Potable Water

Since ancient times humans have understood the importance of clean drinking water and have used various techniques to improve its quality. In modern times, municipal and public water treatment systems began providing water to consumers worldwide, and safe drinking water became first a public health issue and then a human rights issue. Many countries have drinking water regulations and have set standards for maximum allowable levels of contaminants in drinking water. In wealthier nations, people have been living for nearly a century in a “water paradise,” with inexpensive and safe drinking water readily available in most places. In many developing countries, people lack access to safe water; waterborne disease is a major cause of death, especially among children under 5; and countries that have set drinking water standards often lack the resources to implement or enforce them. The World Health Organization (WHO) has developed a set of standards and guidelines for implementation to help countries lacking regulations and, along with the United Nations Children’s Fund (UNICEF), has set goals aimed at providing all people with safe drinking water, especially focused on the poor and disadvantaged of the world. This chapter provides an overview of drinking water in ancient times, the development of water treatment systems, the evolution of water analysis and drinking water standards, examples of current standards and regulations around the world, emerging standards and regulatory challenges, and global drinking water goals.

Providing access to potable water and sanitation has become a human right through various designations in international treaties and declarations. Many countries and international organizations have established water quality guidelines for potable water supplies, thereby defining standards for treatment processes to meet. Unfortunately, potable water for all is a goal that has not yet been fully realized. Water-related diseases remain the number one cause of death for children under five worldwide; these problems are particularly evident in rural areas of developing countries. In addition, emerging contaminants and disinfection by-products have been linked to chronic health problems for people in the developed and developing world. This chapter provides an overview of critical problems relating to the provisioning of global potable water. First, current health impacts of water-related illnesses as well as natural and human influences that will alter our current water supply in the coming decades are reviewed. The technical limitations to water treatment in both developed and emerging economies are then discussed. Additionally, a brief look at the social and political factors influencing potable water access such as government capacity, competing interests, and the influence of food choices on water availability will be discussed. Finally, some current innovative approaches and suggested strategies for water management in the future are presented.

Humans use a large variety of chemicals in their everyday lives including over-the-counter medications, prescription drugs, and personal care products. The chemicals that comprise these items enter wastewater treatment systems when they are manufactured by companies and used by consumers. Wastewater treatment plants have various removal efficiencies, causing these chemicals, generally referred to as “emerging contaminants,” to enter surface water bodies. In addition to human sources of emerging contaminants, veterinary pharmaceuticals and hormones are given to livestock raised in concentrated animal feeding operations. The land application of biosolids and animal waste to agricultural fields as a fertilizer source also introduces emerging contaminants into the environment. Recent advances in technology have allowed researchers to detect these compounds in water samples at significantly lower concentrations, thereby allowing researchers to assess the exposure of humans and aquatic species to concentrations at the parts-per-trillion level. This chapter provides an overview of the types of emerging contaminants found in potable water sources, their major sources, issues associated with their removal in treatment plants, and a social perspective of the public’s concerns regarding emerging contaminants in their potable water.

This chapter addresses general characteristics of water distribution systems with focus on minor systems. Major systems are water mains that bring drinking water from water treatment plant to the building premises. Minor systems include service lines that connect major systems to minor system and in-building plumbing system. This chapter provides a detailed review of minor systems and mechanisms of minor systems’ failures and describes experimental studies designed to replicate the range of pressures encountered in actual minor water distribution systems and how a pressure transient triggered within major and minor systems can impact service lines with possible contamination intrusion in minor systems. It is demonstrated that hydraulic transients triggered from water mains result in low-pressure events in service lines which can allow possible intrusion of microbial and chemical contaminants in service lines. It is concluded that the structural integrity of service lines and the hydraulic integrity of water distribution systems should be maintained in order to minimize public health risks from contaminant intrusion in minor systems and tap water.

Feedbacks between water and energy complicate the daunting task of supplying safe drinking water to a growing population. Potable water treatment and distribution require large quantities of energy and at present largely rely on fossil fuels. While the available fuel source dwindles, the demand for energy to supply drinking water will likely increase due to a growing global population, higher demand for enhanced water treatment and distribution, and the necessary use of energy-intensive alternative water sources such as wastewater and saline water. Electricity production also requires significant quantities of water and may be in direct competition for freshwater resources with potable water supply. The quantity of water used in electricity production will likely increase in future years with rising electricity demand and changes in electricity production. Electricity production can also contaminate water supply sources. Finally, climate change is affecting precipitation patterns and water demand, which will further complicate supplying drinking water to a growing population. This chapter provides an overview of the ways in which the water–energy nexus creates challenges and opportunities in meeting potable water demand.

Both population growth and movement put forth the need for increased regional water supplies across the globe. While significant progress has been made in the area of building new infrastructure to capture freshwater and divert it to urban and rural areas, there exists a considerable difference in the supply and demand of high-quality water. The cost and non-sustainability of diverting ever increasing volumes of water to stressed areas have become difficult to justify. Therefore, a key step in finding a solution to it is to identify alternate water resources. Given that approximately 45 million cubic meters of municipal wastewater is discharged every day in the United States, researchers and water industry planners have identified municipal wastewater as a viable source for water reuse. Given this potential source, an appraisal of the varying qualities and characteristics of municipal wastewater affecting water reuse is made. This is followed by a discussion on different sectors such as urban, agriculture, and industry that are potential consumers of reclaimed water. The conventional and advanced treatment technologies used to treat municipal wastewater to meet reuse standards are then evaluated; and a number of case studies demonstrating water reuse schemes in different parts of the world are described in brief.

Availability of freshwater is the prime mover of the human life activities. The advances in desalination technologies clearly show that desalinated water can be used as a substitute for freshwater to be used as potable water. A breakthrough in reverse osmosis costs has been reached, particularly in decreasing energy consumption. The introduction of nanotechnology in the membrane manufacture has resulted in reducing the volume of rejected brine which in turn alleviates the brine disposal issue. Several recent studies show that desalinated water for development of isolated areas is economically competitive to transportation of freshwater by pipeline. The introduction of solar energy to power desalination process has given a new dimension to the expansion of desalination technology. Several studies show the importance of solar desalination in countries suffering from freshwater shortage, particularly in isolated areas. This chapter presents an overview of desalination technologies with emphasis on solar energy-driven units. Some case studies are highlighted. The chapter concludes with a discussion of future avenues in solar desalination.

This chapter discusses the rationale beyond global expansion of bottled water, components of bottled water industry, and problems associated with bottled water production and consumption; energy demand; health concerns; and plastic pollution. From technology perspective, bottled water can be considered a decentralized water system which distributes water for human consumption via a portable container instead of a pipeline which is a required component for transporting water via conventional water supply infrastructure. It is concluded that the current bottled water industry is not a part of a sustainable solution for the overall challenge of providing safe drinking water worldwide. However, bottled water can be a part of an overall solution to global lack of safe drinking water and community development if innovative water treatment technologies, renewable energy use, and biodegradable plastic (or similar materials) are incorporated into bottled water production and infrastructure system design.