Water Quality and Quantity Issues: The Next Environmental Crises?

The issues facing both the quality and quantity of water supplies demand immediate attention.
For millions of years, a fixed quantity of water has existed on this planet. We are neither gaining nor losing water in terms of quantity. Unfortunately, humankind is doing a great job of contaminating it.

Every time water goes down the drain, whether to a sewer, a septic system, a storm drain or wherever, it carries contaminants with it, which obviously affect quality. Included are unmetabolized pharmaceuticals, chemicals and particles from hand and face washing, bathing, laundry, the toilet, not to mention the almost innumerable contaminants from agriculture and industry activity. Many of the contaminants are in tiny concentrations, and as our ability to measure smaller concentrations — now at the nanogram per liter, or parts per trillion (ppt), level — more and more contaminants are discovered, some we were not even aware of. To put it into context, one part per trillion is equivalent to one second in 32,000 years. There is every reason to believe that as analytical chemists become capable of measuring even smaller concentrations — think parts per quadrillion, one-thousandth of a ppt — even more contamination issues will be identified.

Links between these contaminants and human health are sorely lacking, but many risk assessment studies are ongoing, and, in this writer’s opinion, these links will surely come, and there is lots of anecdotal evidence supporting this belief.

As the global population continues to grow, the demand for additional quantities of water for personal use will increase proportionately. One estimate indicates that currently, 25 percent of the earth’s population is experiencing water shortages. Also, the huge influx of digital influences such as artificial intelligence underscored by data center growth creates an even greater demand for water. It is estimated that each data center could use as much as 5 million gallons of cooling water per day. And climate changes are predicted to create many areas of regional water shortages.

This article addresses the sources of water contaminants, their possible health effects, and describes some of the technologies utilized to remove them. It also identifies strategies to address the issues associated with water shortages.

Water Quality: Dissolved Solids

Water supplies for residential, commercial and industrial applications almost always require some treatment. Generally, the minimum quality requirement is to drinking water quality standards. Many countries have set their own standards; however, most are based on those of World Health Organization or the U.S. Environmental Protection Agency.

The EPA National Primary Drinking Water Regulations lists less than 100 specific chemicals that can affect human health if the concentration in a water supply is above a specific maximum concentration level (MCL). Given that there are at least 85,000 chemicals in water supplies and less than 150 have gone through the required rigorous and complex risk assessment protocol, there is a long way to go to determine how many of these may be harmful.

It is important to note that although many contaminants are naturally in the water, the majority of harmful chemicals come from human activities, wastewater going down the drain.

In the home, no matter the water use, contaminants are carried down the drain. The same is basically true with most commercial activities. Industrial wastewater usually comes from manufacturing operations where it may be used for rinsing, cooling, or in the manufacturing process itself. Virtually all of the above ends up in a wastewater treatment plant along with sewage and other biodegradable waste, which is broken down into benign materials, mostly sludge. On the other hand, the vast majority of the soluble chemicals end up in wastewater that is directed to a river or other water body that becomes the water supply for a downstream community.

A particularly notorious class of chemicals commanding considerable media attention over the last several years is known as PFAS — per- and polyfluoroalkyl substances. They constitute a family of more than 16,000 manufactured chemicals which are water soluble and tend to bioaccumulate in humans.

If the wastewater is directed into a septic system, the treated water percolates into the earth where it usually enters an aquifer or other water supply and ultimately meets the same fate as above.

It’s a fact of life: virtually every time water goes down the drain, it is carrying contaminants that likely end up in someone’s drinking water.

Chemicals are used to manufacture 96 percent of consumer products; the average adult uses nine products per day containing 126 different chemicals.

Fertilizers, pesticides, herbicides and antibiotics are all also used in agriculture and animal husbandry operations. Weather events generating runoff from lawn and agricultural surfaces also contribute to this contamination.

Figure 1 illustrates the sources and fate of water-borne contaminants in the environment. It emphasizes pharmaceuticals, but represents all of the soluble contaminants.

PFAS Health Risk

PFAS can bind to blood proteins, penetrate the liver and have been associated with the following:

• Cancers;
• Pregnancy complications;
• Thyroid disease;
• Ulcerative colitis; and
• Numerous other issues, including tooth decay.

To date, there have been very few conclusive links between PFAS and a particular disease; however, two compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) have recently been placed on the EPA’s Primary Drinking Water List. Effective in 2031, all U.S. municipal water must contain no more than 4 ng/L (ppt) of either compound. Of the greater than 16,000 different PFAS compounds in the environment, less than 10 have undergone risk assessment, and there is every reason to believe that many more will ultimately be considered health risks and end up on the Primary List.

Every time water goes down the drain, whether to a sewer, a septic system, a storm drain or wherever, it carries contaminants with it, which obviously affect quality.

Treatment

There are several technologies capable of removing and/or breaking down these dissolved chemicals. The vast majority are organic, and activated carbon adsorption is effective at removing many organic compounds. The “spent” carbon can often be landfilled and many of the non-PFAS contaminants are subject to biodegradation. PFAS are extremely difficult to break down chemically, but significant advancement is being made with technologies to reduce these compounds to their basic chemicals — fluoride, water and carbon dioxide — and at least two have been employed on an industrial basis.

The family of membrane technologies — microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) — is very effective for the reduction of a wide range of contaminants. MF and UF will target higher molecular weight pharmaceuticals and personal care products (PPCP) organic compounds, while NF and RO are most effective on the more ionic, or polar, and lower molecular weight organic compounds. These membrane technologies are designed to reject the contaminants into a separate concentrate stream that is usually discharged to drain. They are very effective when used to treat water specifically for drinking and culinary purposes. Of course, these technologies don’t destroy PPCPs, they just redirect them into the drain. Such notorious contaminants as lead and nitrate are also readily removed by reverse osmosis.

Table 1 summarizes the PPCP treatment properties of both activated carbon and membrane technologies.

Distillation is also an effective technology for the reduction of water-borne contaminants. This process involves boiling the water and then condensing the water vapor to produce purified water. A potential problem is that those organics with boiling points close to that of water, volatile organic compounds, may also evaporate and end up in the distillate. Activated carbon can be utilized to help mitigate this problem. A downside of distillation is the energy required to boil water and to cool the distillate.

The technologies known as advanced oxidation processes (AOPs) utilize destructive technologies such as ultraviolet (UV) irradiation, ozone and hydrogen peroxide in various combinations and concentrations to break organic bonds, and generally produce more benign chemicals. Depending on the characteristics of the chemicals resulting from these oxidation processes, they may or may not be less dangerous; however, the resulting chemicals may be more easily removed by the other processes. In the wastewater treatment industry, AOPs are often used to inactivate, or kill, microorganisms.

It may be that harnessing the elusive hydroxyl radical (•OH) will be required to more completely break down some compounds. The technologies to produce this very powerful oxidant have escaped widespread practical application so far, but it should become reality in the not-too-distant future.
The point of use (POU) “undersink” reverse osmosis (RO) units designed to treat drinking water for a single tap (see Figure 2), readily available from water conditioning dealers and DIY stores, have been shown to be capable of removing an estimated 60 to 80 percent of all PPCPs. Because they all incorporate both activated carbon and RO membrane technology, they should all work equally well. This is the best possible solution to the PPCP issue for residential water treatment at this time.

A typical POU RO unit is commonly located under the kitchen sink, but can even be placed in the basement or another remote location. Tubing can also be directed from the storage tank to the refrigerator for ice and water-in-door applications. Although less commonly utilized, POU distillers are also available.

Obviously, one can, and should, become a personal steward of our own environment. This includes diligence about what we throw down the drain, as well as our overall water usage.

Regardless of the treatment technology selected, they all require maintenance, primarily dictated by the characteristics of the water to be treated. Usually, the issue is suspended solids in the water supply, or certain chemicals that may become insoluble during the purification process. For example, POU reverse osmosis units and distillers should be fed with softened water.

Individual Behavior

Obviously, one can, and should, become a personal steward of our own environment. This includes diligence about what we throw down the drain, as well as our overall water usage. There is evidence that people are becoming more careful about how they dispose of unused pharmaceutical products. Many pharmacies accept them at no charge, and, at the very least, more consumers are disposing of them in the trash rather than the toilet.

Personal practices must be individually monitored regarding purchases and disposal of personal care products. Fortunately, this attitude seems to be taking hold, albeit very slowly.

Water Quality: Suspended Solids AKA Microplastics

In addition to the plethora of dissolved chemicals in water, an equally concerning family of contaminants is categorized under the heading of microplastics. These are suspended solids consisting of tiny pieces of plastic which have become ubiquitous throughout the world.

It is said that plastics are the defining material of our age. An estimated 523 million tons were produced globally in 2022, and this quantity could easily double by 2050. More than 98 percent of plastics are made from fossil fuels and are not water soluble. The problem is that when exposed to sunlight, UV radiation makes them brittle, and they break down into tiny fragments less than 1 micrometer (µm) in size, but do not dissolve. When ingested, such nanoplastics can apparently enter the bloodstream of both humans and animals. Some studies have shown that the average human brain may contain as much as 7 grams — equivalent to the weight of a plastic spoon — of nanoplastics. In addition, there are approximately 16,000 chemical additives in plastic formulations that can be released into the water. Plastic surfaces also may adsorb chemicals and microorganisms from the water and release them once they enter a body. Nanoplastics can be fibrous and come from such articles as fleece clothing or vehicle tires. Most nanoplastics end up in the ocean, and it is predicted that without reducing the production of plastics globally, there will be more plastics by weight than fish by 2050.

Figure 2 illustrates the ubiquity of plastics and the quantities found in the environment.

It is estimated that almost half of plastics produced become single-use items, used once and then thrown away.

Of the plastic produced in the United States, three quarters is discarded. Just 9 percent is recycled, 12 percent is incinerated and the rest is either landfilled or just thrown on the ground.

So far, there is no proven link between nanoplastics and human health. Although many scientific studies are underway, there is a lack of conclusive proof. With so much absolute evidence of damage to marine life and other animals, it is only a matter of time before human health risks are identified.

The challenge is what can be done with the unimaginable quantity of nanoplastics on land, in the air, in our drinking water and in the oceans.

Extensive work is underway to develop microorganisms that will consume these, but with the huge variety of plastic formulations and chemical additives, this is a daunting, if not impossible task.

Alternative Materials

Significant effort is underway to create biodegradable plastics. This is also a challenge and is facing a significant economic barrier because plastics are so inexpensive.

Although plastics are fundamentally ingrained in daily life, individual practices can have a significant and collective effect on the consumption of plastics, including:

• Refusing all single-use plastic bags and straws;
• Taking a reusable bag when shopping;
• Making an effort to recycle all discarded plastics;
• Promoting legislation for plastic bottle reuse, including bottle deposits, and to curtail plastics manufacturing; and
• Shopping only at retailers who promote environmentally sustainable practices.

We must resist the pressures of a “disposable society.”

The POU reverse osmosis technology is very effective at removing nanoplastics in drinking water. Because nanoplastics may be released inside a plastic water bottle, a stainless steel or glass bottle filled with RO water is a much safer choice. A submicron point-of-entry filter will remove most nanoplastics entering the residence.

Water Quantity

It is well understood that climate change will irreversibly affect rainfall patterns with drought in some areas and flooding in others. Decisions regarding the location of new manufacturing or residential developments are often based on availability of energy, trained personnel, and available land, whereas the availability of freshwater supplies is not considered. To address this, unconventional approaches such as atmospheric water harvesting, graywater reuse or rainwater harvesting may be employed; however, one often overlooked approach is wastewater recovery and reuse. Whether the water use is for manufacturing semiconductor devices or as cooling water from a data center, there is no such thing as a wastewater supply too contaminated to be treated and reused. Extensive testing and perhaps piloting may be required, but it is even possible to employ zero liquid discharge technologies to ensure that all the water is reused and only solids leave the facility.

Too often, the decision-makers are not sufficiently knowledgeable about the availability of technologies to treat wastewater to facilitate complete reuse.

The Future

So, what does the future hold?

It is this writer’s opinion that:

• The concentrations of all water contaminants will continue to increase in water supplies;
• Better defined risks to human health from water supplies will eventually be identified and quantified;
• POU RO systems will become a standard appliance in the home;
• People will become better water and plastic stewards; and
• There will be greater use of innovative processes for treating and reusing wastewater from virtually all sources.

Creativity and innovation are human characteristics, and once the chemistry of the problem is known, new products, processes and improvements will be developed. These are exciting times for the water and wastewater treatment industry, as the sector is just beginning to explore what’s possible.