One might wonder where the water in our toilets and showers ends up once it is flushed or runs down the drain. For the majority of homes, water and waste travels through a network of sewage pipes and pump stations that transport it to a nearby wastewater treatment plant.
At the plant, various treatment processes are employed to remove debris, biological and chemical contaminants, and harmful pollutants. Once the water has been sufficiently processed, cleansed, and decontaminated it is transferred to local surface water bodies (lakes, rivers, and streams).
Ramesh Goel in the Department of Civil and Environmental Engineering has been studying the effects of wastewater treatment on Utah’s surface waters. Surface waters generally serve as one of the primary sources for drinking water.
One component of wastewater that Dr. Goel is investigating is phosphorus. Phosphorus is essential for human and animal health, plant growth, and bacterial growth. However, too much phosphorus in the environment can cause extreme overgrowth of harmful algae that can lead to an ecosystem imbalance. “Because phosphorus already exists in the sediments of many surface water bodies, we don’t want to be adding more of it to our rivers and lakes through wastewater,” says Dr. Goel.
Harmful algae produces cyanotoxins that hurt birds and other wildlife that drink the water it grows in. Birds can also be harmed by eating fish or shrimp that feed on algae. He adds that tap water, however, is not affected because potential algae toxins are removed before water arrives in your home.
Excessive amounts of algae can also impede sunlight from penetrating through surface waters, which can be a problem for certain aquatic organisms that rely on sunlight to live. Another problem involves the aesthetic quality of water. “You wouldn’t want to swim in water with a large amount of algae floating on the surface,” says Dr. Goel.
Due to special treatment required to remove phosphorus and a lack of awareness about its effects over time, the majority of wastewater plants in Utah do not attempt to remove phosphorus during the treatment process. Consequently, phosphorus from human waste passes through into surface waters. And after so many years of collecting extra phosphorus, Utah’s rivers and lakes are being hard hit.
Some other states are ahead of Utah in removing phosphorus from wastewater, says Dr. Goel, who is the sole investigator at a Utah university doing this type of research.
Dr. Goel is working with Utah wastewater treatment plants to devise a workable solution. Although phosphorus can be removed through chemical precipitation, which involves the use of aluminum sulfate, the process is costly and creates chemical sludge—another waste material—that has to be disposed of. A more cost-effective, environmentally friendly method of removing phosphorus is through bacteria called polyphosphate-accumulating organisms (or PAOs).
Dr. Goel is currently investigating the presence and role of PAOs in many full-scale wastewater treatment plants in Utah. The ultimate objective of Dr. Goel’s ongoing research is to help plant operators and district managers achieve safe and effective biological phosphorus removal without much capital cost.
“I tell them they wo’t need to construct a new plant or spend millions of dollars on upgrading”, he says. “The cost would be minimal to treat wastewater with PAOs.”
“Down the road, the EPA [Environmental Protection Agency] will require us to do something about the presence of phosphorus in our lakes and rivers,” says Dr. Goel. “With Utah water quality deteriorating as rapidly as it is, we should begin correcting the problem now.”
For more information on Dr. Goel’s research, visit his home page.