Monthly Archives: February 2024

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.