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Mechanical vs. Chemical Wastewater Clarification: The Pros and Cons

According to the Cybersecurity & Infrastructure Security Agency, the U.S. has 16,000 public wastewater treatment systems. In addition, the EPA estimates that over 20% of U.S. households are on an individual septic system or community cluster system. The wastewater that comes from these systems requires careful treatment to remove pathogens, pollutants, and solid waste. 

When a wastewater treatment facility gets wastewater from the sewer system or trucks that pump it out of septic tanks, it needs to be screened to remove plastic and other hard waste like branches, bones, etc. It must have the sludge and fats/oils/grease (FOG) removed, and the remaining wastewater must be carefully tested until it meets EPA guidelines. Only then can it return to a body of water or water treatment plant for reuse. 

Wastewater clarification and sanitizing is essential to prevent the spread of disease. It also prevents contamination in lake and river water, which can help algae blooms thrive and harm aquatic animals and animals that use that water for swimming or drinking. It keeps bacteria from entering into the meat of shellfish that people eat. To make sure water is clarified correctly, water treatment plants use mechanical or chemical clarification, and each has pros and cons.

How Does Mechanical Clarification Work?

Mechanical clarifiers are tanks where wastewater settles after passing through filters that capture solids like fat deposits, menstrual products, plastic wrappers, etc. Skimmers run over the top of the tank in continual circles picking up floating waste, while sludge is pushed to a central hopper in the bottom of the tank to be pumped out.

Water can be further treated using filters and UV treatment to remove impurities and contaminants. Activated charcoal is one filtration material, but plants have also had success with coconut fibers, sand, and peat.

Pros and Cons:

  • Pro – It’s simple and doesn’t require fluctuating levels of chemical additives.
  • Pro – It can be twice as fast.
  • Pro – It’s one of the most cost-effective options, especially in areas where people are already stretched thin financially.
  • Pro – It’s better for the environment as no chemicals are being used.
  • Con – Produces more sludge that must then be managed.
  • Con – Lightweight particles may be harder to capture.
  • Con – Clarifier tanks take up more space, which can be hard in areas where there is limited land.

How Does Chemical Clarification Work?

Chemical clarification involves the use of a chemical to cause suspended particles to clump together, which forms larger solids that float to the surface. That makes them easier to remove because they settle faster than small particles. 

With chemical clarification, processes known as coagulation and flocculation take place. The chemical additives, such as caustic soda, lime, iron, aluminum salts, and polymers are mixed in causing the suspended particles to coagulate. As they bind (flocculation) the larger clusters, called flocs, float to the surface for easier removal. This method also has pros and cons.

  • Pro – The floating suspended solids are easily removed, which leads to cleaner water.
  • Pro – A smaller footprint is needed, which is good if your plant has limited space.
  • Pro – It’s better at capturing tiny particles that often get missed in mechanical clarification because they bind together.
  • Con – Costs more than mechanical due to the cost of chemicals, and an increase in incoming wastewater will require quick adjustments to the amount of chemicals used, so costs can increase as workers put in more hours and increase the use of chemicals.
  • Con – It’s a more complex process, which means wastewater treatment plant operators may need extra training.
  • Con – The chemicals can be harmful to the environment, so they must be removed before treated wastewater’s release and carefully handled if there is an accidental spill.
  • Con – The amount of sludge increases, so you have to have a sludge management plan in place.

Which Method Is Best for Your Municipality?

Which is best for your wastewater treatment facility? Consider these five points.

The Characteristics of the Wastewater Your Facility Treats

What are the main qualities and characteristics of the wastewater you treat? Chemical clarification is considered to do a better job of removing contaminants like heavy metals. If you treat a larger volume of industrial wastewater, it’s something to consider.

Your Municipality’s Budgetary Constraints

As is true in most of life, you have to consider the budget. While you might prefer the idea of chemical clarification, consider the costs of both options and the average salaries of people in your municipality. If you drastically increased water and sewer bills, could they afford it or would they be at risk of financial hardship?

The Discharge Standards You Need to Meet

When you are permitted to operate a wastewater treatment plant, the EPA’s permit has discharge standards you must meet. If you fail at that requirement, the fines can be steep. Consider which of the two clarification methods ensures you meet those standards in the most cost-effective manner possible.

The Size of Your Plant and Availability of Additional Land

How much land does your facility have? If you opt for mechanical clarification, the tanks take up space. As new homes are built and businesses come in, new equipment may become necessary to keep up with the increased flow rates. Do you have the space available for new clarifiers? If you don’t have a lot of space, mechanical clarification might not be feasible.

Your Area’s Environmental Concerns

What are some of the concerns already impacting the environment in your area? As you release treated wastewater to rivers, lakes, the ocean, etc., you need to make sure you’re not accidentally discharging water with higher levels of dissolved salts and other chemicals used during clarification.

Finally, you have to consider environmental concerns regarding sludge. When you use chemical clarification, you’ll have more sludge. If you only have one or two landfills in the state and they’re already reaching capacity, you’d need to find another way to dispose of the sludge to avoid straining other city and town services. 

You could consider incinerating it or processing it for fertilizer, but that’s more work, which means more staff, and that can mean higher costs for your district. You have to consider all of that when determining the best option for your community and budgetary constraints.

Lakeside Equipment has been in the water clarification field for close to 100 years. Reach us online or over the phone to discuss your plant’s size, wastewater treatment needs, and your community’s budget. We’re experts in wastewater treatment processes and equipment and can help you find an efficient, cost-effective solution.

Wastewater Clarifiers and Sludge Management: Integrated Approaches

In the U.S. alone, there are over 16,000 publicly-owned wastewater treatment facilities. Those plants treat around 34 billion of wastewater every day. Yes, that’s billions, not millions, per day. About 75% of U.S. households have their sewage treated at a municipal wastewater treatment plant, and the heart of any treatment process is to separate the water from the waste products. 

It’s clear what happens with water once it’s cleaned and meets EPA guidelines for release back to a water source or water treatment plant for household use, but what about the sludge? Where do the solids end up? It comes down to integrated approaches between wastewater clarifiers and sludge management.

Wastewater Clarifiers: Understanding Their Role in Wastewater Treatment

When wastewater enters a facility from sewer lines or septage haulers, it’s a messy mix of solids, water, and even trash. Solids like plastic, flushable wipes, food particles, lint, dirt/grit, toilet paper, and feces have to be separated. 

Trash rakes can remove items like plastic applicators, toys that children flush without realizing how bad that is, and other pieces of trash. This equipment can also capture things like bones of animals that died in the sewers or that came in from food manufacturing plants.

The remaining wastewater continues to clarifiers where filters capture solids and sludge sinks to the bottom for easier removal. The remaining water moves to additional treatment steps. There are also different clarifiers:

Primary:

Primary treatment begins with sewage entering the plant and passing through screens and trash rakes. It then moves to a grit chamber to remove items like pebbles, sand, and other gritty particles that could damage seals and mechanical aspects of the wastewater treatment equipment. 

Secondary:

Secondary treatment is beneficial for removing some of the harmful contaminants and nutrients found in wastewater. Wastewater may pass through trickling filters to help capture some of the pollutants, bacteria, and chemical hazards. PCBs are a newer concern.

Another aspect of secondary treatments is the use of activated sludge, which adds oxygen and encourages microorganisms to digest some of the tiny particles of sludge, which speeds up the treatment process. 

Tertiary:

It used to be that primary and secondary clarification processes were enough. That’s no longer the case. Tertiary is used to help remove non-biodegradable pollutants like nitrogen and phosphorus. This is especially important as those two items are known for increasing the growth of algal blooms in lakes, rivers, and other water sources. Algal blooms harm fish and wildlife.

Tertiary clarification also helps remove dissolved salts, heavy metals, parasites, and viruses that secondary clarification measures couldn’t remove. 

As sludge settles throughout the clarification process, you have all of that sludge and solids that must be managed. This is where a sludge management plan is essential.

Sludge Management: Regulatory Concerns and How It’s Managed

All wastewater treatment plants have a permit from the EPA that regulates the amount of different minerals, chemicals, and metals that can remain in the water that’s released. Staying within these limits is essential for avoiding fines. The same requirements are in place for any sludge. 

Sludge ends up being used in one of three ways. Some plants send it to landfills where it joins other trash. It can be composted and eventually used to provide nutrients to plants and trees in fields and forests. It can also be burned in incinerators.

With wastewater treatment, the breakdown of sludge as microorganisms feed off tiny articles does release methane. That methane can be captured and used as an alternative fuel for heating and cooling the buildings in a wastewater treatment plant, which is a great way to use the resources created from treatment processes.

When the sludge is going to be used for land application, it must first be tested to make sure that the arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, PCBs, selenium, and zinc levels do not exceed maximum concentrations.

In addition, land application requires pathogen controls to meet Class A or Class B rules. Class A applies to sludge that is applied to home gardens and lawns. Class B is only offered if the sludge fertilizer will not come into contact with food crops for grazing pastures for a specified period. Once a farm or ranch uses sludge as a fertilizer, it may be upwards of three years before anything is allowed to grow in that field, or animal fodder can be harvested from it.

In 2022, the Michigan Department of Agriculture and Rural Development found that an area farm had used untreated sewage for fertilizer. The resulting crops were sold to grocery stores and directly to consumers. 

Over a dozen retailers had to tell shoppers to stop using the cabbage, cucumbers, eggplant, green beans, onions, peppers, summer squash, sweet potatoes, tomatoes, and zucchini that the stores had sold due to the risk of e. coli, hepatitis A, norovirus, and rotavirus. That’s why it’s so important to follow EPA guidelines.

The Future of Sludge Management

With AI and automation increasing in use, it’s only going to get easier to remove as much sludge as possible and ensure that it’s managed properly. Whether you use it for power generation or sell it as fertilizer, you’ll benefit from having AI continually test and analyze results to tell you when it’s optimal to move to the next stage.

Another benefit of AI is that it can closely track flow rates and increase pumps and motors to avoid having your plant flood during a long storm or be forced to release untreated sewage into the environment. If something is wrong, AI could divert lines to ensure extra wastewater goes to holding tanks until things calm down.

For many years, other countries have used cow patties to make bricks and build homes. The reuse of purified sludge as concrete filler, concrete aggregates, and brick-making materials is another trending use. It’s an eco-friendly way to use sludge and stop taking up valuable space in landfills.

The Best Approaches For Integrating Clarification and Sludge Management

When you’re establishing a wastewater treatment facility or upgrading your equipment, you want to make sure you follow the EPA’s guidelines. You also need to follow state regulations. It’s best to work with experts in wastewater management equipment to ensure you’re creating a feasible, efficient, cost-effective system that removes sludge as quickly as possible and uses that sludge as a valuable resource.

It’s also best to work with manufacturers and industrial plants to ensure they’re pre-treating wastewater. It reduces the burden on your plant. If you have three poultry processing plants nearby, the number of bone fragments, feathers, and fatty tissue will drive up water treatment costs, which makes locals unhappy as rates increase. Make sure area businesses are doing their part.

As weather patterns keep shifting and leading to storms of unprecedented levels, wastewater treatment plant owners and operators need solutions that separate sludge and treat wastewater quickly and effectively. Raw sewage releases during heavy rainfall aren’t good for the environment’s animals, people, and aquatic life. 

Make sure your plant is ready for the future. Recover valuable resources, protect the planet, and do all of this while reducing overall costs. Lakeside Equipment can help you develop a sustainable, efficient sludge management process. With close to 100 years in water treatment, we have the insights and equipment your plant needs for optimal performance.

The History and Evolution of Wastewater Treatment Plants

Water treatment structures date back to the years BC. Records in Ancient Greek and Sanskrit writings go back as far as 4000 BC detailing the steps used to clean and treat water. They’d boil or expose the water to sunlight and filter it through charcoal to remove odors and unpleasant tastes and make it clear instead of cloudy. Ancient Egyptians’ records showed they’d use alum to settle cloudy water. 

Those are the earliest recorded methods used to treat water. Technology has changed a lot over that time. Wastewater treatment plants have come a long way. Take a closer look at the evolution of wastewater treatment over the centuries.

Filtration Becomes a Popular Option for Removing Particles

While the Ancient Romans and Egyptians may have been the first to focus on filtration, the method of filtration would change over the years. 

To treat water, you had to also look at turbidity. What is turbidity? It’s a measurement of particles like organics, sediment, etc. in water. When water is turbid, it’s cloudier. 

In the 1800s, Europeans used sand, which was readily available, to filter water. Cholera outbreaks in the 1800s would raise the awareness of needing more than filtration as microscopic organisms, bacteria, and viruses weren’t always caught with filters.

This was especially important in 1855 when Dr. John Snow proved cholera was a waterborne illness. Louis Pasteur also demonstrated this when he demonstrated how microscopic organisms passed through things like milk and water, leading to pasteurization. Filtration wasn’t enough. 

Facilities for Treating Wastewater Were Also Necessary

Filtering wastewater was only a small part of the process. As past generations learned, there also had to be a way to get wastewater to that facility and ponds, vats, or pools that would store the wastewater while it was treated. This led to advancements in the structures used for treating the water. 

The Indus Valley Civilization

The Indus were the first culture known to have indoor plumbing. They had terracotta pipes that led from buildings to brick-lined drain ditches in the city, where waste went into underground tunnels and back into the environment. The problem was that no one at that time understood the impact this untreated sewage had on the soil and water supplies in the area.

The Rise of Pollution in the 18th and 19th Centuries

Getting back to the Indus, it wasn’t until the Industrial Revolution that people understood the issues surrounding untreated sewage returning to rivers, streams, lakes, and oceans. As urbanization increased people flocked to cities for work. 

You’ve probably heard of the past when people used buckets instead of a working toilet and emptied those buckets into channels along the road. Eventually, all of that waste ended up in rivers. The Thames in London was one of them. 

Wastewater from industries also ended up in the Thames, but the tributaries leading to the Thames were where Londoners and outlying communities gathered their drinking water. Essentially, people were drinking sewage water and making themselves sick with diseases like cholera and typhoid. Better wastewater treatment systems became an urgency.

The Metropolis Water Act was passed in 1952, which banned the use of water from the Thames. People and water delivery companies had to start sourcing water from other areas. The use of sand and crushed shells was also required as a means to purify water. But, it didn’t stop the “Great Stink of 1858.” All of the waste in the Thames heated up during an unusually hot summer. The city reeked of raw sewage, which spurred the need for a better solution.

In 1865, London’s first wastewater treatment plant was built. It used gravity to settle waste in the water so that those solids could then be removed before the water went into the Thames. It wasn’t perfect, but it was a start. 

As science learned more about raw sewage, the need for biological treatments came into play. The activated sludge process, which is still used today, was established in 1914. Microorganisms were used to help feed on the organic matter in wastewater and help break it down more quickly. 

The First Laws Regarding Wastewater Hit the U.S.

While other countries went through their own woes regarding wastewater, the U.S. watched the population grow as people left Europe for America. Per the 1900 Census, the population reached 76.3 million that year. New York, Pennsylvania, Illinois, and Ohio were the most populous states at that time. Wastewater issues were arising and regulations were needed. Therefore, the U.S. passed The Federal Water Pollution Control Act of 1948

Surprisingly, the first major law in the U.S. didn’t pass until 1948, but it wasn’t as good as it needed to be, so drastic changes were made to it in 1972. Renamed The Clean Water Act, it set national regulations for the release of wastewater into U.S. waters. It handed the EPA the authority to establish pollution control standards and programs. It finally made it illegal for people to discharge wastewater without a valid permit, and cities wanting to build wastewater treatment plants had construction grants available.

The Future of Wastewater Treatment

Where is the future heading? The environment is a driving factor in wastewater treatment. With water pollution a problem in the world’s streams, ponds, rivers, lakes, and oceans posing a risk to animals, aquatic creatures, and the environment, wastewater treatment has to be done correctly, quickly, and efficiently. Problematic raw sewage dumps from flooding are problematic and have to be addressed. 

To address these problems, researchers are looking at a few specific areas of water treatment operations.

Advanced Treatment Requirements

You’ve probably heard about microplastics. These tiny particles of plastic are being found on everything from bees to the blood of humans. There are also PCBs, a manmade forever chemical that is tied to cancer and developmental issues in fetuses and children.

Finding a way to remove microplastics from wastewater is important, but it has to be done cost-effectively, and the treatments used have to get as much microplastic and PCBs as possible, which can be a big hurdle to overcome.

Artificial Intelligence, Automation, and Smart Technology

Artificial intelligence, AI for short, automation, and smart technology are certain to play a big role in helping wastewater treatment plants optimize their performance and lower energy consumption. With smart technology, operators won’t have to drop everything to go check on settings or test results, they could be doing a hands-on task and get insights through voice commands. 

AI and automation can analyze and make immediate adjustments without needing a wastewater treatment plant operator to drop everything and go adjust settings. It will be possible for engineers to get reports when they’re off-duty. If there’s an emergency, they’ll get a notification. Otherwise, the AI technology and automated system monitors and adjusts to optimize performance.

Pre-Treatment for Industries

Industrial wastewater from manufacturing plants, food processors, and even breweries strains wastewater treatment plants. The extra work needed to treat that wastewater takes more time, energy, and money. 

In some communities, it’s becoming a concern and measures are being taken to prevent this additional strain. Smaller on-site wastewater treatment plants are being required to pre-treat water before it goes to the sewers. Grease traps in restaurants also help.

Expanding the use of treated wastewater for irrigation, industrial processes, and even drinking water after further treatment.

Reuse

Across the country, some areas are running out of drinking water. The reuse of wastewater is going to be the future. Some communities are already doing this with great success. Sewer water goes through wastewater treatment and travels to a water treatment section where it’s purified for use as drinking water and typical household use for laundry, showers/baths, and cooking.

Wastewater treatment plants keep evolving, and the introduction of automation and AI to the equipment is expected to make wastewater treatment more efficient and effective. With this technology carefully monitoring flow rates, storm patterns, and processes, energy consumption decreases, which drives down the cost of treating water, which your community will appreciate. Plus, the risks of raw sewage releases decrease, which is better for the environment.

Embrace the future of wastewater treatment by working with an expert. Lakeside Equipment has been helping clean water for close to a century. You won’t find a company with more expertise and insights into cleaning water effectively and efficiently. Talk to Lakeside Equipment about the improvements that set your facility up for the future.

The Importance of pH Control in Biological Wastewater Treatment

The Encyclopedia of Ecology defines biological wastewater treatment as a process where “organisms assist in environmental cleanup through their own life-sustaining activities.” Instead of treating water with chemicals, algae, beneficial bacteria, fungi, metazoan, and protozoa are all microorganisms used to feed on the organic material, which is important to their lifecycle and also helps clean the water.

But, as microorganisms eat these materials, they produce methane and carbon dioxide. The resulting odors make it a less-than-desirable process for anyone living downwind of a wastewater treatment facility. This is a leading reason pH control is an important part of biological wastewater treatment.

The Benefits of pH Control in Biological Wastewater Treatment

A balanced or neutral pH is 7.0, but pH can range from 0 to 14. If it is higher than 7.0, wastewater is acidic and needs to be lowered. If it’s over 7.0, it’s alkaline and needs to be lowered. 

Before treatment begins, raw wastewater usually has a pH as low as 6 or as high as 8. When it’s high, it’s often caused by too much algae growth in open wastewater lagoons or the wastewater is already high because of industries that use lime, lye, or sodium hydroxide.

A low pH is often because of high ammonia levels. It’s the most common problem wastewater facilities face when they use activated sludge systems. By making sure you keep the pH balanced, your plant benefits in several ways. 

Heightened Efficiency

Plants with a healthy pH work efficiently. They’re less likely to run into imbalances that require extra effort to repeat water treatment steps to remove extra sludge, increase aeration, and grow healthy colonies of microorganisms. You treat water faster, better, and more cost-effectively.

Reduced Sludge Production

When your wastewater has a balanced pH, sludge production lowers and sludge disposal costs drop. You have less sludge to compost, incinerate, or haul to a landfill, which means you save money.

Improved Removal of Organic Matter

Healthy microorganisms remove more organic matter. When water is treated quickly, it lowers your energy consumption and saves your plant money. You’re also not releasing treated water to area lakes, streams, and rivers before it’s safe, which can lead to massive fines for raw sewage releases.

You’re not sacrificing quality for savings. You get both, which makes everyone happy.

Compliance With EPA Regulations

When a permit is issued, every wastewater treatment plant has EPA standards they must meet before releasing treated water to a water treatment plant for reuse or to a local body of water. If you’re not in compliance, the EPA can issue fines.

Fines for negligent violations range from $2,500 to $25,000 per day and up to a year in prison for the first violation or two years and up to $50,000 from the second year on. 

Intentional violations have fines of $5,000 to $50,000 per day and a 3-year sentence. Subsequent violations increase the fines to as much as $100,000 per day.

If a wastewater treatment plant violates its limits due to the acts of an industry that violated pre-treatment, the industrial business can be fined. It’s just as important for a company to pre-treat any industrial wastewater. In 2023, a beef processing plant in Nebraska paid $275,000 in fines for failing to properly treat its wastewater before releasing it. This wasn’t the first time, the company paid $1.2 million in fines in 2011.

What Happens if You Don’t Control Your Wastewater’s pH?

A lot can go wrong when you’re not monitoring and correcting your wastewater’s pH.  The microorganisms you use will slow down and grow at a slower pace. That allows harmful bacteria to increase their activity. As the balance of microorganisms and bacteria become imbalanced, your wastewater treatment plant loses stability. You’ll end up having to start over to have a thriving colony of microbes again.

Because your microorganisms aren’t thriving, organic matter and pollutants aren’t effectively removed from your wastewater. Sludge increases and becomes harder to get out of the wastewater, as it doesn’t settle as quickly.

Imbalanced pH levels can also corrode your equipment and damage your municipality’s infrastructure. It also puts area waterways at risk of contamination and problems with algal blooms, which harm the wildlife and aquatic life.

Plus, you face the fines from the EPA as listed above. Having properly treated wastewater is important before you release wastewater into a lake, ocean, or other body of water. You need a system that works quickly, correctly, and handles higher flow rates.

The EPA fined a Massachusetts wastewater treatment plant $200,000 for combined sewer overflows when heavy rain increased flow rates. As they’d been fined back in 1988 for the same issue, they must spend $200 million to separate their sewer and stormwater runoff systems. 

Tips for Maintaining Proper pH Control 

How do you ensure you have the right pH in every stage of wastewater treatment? There are several things to do. It’s not a one-size-fits-all situation. Your wastewater treatment plant’s flow rates and contaminants play a role. A wastewater treatment plant dealing with mainly residential wastewater will have different needs than one surrounded by restaurants and businesses.

Add Acids or Alkalis 

When the pH is too high, acids need to be added. Plants may use carbon dioxide or sulfuric acid to lower the pH. If the pH is too low, lime or caustic soda are possible additions.

Add Buffering Agents 

Once the pH levels are balanced, they need to be stabilized. This is done with chemicals like carbonates or phosphates. Ideally, you want to take steps that stabilize pH from the start. Optimizing wastewater treatment processes is ideal.

Implement Real-Time pH Measurements 

Plant automation saves a lot of time and hassle. Look into sensors that continually measure pH, temperature, dissolved oxygen, and other important aspects listed in your EPA permits. When you have real-time information on your wastewater’s quality, it’s easy to take corrective measures to maintain proper pH control.

Optimize Your Plant’s Processes

Instead of needing to use things like lime or sulfuric acid, optimize your plant. Aeration, organic loading, and establishing healthy levels of nutrients are important. This requires having the best equipment with aerators, real-time monitoring, screening, and filtration. 

If you’re aiming for a functioning, effective biological wastewater system, you need the best equipment for the job. Talk to Lakeside Equipment, experts in clean water, to find out what your plant is doing well and what will help ensure your pH levels remain balanced and keep your system in perfect order.

The Future of Sludge Screening: Trends and Technological Advancements in 2024

With a new year come new laws and regulations. It also comes with new trends and technological advancements in the world of wastewater treatment. What are some of the improvements and changes in sludge screening that Lakeside Equipment is watching?

Law and Regulation Changes in 2024

In January 2024, the EPA is holding two public hearings on a proposal affecting meat processing plant wastewater. The EPA wants to impose stiffer restrictions on nitrogen limits and establish regulations on phosphorus. Oil and grease filters will be required to remove FOG from processing plant wastewater. 

Other limitations on high-salt wastewater and higher levels of E. coli bacteria are also being considered. The goal is to lower the pollutants municipal wastewater treatment plants deal with.

Certain states have their own wastewater regulation changes happening in 2024.

  • California – Water agencies are now allowed to recycle wastewater for use as drinking water in schools, homes, and businesses.
  • Florida – Florida’s HB 1379 bans the use of a septic system from all but rural homes. Homeowners must connect to the local sewer system or install their own on-site nutrient-reducing water treatment system.
  • North Carolina – On-site wastewater rules are changing, and one of the biggest is that the local health department now has some say in any improvement permit or construction project, including septic systems.

How will any of this affect sludge screening? Sludge screens help remove solids from wastewater before it moves to the next process in wastewater treatment. When people consider what they’re flushing, it helps wastewater treatment plants avoid unnecessary clogs and equipment wear and tear.

Changes and Improvements in Technology

Each year brings better technology and improvements in wastewater treatment equipment like sludge screening. With automation, the system can track increased flow rates and adjust motors and pumps as needed. They can increase or decrease the amount of chemicals used after analyzing the current water quality. 

Predictive maintenance eliminates sudden breakdowns that take parts of your system down for emergency repairs. Sealed oil within motors and components that are above the water level also makes repairs and maintenance easier than ever.

Here are nine products we offer that provide sludge screening benefits.

Raptor Complete Plant

Grit removal is an important part of wastewater treatment as it keeps items like bone fragments, coffee grounds, and sand from damaging components or clogging lines. A Raptor Complete Plant screens waste through a screw that pushes the dewatered waste through the chute. It also has a grit chamber for grit removal.

Raptor FalconRake Bar Screen

The FalconRake Bar Screen resembles a ladder. As wastewater enters the chamber, the steps of the bar screen capture solids and travel to the top of the ladder where they are deposited over the side. The bars then go back down to repeat the process. As this sludge screening equipment is vertical, it doesn’t require a lot of space. It’s ideal for fast removal of debris and high amounts of sludge.

Raptor Fine Screen

The bottom of the fine screen is a basket that spins in the wastewater collecting debris and sludge, while dewatering and compacting the waste matter in one system. Sludge travels up a chute to the collection bin. It uses a dual spray wash system to ensure organic matter remains in the wastewater flow, and rake teeth clean the screens to prevent jams and clogs.

Raptor Micro Strainer

The Raptor Micro Strainer is a system with a screw that screens, washes, compacts, and dewaters sludge and solids in one smaller system, which makes it a good choice for smaller facilities. As wastewater flows into the chamber, it draws sludge up the screw and is screened. 

A spray wash system keeps organic matter in the wastewater flow. Wastewater presses out of it, and the solids and sludge continue up the transport tube to a bin where it can become compost, head to incinerators, or go to a landfill.

Raptor Multi-Rake Bar Screen

The Raptor Multi-Rake Bar Screen is a vertical sludge screening rake that captures waste in the rake bars, brings them to the top for depositing into a container, and returns to get more. It’s a low-maintenance sludge screening option with rake teeth to help clean each bar while it’s in use.

Raptor Rotating Drum Screen

In districts where the amount of sludge is high, a rotating drum screen is helpful. A large basket sits in the bottom of the tank and captures sludge in screens that range in size from 0.02 to 0.25 inches. Like other systems, the sludge is compacted, dewatered, and pushed up the chute to a bin for composting, incinerating, or hauling to a landfill. It can reduce volumes by 50% and the weight of sludge by as much as 67%, which saves money.

Raptor Rotary Strainer Screen

Wastewater flows into a tank where there’s a rotating screen with mesh ranging from 0.01 to 0.1 inches. The cylinder sits horizontally and captures sludge while ensuring wastewater continues to the next steps through the opening below the screens. The blade assembly automatically cleans itself as waste leaves the chute and travels to a collection bin on the opposite side of the influent area. 

Raptor Septage Acceptance Plant

For wastewater districts that take septage from residential septic systems, the process of pumping septage from trucks, screening, washing, dewatering, and removing sludge at once is essential. A septage acceptance plant does that. Our system can accept two trucks to empty their loads at the same time.

Raptor Septage Complete Plant

In areas where the amount of fats, oils, and grease are high, such as a community where restaurants aren’t on sewer lines, our Septage Complete Plant is designed to handle high levels of sludge, leachate, FOG, and industrial waste. While screening sludge, it also handles grit removal.

Planning for Weather-Related Hurdles

If the past year showed anything, it’s that there is an incredible need to be proactive and plan for the unexpected. Historic flooding hit Vermont not once but twice, and one of those flooding events hit in December when snow is more likely. Instead, over a dozen of the state’s wastewater treatment plants dealt with sewage overflows. Flow rates were up to eight times more than normal because of days of rain.

Vermont is just one of many states where some wastewater treatment plants are still connected to storm drains. When rain hits, it flows into storm drains and straight into sewers where it floods treatment plants and strains the infrastructure. Adjusting for these flow rate increases is important, but you also need screens that can handle the increase.

When did you last have your system assessed? If your equipment is decades old, it’s time to analyze your facility’s current flow rates, what happens when there is heavy snow or rain, and how you can make improvements that ensure your system isn’t overwhelmed.

Talk to Lakeside Equipment’s experts about the latest technology in sludge screening. Our water treatment business is getting close to 100 years in business, and we are experts in the effects of changing weather patterns, the most cost-effective upgrades, and energy-efficiency measures that end up covering the cost of the upgrades you choose. Reach us online or send an email to let us know how we can help your wastewater treatment facility become more efficient and effective.

Energy Efficiency in Clarifiers: Reducing Costs in Wastewater Treatment

Clarifiers play an important role in wastewater treatment, but they also use a lot of energy. Primary and secondary stages consume the most electricity in a plant. If you stop and think about the fact that 25% to 40% of a wastewater treatment plant’s annual budget covers annual electricity bills, the importance of energy efficiency is clear.

It’s estimated that the nation’s plants use around 30 terawatt hours of electricity combined. That accounted for around $2 billion. Finding ways to cut costs is important for the environment and the people in your district. Rising costs put a strain on household budgets, so people don’t want to hear their water bills are skyrocketing as well.

A Quick Look at How Wastewater Treatment Is Handled

Take a closer look at the basics of a wastewater treatment plant. Plants often have different needs based on the businesses and residential homes in the municipality. A plant that accepts septage needs to have a place for trucks to pump out their trucks after pumping out a residential or business septic tank. A city wastewater treatment plant in an industrial area will have other requirements. All of this determines the best wastewater treatment plant design and equipment. The processes are similar, however.

Wastewater enters a treatment plant and goes through two key stages, primary and secondary treatments. Sometimes, a tertiary treatment is added to help chemicals kill harmful bacteria.

In the primary stage, solids settle and are pumped out as sludge. Screens remove other solids like plastic wrappers, applicators, baby wipes, sticks, etc., and those materials are removed to containers to go to landfills, incinerators, or compost facilities. The main steps in primary treatment are:

  • Screening/trash rakes
  • Grit removal
  • Sedimentation/clarification

After this, the wastewater enters secondary treatment. In the secondary stage, wastewater goes through a biological process to further break down materials and purify the wastewater until it’s safe enough to send to a water treatment plant that prepares the water for household use or is released to a lake, stream, or other body of water.

It’s filtered through trickling filters or enters tanks for the activated sludge process. It’s aerated and sludge settles and is returned to the start of that process. The remaining water travels into a sedimentation tank or clarifier and may undergo chemical disinfection in a third stage. That chlorine will be reduced to safe levels before it’s released.

Because some plants have to deal with heavy metals, PCBs, and other pollutants, other steps may be required. Some components in a wastewater treatment plant use the flow of the water to move things from one point to the next, but other components require a lot of electricity. Plus, you have the lighting, heat, cooling, and computers within a plant adding to the energy consumption.

Why Do Clarifiers Drive Up Energy Costs?

If you’re looking specifically at some of the equipment that accounts for the majority of a plant’s electricity consumption, clarifiers are on the list. What makes them consume a lot of energy?

Water enters a clarifying tank to travel in a circular motion, similar to a whirlpool flow. However, the tank has hydraulic scrapers that help push sludge to the center where it is pumped out. Pumps and scrapers run around the clock to rid the wastewater of as much sludge as possible, so the energy use is constant. 

At the same time, scum collects on the surface. Scum consists of lightweight, floating materials like foam and fats, oils, and grease (FOG). This scum is removed by a race skimmer that continually circles the surface and pushes the scum to the “scum pipe” where it’s removed. Again, a motorized skimmer runs continually, which also increases energy consumption.

There’s another problem with an inefficient clarifier. Not only does it consume a lot of energy, but that energy increases greenhouse emissions, which isn’t ideal. Plus, you might find your plant struggling to keep up with the demand as new homes and businesses go up. Many plants are already at 81% capacity or worse. About 15% have exceeded or reached maximum capacity. An efficient plant solves that problem.

How Can You Improve the Energy Usage of Primary and Secondary Clarifiers and Your Plant?

Once you’ve pinpointed what equipment runs constant and consumes the most energy, you can start looking for ways to increase energy efficiency in your wastewater treatment plant. 

Upgrade older equipment:

One of the first steps is to look at the age of your mixers and pumps. Older equipment is going to use more energy. 

With eyes looking for ways to make mechanical and electrical equipment as energy-efficient as possible, newer pumps and mixers consume less energy while doing the same work. Plus, newer pumps and mixers require less maintenance and repair, so you’ll also save money on those expenses. 

It’s worth looking into any grants or energy-efficiency tax credits you gain by upgrading your wastewater equipment. Even a low-interest loan for energy-efficient upgrades becomes a great way to lower your operating costs.

If you’re working with older equipment, it’s a good time to research high-efficiency clarifier designs. Dissolved air floatation systems remove FOG, suspended solids, and metals well, but it does require training. Invest in your employees as it will pay off in the long run. 

Variable speed drives on your facility’s pumps and mixers also ease the strain and energy consumption by scaling back when wastewater flow rates decrease and ramping back up when they pick up again, usually in the morning when people are getting ready for school or work.

Maintain and inspect equipment on a schedule:

Ensure your equipment is maintained and repaired before a small problem turns into a major one. Set up a routine for maintenance around your treatment plant and make sure the tasks on that list are completed on schedule. 

Automate your plant:

Do you use a SCADA system that allows computer analytics to monitor wastewater treatment processes and flow rates? Computer systems can adjust equipment without needing someone right there. SCADA automates pumps, valves, filtration systems, UV lighting if that’s used in your plant’s disinfection process, chemical levels, tank levels, and flow rates. The SCADA system can alert the appropriate person if there’s an issue. 

Look into renewable energy:

Finally, look into renewable energy sources like wind power and solar power. Even the methane produced during wastewater treatment is a viable energy source for powering your plant and heating your buildings.

Work with a professional in wastewater treatment equipment:

Arrange a consultation with experts in energy-efficient wastewater treatment plant designs and equipment. If you’re looking for cost-effective ways to make clarification energy efficient, Lakeside Equipment can help.

Our company has been in the business for close to 100 years, and our engineers and designers are experts in saving money on energy consumption. Lakeside Equipment offers several different clarifiers to match our clients’ needs. We’re happy to help you figure out how to make improvements that fit your budget and plant needs.

Addressing Common Challenges in Wastewater Bar Screen Operation

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.

Understanding Sludge Screening Systems: A Comprehensive Guide

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.

 

Static Screens in Wastewater Treatment: Applications and Advantages

One of the first steps a wastewater treatment plant takes to treat water is to run it through a static screen. If your plant isn’t performing this preliminary treatment step, it’s worth your consideration as they’re a cost-effective way to get a jump start on wastewater treatment.

What Does a Static Screen Do?

When wastewater flows into a treatment plant, a static screen sits in front of the remaining wastewater equipment. Wastewater enters the system, passing through a stationary static screen first to remove as many solids as possible.

Think of it like a mesh screen that keeps bugs from entering your window at home. In this case, it’s a durable screen that catches particles like plastics, feminine products, foods that weren’t digested, hardened particles of grease, and paper products. 

Items that get captured are composted or removed and taken to a landfill. Many plants compost them over time, and that compost can be used in forests. This makes it easier for the next stages of wastewater treatment, such as grit removal.

In addition to a municipal wastewater treatment system, static screens benefit businesses that are under orders to pre-treat industrial wastewater or who want to do their part. It includes companies like chemical processing plants, paper mills, breweries, food processing plants, and plastic and metal processing plants. If you have a stormwater system, they are fantastic for removing plastics, trash, and fallen sticks and branches after a storm.

Learn About the Different Types of Static Screens

There are different types of static screens, including two primary ones that most plants use. The options include:

Band Screens

Band screens are typically installed at the start of a single flow or direct flow channel. It has guides along each edge of the screen panels to ensure movement and alignment remain steady as the chains move around the system to keep the static screens in constant motion. 

The filter mesh is welded and has a frame that acts as a bucket that deposits materials into a collection area. As materials are deposited, spray nozzles clear the grills of debris.

Step Screens

Step screens have different stainless-steel bars with the screen that moves upward to the top, depositing the solids they collect. It almost resembles an escalator. If you can imagine an escalator with mesh that catches the materials instead of solid steps, you have a good understanding of what step screens look like.  

Wedge Wire Screens

Wire wedge screens are self-supporting and either a cylinder or flat panel. Wastewater travels onto the panel or cylinder and falls through the mesh, while solids go over the top to the collection area. It’s usually made from stainless steel due to its durability and anti-corrosion qualities. 

Step and wedge wire screens are the most commonly used static screens, but it’s important to consider what’s best for your wastewater treatment plant. The current design, space, and budgetary constrictions all influence your final decision.

Advantages of Static Screens in Wastewater Treatment

What are the advantages of static screens in wastewater treatment? One of the first benefits is that they’re cost-effective. They do not require electricity, and the purchase and installation costs are not out of reach, especially when you consider that they help make the rest of the wastewater treatment process a little easier to manage. Static screens also require very little maintenance, so you won’t need to spend a lot of time training or hiring additional workers to keep the screens maintained.

They clean themselves with water spray or bar rakes that clear the screen’s bars as the system moves around with the water’s current. Some are also self-reversing to clear any jams that may occur after a storm where large branches enter systems that combine wastewater and stormwater runoff.

Static screens do their job effectively. The mesh screens capture a lot. They can remove small particles of solidified grease, corn skins that are harder for a body to digest, or bone particles from animals that get into a sewer and end up in wastewater. With these items removed before the remaining wastewater treatment measures take place, it eases wear and tear on equipment and gets the treatment process started faster.

With a static screen, they don’t need ideal conditions in order to work correctly. It doesn’t matter if flow rates increase or decrease or if temperatures are colder or hotter than usual. Static screens will work effectively in any condition.

Because static screens come in a variety of sizes and formats, it’s easy to fit one into your existing system. Some require very little headroom. When you’re shopping for the best static screen, finding a variety of sizes ends up helping out if you have little space.

Tips for Choosing the Right Static Screen for Your Facility

The best static screen for wastewater treatment depends on your current setup. Work with an expert in wastewater treatment equipment to learn more about your options, the costs, and how to incorporate static screens in your plant.

Lakeside Equipment brings decades of expertise in water treatment to the table. We offer a variety of screens to ensure every customer gets the right equipment for their needs. Our line-up includes:

  • Raptor® FalconRake Bar Screen: This step system doesn’t require much space and is a cost-effective and low-maintenance option. Bars can be spaced as close as ¼ inch.
  • Raptor® Fine Screen: The Fine Screen is a cylinder static mesh screen that’s angled and has a rotating rake that travels around the screen to clean between the bars, which prevents clogs.
  • Raptor® Micro Strainer: The Micro Strainer is meant for lower use in a smaller facility. It’s a great option for a business that wants to pre-treat wastewater or for a smaller municipality. Stainless steel components and thicker baskets and tubes increase the system’s durability and lifespan.
  • Raptor® Multi-Rake Bar Screen: Stainless steel construction, including the roller chain, with rectangular or trapezoidal bars that act as steps and capture solids. This system has an auto-reverse to prevent jams.
  • Raptor® Rotary Strainer Screen: This wedge wire system is designed with mesh openings of 0.01 to 0.1 inches. It’s in a self-contained unit with stainless-steel construction to prevent corrosion. 
  • Raptor® Rotating Drum Screen: Wedge screen systems can use the cylinder mesh system, and that’s what this rotating drum screen does. The stainless-steel drum captures solids, while the liquids pass through. It’s a multi-purpose system that screens, washes, compacts, and dewaters.

Ask us about our line of Raptor® screens for your larger wastewater treatment plant or the Raptor® Micro Strainer for small facilities. Our wastewater equipment specialists help you make the right choice that’s in your budget and does everything you expect.

Screw Pump Troubleshooting: Common Problems and Solutions

Within a wastewater treatment or water treatment plant, a screw pump moves all of that liquid at a constant speed in the most efficient way possible. Screw pumps are designed to avoid clogging and excessive wear. They don’t require much maintenance, but that doesn’t mean they never experience issues. Here’s a list of common screw pump problems and how to resolve them.

What Is a Screw Pump?

Before getting into common screw pump problems, it helps to know how they work. There’s a giant screw inside a trough or pipe that continually rotates. As it does, water pushes from the bottom of the screw to the top with the help of momentum, the screw’s ridges, and the sides of the trough or pipe. This moves liquids from a lower point like a pool or wet well to a higher point like a basin or tank.

What Issues Are Common?

What are the most common issues people experience with their plants’ screw pumps? These six issues are the most likely to occur.

Cavitation

Sometimes, pressure changes in liquid form small cavities, and then allow vapor and gases to fill those pockets that implode. This is known as cavitation and occurs when the static pressure is lower than the liquid’s vapor pressure. 

Why does cavitation occur? If there is insufficient suction pressure, it’s common. Having high fluid viscosity or gas and air in the fluid are other causes.

When cavitation happens, it creates vibrations that can damage the mechanics within the pump and lead to the failure of the bearings, seals, or shaft. It’s important for the pressure at the suction portion of the pump to remain steady. Reduce the pump’s speed and increase the level of fluid in the suction tank. If gas or air are present, remove them before the liquid makes it to the screw pump.

High Pressure With the Discharge of Liquids

A high discharge pressure is often tied to a blockage in the discharge line. It also occurs if the valve is closed. Those can be easy fixes. Find the blockage or open the valve. It also occurs if the pump speed is set too high. Again, it’s an easy fix. 

Leaks

Leaks also create noises as the fluid levels being moved through the screw pump aren’t adequate. You should notice leaks as you’ll find fluid where it shouldn’t be. They usually occur when seals are worn or fittings are loose. The repairs for leaks involve replacing worn or damaged seals and tightening or replacing loose or broken fittings.

Loss of Flow or No Flow

If your system is not pushing water at all or the flow rate has greatly diminished, it’s often a sign that your motor is working too slowly or is overloaded. It can be tied to a loose belt if the pump is belt-driven. It can also be tied to insufficient suction or the suction pipe being inadequately sized. If the fluid pressure is too close to or matches the vapor pressure, it can lead to issues with flow. If the viscosity of the liquid is too high or the liquid is too hot, flow rates are also impacted.

When any of this is happening, the motor needs to be examined. Make sure everything is lubricated correctly, that belts are tight, and that a variable frequency drive is set correctly. Check the fluid’s temperature and viscosity, and change speed and suction rates if needed.

Loud or Excessive Noise

Is your screw pump making loud rattles, bangs, or grinding noises? Those are not normal noises and need to be investigated. A screw pump makes noise, but excessive or extremely loud noises are not okay.

Loud or excessive screw pump noise is a sign of a clog, cavitation, blocked suction or discharge, misalignment, or worn or damaged bearings. If there are problems, have the repairs made ASAP. Alignment may need to be adjusted. Any blockages need to be cleared.

Make it a point to know how a maintained, properly functioning screw pump sounds. The easier it is to identify the normal noises, the easier it is to determine when a noise isn’t the same. 

Overheating

While the maintenance of a screw pump is minimal, you still need to make sure the pump components are lubricated and working properly. When there is too much friction, overheating is possible and damages a pump in a short time.

Overheating is often linked to operating pumps at too high a speed, clogged lines, or air leaks within the system. All three of these possible causes have to be addressed. 

If you are running your pump faster than is needed, slow it down and see if the problem goes away. Check the lines for clogs, and look for air leaks. Finally, check the lubrication levels and make sure there is adequate lubrication within the pump.

Don’t Delay Troubleshooting Issues

Never delay your attempts to troubleshoot issues. If there is a problem and you wait too long, the repairs could become far more costly. Identifying issues in the earliest stages can save money in the long run. Especially if you have a screw pump expert like Lakeside Equipment to help with the repairs.

Most problems are avoidable if you perform routine maintenance on your screw pumps. You should always keep an eye out for leaks or unusual noises. If there are any concerns, call in an expert. It’s better to pay for an inspection and learn nothing is wrong than to wait and have your pump fail and need to be replaced.

Two Types of Screw Pumps

When you’re investing in screw pumps in your plant, there are open and enclosed screw pumps. Enclosed screw pumps have the screw installed within a solid pipe. Open screw pumps are in a concrete or steel trough. 

Lakeside Equipment offers two types of enclosed screw pumps: Type C or Type S. Type C has a smaller horizontal footprint and an outer rotating tube, while Type S has a stationary tube with a pivot feature to reduce the maintenance needs on the lower bearing. There’s no grouting work required, so installation costs are lower.

Open screw pumps don’t clog, so you don’t need to pre-screen your wastewater. Installation doesn’t require a wet well, and maintenance is minimal. But, they’re going to require a lot of concrete, steel, and possibly grout to build the troughs. 

Which is right for your plant’s needs? Talk to the experts at Lakeside Equipment about your goals and plant design and we’ll help you figure out the right solutions for your budget, volume, and space.