Effectively dewatering wastewater sludge has traditionally involved belt presses, rotary fan presses, screw presses and centrifuge. However, these technologies can only remove water to a limited extent.
The ELODE sludge dewatering system is an effective solution that separates solid and liquid components for easier disposal. Its compact design installs easily into a facility’s dewatering process. Compared to thermal drying, ELODE sludge dewatering equipment is more cost-effective and energy-efficient.
Sludge dewatering is the process of minimizing waste by weight and volume in preparation for effective disposal. Sludge is a semi-solid slurry byproduct of many municipal and industrial procedures.
Sludge dewatering centrifuges and presses usually yield about 15-23% solids. Thermal dryers can get that number up to 40%, but they come with high equipment costs and a large footprint. There are few technologies that can achieve between 23% and 60% solids and thus offer better water removal at a reasonable price range.
The ELODE sludge dewatering system was developed to meet this need. It enhances existing systems that produce dewatered products called cakes. The ELODE system flattens sludge cakes onto a belt and applies a direct current that rearranges the molecules in the material to release the water. The water drains from the belt into a sump and returns to the facility’s headworks.
In just two to three minutes, the ELODE system can double solid content. For example, if you are currently operating at 15% solids, our system can raise that level to 30% or even more. The ELODE dewatering process also takes up less floor space and can be retrofitted to most existing equipment.
How Does ELODE Save Money and Energy?
Eradicating sludge residue can be expensive when using conventional thermal drying methods. Because the ELODE system uses an electrical field instead of boiling away excess water, it saves significant energy and operating costs. Although the technology does produce some heat, it is far less than that produced by thermal dryers. ELODE uses about 120 kilowatts per ton of wet cake, which is more than mechanical dewatering but far less than thermal drying.
Shortly after investing in ELODE equipment, you will see a quick payback. This especially applies if you operate for large urban areas that pay higher rates for landfilling. For example, if it currently costs you $60 per wet ton to landfill solids, the ELODE system can help you cut your costs in half.
Try ELODE’s Innovative Dewatering Technology
While mechanical presses and centrifuges offer limited dewatering capabilities, thermal dryers consume enormous amounts of energy to dewater sludge. ELODE presents a balanced solution. Unlike thermal drying, our electro-osmosis dehydrator can save money and energy while effectively boosting solids content.
Whether you process food wastewater or municipal wastewater, Elode USA Inc’s dewatering systems can help you dewater sludge while cutting transportation, disposal, and storage costs. Contact Elode USA Inc for more details about our sludge dewatering system.
Raw, untreated sewage is a serious hazard to the environment as well as to the nearby population. However, through proper treatment, wastewater facilities can keep up with demand, reduce pathogenic risks, and reintroduce clean water back into the environment. Learn more about the role of sludge treatment in improving wastewater processing.
When municipal wastewater treatment centers process wastewater, they generate sewage sludge as an unwanted byproduct. This semi-solid sludge is made up of chemicals, plant nutrients, organic material, and inorganic waste. This material is also full of bacteria and pathogens, making it dangerous to process and store without the right tools and procedures in place. Treatment is one of the most important parts of wastewater processing, as it alters the sewage sludge to minimize environmental hazards as well as safety and health concerns.
Sludge Treatment Process
The sludge treatment process incorporates these four stages:
1. Sludge Thickening
One way to help control sewage sludge is to thicken it. This can help control the flow of semi-solid fluid, reduce its overall volume, and make the material easier to process.
Before sludge thickening occurs, many systems add clarifying agents and mix them into the fluid. After reaching primary or secondary clarifiers, the sludge is then stirred to help the material settle and thicken. A gravity thickener reduces the final volume of the material. In the primary stage, the sludge is between 8 and 10 percent solids. Secondary sludge can contain up to 4 percent solids after thickening.
2. Sludge Digestion
Now that the sludge is more compact and easier to handle, wastewater treatment plants can start to address the pathogens and bacterial hazards in the sludge. Sludge digestion processes break down the material so it decomposes and turns into stable components. The dangerous pathogens are digested, and the lingering solids lose mass. After this stage, treatment facilities can dewater the sludge without worrying that pathogens will adversely affect the environment.
Let’s take a closer look at the sludge digestion process, which usually involves two stages:
Heating and Mixing: The sludge is mixed in a closed tank to break down the material. It is also heated to encourage the growth and activity of bacteria that anaerobically eat the pathogens in the sludge. Certain acid-forming bacteria can consume the lipids and proteins in organic waste to produce water-soluble, less hazardous byproducts. Those byproducts, in turn, become fatty acids.
Gas Production: Treatment facilities move the sludge into a second tank, where aerobic digestion takes place. Gases start to separate from the sludge as more bacteria break down the sludge. While the resulting CO2 is often a waste product, the facility can collect the methane to provide power for the digestion tank and other functions.
Once the treatment process has collected the methane for power applications, the sludge can move to the dewatering stage, which separates salvageable water from the material. Up to 85% of the volume of sludge can be water. When facilities dry and dewater the sludge, they can both safely reintroduce water to the environment and significantly reduce the total volume of remaining waste.
Next, the sludge passes through a centrifuge, which uses centrifugal forces to press the water out of the sludge and isolate the dried, solid remainder of the sludge for disposal. Some treatment facilities use a filter press instead to press all the water out of the sludge and compress the remaining solids.
Two of the most common processes for drying sludge are depositing the material along sludge-drying beds and processing the sludge in solid-liquid separators (thermal dryers).
Now that water has been removed from the sludge, the remaining cake can be disposed of through:
Incineration and coverage
Use as a fertilizer (depending on the makeup of the sludge)
Benefits of Wastewater Treatment
Proper wastewater treatment has several benefits, ranging from easier and safer waste disposal to the formation of useful byproducts. Consider these crucial benefits:
By treating and releasing water from sewage sludge, facilities significantly reduce the total volume of remaining waste. This reduces adverse environmental effects and also reduces the total disposal cost of sewage sludge cake.
By collecting methane, facilities can power the digestion tanks and other processes in their treatment stations. This lowers the total energy consumption and can even make some wastewater treatment processes self-sustainable. In the event that the sewage sludge produces excess methane and generates extra electricity, that power can be sold to the regional or national grid.
Safe, biodegradable material in dried sewage sludge can be used as a fertilizer, increasing agricultural production and decreasing sewage storage demand.
Contact ELODE for the Right Sludge Treatment Process
By investing in wastewater processing that includes sludge treatment processes, you can reduce negative environmental effects, increase energy efficiency, support sustainable processes, and more. Wastewater processing produces positive short-term and long-term effects that help combat water shortages and other crises around the world. Contact our team today to learn more about how ELODE is developing and innovating sludge treatment processes.
Numerous industrial and municipal processes generate a substance referred to as “sludge,” a semi-solid byproduct containing a mixture of liquids and solid waste. Sludge disposal is highly regulated, making it essential for municipalities and industrial businesses to treat and dispose of it in a way that complies with regulatory guidelines and sustainability initiatives.
Sludge dewatering processes remove the bulk of the moisture from sludge, leaving behind solid filter cakes. Removing water from the sludge significantly reduces the weight and volume of the waste component, making it easier and safer to dispose of it. It also makes the separated wastewater itself easier to treat.
Sludge dewatering offers numerous benefits for wastewater treatment, including:
Less solid waste. Disposing of sludge—or attempting to treat it—in its initial form comes with a variety of difficulties. Most notably, the weight and volume of the sludge itself presents significant challenges for treatment and disposal operations. Separating the liquid and solid components of the sludge notably reduces the volume of solid waste that organizations must dispose of.
Water reuse. The water removed from the sludge can be treated to remove contaminants, then reused as greywater in commercial, industrial, or municipal processes. This type of water sees frequent use in washing and rinsing, heating and cooling systems, fire suppression systems, and more.
Lower storage and transportation costs. Hauling sludge away from an industrial site for disposal requires tankers to make many trips between the origin location and the disposal facility. Generating solid cakes of dewatered waste reduces both volume and weight, requiring significantly fewer trips to the disposal site and lessening the need for on-site waste storage.
Consistency. Sludge transport poses leak and spill risks, especially when routed through residential areas. Employing two-stage sludge dewatering systems creates cakes with consistent levels of dryness. Using high-solid dried cakes virtually eliminates the risk of leaks or spills during transportation and storage.
Automation compatibility. While manual filter-pressing can be somewhat labor-intensive, modern solutions are available with semi-automated and automated components. Sludge dewatering filter presses may leverage advanced control systems that manage automatic cloth washers, assisted cake release systems, automated centrifuge operation, and more.
Sustainability. Sludge collection and disposal poses a lot of unnecessary risks for the environment at every phase. Conversely, sludge dewatering allows for much safer, more efficient disposal of industrial and municipal waste. Separating water for treatment ensures that wastewater won’t seep into the ground at any point in its lifecycle, and also lessens the need for new water to enter into the process cycle. With less waste for disposal and fewer transportation requirements, sludge dewatering also helps to reduce emissions associated with freight transportation.
Sludge dewatering allows industrial businesses and municipal entities to separate sludge into separate liquid and solid waste streams, facilitating easier and more cost-effective recycling and waste disposal. While single-stage dewatering systems may produce cakes of varying consistency and leave behind too much water, incorporating a secondary dewatering system into the process line can help to remove additional water from first-stage sludge cakes.
ELODE specializes in second-stage dewatering systems that pay for themselves over time through savings in sludge disposal, storage, and transportation. For assistance with implementing secondary sludge dewatering solution for your facility, please don’t hesitate to contact us today.
Sludge is a byproduct of a wide range of industrial applications, from power generation to oil refining to drinking water and wastewater treatment. Due to its high liquid content, it is difficult and, consequently, expensive to store and transport for disposal in an unprocessed form. That’s why many industrial facilities invest in dewatering equipment, which is used to separate the sludge’s solid and liquid components to facilitate disposal operations.
There are many sludge dewatering methods, all of which reduce the volume and weight of the sludge to make it easier to handle and transport. Three of the most commonly used involve employing a centrifuge, a plate and frame filter press, or a belt filter press. Each piece of equipment offers distinct advantages that make it suitable for different dewatering applications. Below, we provide an overview of these three sludge dewatering systems to help readers select the right one for their needs.
Centrifuges operate under the principle of buoyancy. They use high rotational speeds—i.e., they spin—to separate components by density. Components with higher densities (e.g., sludge solids) fall to the bottom, while components with lower densities (e.g., sludge liquids) rise to the top.
The primary benefit of centrifugal dewatering operations is processing speed. They quickly produce between 25% and 35% solids by weight. They are generally used in dewatering applications where the main priority is the recovery oil rather than the quality of the solids. However, they do come with their share of faults. Centrifuges are high energy, not easy to operate on/off, and are difficult to maintain.
Plate and Frame Filter Press
Plate and frame filter presses separate liquids from solids using recessed-chamber filter plates. The filter plates combine to form a chamber, which pressurizes the sludge. The liquids are squeezed through the filter cloth that lines the chamber while the solids remain on the surface of the filter cloth. The entire process takes 4 hours for each batch.
The main benefits are that the solids are formed as stackable cakes, which makes them cost-effective to transport and the equipment does not require any special license to operate.
Belt Filter Press
Belt filter presses follow a four-stage dewatering process. The four stages are: 1) pretreatment, 2) gravity dewatering, 3) pre-pressure dewatering in the wedge zone, and 4) press dewatering.
The key benefit of belt filter press dewatering operations is high volume capacity. The continual action of the dewatering process is highly effective for processing high volumes of sludge. However, the quality of the filter cake is lower than that of filter cake produced by other methods (between 11% to 20% solids by weight).
Learn More About Sludge Dewatering From the Experts at ELODE
Sludge dewatering is an important process in many industries. By separating the liquid and solid components of sludge, it improves the cost-effectiveness of disposal operations.
Want to learn more about sludge dewatering and the various methods available? Ask the experts at ELODE! We supply second-stage dewatering systems designed to further improve the dryness and reduce the weight of sludge, which can result in significant sludge transportation, storage, and disposal cost savings. Our dewatering experience can help us answer or address any questions or concerns you may have about centrifuges, plate and frame filter presses, belt filter presses, or other dewatering systems. Additionally, we can assist you in selecting the right solution for your sludge dewatering needs.
Sludge dewatering is a process in which a sludge slurry (sludge) is made more solid by removing water from its contents to form a sludge cake. A wide variety of municipal and industrial processes will create sludge cake after it is dewatered using various presses to form higher solids content versus a watery sludge slurry. While dewatering does not in itself treat the sludge, separating the components ultimately makes it easier and more cost-effective to treat the waste products, as the liquid and solid components will often require separate treatments due to separate contaminants. In this blog, we will discuss the advantages of further sludge dewatering, as well as the technologies behind this important process.
Sludge dewatering is a reliable and efficient method of concentrating waste into high solid filter cakes, thus making them significantly easier to dispose of. It also prevents mudslides at the landfills, which is hazardous to the landfill operators, as well as preventing the contamination of groundwater due to leachate. This process can also serve an important role in a company’s sustainability initiatives. Simplifying the sludge disposal process is important for both public and private sectors, as regulatory agencies require companies to dispose of this substance in an approved way that is both environmentally safe and in line with company requirements. Regulations are starting to prevent the disposal of organic waste in landfills.
The Benefits of Sludge Dewatering
Waste Volume Reduction
By removing the moisture from the slurry, sludge dewatering reduces both the weight and volume of the final waste product. This significantly lowers the ultimate cost of disposal. It also further reduces the leachate production in a landfill and lowers the dangers of a landslide caused by high moisture sludge cake. Recently this has caused a sharp increase in tipping cost by the landfill operators.
Reduced Transportation Costs
Dewatered high solid cakes are lightweight and compact. As such, this process helps manage sludge accumulation and reduces the cost of transportation and storage.
Lower Risk of Spilling/Leaking
In addition to being more lightweight, dry high solid cakes are much less likely to spill or leak onto the road during transportation. This is especially beneficial when transporting waste products through residential areas.
Sludge dewatering makes wastewater recycling much easier. Once the wastewater has gone through treatment, local industries and communities may be able to reuse it. This cuts down on the carbon footprint by reducing the number of trucks on the road.
As it reduces the volume of waste to a more compact size, sludge dewatering is an eco-friendly process of waste disposal. The dry, high-solid cakes are also environmentally friendly due to the fact that the sludge cake may be reusable. You cannot incinerate a low solid cake from mechanical presses unless additional fuel is added. However, a much drier sludge cake can be incinerated or used as a fuel source.
Types of Technologies for Sludge Dewatering
To separate the liquid and solid components of sludge, there are three distinct types of dewatering techniques.
Using a high rotational speed, a centrifuge is able to separate components of varying densities. Components of lower densities will rise to the top of the mixture, while high-density components will fall to the bottom. This uses high energy, has a long startup process, and is an expensive major overhaul of the core working component needed.
Belt Filter Press
Although it cannot produce a high-quality filter cake, a belt filter press is excellent for high volume waste streams that require a large production of filter cake at lower qualities. More specifically, this process provides a continual action that is ideal when the high moisture content in the filter cake is acceptable. Municipal wastewater treatment plants will often utilize belt filter presses.
Using a slow speed, low energy process with less maintenance to dewater sludge, the screw press is gaining popularity. It is more compact but has a lower capacity than belt filter press due to the drain filter surface area of the filter screen.
Sludge Dewatering With ELODE
Sludge dewatering is an efficient and environmentally friendly process that ultimately facilitates the treatment of municipal and industrial organic sludges. Our ELODE non-thermal sludge dryer is a second-stage dewatering machine that will further reduce the moisture content of filter cakes while saving significant amounts of energy.
Mechanical presses are limited in the amount of water they can remove from sludge no matter how slow or hard you press them. If a heated thermal dryer is used to dry the sludge cake, valuable organic properties of the sludge cake will be lost to the hot gas and you will only have useless ash left. To learn more about our sludge dewatering capabilities, contact us today.