Wastewater treatment plants are experiencing numerous challenges across the Midwest. Budgets are limited, influent water dynamics are rapidly changing, older equipment is failing, and municipalities are asked to do more with less.
How does a small team keep up with a tight budget and limited resources?
Is there a way to do more with your existing infrastructure?
Paul Nygaard, President of ICS Group, shared his insight on this important topic. "I am an engineer. I’m a graduate of Michigan Tech University Civil and Environmental engineering with over 30 years of experience. As consulting engineers and as manufacturers' representatives, we have to do everything we can to help our industrial and municipal customers. Our goal is to address the challenges that they are facing right now. The problems that wastewater facilities are facing aren't just technology or equipment, but also limited budgets and staffing issues. "
This blog focuses on the pain points that wastewater plants and operators face every day.
"When you look at wastewater in general, these facilities were likely built when the Clean Water Act was passed in the early 1970's. Most of the mechanical and wastewater treatment plants are approaching 50 plus years old. Some facilities have gone through a number of upgrades or enhancements, so we have aging infrastructure. Most wastewater technology and equipment has a life cycle between a 15-to-20-years."
"Keeping the plant up to date and being consistent with maintenance is one of the biggest challenges. The typical municipal wastewater treatment plant is near 81% design capacity and around 15% of plants have exceeded capacity. That is a big challenge and will get worse because of growing communities and changing populations. Some municipalities will see a reduction in growth or become stagnant and some will increase. Population has a direct impact on the amount of flow coming in and out of the plant and whether or not the wastewater plant is able to achieve its capacity and treatment requirements."
Changing wastewater characteristics is another challenge for operators. What’s going on out there?
"Influent wastewater characteristics are changing rapidly. This isn’t your typical domestic wastewater anymore. There are a lot of emerging contaminants of concern - such as: microplastics, surfactants, PFOS, PFOA, PFAS. Some plants are experiencing higher industrial loads. These industrial loads might be coming from food and beverage, yogurt, cheese, and/or meat facilities. High-strength industrial loads have a significant impact on the biological loading, fluctuation, and flow which can cause a lot of challenges. Water conservation is another challenge for wastewater treatment plants. If a community is in a drought, this affects wastewater treatment plants because of the reduced volume of water. The water is more concentrated and can have a big impact on the wastewater treatment plant biological operation."
State and federal funding for wastewater is also a challenge.
"Is the funding going to be enough for projects or an expansion? Is there a way to do more within your existing infrastructure? Do we have to go into a full-blown plant expansion to increase plant capacity? Or can we simply replace equipment that can help solve some of these challenges?
Capital expenses (CAPEX) and operational expenses (OPEX) is a big driver for plant or equipment upgrades. How much money do you have available for an upgrade? What is it going to cost? Is it going to impact and increase operating costs? Or we can improve overall plant efficiency with new technology?
Staffing shortages are another problem. There are a lot of older operators and people who are running these plants who are reaching retirement age. Who is going to replace them? If these positions aren’t back-filled, wastewater plants will have to do more with less staff. How do facilities manage all of these challenges with a limited budget and resources?"
Throughout this blog, we will focus on the areas of collection systems, primary treatment systems, secondary treatment and biosolids management. These are the big problem areas for operators in wastewater facilities. We are going to discuss the equipment we offer that addresses the challenges of operators without significantly impacting manpower and capital budget. In most circumstances, if not all, this featured wastewater technology will have the ability to help wastewater treatment plants reduce their operating costs by improving overall operations.
"The challenges wastewater operators face is primarily related to lift stations and mechanical equipment that is associated with the lift stations. Lift stations often experience plugging and ragging from sanitary wipes. When a rag or ball starts to form in the volute of a pump, if that doesn’t get mitigated right away that will cause imbalances, mechanical disruption, and it will plug the pump. Operators will have to visit the lift station to address these issues."
Other concerns with lift stations are fats/oils/grease (FOG), fatbergs and fat layers that develop on top of a lift station with lower flow rates. "When FOG sits in the system for a while, it is going to develop septicity issues. FOG will have a biological component where you have a lot of BOD and solids, you may end up in a situation where stagnation occurs. Things start to go anoxic and then anaerobic."
"You may get a lot of hydrogen sulfide (H2S) in lift stations and property owners may complain about odor. H2S will also cause corrosion of the internal piping and components. When all of these challenges start to happen, they create employee hazards. If an operator has to work on a lift station in this condition, they may be exposed to a hazardous environment."
"Traditional solutions applied to lift stations may include installing a vertical screen to remove some of the inorganic, stringy material that causes plugging. Another solution includes installing a grinder pump before the water goes into the lift station. You might be able to retrofit pumps to a non-clog or grinder. All of these traditional solutions can be capital intensive, requiring structural and controls work. This goes back to the challenge of the budget."
One of the technologies we represent is straight forward, solves the problem, and is cost-effective. "DERAGGER is a control module that is mounted inside the control panel on the DIN rail. CTs are mounted on the power leads that go down to the pumps. The DERAGGER is real-time pump monitoring. The technology monitors voltage and amperage of that pumping system. It will start to map the power usage curve of the pump."
How does it work? "The first thing we do is make sure the pump is clean before going online. DERAGGER monitors any increase in amperage and reduction in voltage, alerting the pump to go into a reverse cycle and kick that blockage out. This eliminates the potential for the blockage to start. DERAGGER has the ability to monitor unbalanced loads. It can sense if the impeller is out of balance or having bearing issues. This allows the operator to be proactive and effectively manage the lift station. Keeping the volute and impeller clean at all times is vitally important because it can significantly reduce the amount of maintenance and cost associated with the lift station."
Benefits of DERAGGER compared to other technology solutions (which are intensive in manpower and cost standpoint):
Eliminates down time and other costs associated with pump ragging.
If you eliminate the problem, you will reduce the safety risks to operators who have to maintain lift stations.
Wastewater operators have the ability to program a cycle to purge the lift station/cycle lift station turn the pumps on and draw the lift station down (if you have FOG layer that is starting to form, you can eliminate FOG layer)
If you take away FOG, you can take away the possibility of anoxic or anaerobic environments to develop and you’re going to significantly reduce the H2S generation.
Significantly reduces lift station failures.
DERAGGER technology is simple plug and play, all we need are one-line diagrams and information on the pumps and this is one day retrofit.
Technology has the potential to reduce power by 40% by monitoring amperage, voltage, and reducing excessive loads - therefore reducing operational costs.
Typical payback on the DERAGGER is usually in the range of less than a year. When you compare this to a $150,000 fine screen, we can fit a duplex lift station for around $15,000. Plus, you don't have to deal with mechanical pieces of equipment.
Pre-treatment & Primary Treatment
A significant amount of wastewater treatment plants are closer to reaching capacity. "What are some options when you reach plant capacity? Wastewater operators and engineers might go in and look at increasing tank volumes and increasing physical footprint of the facility to be able to handle more load and more hydraulics. Why is this solution not the universal answer to capacity problems? Wastewater facilities can be challenged due to limited footprint. Another big concern affecting facilities is the changing influent characteristics. This is not your typical domestic wastewater anymore. Wastewater facilities are ending up with a lot of weird chemicals and surfactant loadings. During COVID, people started using a lot more soaps and disinfectants and these are considered surfactants. That has caused significant problems in wastewater treatment plants. Industrial loads from food production can also cause a lot of issue."
We have a new technology that is simple to get online and it treats the entire wastewater treatment process. Moleaer manufactures a nanobubble generator system. Nanobubble innovation is a unique technology that has well-proven, significant benefits in wastewater treatment process. Currently, there are over 2,000 projects installed across a variety of industries (agriculture, aquaculture, wastewater, surface water, oil and gas).
How does it work? "The nanobubbles have a direct impact on improving the overall efficiency of the wastewater treatment process by increasing the ability of the biology to go to work.
Tiny nanobubble particles break down the waste constituents more efficiently.
Particles have a high electro-chemically active surface and high internal pressure with neutral buoyancy
Once bubbles are injected into the wastewater, they carry through the wastewater column.
Some of the surfactants, FOG and chemicals attach to the bubbles as it moves through the wastewater process.
When nanobubbles are destabilized, they implode to form natural oxidants without chemicals.
This energy release disrupts the actual molecular makeup of the different chemicals (FOG and surfactants) and breaks down the material to make them more readily degradable."
The Moleaer nanobubble generator is installed at the front end of the plant, after or in the headworks screening and grit removal. The technology has been proven most effective when it is installed right before primary clarification so that the nanobubbles have time to interact with other particles in the water before enhancing the first treatment process. "Some of the benefits that have been realized and documented in white papers and independent studies:
Reduction in surfactants of 35 to 55%
Big impact on TSS enhancement in primary and secondary clarification with TSS removals of 10 to 25%
90% of settling of sludge in less than two minutes in an Imhof cone.
Once we get the solids out of the way, now your secondary aeration process can operate more efficiently.
We see a significant increase in oxygen transfer efficiency, which allows for lower energy at the same DO concentrations.
Proven, reduced energy consumption.
Improves sludge thickening and dewatering. That same application they saw an increase in dewatered cake from 12% to 17% solids.
Reduction in chemical usage.
Significant reduction in odor and foaming on basins.
Within three sludge ages, most wastewater facilities will see results of the technology throughout the entire operation. Any facilities that have a prequalified wastewater project are able to request a pilot of the nanobubble unit, which processes up to 5,000 gallons per minute."
Do you have a plant that has a capacity issue with increased load (hydraulically and biologically?) A typical solution is expansion, adding more tanks, clarifiers, or additional aeration. Or is there another way to deal with capacity and repurpose those tanks? That is where the Nuove Energie technology comes into play.
Nuove Energie manufactures the PrimeScreen. "This technology is a new primary treatment step. It can literally take the place of your primary clarifiers. Just imagine you had a plant that has two 100 ft primary clarifiers at capacity, and they are considering expanding the plant. They may consider adding a clarifier, or you could drop the Nuove Energie PrimeScreen in front of the clarifier. This will take the place of the clarifier and then you can repurpose those clarifiers for potential equalization. Another idea is to convert the clarifier to an aerobic basin and use that capacity to increase your aerobic capacity." Over 2,000 of the PrimeScreen filters have been in operation since the 1980s.
How does it work? A key feature of the Nuove Energie PrimeScreen is it is all stainless-steel construction including the disk filters. When the material gets captured by the disks, the solids come out the side of the unit at 6% to 12% dry solids range. "These solids could be sent directly to a digester without the need for primary treatment or thickening. This would save a process step because the solids are already fairly concentrated. The significant impact of the Nuove Energie technology is that it can eliminate the need for primary clarifiers. Or if you have primary clarifiers and looking to expand primary clarifiers, you may not need to because we can replace the primary clarifiers with the PrimeScreen technology." Benefits of this technology:
High-efficiency primary treatment
We can install the PrimeScreen into an existing structure or channels.
In-channel structure (gravity) or we can pump to the PrimeScreen with force flow.
50-70% TSS removal
20-40% BOD removal
Slurries can be sent over to an anaerobic digester.
PrimeScreen is 90% smaller in footprint than a clarifier, but extremely scalable.
The smallest unit is about 8 ft wide by 16 ft long, processing three to four MGD. Sizing goes up to 200 MGD plants.
Around 200 to 250 micron match on the stainless-steel disks and that is the equivalent of the removal efficiencies at (or above) what 10 states standards recommend for primary treatment design.
Operator can maintain the disks above the water line. Never do any maintenance on mechanical equipment below the water line.
Secondary Treatment, Aeration:
There are numerous issues with secondary treatment, especially when it comes to expansion and the challenges with aeration. "Traditional aeration utilizes fixed grids which are installed on the bottom of a tank. Typical aeration is your 9” fine bubble diffusors or flexible membrane diffusors. The big issue with fixed grid diffusors is they wear out over time and the operator will have to do maintenance. What does that entail? The wastewater operator will drain the plant down, go into the tank and clean up the grit/biological matter that settles. Keep in mind, the plant is offline from a maintenance standpoint. That is a big deal because it takes a lot of effort. All the material needed to clean the bottom of the tank, repair disks and cracked pipes - these issues become more prevalent when you have maximized your existing plant capacity."
How are we going to add more aeration capacity when you have a limited footprint? "Changing influent characteristics can increase the requirement for dissolved oxygen and air into the system and that will drive up operational costs for energy. Maintenance below the water line is also a big challenge. You can’t visually inspect the aeration to see if something is going on (unless the issue is identified from the surface.) Aeration is the biggest energy consuming point in a wastewater treatment plant. Did you know, 40-60% of energy usage in a dissolved oxygen aeration basin (like an activated sludge process) can be attributed to the detrimental impacts of surfactants alone on oxygen transfer."
Benefits of Jaeger Aeration:
Reduce operating expenses related to energy usage by 20 to 40% (you will achieve better distribution of dissolved oxygen within the reactor itself.)
These diffusors can be made from EPDM, silicone, polyurethane with an expected life of 10 years which helps with maintenance.
Example of efficiency gains here, one of the pink strips is equivalent to nine 9” disc diffusors.
We are able to pair the diffusors with the OxyLift design.
A completely retrievable system eliminates the need for the operator to pull the basin down.
One OxyLift frame is the equivalent of a 162 9” diffusors.
Technology is not limited by tank geometry.
When we discuss aeration, there is mixing component for dissolved oxygen transfer. "Normally, aeration and tank mixing will drive up energy costs. If you can find a way to help the operator decouple the mixing energy from the aeration energy, this can have a big influence on the size of the aeration system and how much horsepower you are applying. Aeration can be energy intensive when coupled with tank mixing. You could potentially get solids deposition within the tank and it could lead to ineffective mixing. Again, wastewater operators could have to deal with rotating mechanical mixer maintenance below the water line."
We work with a large bubble mixing system by Pulsair. These diffusors, which we call accumulator plates, sit right on the floor and they are programed to pulse large amounts of energy and large bubbles into the aeration basins. Pulsair effectively mixes every corner and surface of the tank, from the top to the bottom. Benefits of Pulsair tank mixing:
Accumulator plates sits below the aeration grid.
Reduce the need for in-tank maintenance or cleaning, which is a big deal for the operator.
All stainless-steel construction.
Easy to design and install.
Our last topic of discussion is biosolids management. "Biosolids and sludge management is a timely topic for wastewater operators, especially when we are talking about emerging contaminants such as PFAS and PFOA. The ICS Group has worked on projects where we have helped wastewater treatment plants deal with biosolids that are contaminated with PFAS and PFOA. When you look at the challenges associated with biosolids management, another concern for operators is the changing regulations. There are more restrictions on land-applying and operators are challenged with limited land-space. These concerns will become more prevalent as we start to see more of these contamination issues and farmers backing up and saying they want the biosolids tested before land applying."
As landfills start to restrict biosolids and land is limited, the cost per acre increases and it becomes an operational expense challenge. Ask yourself "what can we do to help those operators solve that problem?"
Dewatering presses help operators achieve a drier solid. "Traditional technology, such as belt presses, centrifuges, rotary presses can be high maintenance. They can use a lot of water, consume a lot of energy, and take up footprint. We work with Process Wastewater Technology (PWTech) and offer the Volute dewatering press.
This is an image of an install at the Marinette facility. This wastewater facility processes 21,000 GPD at roughly two and half feed solids. The PWTech Volute Dewatering Press is about 12 feet long by 6 feet wide. The press uses about 5 horsepower total and about 20 to 40 gallons per hour of wash-water. The Marinette team arrives in the morning, presses the start button and walks away. They will let it run five days a week, 24 hours per day. We are helping them reduce their energy consumption. Maintenance on the dewatering press is simple. Marinette's wastewater team is small, and they don't have time to babysit the system. This particular technology has two screws in the image but PWTech has the ability to design a press with six screws on a skid. Having multiple screws gives you built in redundancy." Additional information on the PWTech Volute Dewatering Press:
Volute Press is completely self-contained and fully automated.
Built in redundancy.
Maintenance on this machine is every 15,000 hours.
The upper assembly cartridge comes out on a rail and takes roughly 4 hours to rebuild the press.
Can we do more with the existing infrastructure, reduce manpower, and maintenance requirements from an energy usage standpoint? Yes.
"What they do at this facility, because they have a PFAS problem, the dewatered cake discharges at 22-23% into cake pump and is conveyed to a biosolids dryer. All of this equipment was put into a footprint of 15’ x 55’ into existing building. The Marinette team came to us with a challenge and stressed the importance of using the existing footprint. We were able to engineer this and put into an existing building."
Not all biosolids dyers are created equal. The Shincci technology is actually a dehumidification system, not a dryer. The cake is dried to over 90%, which gives the customer the ability to manage the volume of solids. "With the example of Marinette, because the biosolids are contaminated they only have one outlet for their biosolids. The plant was able to reduce the volume of sludge by 60 to 80%, achieving 90% dry solids and achieving a huge volumetric reduction."
"The Shincci technology is fully automated. The press and biosolids process is fully automated where the facility runs for 5 days per week, 24 hours per day. They turn it on Monday morning and shut it off Friday afternoon. We helped the Marinette team solve the problem with a cost-effective solution. Most importantly, the solution didn’t create additional challenges for the wastewater team."
How the Shincci sludge dehumidification technology it works:
Temperature inside the system is at 70 to 75 ℃ during the treatment process.
Once the wet sludge cake is dried to low-percent total solids (90% TS by weight), most of the water contained in the wet sludge cake is evaporated.
Once the dried biosolids reach the end of the lower belt and drop into the conveyor, the biosolids temperature drops very quickly (you can touch and hold by hand the materials coming off the lower belt).
There is no need for adding any system to cool down the final dried product.
Benefits of the Shincci sludge dehumidification technology for your biosolids project:
The Shincci USA sludge dehumidification system is the lowest energy consuming dryer system currently available.
The sludge dehumidification system uses only 1.2 to 1.4 kwh of electrical power per gallon of water or 440 to 490 BTU/pound of water.
Ultra-high energy efficiency through the use of a patented recirculating heat pump system, allowing the facility to save at least 50% less energy than any other available sludge dryer system.
The system operates at a temperature below 80 C, thereby eliminating the risk of combustion within the dehumidifier.
Does not require explosion proof requirements.
Virtually no odor, does not require air permit.
Does not require additional complex systems such as air scrubbers or dust suppression.
Approximately two man-hours per week for general maintenance.
Can we help wastewater facilities improve plant capacity by simply adding technology instead of having these major expansion projects? Yes.
Our team assists facilities adjust to changing influent challenges and effluent regulations.
Can we upgrade efficiency without having to do a whole plant upgrade? Yes.
Our team works with wastewater technology systems which can be as automated as possible, keeping manpower limited, so wastewater teams can do more with less.
In conclusion, we want engineers and end users to look for technology solutions that can help aging wastewater treatment plants to continue to meet their required regulations without breaking the bank, using additional manpower, or creating more complexities in the operation.