The pumps that are used to treat wastewater can be classified as either a centrifugal or positive displacement pump. There are pros and cons to both of these types of pumps, so it’s not always easy to determine which one is right for your needs. To make the right choice, it’s important to learn the differences between centrifugal and positive displacement pumps.

How Centrifugal and Positive Displacement Pumps Operate

To understand how these pumps are different, you must first learn how each pump operates. Positive displacement pumps draw a fixed volume of liquid into the pump through the suction valve, trapping it within a cavity found inside the pump, then forcing it out through the outlet valve. The manner in which the liquid is forced out through the outlet valve will vary depending on the type of positive displacement pump. For example, a piston positive displacement pump is designed to force liquid out using a piston that moves up and down through the body of the pump. Other positive displacement pump models, such as screw pumps and gear pumps, do not have components that move up and down. Instead, these pumps use rotating components to force liquid from one side of the pump to the other.

Centrifugal pumps are known for their simplistic design. The most important component of a centrifugal pump is the impeller, which is a rotating device that moves fluid through the pump. The impeller rotates to draw fluid into the pump, then transfers kinetic energy from the motor to the fluid, which moves through the pump and exits through the discharge valve.

How Pressure Affects the Flow Rate

One of the main advantages of a positive displacement pump is its ability to produce a consistent flow rate. The flow rate of a positive displacement pump will remain constant when there are changes in pressure.

However, this is not the case with centrifugal pumps, which are designed to react to changes in pressure. The efficiency of a centrifugal pump peaks at a specific level of pressure. Whenever the pressure is not at this specific level, the efficiency of this pump will decrease. Therefore, the flow rate of centrifugal pumps will be affected by changes in pressure.

How Viscosity Affects the Flow Rate

Another difference between centrifugal and positive displacement pumps is the way the viscosity of the fluid affects the flow rate. As viscosity increases, the flow rate of a centrifugal pump will begin to rapidly decrease. The exact opposite is true of positive displacement pumps. As the viscosity increases, the flow rate of a positive displacement pump increases as well. This is because highly viscous liquids quickly fill the internal clearances of a positive displacement pump, which produces a greater volumetric efficiency. For this reason, it is important to choose a positive displacement pump to handle liquids that are highly viscous.

Shearing of Liquids

The speed of the spinning impeller found within the centrifugal pump design makes it less than ideal for handling shear sensitive mediums. Positive displacement pumps are not designed with any high-speed components, which means these pumps will not apply a great deal of shear to mediums. Because of this, it is best to choose a positive displacement pump when handling mediums that are shear sensitive.

Suction Lift Capabilities

Some centrifugal pumps will have suction lift capabilities, however the standard models do not. Positive displacement pumps do have suction lift capabilities. Consider the piston pump, which is a traditional positive displacement pump model. The piston is the component that moves up and down to force water from one side of the pump to the other. When the piston moves upwards, the pressure in the body of the pump goes down, which will open the suction valve and allow water to flow freely into the pump. The suction valve will close when the piston moves downward and increases the pressure inside the body of the pump, which pushes the water out of the pump.

When to Use Centrifugal and Positive Displacement Pumps

When choosing a pump, it’s important to consider the conditions in which the pump will operate. It is best to use a centrifugal pump to handle a large volume of low viscosity fluid in a low pressure environment. The centrifugal pump works best when it is transferring water, however it can also handle the transfer of low viscosity chemicals and fuels.

Because of its simplistic design, centrifugal pumps can be made out of a number of different materials, including plastic, stainless steel, and cast iron. This makes it more versatile since its design can be adjusted to fit your needs. This type of pump is also very compact, which makes it the ideal choice when there is not much space for a pump.

Positive displacement pumps are often installed to pump oil, sewage, and slurry. Positive displacement pumps are also ideal for pumping fluids that contain solid materials. In general, positive displacement pumps are used whenever the conditions are not ideal for centrifugal pumps. For example, the flow rate of a centrifugal pump is greatly affected by changes in pressure. Therefore, it is best to use a positive displacement pump when there will be changes in pressure, since this will not impact the flow rate of this type of pump.

To learn more about centrifugal and positive displacement pumps or to place an order, contact Lakeside Equipment Corporation today. For decades, Lakeside Equipment Corporation has been committed to providing high quality and reliable products and services to customers around the world. Let us guide you through the process of finding the right centrifugal or positive displacement pump for your needs. Call 630-837-5640 or visit our website to connect with one of our knowledgeable representatives today.

Any wastewater treatment plant will deal with sludge on a daily basis. Sludge is a semi-solid material resulting from wastewater treatment, water treatment, and other industrial processes. When it comes to wastewater treatment, sludge is often made up of fecal matter, food particles, microorganisms, and inorganic solids from things like medications people take or toilet paper pulp.

As part of the wastewater treatment process, sludge needs to be screened. The more that’s removed, the better it is for the remaining processes. Sludge screening systems are the key to removing as much sludge as possible before the other sewage sludge treatment steps.

What Does a Sludge Screening System Do?

A sludge screening system is the first step in removing solids from wastewater as it comes in from a sewer or is hauled in by trucks from residential septic systems. The screens can remove items that never should have been flushed, such as baby wipes or plastic wrappers, and help remove fats, oil, and grease (FOG), hard food particles like corn, bones, and pieces of nuts. Hair is another issue as it goes down the drain in a shower, bath, or sink and ends up in the wastewater.

These solids are removed by pumping the sludge through fine screens. Sludge is washed and compacted to remove any excess water. When the compacted sludge has been processed, It’s moved to another area for composting or further processing. Eventually, it can be used for fertilizer once it’s composted and mixed with lime, if needed, or incinerated to convert it to a fine ash that’s added to a landfill.

What Are the Benefits of Sludge Screening?

If sludge isn’t removed, it makes it harder to clean wastewater for release to a river, pond, lake, or ocean. Sludge contains phosphorus, and phosphorus feeds algal blooms in water. In a lake, algal blooms can impact the health of wildlife and aquatic animals.

Sludge can also create clogs in pipes. That’s not ideal as it can slow or stop wastewater’s movement from one area to the next. It can lead to disastrous and costly overflows or backups. Pressure from a clog can damage pumps and valves, so sludge screening helps prevent damage and emergency repairs.

Digestion that takes place during sludge treatment is handled with or without oxygen. Anaerobic is the form that uses oxygen. It’s more affordable and helps create biogas that can be used for heating and electricity. The biogas resulting from anaerobic digestion can also be converted into biomethane for use in the natural gas grid or fuel for certain vehicles.

You can also take sludge and mix it with lime to compost it. Once it’s composted, it can be used as a fertilizer. Sludge can also be incinerated to ash and added to a landfill. It creates a new way to use materials that could otherwise become a health risk in that community.

What Can Impact Sludge Screening?

What impacts sludge screening? Your wastewater treatment plant’s flow rates impact it. If the flow rate is faster than a screen handles, there are going to be problems. You need to have screens that are equipped for your highest flow rate.

The screen sizes also impact how well your system works. If the screen is too fine, it may take too long to process things. If it’s too wide, you might not effectively capture as much sludge as you were hoping. 

The contents of the sludge coming into your treatment plant also impact sludge screening. If you live in an area with a lot of restaurants, the sludge coming into your plant may have more food particles and FOG than a plant with nothing more than residential homes.

How Do You Choose the Best Sludge Screening System For Your Wastewater Treatment Plant?

How are you supposed to choose? It’s going to require you to consider a few factors. First, what are your flow rates, and what are the solids usually composed of? Do you end up with more paper pulp than food waste or more FOG than other areas? 

You don’t want a sludge screening system that leads to head loss. Head loss is a situation where pressure in a pipe decreases due to friction. You need to avoid that when possible.

Do you have a large maintenance team or do you need a system that takes care of itself for the most part? With a small maintenance crew or maybe just one maintenance worker, you should consider a low-maintenance system. 

Screens usually need to have the chains inspected and tension adjusted when needed, bearings need to be greased, solenoid valves may need adjustments, and a periodic inspection is important. It’s always a good idea to check fasteners and make sure the vibrations of the machine haven’t loosened any connectors. If you can get a system that is above water vs. below water, these maintenance tasks are easier to manage.

What Are the Different Types of Sludge Screening Systems?

Lakeside Equipment offers a variety of Raptor® screening products for grease traps, industrial wastewater, scum, sludge, and wastewater. Our options include:

FalconRake Bar Screen: Stainless steel, corrosion-resistant construction that requires minimal headroom. This system is a low-maintenance option where bars travel up through the incoming wastewater and over the arm in a continual loop. As bars hit the top of the arm, the sludge drops to a container and the fluids drop through the wastewater screen to move to the next step in processing.

Fine Screen: The Fine Screen uses rotating rake teeth to get in between the screen’s bars to keep pushing sludge through these options. While the sludge is removed, it’s also dewatered and washed to remove organic materials. The sludge is drier and weighs less.

Micro Strainer: For lower volumes, a Micro Strainer may be ideal. It has a thicker screening basket and transport and polymer bearings to extend the equipment’s life. It’s made from corrosion-resistant stainless steel. This four-in-one system has screens to filter and remove solids, a washing system, a compactor, and a dewaterer to get as much wastewater out of the sludge as possible before moving it to the next step. The sludge ends up in a barrel.

Multi-Rake Bar Screen: A multi-rake bar screen looks like a big ladder with wide rungs that are controlled by a drive assembly. Rakes capture the sludge and bring it up to the top where the sludge is collected and pushed to a container for processing while wastewater drops into the trough to continue through the wastewater treatment process.

Rotary Strainer Screen: Wastewater comes into a cylinder and water drops through the rotating wire screen cylinder with the sludge removed using an auto-cleaning blade as the solid sludge passes through a discharge suit.

Rotating Drum Screen: A rotating drum screen is ideal for smaller particles, so it’s typically used more to remove scum from wastewater.

Ask a professional for advice. Wastewater treatment equipment specialists can talk about your current system, what you hope to achieve, and work on the best way to upgrade your wastewater equipment to get the best performance possible. Our team at Lakeside Equipment is happy to go over the different sludge screens available and what the benefits are for each one.

For decades, engineers have used screw pumps for wastewater plant lift stations, storm water pumping, and other industrial applications. These pumps are used to move large volumes of liquid, but their design also makes it easy for large objects to pass through without clogging the system. This means water that is contaminated with various objects can be pumped with ease.

Screw pumps can also be operated when no water is present. This means there is no need to install additional parts to stop the pump from running in dry conditions. The pump can continue to operate regardless of how little water is present.

Screw pumps are not only efficient, they are also low maintenance. The pumps are designed with very few moving parts, and these parts constantly run at a slow speed. This innovative design minimizes wear and tear and the need for repairs.

Screw pumps can be used in a variety of industrial settings. However, there are two main types of screw pumps that engineers must choose between: open and enclosed. Before placing an order, it’s important to understand the differences between these two designs.

An Introduction to Open and Enclosed Screw Pumps

Before learning about the benefits of both open and enclosed screw pumps, it’s best to learn the differences between their designs.

An open screw pump has four components: a spiral screw, upper bearings, lower bearings, and a drive assembly. Open screw pumps are placed within concrete or steel troughs at a slight angle, leaving their screw-shaped design exposed.

Enclosed screw pumps are very similar to open screw pumps, however they are encased within a tube so their screw-shaped design is not exposed. Because the pump lies within a tube, it does not need to be placed within a cement or steel trough.

There are two types of enclosed screw pumps: Type S and Type C. Both of these types are enclosed within tubes, however the tube in a Type S design is stationary, whereas the tube in a Type C is not. Type C pumps are designed with two spiral flights welded to the inside of the pump’s tube, which rotates as it operates.

The Benefits of Open Screw Pumps

The open screw pump is known for its simplicity and reliability. These pumps are incredibly low maintenance as it is, however they can become even more durable. If the lower bearing is designed with a permanently greased lubricated roller bearing or a sleeve bearing, this will minimize the wear and tear even further.

If a repair is needed, it may be easier to identify the issue on an open screw pump than it would be on an enclosed pump. This is because the open design of an open screw pump makes it possible to see all of the moving parts.

The bottom of an open screw pump can operate in both submerged and non-submerged conditions, which makes it more versatile than other screw pumps.

The Benefits of Enclosed Screw Pumps

As previously mentioned, enclosed screw pumps are encased within a tube, which eliminates the need for a steel or concrete trough. Because it does not need a trough, it is considered easier to install than an open screw pump. It’s also a better choice for clients who are in need of a quick replacement and do not have the time to install a trough.

Both open and enclosed screw pumps are efficient, however the Type C pump operates at the highest efficiency. In fact, it is estimated that the Type C pump is between 5-10% more efficient than the open screw pump, which is why it has become a popular choice.

The Type C enclosed pump has a maximum inclination of 45 degrees, whereas the open screw pump and Type S enclosed pump both have a maximum inclination of 40 degrees. The difference between 40 and 45 degrees may not seem significant, but it results in the Type C enclosed pump leaving a much smaller footprint.

There are benefits to the Type S enclosed screw pump, too. The top of Type S enclosed pumps can be fixed in place or mounted onto a pivot. If it is mounted onto a pivot, the tube can be repositioned to adjust the pumping rate. Both the open and Type C designs do not have this flexibility.

How to Choose the Right Type of Screw Pump

There are benefits to both open and enclosed screw pumps, which can make it difficult to determine which is right for your needs. Instead of focusing on the design of the pump, think about how the pump will be used. These are the factors that should be taken into consideration when selecting a screw pump:

• Capacity
• Speed
• Inclination
• Number of Flights
• Horsepower

For example, the number of flights in a screw pump will have an impact on the output capacity of the system. This is because each additional flight increases the output capacity of the pump by about 25%. Therefore, it’s important to calculate the maximum output capacity needed so you can determine how many flights you will need. By approaching the decision in this manner, you will be able to select the perfect open or enclosed screw pump for your needs.

To learn more about open and enclosed screw pumps or to place an order, contact Lakeside Equipment Corporation today. At Lakeside Equipment Corporation, we are committed to treating water so it can be used as drinking water or safely returned to the environment. Since 1928, we have provided local governments and corporations with the high quality services and top-of-the-line equipment they need to help us achieve this goal. Call 630-837-5640 or visit our website to connect with a representative today.

As wastewater comes into a plant, one of the very first steps is to remove large solids. A bar screen is important for that reason. Despite ads, printed media, and other warnings that people stop flushing plastic wrappers, rags, baby wipes, and plastic applicators, it still happens. 

When a wastewater treatment plant is intertwined with storm drains, twigs, leaves, branches, cans, bottles, and plastic bags get into the wastewater. Bar screens remove these items to prevent clogs and damage to wastewater equipment. However, there are always challenges with wastewater bar screen operations that need to be considered.

Six Common Challenges of Wastewater Bar Screens and How to Overcome Them

What are some of the most common challenges with the operation and maintenance of wastewater bar screens? There are six at the top of our list.

The Accumulation of FOG

Fats, oils, and grease, aka FOG, are an annoyance that wastewater treatment plant operators deal with regularly. When FOG clings to trash rake bars, it builds up and solidifies into a stuck-on mess. Talk to city officials about requiring grease traps in restaurants and commercial kitchens in your municipality. Grease traps catch FOG for easy removal and keep it out of sewer lines. 

That will cut down on FOG, but it won’t remove it all. You need to degrease your bar screen regularly to keep it from creating clogs and slowing flow rates. Ask a wastewater treatment equipment specialist about the best screening materials for plants that get high quantities of FOG.

Clogs From Debris

Debris like branches, cans, bottles, and plastic bags are problems when they get stuck and reduce wastewater flow rates. While the role of a bar screen is to remove them, no system is foolproof. Items can get stuck and need clearing. 

Prevent debris accumulation by checking that the bars in your screen are sized appropriately for the most common materials you have to remove. If you get a lot of bottles and cans because your system is connected to stormwater, you might find wider spacing is fine. But, you get a lot of plastic applicators and they slip right past wider bars, so you need spacing that’s better at catching the smaller items.

You can also look into bar rakes that automatically reverse if there is a jam. By going into reverse, it helps clear the items that caused the obstruction and ensures the system works efficiently and effectively.

Corrosion

Wastewater can be corrosive, and even stainless-steel construction is susceptible to corrosion over time. You can apply coatings to bar screens to limit the damage. Regular inspections of the bars to check for corrosion help alert you to problems before they become a major headache.

If your wastewater treatment plant is in an industrial area, talk to city officials about requiring factories to have industrial wastewater treatment plants and treat their water before releasing it to the sewer system.

Mechanical Wear and Tear

Wear and tear from regular use is bound to happen. With planned maintenance and routine inspections, you can catch damaged or worn parts before the damage becomes a major inconvenience. Make sure your wastewater treatment plant has the appropriate screens in place to prevent damage. Look for durable construction, too. You might find that composite parts last longer than metal or plastic ones. 

Sand and grit also wear out components. A grit collection system is an essential part of a wastewater treatment plant, so make sure it’s part of your system.

Ragging

Rags are a headache. Look into rag catchers placed before your bar screens to catch rags, baby wipes, pads, and other fibrous materials before they get into your bar screen. When they reach a bar screen, they can wrap around components and get snagged, which creates extra work for your maintenance team.

Weather and the Unexpected

Not every system is connected to a stormwater system, but some still are. The U.S. is working hard to get cities and municipalities to separate systems and come up with ways to help with unexpected rainfall that leads to flooding of storm drains and wastewater treatment plants.

When weather creates high flow rates, your system may not be prepared. Have protocols in place for weather events, power outages, or unexpected equipment breakdowns. Measures that automatically adjust flow rates and help avoid overworking bar screens are essential.

Setting up a lot of green spaces between sidewalks and roadways provides one way to use up water. Adding rooftop gardens, turning concrete lots into parks and playgrounds, and tree-lined streets all help keep stormwater from rushing to storm drains. It also helps lower the risk of erosion.

What Does a Bar Screen Do?

Think of a bar screen like an escalator. It has steps that travel upward from wastewater areas and collect items on the bars as the steps move upward. At the top of that bar screen, the items get raked into a collection bin for composting or incineration, and the steps go back down to the wastewater to repeat the process.

Tips for Keeping Your Equipment in the Best Shape

Once you’ve installed wastewater bar screens, you need a regular preventative maintenance plan in place. That includes regular inspections and procedures that ensure your employees focus on efficient bar screen operations.

While a bar screen and trash rake do a great job, you need to have someone monitoring the controls. The ability to check performance remotely helps a lot, but there still needs to be someone performing basic maintenance. Some of the things that require basic maintenance are:

• Adjust and clean solenoid valves
• Check and adjust brushes and scrapers
• Check roller chains for wear and adjust tension as needed
• Inspect and grease the bearings and rack and pinion gears, if needed
• Inspect the tracking system and tighten any loose fasteners
• Periodically check for heavier debris like rocks
• Testing the motor for vibrations and amperage

When you have new wastewater bar screens installed, ask the experts what the best maintenance plan is and if there are any special considerations. Lakeside Equipment’s expertise with water treatment solutions dates back to 1928, so your municipal or industrial wastewater needs are addressed by a professional team with the insights you need.

We recommend two bar screens. The Raptor Multi-Rake Bar Screen excels at removing inorganic solids with low headloss. The FalconRake Bar Screen, also from Raptor, has a heavy-duty design that stands up to severe conditions and doesn’t rely on lower bearings, bushings, guides, or sprockets for minimal maintenance. Ask Lakeside Equipment about the pros and cons of these bar screens and find the right equipment for your plant’s needs.

In 2019, the median pay for wastewater treatment plant and system operators was just under $23 an hour. It’s an important job, but it’s also imperative that districts try to manage costs for the residents and businesses in that area. Optimizing your workforce is an important step, but it’s just the first step to take.

There’s another reason to optimize your employment strategies. The recent pandemic is forcing wastewater treatment districts to make sure employees are spaced for social distancing. With a goal of six feet, careful planning is important. Plus, some workers may be unable to return to work if they have COVID-19 or are caring for someone with the virus. Thought needs to go into the adjustments that keep the right staffing levels without sacrificing productivity.

How do you best manage your employees and make sure the time spent on wastewater treatment operations isn’t wasted time? How do you optimize your operator’s time? These are the best ways to cut costs without sacrificing work quality.

Evaluate the Strengths and Weaknesses in Your Current Wastewater Treatment System

Complete a thorough site review. Look at the equipment you have in your wastewater facility and track flow rates, the amount of maintenance that’s performed each week, month, or year, and how old it is. See how many hours the equipment is at peak flow rates and when the wastewater isn’t coming in as fast. In many communities, morning showers and dinner hours are going to be the busiest. See if that matches up with what the operators experience each day.

Take time to ask the operators of that equipment how comfortable they are and if they encounter frequent issues. If there are problems, what has to be done to fix them. How many hours are operators spending on fixing issues or waiting for maintenance? Now, ask them how much time they spend sitting back and monitoring the different processes. This impacts productivity.

Look at the growth in your district. If the population has increased by 20% in the past couple of years, you have to consider how well your system can keep up with the growth. It could be time to rethink things and plan a major upgrade.

Is weather impacting the amount of wastewater entering the system? Has winter snow accumulation drastically increased over the past decade? Are sudden downpours or an increase in hurricanes more frequent than in the past? You can’t control the weather, but you can design a system that handles the unexpected and more frequent stormwater rushing into the plant.

Put Extra Time and Energy Into Training

Productivity also relies on the employees you have. Operators need to know what they’re doing and how to accommodate any surprises that pop up during the day. If you run into employees who seem to struggle more than others, they may just need some additional training. Look into workshops for them or put them with your best worker to hone their skills.

People learn at different rates. What took one operator a week to learn may take someone else two weeks. Try not to rush workers who are doing their best. If you train them too fast, they’re more likely to make mistakes. Operators who are pushed to learn quickly and don’t feel supported may just walk away. Can you afford to lose an employee and have to start from scratch?

On the other hand, you don’t want to waste time training a worker who is more interested in checking a phone than working. You should take time with someone who is trying hard to master the equipment, but you need to know when it’s a lost cause. Try to spot the dedicated employees from those who simply want the money and aren’t willing to put in an effort. The quicker you can weed out the good from the bad, the more time you’ll be able to dedicate to training the right people.

Embrace Automation and Real-Time Monitoring

When your operators are spending a lot of time fixing issues and manually changing settings, it wastes their time. Embrace automated wastewater treatment equipment that uses modern technology like real-time monitoring and adjusts settings automatically. You still need wastewater treatment plant operators, but they have a helping hand in meeting efficiency goals.

You want a system with real-time monitoring. When equipment points out problems at the exact moment they happen, it’s far more helpful than learning that something’s wrong as wastewater backs up or exits the plant before the raw sewage is properly treated. Untreated raw sewage during heavy rainfall or flooding isn’t ideal and can lead to fines. Real-time monitoring adjusts for increased flow rates and makes changes accordingly.

Computers help operators with efficiency and water treatment quality. Look for equipment that has computerized systems that can handle the routine tasks and alert the operator to potential problems before things get really bad.

Use the Sharp Biological Nutrient Removal (SharpBNR) process control system to monitor and optimize aeration rates during wastewater treatment. If more aeration is needed, the computer automatically adjusts rotor speeds. If aeration can be slower, again the computer will take care of it. SharpBNR is easily paired with SCADA to make sure water treatment processes are meeting goals. The system is designed to send out alerts and alarms as warnings of issues to make sure nothing gets overlooked.

Upgrade to Low-Maintenance Equipment

It’s a good time to look at upgrading older equipment with equipment that doesn’t require the same amount of maintenance. You’ll save money on maintenance, have less downtime, and increase productivity. Your maintenance team may not need to be as heavily staffed, and you’ll be able to transfer workers to other areas where they’re needed.

Start with the screw pumps. Depending on your plant’s size, you may need to save space with a Type C Enclosed Screw Pump. If you have plenty of space, an Open Screw Pump may work better. Your key consideration needs to be clog-free designs that improve efficiency.

Screening products are another component in wastewater treatment plant efficiency. The Raptor Multi-Rake Bar Screen uses a set of rakes to get into the screen’s openings to remove debris quickly and completely. This system is designed to be low maintenance and goes into reverse to free up jams.

Those are good places to start. Look at your list of current wastewater treatment equipment and see what’s older and going through frequent repairs. Upgrading that equipment is ideal. If it’s simply not in the budget, replacing worn parts is the second-best option. Energy-efficient motors and pumps will make a difference.

Partner With an Expert

When it’s decided that you should upgrade or replace equipment, select engineers and installers who will make sure your system meets your budget and exact needs. Choose your partner in wastewater treatment upgrades carefully. You need to balance costs with expertise, and some companies just don’t have the same experience as others.

Have you considered having experts walk through your wastewater treatment plant and offer suggestions for optimizing your system? It’s a good place to start. Lakeside Equipment’s engineers design efficient, cost-effective systems that are customized to a client’s needs.

Lakeside Equipment’s foundations go back 92 years. Our experts have helped communities across the U.S. plan, engineer, and maintain their water treatment systems. We provide quality wastewater treatment equipment that’s designed to meet your budget and operation goals. Give us a call to discuss your needs.

Wastewater treatment plants are there to clean and purify water that arrives through sewer lines, septage haulers, etc. The process removes bacteria, solids, and other impurities until the water is clean enough to go back into the district’s water supply or get released into area bodies of water.

What about pharmaceuticals? Can wastewater treatment plants remove pharmaceuticals before the water returns to public water sources, lakes, streams, and other water sources? Studies show that many drugs end up in treated water even after a normal treatment process.

Wastewater Treatment May Not Remove Everything

In a month’s time, it’s estimated that close to 46% of Americans have taken at least one prescription drug. As you get older, chronic health conditions are more likely. Around 85% of American’s aging adults (60 or older) take medications daily. Adults aren’t alone. It’s found that about 18% of children 12 or younger take at least one prescription medication.

You probably take vitamins, herbal remedies, over-the-counter meds, and/or prescriptions on a daily basis and never stop to think about the impact they have on wastewater. Pharmaceutical plants and the liquid manure from livestock treated with veterinary pharmaceuticals that gets spread on fields aren’t the only cause of these compounds getting into groundwater and streams.

The reality is that the medications people take also find their way into your wastewater. They’re excreted through fecal matter and urine or expired or unneeded pills are flushed down drains or toilets. The wastewater treatment process does what it can to remove them. The problem is that water treatment can’t get all of the drugs out of the water.

A study looked at the wastewater from 50 of the nation’s wastewater treatment plants. Pharmaceuticals were found in all 50 samples. Valsartan (blood pressure medication) had the highest levels, but atenolol (blood pressure), carbamazepine (epilepsy), and metoprolol (heart/beta-blocker) were also found in high levels. While it’s uncertain the levels remaining after the water is cleaned is dangerous to humans, questions arose as to whether the drugs would harm aquatic animals.

In 2020, a University of Cincinnati biologist decided to look at the effects of estrogen (birth control pills) on freshwater fish. As estrogen had been found in streams near wastewater treatment plants, the study looked to see what would happen if native fish were exposed.

In the study, the researchers focused on a native fish that has live births rather than lay eggs. They put them in fresh water that contained a controlled level of estrogen. The fishes’ fertility was affected and fewer babies, especially males, were born to the fish in the study. The shocking thing is that the researchers had used levels of estrogen that were 16 times lower than was found in the streams.

Many people today take antidepressants. How well is wastewater treatment removing antidepressants? Researchers took a look at the tissue of fish found upstream from two wastewater treatment plants in Colorado and Iowa. Fish found upstream showed no signs of antidepressants.

They also collected fish five miles downstream of where the same wastewater treatment plants were releasing treated water. Those fish had noticeable levels of common antidepressants like fluoxetine (Prozac) and sertraline (Xanax). The water samples also tested positive for containing those and bupropion (Wellbutrin), citalopram (Celexa), and venlafaxine (Effexor XR).

What about antibiotics? One of the first was penicillin, but science advanced and many of today’s antibiotics are synthetics like sulfonamides or semi-synthetics like amoxicillin. A study of water within the Great Lakes found that wastewater contained several pharmaceuticals including two antibiotics.

So many medications are being found in water that’s been treated and released to streams, rivers, lakes, and ponds. They’re making their way into the oceans. It’s shown that the drugs can impact fish, mammals, crustaceans, shellfish, and other aquatic creatures.

Federal Regulations on Wastewater Treatment Don’t Cover Pharmaceuticals

The Federal Government maintains a list of chemicals, metals, and other contaminants that must be removed from wastewater before it’s released. Pharmaceuticals are not on that list. While attention is being raised, only four compounds found in pharmaceuticals for human use are even being considered. Three of them are in birth control pills and one is an antibiotic.

This is concerning as a 2007 study tested for 17 different pharmaceuticals in samples taken from 20 different municipal water systems. More than 50% of the water samples tested positive for carbamazepine (anticonvulsant), ibuprofen (NSAID pain reliever), iopromide (contrast agent for scans of the body), meprobamate (tranquilizer), and phenytoin (anticonvulsant).

A second in-depth study went back and found meprobamate and phenytoin in 50% of the samples. While the levels were too low to impact humans, it does raise concerns on how these medications affect fish and other aquatic creatures.

Many wastewater treatment plants are already removing pharmaceuticals, but only a percentage is removed through typical wastewater treatment plans. There’s still a percentage making it into the water. Which leads to the question of what else can be done.

What Steps Help Remove Pharmaceuticals?

How well wastewater treatment removes pharmaceuticals depends on what system a district uses. Activated sludge is one of the more common treatment processes. It uses microorganisms to break down contaminants. It’s not overly effective on pharmaceuticals. Dr. Diana Aga, a chemistry professor, says more pharmaceuticals would be removed if wastewater treatment plants paired activated sludge with granular activated carbon filters.

What steps in water treatment help remove the medications people take? A study looked at the different water treatment steps and whether or not they were partly effective at removing certain medications.

• Anabolics/Steroids – Reverse osmosis was most effective, but nanofiltration, ozonation, and granular activated carbon was also useful.
• Antibiotics – Ultrafiltration with powdered activated carbon and reverse osmosis were effective.
• Carbamazepine (Anticonvulsant) – Ultrafiltration with powdered activated carbon and reverse osmosis were the most effective treatment methods.
• Diazepam (Sedative) – Reverse osmosis was the most effective with ultrafiltration using powdered activated carbon as a second-best choice.
• Diclofenac and Ibuprofen (NSAID) – Reverse osmosis and soil aquifer treatments were the best options, and granular activated carbon filters also worked well on
• Paracetamol (Tylenol) – Ozonation and reverse osmosis were the most effective ways to remove this pain reliever from wastewater.

There is a lot of evidence in filtration being the best way to remove pharmaceuticals. Your wastewater treatment plant can help get pharmaceuticals out of the wastewater that’s treated and released. What is your plant’s design? Have you set up a system that pairs activated sludge with some form of carbon filtration? Maybe it’s time to consider a change that helps keep pharmaceuticals out of the water while also improving your plant’s expenditures.

Is it time to upgrade your wastewater treatment equipment? If you’re looking to clean wastewater effectively and efficiently, modernizing some equipment can help improve your plant’s performance while lowering electricity costs. Your district saves money, which makes everyone happy.

Lakeside Equipment has been a leader in water purification for close to a century. Talk to us about our Learn more about the steps to take for cleaner water and lower energy costs.