtailed and great crowds formed to wait their “turn” at the public pumps.

In the New World, the first public water supply system consisted of wooden pipes, bored and charred, with metal rings shrunk on the ends to prevent splitting. The first such pipes were installed in 1652 and the first citywide system was constructed in Winston-Salem, NC, in 1776. The first American water works was built in the Moravian settlement of Bethlehem. A wooden water wheel, driven by the flow of Monocacy Creek, powered wooden pumps that lifted spring water to a hilltop wooden reservoir from which it was distributed by gravity.

One of the first major water supply undertakings was the Croton Aqueduct, started in 1835 and completed six years later. This engineering marvel brought clear water to Manhattan Island, which had an inadequate supply of groundwater. Although municipal water systems might have provided adequate quantities of water, the water quality was often suspected.

The earliest known acknowledgment of the effect of impure water is found in Susruta Samhitta, a collection of fables and observations on health, dating back to 2000 BCE, which recommended that water be boiled before drinking. Water filtration became commonplace toward the middle of the nineteenth century. The first successful water supply filter was in Parsley, Scotland, in 1804, and many less successful attempts at filtration followed. A notable failure was the New Orleans system for filtering water from the Mississippi River. The water proved to be so muddy that the filters clogged too fast for the system to be workable. This problem was not alleviated until aluminum sulfate (alum) began to be used as a pretreatment to filtration. The use of alum to clarify water was proposed in 1757, but was not convincingly demonstrated until 1885. Disinfection of water with chlorine began in Belgium in 1902 and in America, in Jersey City, in 1908.

Between 1900 and 1920 deaths from infectious disease dropped dramatically, owing in part to the effect of cleaner water supplies. Human waste disposal in early cities presented both a nuisance and a serious health problem. Often the method of disposal consisted of nothing more than flinging the contents of chamberpots out the window. Around 1550, King Henri II repeatedly tried to get the Parliament of Paris to build sewers, but neither the king nor the parliament proposed to pay for them. The famous Paris sewer system was built in the nineteenth century. Storm water was considered the main “drainage” problem, and it was in fact illegal in many cities to discharge wastes into the ditches and storm sewers. Eventually, as water supplies developed, the storm sewers were used for both sanitary waste and storm water. Such “combined sewers” existed in some of major cities until the 1980s.

The first system for urban drainage in America was constructed in Boston around 1700. There was surprising resistance to the construction of sewers for waste disposal. Most American cities had cesspools or vaults, even at the end of the nineteenth century. The most economical means of waste disposal was to pump these out at regular intervals and cart the waste to a disposal site outside the town. Engineers argued that although sanitary sewer construction was capital intensive, sewers provided the best means of wastewater disposal in the long run. Their argument prevailed and there was a remarkable period of sewer construction between 1890 and 1900. The sewerage systems in America were built in 1880. One of the system namely Memphis system was a complete failure. It used small pipes that were to be flushed periodically. No manholes were constructed and cleanout became a major problem. The system was later removed and larger pipes with manholes were installed.

Initially, all sewers emptied into the nearest watercourse, without any treatment. As a result, many lakes and rivers became grossly polluted. Wastewater treatment first consisted only of screening for removal of the large floatables to protect sewage pumps. Screens had to be cleaned manually and wastes were buried or incinerated. The first mechanical screens were installed in Sacramento, in 1915 and the fist mechanical commuter for grinding up screenings was installed in Durham. The first complete treatment systems were operational by the turn of the century, with land spraying of the effluent being a popular method of wastewater disposal.

Civil engineers were responsible for developing engineering solutions to these water and wastewater problems of these facilities. There was, however, little appreciation of the broader aspects of environmental pollution control and management until the mid-1900s. As recently as 1950 raw sewage was dumped into surface waters in the United States and even streams in public parks and in U.S. cities were fouled with untreated wastewater. The first comprehensive federal water pollution control legislation was enacted by the U.S. Congress in 1957.