Part of the 2019 UF IFAS social media survey across Florida found that many Floridians understood how septic systems worked, but fewer understood how sewer systems functioned. This article is going to try and tell you the basics of how sewage treatment works.
As we just mentioned, many people have no idea where their sewage goes after they flush – nor do they care – as long as it does not stay here 😊. When we flush – it goes – and that is all we think about. This is one of the advantages of sewer over septic – you do not have to maintain anything. You just flush and go. However, we will see in Part 4 that there are some things that are still on us to help keep sanitary sewage from reaching our coastal waterways.
So – where does the sewage go when we are on a sewer system?
The raw sewage leaves our house through a pipe called the lateral. This line connects to the municipal sewage line under the street. From here it flows to the local sewage treatment facility. In some communities, this is downhill from the residential area, and the sewage flows via gravity. In others, it is uphill and must use a series of pumps, or lift stations, to get the raw sewage to the treatment plant.
Sewage treatment facility.
Image: Oro Loma Sanitary District.
Once it reaches the plant the sewage undergoes PRIMARY TREATMENT. This is a series of methods that physically treats the waste. Often, stop #1 is a screen that removes large objects. You would be surprised what ends up in the sewer lines heading to the treatment facility. Wood, boxes, and plastic bags. I heard one treatment plant found a small hog in their screen system.
Once past the screens the wastewater is run through a grit chamber. This continues the physical process of removing large objects from the wastewater as it trickles through. Material such as sand and rock settles to the bottom of the chamber. This settled material can be removed, treated, and disposed of.
The effluent (water) continues on to stop #3 – the settling tank. Here it is allowed to sit so that smaller fine solids can settle to the bottom of the tank – not that different if you placed muddy water into a clear 1-gallon jar and allowed it sit, the mud would slowly settle to the bottom making the water clearer. This settled material contains much of the solid waste from when we went to the restroom. Here it is called sludge. The sludge is drained off, treated, and usually dried in a pile that would resemble dirt. Some communities load this into trucks and take it to a designated area in the landfill. Some communities will use it as a fertilizer on crops. Some countries allow this but not for crops that will be used as food. I heard some locations around the world use the dried material to form bricks and building materials.
Studies show that primary treatment can remove as much as 60% of the suspended solids and 30-40% of the organic waste that is oxygen-demanding in an aquatic system.
But…
It does not remove pathogens that maybe be in the sewage, phosphates and nitrates that can cause eutrophication, salts which alter the salinity and living conditions for aquatic life, radioisotopes, nor pesticides. For this, we will need secondary treatment.
The clearer effluent remaining after settling moves to SECONDARYTREATMENT. Where primary treatment was a physical method of treating wastewater, secondary treatment is a biological method. Stop #1 is the aerationtank. Here the effluent is aerated using a sprinkler system that provides oxygen so that the microbes living in the tank can further break down any pathogens and other biological demanding waste. This treated water is then sent to a second settling tank where more sludge is allowed to settle. The settled sludge is then cycled back into the aeration tank – and the process continues. The clearer water at the surface of the second settling tank is then sent to a tank where is disinfected – often with chlorine. If balanced correctly, the amount of chlorine added is enough to kill much of the remaining bacteria but not high enough to be a threat to the environment. This water is then analyzed for contaminants, including fecal bacteria, and – if it passes the test – is discharged into a local waterway as treated sewage. Studies have found that a combination of primary and secondary treatment can remove 95-97% of the suspended solids and oxygen-demanding waste, 70% of most toxic metal compounds, 70% of the phosphorus, and 50% of the nitrogen.
For many communities this is good and is the end of the line. For others, they are willing to spend additional dollars and move to more advanced treatments before discharge – what is called TERTIARY TREATMENT. One method of tertiary treatment is using a series of filters that can reduce the levels of phosphates and nitrates remaining in the effluent. These compounds are the ones that trigger eutrophication and algal blooms and many communities feel the extra charge on their bill is worth it. These filters can actually remove some viruses. Some use chlorine for a second round, however studies have shown that increased amounts of chlorine can react with organic materials to form chlorinated hydrocarbons – which have been linked to cancers, miscarriages, and damage to human nervous, immune, and endocrine systems. For those going this route, many have opted for UV radiation or ozone treatment in lieu of more chlorine.
After either secondary or tertiary treatment, many municipalities run their treated effluent through a marsh or swamp before it reaches the open water systems. Studies have shown that these plants are very good at up taking nutrients, and some other contaminants, as the water flows through them.
Many feel this is a better method of treating human waste than a septic system. One point is that YOU do not have to manage your tank – the city does. Though this is true there is a monthly bill to pay for this service and some would rather not pay that. It is also important to understand that you are not quite off the hook yet. There is maintenance needed to the sewer system BY THE HOMEOWNER, and we will discuss this in Part 4.
Over the course of the last week, we have been discussing invasive species issues from across the panhandle. The primary purpose was to provide information for local decision makers to develop management plans for these species. The second was to educate the local residents about which species are the largest concerns in their counties so that they too could help with management.
Cogongrass (Ray Bodrey)
Three species came up more than once: lionfish, feral hogs, and cogongrass. All three of these present large problems for the panhandle and all three are well established – party of the “dirty dozen”. In each case eradication is probably not an option. But as Ian Stone’s article from Walton County on cogongrass shows, a well thought out plan with buy in from everyone can make a difference on how bad of an impact they will have. Georgia was able to significantly reduce the impact of this grass with their comprehensive plan. The 2018 Lionfish Workshop in Ft. Walton Beach also showed that a team effort across the panhandle has helped manage that problem. Though we did not hear from Chinese Tallow, Chinese Privet, or Japanese Climbing Fern, similar efforts can go along way to reducing their impacts as well.
Cuban Treefrog
Photo: UF IFAS
We also learned about “new kids on the block” with Giant Salvinia and Cuban Treefrogs. Depending on how widespread these species are currently, eradication is possible. What it will take is an Early Detection and Rapid Response (EDRR) approach. To be successful at this local decision makers and residents will need to know:
Which species are potential threats to their counties.
How are those species transmitted.
How are they managed.
How many do you currently have in your county.
At this point the community can develop a plan to eradicate what you have and keep anymore from entering. You can find answers to these questions at your county extension office, your local CISMA website, and the EDDMapS website.
Again, with a team effort, we should be able to manage invasive species in the panhandle and reduce their impacts. As always, you can contact your county extension office for more information on invasive species issues in your area.
There are more invasive plants issues in Escambia County than animal ones; but we do have animal invasives. Some have been with us for some time, like the feral hogs which will be posted in a different article, some are more recent. In this article we are going to focus on two species that could become real problems for us without some management plan – the lionfish and the Cuban treefrog.
The Invasive Lionfish
The red lionfish (Pterois volitans) has been in the local news for some time – but as a Gulf of Mexico problem. The fish is from the Indo-Pacific region of the world and was brough here for the pet trade. The first records we have of it in the wild were in southeast Florida in the 1980s. We are not 100% sure how they reached the Atlantic Ocean, but they did – and they did well.
Lionfish display a courtship dance where, near sunset, the males and females rise off the reef in a rotating swimming pattern and then fertilize their eggs. On average, each female will fertilize 30,000 eggs every four days! These fertilized eggs are encased in a gelatinous sac that drifts with the currents and is a method of spreading the species across the region. Originating in southeast Florida, the Gulf Stream dispersed them north along the coasts of Georgia and the Carolina’s. From here the invasion moved east to Bermuda where the Atlantic currents cycled them back south to the Caribbean, here they invaded every reef system in the region. From the Caribbean they found there way to the Florida Keys and eventually into the Gulf of Mexico. The first record in Escambia County was in 2010. It has been described as one of the most prolific, and successful, invasions of a non-native species ever.
Studies show that the invasion in the Pensacola area was particularly bad. One study showed that the densities in our area were some of the highest in the south Atlantic region. Another study showed they had preference for artificial over natural reefs. In response, the Escambia County Division of Marine Resources, partnering with Florida Sea Grant, developed a series of local workshops to educate the public about the issue.
From these meetings nonprofits formed that began to have “rodeos” and “roundups” providing prizes to divers who could remove the most, the largest, and even the smallest lionfish. Eventually the Florida Fish and Wildlife Conservation Commission (FWC) joined in and created the Lionfish Removal and Awareness Day (LRAD). This event, which began in Pensacola, attracted thousands of curious people, chefs cooking samples, and divers from across the region. These efforts, along with an increase in commercial harvest (the fish is edible) have made a significant impact on populations in waters less than 200 feet (where divers can safely work) – but lionfish can live as deep as 1000 feet.
In 2019 a gentlemen fishing on the pier at Ft. Pickens caught one on hook and line. Charter captains have been catching them on hook and line for a few years but it was not common and usually in low numbers. Over the nine years since the first record, there had also been three records within Big Lagoon, so – finding one inside of the pass was not new, but concerning. Partnering with the Ocean Strike Team, Sea Grant conducted a series of survey dives to assess the status of lionfish near the pier and jetties of Ft. Pickens. They found them – though in small numbers, lionfish were present.
The question now is how far within the bay has this invasion spread. The concern is two things.
Lionfish are gregarious feeders – eating just about anything they can get into their mouths. Offshore they are known to eat no fewer than 70 species of small reef fish, including the commercially important vermilion snapper, and several invertebrates, including shovel nosed lobsters. If they invade the bay, we are now looking at juvenile shrimp, blue crabs, flounder, redfish, and more. The impact could be very big.
They are venomous. Not by bite, but by spines. Though it has not killed anyone, the “sting” of a lionfish is extremely painful and placed some in the hospital. With numerous locals and visitors swimming in our estuarine waters, encounters with this fish will occur, and problems with envenomation will follow.
The response needed from the county is to develop a management plan for this fish in our bay. Studies show that the most effective, and least costly, methods occur at the early stages of the invasion – Early Detection Rapid Response. There are several agencies, including Florida Sea Grant, ready to assist with this.
Cuban Treefrog
Photo: UF IFAS
As the name implies, the Cuban treefrog (Osteopilus septentrionalis) is from Cuba – though it is native the Bahamas and the Cayman Islands as well. Records show they arrived in the Florida Keys in the 1920s – most likely “hitchhiking” on boats crossing the Florida straits.
This is a large treefrog, can reach six inches – compared to the two inches of our native frogs, and quickly moved in consuming local wildlife. As with many invasive species, their numbers increased quickly, and they became common across the landscape. In most locations where Cuban treefrogs were present, NO native frogs could be found. Studies show that in pools where Cuban treefrog tadpoles exist, no native tadpoles survive. Native frog populations began to decline. This is a large treefrog, not only do they consume native frogs, but they also consume small lizards, snakes, and all sorts of insects.
But the problem goes beyond native ecology. These treefrogs love to be around humans. Residents complain of the numbers of these large frogs on their doors and windows in the evening. They defecate making a large mess and the calls of the males sounds like a squeaky screen door keeping folks up at night – especially when they are abundant and there are no other frogs in the neighborhood. They are known to enter vent pipes in the plumbing, sometimes clogging these pipes, often appearing in your commode when you lift the lid to use the restroom. People do not like them. They are also known to hideout in electric panels and often short circuit home electrical and HVAC systems. Some of these problems become costly to the property owners.
The Cuban treefrogs have dispersed out of south Florida. They are now established as far north as Gainesville, Jacksonville, and Cedar Key. But records in the Florida panhandle, including Escambia County, are increasing.
Our part of the state was once immune to invasions of tropical species such as this frog. Our winters were cold enough to eradicate the few that made it here. We think the most frequent method of invasion is by hitchhiking – just as they originally did. Many of the landscaping plants we purchase for our homes and neighborhoods are grown at large nurseries in south Florida. These plants are loaded onto trucks and brought here – bringing Cuban treefrogs, Brown anoles, and many other small frogs and lizards that can be a problem for us. It appears that our winters are becoming milder, and these invaders are now surviving. Dr. Steve Johnson (University of Florida) has verified a breeding colony of Cuban treefrogs in Bay County. Records and calls from Escambia and Santa Rosa counties are increasing. We do not know whether these populations are breeding – but the concern is there.
Florida Sea Grant plans to develop a citizen science monitoring project in the spring of 2023 to assess the status of these frogs in our county. As with the lionfish, early detection – rapid response is the key to managing them.
If you are interested in participating in either the bay lionfish surveys, or the Cuban treefrogs surveys in Escambia County, contact Rick O’Connor at the Escambia County Extension Office.
National Invasive Species Awareness Week (NISAW) is a national initiative where agencies and organizations provide information on invasive species issues to decision and policy makers. It can also be a time where we provide that information to the general public.
Invasive species are a global problem threatening biodiversity everywhere. Many create economic problems for the communities they invade, and management can be costly. The University of South Florida has estimated the cost to be around $21 billion a year in the U.S. alone. The most effective method of management is to detect the invader early and respond rapidly.
The Invasive Species Curve
Florida is certainly no stranger to invasive species. In fact, with our climate and international travel, we have some of the largest problems. The Burmese python is a well known, but we also have problems with lizards, frogs, snakes, fish, snails, insects, mussels, and a large variety of plants. The state is divided into 15 Cooperative Invasive Species Management Areas (CISMAs). Two of these – Six Rivers and the Apalachicola Regional Stewardship Alliance (ARSA) cover the panhandle. Members of these CISMAs (which includes UF IFAS Extension) conduct management and education projects on local invasive species within their areas and also have a EDRR list for that area. An EDRR list is the Early Detection Rapid Response – the ones to be on the look out for.
Over the next few days UF IFAS Extension Agents from across the panhandle will be posting articles about the larger threats in their counties. We will be posting these by county so that both decision makers and the general public will be able to see which species are of most concern in their region.
If you have questions about invasive species in your area, or how to manage them, you can contact your county extension office for help.
The Forest Landowner Academy is the first of its kind offered by the UF School of Forest, Fisheries, and Geomatics Sciences (SFFGS) on the UF/IFAS Extension Online Learning catalog. Forest Landowners, and others in need of forest management education, are encouraged to enroll to connect with SFFGS forest management experts and receive quality core educational content on forestry and multiple-use stewardship concepts!
The seven course modules cover a variety of topics including:
Understanding your forest resources
Developing your management plan
Timber management
Marketing forest products
Other forest enterprises such as pine straw and hunting leases
Wildlife management
Planning for the future
Each module include an assessment questionnaire where you can apply what you’ve learned to your land or situation and begin or continue planning and making contacts. In addition being better prepared and equipped to be good stewards of their forest resources, those completing the course will earn a University of Florida Certificate of Completion.
This course is relevant for Florida forest landowners and land managers, as well as those in the neighboring coastal plain regions of GA and AL. Participants will build on this course as they receive information and attend educational events offered by the Florida Land Steward Program and other partners in Florida and neighboring states.
