Thousands of pharmaceuticals are being used today to treat various diseases. Pharmaceuticals have been described as contaminants of emerging concern, because of their potential adverse effects on humans and the ecosystem. For instance, antibiotics can give rise to antibiotic-resistant bacteria, which can bring about irreparable harm to humans. Other pharmaceutical contaminants can cause various other problems such as the development of reproduction disorders, birth defects, severe bleeding, cancers, organ damage, endocrine disorders, and toxic effects on aquatic organisms.

Unique among all the contaminants that adversely affect surface- and groundwater quality, radioactive compounds pose a double threat from toxicity and ionizing radiation. The high energy potential of many of these materials makes them both useful and hazardous. The unique properties of radioactive materials make them invaluable for medical and energy applications. However, mining, production, use, and disposal of compounds and their byproducts provide potential pathways for their release into the environment, posing a risk to both humans and ecosystems. This chapter presents an overview of the sources and uses of radioactive compounds in the United States, biogeochemical processes that control mobility in the environment, examples of radionuclide contamination, and an overview of remediation strategies.

Treating and reusing wastewater can augment water scarcity in water-stressed regions in the world. Additionally, wastewater streams contain useful resources that can be recovered and recycled to improve the economics of the water treatment processes. Another aspect that has been reported in the past few decades is the detection of novel contaminants of concern in the wastewater samples that often escape treatment and remediation. Studies have demonstrated that the conventional wastewater treatment practices are not sufficient to address resource recovery and emerging contaminants aspects. In this chapter, first, conventional wastewater treatment process based on activated sludge is presented, and subsequently novel wastewater treatment methods have been discussed. Theoretical aspect of each method is described, and its implementation in pilot or full-scale study has been highlighted. For increasing the water recovery rate from waste streams, membrane-based treatment technologies such as reverse osmosis will be crucial. Ion-exchange, adsorption, microalgal, and bioelectrochemical systems can be advantageous from resource recovery perspective. Further, epidemiological aspects of wastewater have been highlighted and the recent spread of COVID-19 has been discussed with respect to the virus’ detection in toilet wastewater.

Arsenic is a metalloid and the major cause of concern for the pollution in drinking water and soil. The toxicity issues with the health, while its consumption more than the WHO permissible limit is the major reason for the death of the people, due to contaminated drinking water consumption. With respect to toxicity arsenic(III) form is considered more dangerous. Various methods and technologies have been developed against this global problem. The physical, chemical, and biological remediation technologies were developed to reduce the hazardous effects. The rock mining, volcano eruption, and contaminated soil leaching are the major sources of the groundwater contamination. Biobased remediation methods are focusing these days due to their less side effect and nontoxic nature of the treatment process such as biosorption, biomethylation, and bioaugmentation. This chapter describes the forms of arsenic, their causes, health effects, case study, different types of treatment technologies, and their use in household and commercial level. New advancements based on nanolevel treatment technologies are coming in future to completely remove the arsenic from consumable water and can also provide the benchmarks to develop more accurate technological advancement in removing total contaminations from each kind of source.

The world is not on track to meet its goal for ensuring availability and sustainable management of water quality for all—as indicated in United Nations Sustainable Development Goal 6 (SDG 6). Quality of water crisis continues to be rated as a top global risk considering pollution severity and threat to public health trend in the face of climate change. This chapter highlights the issue of “coordination gaps” in terms of policymaking, pollution prevention technology, financing, monitoring and data management, accountability, risk assessment, and capacity building as a part of water governance for improving water quality. In this context, this chapter attempts to promote policy understanding and coordination at horizontal and vertical level institutions to take risk-informed integrated decision. This chapter also emphasized on science-driven policy solutions and adopting good practices including engagement of public, private, and civil society for reducing water risk and uncertainty at local to global context.

Water quality worldwide is poor even though some advanced countries enjoy relatively clean water. This compels almost 1.2 billion people to drink unclean water at present. According to the United Nations, 2.7 billion people will not have clean water by 2025. Earth is a water planet, composed of 70% water; only 3% is fresh water and only 0.06% is available without problems. Over 80 countries in the world suffer from water shortages. Contamination of water from various chemicals is a major point of concern because countless inorganic and organic compounds can pollute our groundwater and surface water.

Africa is the second driest continent after Australia with fast-growing population and urban centers. Water scarcity is acute in the east, south, north, and large parts of Central Africa. Cities and towns are growing fast and most of them do not have sufficient piped water to their urban dwellers. Climate change has altered the rainfall pattern and quantity. Future water supply for agriculture, household consumption, and recreation are either insufficient or contaminated with pollutants. Water conservation alone will not provide future water without implementation of major waterworks and desalination processes. Methods of improvement of water quality for domestic consumption are presented in this chapter. The chapter reports work on clay ceramics made locally by women pottery workers and frustum made in the laboratory combining Moringa oleifera wood to make pores in both clay works. Second, two nanoparticle composite catalysts of TiO2-NO3 and TiO3-WO3 were synthesized and studied and previously reported for the efficiency in Escherichia coli disinfection, dyes discoloration, and pesticides mineralization. A new synthesis of TiO2-WO3 composite is reported and its characterization is discussed. The effectiveness of the clay ceramics and nanoparticle composite catalysts is reviewed.

Effective integration of the principles of green chemistry into water remediation research and practice has offered promising novel solutions to combat the current global challenges. This chapter reviews both established as well as cutting-edge techniques (advanced green technologies) for sustainable water remediation, including nanotechnology-enabled water treatment processes, biofiltration, bioremediation, cycloelectrowinning, and photocatalysis. To motivate the readers, there is a special emphasis on several award-winning green technologies that highlight the fact that the most effective way to deal with the water pollution is to use the least harmful ways to prohibit contaminants or redesign pathways that would lead to virtually no waste or least waste generation. Additionally, a special subsection has been devoted toward large-scale reactors utilized for real-time contaminant removal/degradation installed at different polluted sites.

Our water supplies are at risk from accidental and intentional contamination. An all-hazards approach to securing our water supplies is required to protect us from unknown and unexpected events. To detect, understand, and respond to such events, a water safety plan approach is warranted. Monitoring is a key component of any water safety plan and requires a different type of monitoring than has traditionally been carried out. This chapter explores the threat to our water and some of the technologies that are available to help guard against these threats.

Pure drinking water (potable water) is absolutely essential for our survival. More than 1 billion people in the world have limited access to safe drinking water. Furthermore, nearly 2.6 billion people have issues relating to poor sanitation that results in inferior water quality. Over 1 million people die every year from sicknesses communicated through use of unsafe water. Drinking-water pollution is caused by the careless disposal of pharmaceuticals, fertilizers, pesticides, and a large variety of other chemicals. This results in contamination of our drinking-water sources with heavy metals, radionuclides, pesticides, plastics, organic nutrients, inorganic pollutants, pharmaceuticals, etc. Polluted drinking water is a major cause for a variety of different diseases in human beings. To solve these critical issues, it is necessary to purify contaminated water. Nanomaterials and nanotechnology can play an important role in water purification. Discussed in the chapter are drinking-water regulations, limitations of conventional water purification methods, nanotechnology-based water purification methods and their applications for purification of water containing arsenic, lead, pharmaceuticals, or perfluoroalkyl substances.