Wastewater Series: How Geomembranes help to improve water quality, lower costs and increase efficiencies in wastewater treatment
Part 1: Wastewater Industry in North America
“We still think of air as free. But clean air is not free, and neither is clean water. The price tag on pollution control is high. Through our years of past carelessness, we incurred a debt to nature, and now that debt is being called.”
– Richard M. Nixon State of the Union Speech, January 22, 1970.
One of the largest uses of geomembranes is in the water/wastewater industry. Water and wastewater are often discussed in terms of their combined impact, as one provides the water that, for the most part, is treated by the other. Some treatment processes are similar, and the quality of drinking water can be severely impacted by improper wastewater management. In this series, the focus will be on the wastewater segment and how geomembranes are used in that industry.
History of Wastewater Treatment
Various sources give widely varying timeframes on when treatment of human waste began. The exact culture which can be given that honor is also conflicting. Regardless, there are numerous mentions of managed treatment or disposal over 2000 years ago. It seems the Romans around 500 BC were the first to build a main water collection and transport channel (Cloaca Maxima) designed to carry rainwater out of the city. Some sources indicate these appurtenances were also used to carry wastes away from populated areas, making this the first noted use of water as a carrier of wastes. Water has long been recognized as, and is today, the most efficient method to move continuously generated domestic wastes.
The National Gallery of Art, Washington D.C.
https://www.nga.gov/collection/art-object-page.125227.html
It was early in the 19th century, after outbreaks of cholera, that water closets in larger towns were connected to storm sewers. Of course, this continued to transfer the problem to surface water pollution. Simple dilution of wastes was successful in masking the effects of these materials until the load exceeded the assimilation capacity of the receiving water body.
All of this said, wastes were simply being transported to open waterways and natural attenuation provided some level of organic degradation. Sewage treatment became necessary in the late 19th/early 20th century, principally in the U.S. and the U.K., as population centers could no longer rely on surface waters to solve the problem. Early treatment efforts consisted of solids removal process (Imhoff tanks, similar to septic tanks) and holding ponds where land was available. More formal biological treatment followed shortly after this era.
Wastewater Treatment Regulatory Actions in the U.S./Canada
Prior to 1948, various minor laws in the U.S. attempted to address the growing health and environmental impacts from the discharge of raw sewage. The only notable one was the Refuse Act which was only aimed at preventing the dumping of materials which might cause navigational issues. In 1948, the Federal Water Pollution Control Act (FWPCA), was passed to deal with the increased amount of wastewater being generated in the post-World War II growth era. It was largely ineffective in many ways including lack of clarity in enforcement actions and no real measures to prevent pollution.
Thomas James, Cleveland State University. Michael Schwartz Library. Special Collections.
https://clevelandmemory.contentdm.oclc.org/digital/collection/press/id/605/rec/1
Public attention to the problem of surface water pollution was magnified when, in 1968, the Cuyahoga River in Cleveland caught fire due to massive amounts of industrial discharges. That event was the impetus to the passage of the Clean Water Act of 1972 (CWA), which was a total rewrite of the FWPCA and is the law governing management of wastewaters today. It was, and is, a comprehensive set of regulations, rules, guidelines, and enforcement mechanisms that has greatly improved the quality of surface and ground waters. Various levels of treatment are mandated and are technology-based. The success of this law can be somewhat attributed to the fact that the Environmental Protection Agency had been created in 1970 and has been instrumental in administering it.
According to the 2021 ASCE Infrastructure Report Card, there are now over 16,000 regulated Publicly Owned Treatment Works (POTW), serving 238 million people. The remainder are served by septic tanks and private treatment systems. All point discharges of wastewater are regulated under the CWA.
The primary Federal law controlling wastewater releases in Canada is the Fisheries Act. As part of that legislation, the Federal government established (on-going) the Wastewater Systems Effluent Regulations which provide baseline municipal effluent quality standards administered on a provincial level. The system is like that in the U.S. In 2017, 86% of the Canadian population was served by almost 2000 municipal treatment plants.
The worldwide water and wastewater treatment industry is estimated to be as much as $350 Billion/year with approximately half being in the U.S/Canada alone. Owners, customers, and designers are always looking for ways to meet increasing demands for capacity and quality. Geomembranes often provide innovative answers to those demands and are used in wastewater Collection and Equalization, Treatment and Residuals Management to increase efficiencies, lower costs and meet regulations.
In the next post of this series, the processes used today for treatment of wastewater will be reviewed. Geomembranes are an integral component of many of these processes.
