A wastewater centrifuge is a continuous industrial separator that uses high centrifugal force to dewater sludge, thicken solids, and clarify contaminated water. Decanter centrifuges handle high-sludge wastewater from municipal, manure, mining, food, and industrial streams, while disc-stack centrifuges polish lower-solids water and oily wastewater by removing fine suspended particles, oil, water, and sludge.
Indicative Pricing
Systems with full stainless-steel wetted parts (piping, valves, tanks, and centrifuge) start around the mid-$60s, EXW Warren MI - US engineered and built in Michigan, test-run before shipment, and backed by a 6-month mechanical warranty, US engineering support, on-site startup, and ongoing technical support.
Types of Wastewater
Wastewater is a generic term for water with solid or liquid contaminants. For example, municipal wastewater has organic sludge, and industrial wastewater carries industrial or inorganic sludge, etc.
Generation in large volumes is the other aspect of wastewater; therefore, the separation equipment must process large amounts of contaminated fluid.
Wastewater from the sources, as mentioned earlier, contains bulk sludge, which is easier to separate. On the other hand, wastewater from mines and oilfield drilling operations contains fine, suspended solids requiring smaller mesh filtration or higher g-force centrifuges.
We also have industrial effluent water, which contains oil in addition to the solids or sludge. This application may need two different centrifuges to separate the sludge and the oil from the de-sludged water.
Wastewater Centrifuges — Types and Capacities (Full Article)
Separation Technologies for Wastewater
Filtration is not an option for this application, given the type and volume of wastewater that needs to be purified. Other separation technologies, such as belts and filter presses, have limited uses in wastewater separation duties. These technologies often suffer from labor intensity and equipment reliability issues that limit their widespread use in modern wastewater treatment plants.
Mechanical separation using a wastewater centrifuge has many advantages for continuously processing large quantities of wastewater. As with all technologies, centrifuges also have some drawbacks highlighted below.
Wastewater Centrifuge Operation
A wastewater centrifuge utilizes a centrifugal force of 3,100 Gs or higher to separate wastewater from sludge. The denser sludge accumulates on the bowl periphery, where an internal auger (scroll) scrapes it towards the discharge ports.
Simultaneously, the clarified water flows out through the liquid outlet at the opposite end of the bowl. This process happens continuously, allowing for high-volume throughput without the downtime required for filter cleaning or media replacement.
Types of Wastewater Centrifuges
Three types of centrifuges apply to wastewater depending on the type and amount of sludge. The following sections describe these broad categories for industrial and municipal use. For a detailed technical comparison, see our decanter vs disc stack centrifuge comparison.
Sludge Thickening or Sludge Dewatering Centrifuge
A sludge dewatering or sludge thickening centrifuge is a decanter-type horizontal de-sludger that can remove water from slurries to thicken the sludge. In other words, a heavy-duty industrial centrifuge dewaters and concentrates (thickens) the sludge, also known as a sludge thickening machine. These machines are available in different sizes to continuously process large quantities of sludge-laden water.
Livestock farm manure, municipal sewage, car washes, and oilfield drilling mud produce wastewater with high sludge content of up to 50%. The primary objective of such applications is to reduce the sludge volume to minimize handling and disposal costs. The recovered water is often clean enough to be reused or discharged with minimal environmental impact.
Clarifying Centrifuge for Mining Effluent
A wastewater clarifier centrifuge is a disc-stack type, a high-speed, self-cleaning separator that produces very high centrifugal forces that can separate micron-level suspended particles. The particles are pushed toward the bowl wall and automatically purged during the cleaning cycle. The cleared centrate discharges the bowl continuously through a centrally located outlet port.
Wastewater from mining applications is one such example. This stream contains minute silt and clay particles that are difficult to separate with a wastewater decanter. A high-speed disc centrifuge has sufficient g-force to pull out these particles and clarify the water.
Separator for Industrial Oily Wastewater
Industrial wastewater often carries oil in addition to sludge. This oily water is challenging because it cannot be disposed of in standard drains. A three-phase industrial centrifuge separates the oil from the water, making it disposable.
Industrial cleaning fluid containing shop-floor sludge and oil from the manufacturing run-off is ideal for separation with a liquid-liquid-solid separator.
Benefits of Centrifuges for Wastewater
Centrifuge offers many benefits compared to other dewatering and separation technologies. A brief description of some of the advantages follows.
Reduced Transportation and Disposal Expenses
Centrifuges produce dry sludge cake, significantly reducing transportation costs (up to 50%). Dry sludge also reduces disposal costs because the disposal volume is a fraction of the wet sludge.
Equipment Durability and Longevity
Industrial decanters are heavy-duty machines that have long service lives. Their material of construction (Stainless Steel) provides corrosion resistance in corrosive processing applications.
These centrifuges have superior erosion protection in critical areas for enhanced wear protection. It is not uncommon for these dewatering machines to operate for decades without needing replacement or even significant rebuilds.
Low Operating Expense
Unlike belt and filter presses, centrifuges do not use filter media, significantly benefiting these machines' users. Also, this eliminates the labor cost related to media replacement.
The only operational expense associated with centrifuges is maintenance. The only parts that need occasional replacement are the bearings because a decanter has fewer moving parts than filter presses.
Minimized Operator Requirements
Most sludge-thickening and dewatering centrifuges are fully automatic. The control systems have built-in sensors with self-correcting features to allow operator-free processing.
Other methods mentioned above need manual service to replace media or perform other periodic functions.
Compact Size for Processing Capacity
Centrifuges are compact when compared to other dewatering equipment. For equivalent capacity, a decanter footprint is often a fraction of other comparable machines. This small size makes them a viable option for wastewater de-sludging in confined areas in treatment plants.
The centrifuge equipment's compact size means that its location can be changed or moved to the worksite for ease of use and flexibility. A typical NX-314 decanter measures just 3 feet by 8 feet by 4 feet high while processing up to 80 GPM.
Wastewater Centrifuge Specifications and Sizing
Centrifuge specifications and sizing depend highly on your specific process and throughput requirements. Below are the technical details for the most common Alfa Laval dewatering and clarification systems.
Dewatering Decanter Specifications
| Specification | Alfa Laval NX-418 | Alfa Laval NX-314 |
|---|---|---|
| Rated Capacity | 170 GPM | 80 GPM |
| Waste Water (5% Sludge) | 100 GPM | 40 GPM |
| Waste Water (10% Sludge) | 60 GPM | 25 GPM |
| Motor Power | 20 ~ 25 HP | 10 ~ 15 HP |
| Weight | 4,000 Lbs | 2,500 Lbs |
| Dimension (L×W×H) | 3′ × 10′ × 4′ | 3′ × 8′ × 4′ |
| Bowl Material (MOC) | 316L Stainless Steel | |
| Wear Protection – Auger | Tungsten Carbide Hard Surfaced Auger | |
| Wear Protection – Sludge Ports | Stellite Bushings | |
| Wear Protection – Inlet Feed Zone | Hard Surface or Stellite Insert | |
Wastewater Clarifier (Disc Stack)
| Specification | WHPX-513 | WHPX-407 |
|---|---|---|
| Rated Capacity | 100 GPM | 30 GPM |
| Waste Water (5% Sludge) | 80 GPM | 12 GPM |
| Motor Power | 15 HP | 10 HP |
| Efficiency | Particles down to 0.5 µ | |
| Skid Weight | 4,000 Lbs | 3,500 Lbs |
| Dimensions | 6′×7′×7′ | 4′×5′×6′ |
| Bowl Material (MOC) | 316L SS w/ Some Red Metal Parts | |
| Disc Stack Configurations | 2-Phase or 3-Phase | |
| Control System | Fully Automatic PLC & Touchscreen | |
Case Studies: Wastewater Sludge Dewatering
Dolphin Centrifuge has supplied industrial decanters and disc-stack clarifiers for hundreds of unique wastewater challenges. Below are selected real-world applications where our systems reduced disposal costs and optimized water recovery. For additional proof of separation performance, see our anonymized sample testing examples.
Bakery Wash-Water
A bakery in Texas processing 20,000 GPD of wash-water contaminated with flour and organic residues used a Dolphin-modified Alfa Laval NX-414 Decanter to recover clean water for sewer discharge.
Composting Leachate
A California university combined a Sharples P-3000 Decanter with an Alfa Laval WHPX-510 to manage high-solids leachate carrying residual organic oils.
Onion Factory Process Water
One of the largest onion producers in California uses our Alfa Laval NX-416 2-Phase Decanter to dewater organic sludge from wash-water at 40 GPM.
Automotive Wash-Water
A Detroit-based auto supplier generated over 10,000 gallons of wash water from floor and pit washing every week. The wash water carried oil in addition to the sludge. Dolphin Centrifuge supplied a 2-step water recovery system with an Alfa Laval NX-314 Decanter, followed by an Alfa Laval MOPX-207 'Self-Cleaning' 3-Phase Disc-Stack Centrifuge as a polisher to remove the oil.
Tortilla Factory Wash-Water
Dolphin Centrifuge supplied an Alfa Laval NX-314B-31 Decanter to thicken the flour sludge in a tortilla factory wastewater stream. The compacted sludge reduced waste hauling and disposal costs by over 60%. Separated water was clean enough for sewer discharge.
Small Municipal Water Treatment Plant
A small municipality in the mid-west needed a sludge-thickener for their sewage treatment operation. Dolphin Centrifuge supplied an Alfa Laval NX-418B-31 Decanter centrifuge with a Chemical Dosing attachment. Municipal sewage dewatering is a common application, and the decanter works as expected to produce dry cake minimizing disposal costs.
Wastewater Centrifuge Models for Sale
Dolphin Centrifuge maintains a diverse inventory of Alfa Laval wastewater centrifuges in Warren, MI. All systems are fully reconditioned to OEM standards and shipped as turnkey, plug-and-play modules.
Dewatering Decanter Centrifuges (High Sludge)
| Model | Capacity | Standard Options |
|---|---|---|
| Alfa Laval NX-418B-31G | 20 to 100 GPM | Feed Pump w/ VFD; Sludge Auger w/ Gear Reducer; Bearing Temp Monitoring; Automatic Back-Drive Control. |
| Alfa Laval NX-314 B-31G | 3 to 40 GPM | Feed Pump w/ VFD; Fluid Tank w/ Level Sensor; Sludge Auger; Torque Lock safety system. |
| Sharples P-3400 | 20 to 100 GPM | Feed Pump w/ VFD Control & Torque Lock; Bearing Temp. Monitoring System. |
| Sharples P-3000 | 3 to 40 GPM | Feed Pump w/ VFD Control & Torque Lock; Bearing Temp. Monitoring System. |
Clarifier & Separator Models (Oily Wastewater)
| Model | Type | Typical Use |
|---|---|---|
| Alfa Laval MOPX-213 | 3-Phase Centrifuge | High-capacity oily water separation up to 80 GPM. |
| Alfa Laval WSPX-307 | Self-Cleaning Clarifier | Precision silt removal and water polishing up to 15 GPM. |