Sewage Treatment Plants

Flush the toilet, and away the waste goes. People treat sewage much like they treat their other garbage. As long as it goes someplace else, they are happy to send it away. Sewage treatment plants are operations that take our untreated sewage and, through biological and chemical processes, treat the waste. Some plants are better equipped to do this than others. There are multiple stages in the treatmentment process. The sophistication of the treatment plant near you will determine how much waste is needed to be disposed of and what needs to be done with it.

 

While this subject is anything but glamorous or dinner table conversation, it’s important to discuss.  Sewage treatment plants deserve much of the credit for reducing diseases in many of our modern cities back in the early 1900s. These plants really are a marvel of modern engineering, and without sewage treatment plants, our society would most likely have continued to be plagued with the highly contagious and deadly diseases such as dysentery, cholera, and typhoid, which human waste caused throughout modern history. Incidentally, lack of adequate sewage treatment systems in many countries today is the single biggest cause for contaminated water supplies and diseases ravaging the people living in them. 

 

The expanded definition of “sewage” from the Dover Township, Pennsylvania, website put it elegantly, “Sewage, also called wastewater, is the contaminated water from homes, schools, and businesses. It comes from toilets, showers, clothes washers, dishwashers, etc.  The contaminants include fecal matter, urine, soaps, detergents, food particles, hair, rags, paper, toys, dead goldfish, and anything else that is disposed in a drain.  A person creates an average of 60 to 100 gallons of wastewater every day.” 

 

The township’s website also discusses treatment plants: “Sewers are a network of pipes that bring the sewage to the treatment plant for treatment. Treatment is the continual process of removing contaminants from wastewater and then processing the removed contaminants into a product that can be safely recycled.”

 

As Dover Township’s words make it clear, sewage treatment plants are a necessary part of any community. Without sewage treatment plants, disease would spread throughout the population. An effective sewage treatment operation also protects the public from contaminated water. In countries where there is no sewage system or treatment facilities for human waste, bacteria from sewage gets into the wells and other water sources. 

 

Living in a neighborhood near the municipal sewage treatment can be trying at times. Almost every municipality that has a public water system connecting all the homes also has a sewage treatment plant. The system sends clean, safe water into the house and takes away the dirty water. 

 

Usually, when we think about our wastewater, we think of feces. The reality is that much of the vast volume of waste that flows through the sewage treatment plant is contaminated water. The rest is water from showers, sinks, and drains–residential, commercial, and industrial.  A single industrial user may discharge thousands of times more wastewater in one day than a residential home would in an entire year. Some of that water flowing through the sewage treatment plant is stormwater that ran off the streets. All added up together, only a few percent of the millions of gallons flowing through the plant are any kind of solids. Depending on how many industrial operations and commercial businesses are discharging waste into the system, once the solids are removed, much of the waste flow is made up of 95% or more of water. The solids though are made up of feces and industrial wastes, making it extremely hazardous. 

 

However, this water may contain any number of hazardous materials ranging from radioactive isotopes to toxic waste. The wastewater flowing into the plant is, after all, coming from inside factories, stores, and restaurants in addition to all the dirt, oil, gas, and junk that washes off of the streets. 

 

The vast majority of the liquid waste is treated in the primary and secondary process where it is separated from the solids through aeration and settling. It is then disinfected before it is sent from the plant into either a nearby body of water or used to recharge the water aquifer and go through the cycle again. The result of sewage treatment is clean water, but “clean” is a relative term. There are disputes as to what the discharged water still contains after treatment, but only a small number of chemicals are tested for. The solids that remain are separated out through the various stages.

 

Despite their valuable and necessary function, there are some hazards associated with living near a sewage treatment plant.

 

1. Odors

 

There is almost no way around it. Feces have an odor, and thousands of gallons of it in one place is necessarily going to smell. Many sewage treatment plants try to keep odors under control. Some have enclosed the giant aerator tanks, which is where much of the odor comes from. Many have not, though, instead having open air lagoons filled with sewage sludge, which stinks. There are chemicals that can be added to hold down some of the odor, but for those who live nearby, the odor can be overwhelming. On days when the humidity level is high, the odor may be especially bad. The moisture in the air keeps the evaporated water from the plant and the odor close to the ground.

 

Even treatment plants with covers do have an odor as well. When the plant is running well, the solids are separated quickly from the liquids and passed into another process where bacteria is used to further break down the sewage. As the breakdown continues, hydrogen sulfide gas is created in huge amounts. This smells like rotten eggs, only hundreds of times stronger because of the large volume of gas. 

 

Though they try to minimize it, it is almost impossible not to have some odors from a sewage treatment plant. These odors can make the lives of people living nearby truly miserable. These odors can even come into homes through the cracks in doors and windows and give residents nowhere to escape from the smell. 

 

While some plants do not smell all the time, all plants smell some of the time. Factors like the wind and the weather as well as the effectiveness of the treatment operation all affect how frequently and intensely a plant will smell. In almost every case the odors are caused by one of the gases given off from sewage sludge. While people may see odors as simply a nuisance, they are not without actual harm. Inhalation of the gas affects the respiratory system. Continuous exposure causes irritation of the airways and lungs, increases chances of asthma, and causes people who already have asthma to suffer increased attacks. Moreover, gases from the sewage contain pathogens which have the potential to make people ill in addition to actual particles of feces which is inhaled. 

 

In Waterbury, Connecticut, neighbors near the city-owned sewage treatment plant complained that the odors coming from the plant were a horrible stench. Once the mayor himself checked it out, he agreed. The mayor made a public statement promising action on the odor and agreed with the residents that the odors from the plant were the “worst [he] ever smelled.” 

 

In Asheville, North Carolina, neighbors near the sewage treatment plant are subjected to strong odors almost every night. When the humidity is high, the odors are especially strong. Eventually, one of the neighbors asked the local news station to investigate. Not only do the odors come from the plant, but at the end of the day, all the sewage pumper trucks come to dump their loads, making the odors even worse. Neighbors of the treatment plant are continuously exposed to the pathogens that travel along with the odors as particles. This could lead to increases in gastrointestinal illnesses in addition to respiratory problems. Phr 

 

In Mill Valley, California, a sewage plant is creating such odors that students in a school a short distance away are becoming sick. High levels of hydrogen sulfide gas is drifting towards the school from the sewage plant. Low concentrations of hydrogen sulfide affects the nose, throat, and lower respiratory tract. Continued low-level exposure can cause coughs and shortness of breath. Higher levels of gas may cause bronchitis in some people. Children are especially susceptible as their airways are smaller and breathe more frequently. 

 

In Walker’s Point near Milwaukee, Wisconsin, neighbors of the sewerage treatment plant have been subjected to odors from the plant for years. Currently, the plant releases the gases directly to the outside, bypassing an odor control filter system. The filter broke in 2002; the plant decided it was too costly to fix for over 15 years. The area is frequently beset with high levels of gases from decomposing sewage and composting sludge. Many neighbors suffer irritated throats, noses, and eyes from the high levels of sulfide gases emanating from the plant. 

 

In Liberty Hill, Texas, neighbors of a sewage treatment plant say the odors are so bad that they can no longer enjoy their outside areas. One resident said she doesn’t even want to let her two-year-old daughter outside. The development was built within eyesight of the already existing treatment plant. For over a year, there has been a lingering odor of sewage throughout the community. The treatment plant has been cited by the Texas Environmental Agency for dumping chlorine and human waste into the San Gabriel River. One resident who called the Texas Commission of Environmental Quality while trying to take a sample of water from the sewage plant discharge line reported burning sensations in his eyes, nose and lungs after going near the water. 

 

2. Vermin and Flies

 

Flies are always looking for their next meal and a place to lay their eggs for the next generation. A sewage treatment plant is the perfect hangout. Flies are a frequent visitor to the sewage treatment plant and the nearby neighborhoods. Flies thrive and feed on any waste available near the plant. Spills from trucks transferring loads into the plant attract flies. Plants with open air aerators are an invitation for flies to gather.

 

In Bryan, Texas, the sewage treatment plant had an infestation of flies that was breeding in one of the filters at the plant. The facility shut down the filter to try to get rid of the flies, but the flies infested homes in a two to three block radius of the treatment plant. One apartment owner counted 400 flies in her place. Flies are known carriers of pathogens and, especially as these flies were feeding on raw sewage, the area neighbors may have been exposed to a variety of bacteria. The scattered reports of upset stomachs and diarrhea most likely were caused by the contamination the flies carried and was transmitted each time they landed on the surfaces and food in people’s homes. One person reported sneezing and having a fly come out of his nose. 

 

3. Overflows, Discharges, and Releases

 

A big issue for these plants is what they do with the wastewater separated from the solids. Most sewage treatment plants are located next to a waterway when possible. Usually, the bigger the volume of the waterway for a drain, the better it is for the plant to use. The reason for this is twofold. 

 

For one, large waterways provide a place to easily dispose of the millions of gallons of liquid that are removed. There are standards the government sets that the liquid is supposed to meet before it is discharged from the plant. These standards vary widely depending on factors including the age of the plant and the capacity of the nearby waterway to absorb and dilute the wastewater to safe levels. 

 

For the other, sometimes even the best operated sewage treatment plants have incidents out of their control. Automatic monitors measure the flow of waste into the plant and watch for unusual events. But, when there is an incident caused by a pipeline that carries the waste into the plant, it creates a backup. Pumps that keep the flow moving through areas where gravity is insufficient sometimes malfunction. Other equipment inside the plant could have an issue. All these may cause the usually smoothly running system to back up. 

 

Unfortunately, when it does back up, the first to see it are those closest to the plant. While these incidents are fairly rare, they do happen, and when they do, it makes the homes affected a rather unpleasant place to be.

 

In Craig, Colorado, the sewage treatment plant experienced an electrical shutdown that stopped the sewage pumps. The problem went undiscovered over the weekend, and by Monday, two million gallons of untreated sewage was backed up in the lines. Luckily, the backup that was headed for nearby houses and businesses was caught just before it reached them.

 

In Suffolk County, New York, a mom and her son both came down with aseptic meningitis due to a backup of sewage originating with the nearby sewage treatment plant. Susan Serrano, the owner of the home, told a local news organization, “You could see the feces, you could see things floating that came from the hospital,” she said. “Our home was inundated with this raw sewage. Me and my son were walking in it.” Again in 2014, her home was flooded once more with another backup from the sewage treatment plant. 

 

In Silverton, Oregon, the local sewage treatment plant backed up raw sewage into one resident’s house. The damage caused by the backup was so severe that the local health department told her she needed to move out until complete repairs and cleanup were completed. The city paid for one night in a local hotel. This unfortunate person wound up fighting with insurance companies. In the meantime, they were telling her temporary quarters were her responsibility. The remodeling company refused to do any work because the sewage treatment plan was still not repaired and another backup could happen.

 

4. Sanitary Sewer Overflow

 

Many towns and cities built their waste treatment plants before building booms hit America. The plants were sized to meet the capacity at the time they were built, with some extra for future growth. Very few towns and cities sized their plants for the explosive growth that came. 

 

When a weather event increases the flow of wastewater coming into the plant beyond the capacity it can handle, the plant will allow the waste to bypass its system. It is not unusual for plants in larger cities to have several dozen of these events every year. For instance, in the Pittsburgh area, the Upper Allegheny Joint Sanitary Authority estimated that, for 70 days of the spring through fall recreation season, the rivers are unsafe from sewer overflow events. 

 

The EPA says many of these overflows occur in the Great Lakes states and the northeast portion of the country where the sewer systems also are combined with storm water from the streets. Frequent heavy rain and snowmelt usually predict another bypass is coming shortly. When the amount of waste exceeds the capacity of the plant to handle it, the excess may be diverted into a temporary storage area. That is, if the treatment plant even has a backup storage area. If they have one, it’s usually nothing more than a lined lagoon. If they don’t have one, they use the nearest river or lake. Unfortunately, the outflow is connected to the amount of untreated water coming in. 

 

These events are so frequent that the EPA has a name for them:  Sanitary Sewer Overflow (SSO). The EPA estimates there are between 25,000 and 75,000 of these SSOs each year. The government allows these plants to open up their overflow valves, which were designed to bypass the treatment system, and the sewage is allowed to be discharged directly into the waterway. 

 

An example of an advisory issued by a sewage treatment plant in the Pittsburgh, Pennsylvania, area is as follows: “A combined sewer overflow (CSO) occurs when storm water and sewage carried in a single pipe overload the sewer system and flow untreated into the rivers and streams. CSO’s can carry a variety of pollutants, including raw sewage, debris and bacteria.” They go on to say that they have a complementary advisory program to warn the general public of possible river contamination. While they do not prohibit or discourage recreational river activities, they do encourage recreational users to limit contact with river water when boating, fishing, water skiing, or other river recreational activities. 

 

No matter the fancy language being used, the reality is far uglier. The treatment plant is pouring millions of gallons of raw, unfiltered sewage into the river water. The complementary advisory should do more than discourage recreational activities. They should ask residents to use caution to limit any contact with river water.  

 

In Pine Island, Minnesota, the sewage treatment plant was found to be dumping untreated waste directly into the Zumbro River. When a local resident saw the outflow from the pipes, he called local health authorities. The sewage treatment plant says there is nothing they can do about the dumping. The cost to upgrade the plant to handle the additional waste was too costly to fix. Any people who would normally use the Zumbro River for recreational purposes are exposing themselves to the raw sewage. If the water comes in contact with their skin, it could cause lesions and blistering. If any of the water was ingested could cause severe gastrointestinal illnesses. 

 

Pine Island is not alone. In Nashville, Tennessee, the sewage treatment plant has dumped 4.7 million gallons of untreated waste into the Cumberland River over the past 2.5 years.In Omaha, Nebraska, a sewage treatment plant dumped 65 million gallons of raw sewage a day into the Missouri River. For over two weeks the Omaha plant continued to dump the sewage with no end in sight. They went on to state that communities downstream who relied on the Missouri for drinking water should be safe if they chemically treated their water before using any from their taps. Drinking water with bacteria from untreated sewage can cause severe gastrointestinal illnesses. The CDC had documented almost a half million cases of illnesses related to polluted drinking water in the U.S and tied 251 outbreaks of various diseases to polluted drinking water as well. 

 

5. Radioactive Wastewater

 

A new issue has been hitting sewage treatment plants the past 10 years or so: wastewater from fracking operations. In most states it is illegal to discharge untreated fracking wastewater directly into the environment, so operators have been sending it to wastewater treatment plants. However, treatment plants do not have the ability to remove most of the contaminants the fracking waste contains. In many cases there is a concentration of radioactive particles in the waste. These are carried through the treatment plant and discharged out the other end into aquifers or rivers and lakes. Many states are banning the practice, now that they have become aware of it. Some sewage treatment plants continue though to take it anyway.

 

The same situation is also occurring from the liquid waste from landfills known as leachate. As liquids drain through the landfill and hopefully are caught in the liner at the bottom, they are removed through a leachate collection system. This toxic brew is then mostly disposed of at wastewater treatment plants, which are incapable of removing many of the substances it contains. 

 

As a necessary result, the discharge of wastewater from treatment plants still contains high levels of radioactive substances.

 

At one wastewater treatment plant in Pennsylvania, the operator discovered that some materials discharged into their system were actually killing the bacteria the plant depends on to have the biological processes the plant depends on for treating the waste. As a result of decreased natural activity in the treatment plant, the treatment was unable to properly lower the level of the waste, and waste was being discharged with higher levels of contaminants than they should normally have had after processing, endangering the locals with a wide variety of health risks. 

 

6. Airborne Hazards

 

Sewage treatment has several stages to take raw, liquid sewage and process it into a semi-solid state. Stages such as aeration and dewatering move the still-liquid sewage around. During those processes, the liquid has the opportunity to splash or form water droplets in the air around the treatment tanks. Especially on the days that are windy or very humid, the droplets get carried away, and with them, studies say, pathogens too. If these particles are inhaled by people nearby, it can cause respiratory and gastrointestinal issues.

 

Bioaerosols, as these airborne particles are known, may contain different types of harmful microorganisms. There is the potential for these airborne droplets to carry viruses, pathogenic bacteria, and fungi, just to name a few. Any one of these can cause respiratory, skin, nervous system, and digestive system disorders and diseases in whoever inhales them. 

 

A study done by a group of researchers and published in the Journal of Environmental and Public Health showed concentrations of these microorganisms in neighborhoods near sewage treatment plants with outdoor aerators. These disease-carrying organisms are capable of traveling several miles from the plant, depending on winds and weather conditions. When the researchers compared occurrences of gastrointestinal illnesses with people living near the plant to those who were further away, they found increased reports of nausea, vomiting, and diarrhea occurring frequently in areas a third of a mile near the treatment plant. As the distance from the plant increased, the reports of illness decreased substantially although increased levels of pathogens remained in the air up to a mile and quarter from the plant.

 

7. Industrial Waste

 

To reiterate, industrial waste is also sent to the sewage treatment plant through the same pipes. All of the factories and commercial operations are also tied into the treatment system. There are supposed to be strict guidelines and regulations for pre-treatment of industrial waste before they are sent into the pipes to the plant. There are restrictions on certain chemicals and toxic substances being disposed of this way. However, because the pipes mix all the thousands of sources of wastewater together, there is no way to tell who violated these regulations. This can actually encourage shadier businesses to break the rules.

 

Even when these industries do follow the regulations, there are all kinds of acids, heavy metals, and other poisons they are allowed to send into the sewer. The sewer authority does not monitor for everything at the treatment plant, nor can many types of chemicals and substances be detected and removed. As a result, they go out into the stream or river as it flows to your house. 

 

Tony and I suggest that, if there is a sewage treatment plant nearby, you give it at least two miles of space to avoid the odor issue on all but some of the worst days and during upset conditions at the plant. 

 

If you are downstream, take into consideration the type of waterway and the amount of flow that is usual. Obviously, a big river will carry more volume and be able to better dilute discharges. Seriously consider if you should use the water for recreational purposes. Do you want your children playing in it? Would you want to be downstream from a sewage treatment plant and swim in the water? If you are close to the discharge pipes, use an extra amount of caution. 

 

We also suggest asking the town or state environmental agency about the water test results they have. Many rivers and waterways have a local environmental group keeping an eye on things and running their own independent tests because they trust their results more than the government’s. Get to know these groups and see what they say. Personally, we would trust the test results from these groups before we would trust what the government or utility company tells us. 

 

Sewage treatment facilities are absolutely needed to protect human health and the environment. They are needed to maintain the integrity of the public water supplies by keeping contamination out of our drinking water. However, the further away from residential areas and the more isolated they are, the better for the people living in the community.