Top OEMs for Archimedes Screw Pumps in Wastewater Treatment Plants

Introduction

The Archimedes screw pump remains one of the oldest yet most efficient mechanisms for lifting water and wastewater. Despite the prevalence of centrifugal and submersible pump technologies, the screw pump maintains a critical position in municipal and industrial treatment plants, particularly in headworks (inlet lift stations), stormwater pumping stations, and return activated sludge (RAS) applications. Its operational principle—a positive displacement mechanism using a rotating helical screw within a stationary trough—offers distinct hydraulic advantages that modern high-speed rotodynamic pumps cannot replicate.

For the municipal consulting engineer and plant manager, the Archimedes screw pump represents a high-capital, low-operational-expenditure (CAPEX vs. OPEX) investment. While the civil works and initial equipment costs are substantial, the equipment typically offers a lifecycle exceeding 20 to 30 years with minimal energy consumption and maintenance requirements. However, this longevity is contingent upon precise specification and the selection of an Original Equipment Manufacturer (OEM) capable of delivering rigorous fabrication tolerances and robust bearing assembly designs.

The market for these pumps is specialized. Unlike standard ANSI pumps or submersibles, Archimedes screws are custom-engineered structures that become integral parts of the facility’s civil architecture. Selection of the OEM is not merely a purchase of machinery but a partnership in civil design integration. The manufacturing quality of the torque tube, the precision of the flight welding, and the reliability of the lower bearing assembly are the primary determinants of whether a station will operate for three decades or suffer from catastrophic fatigue failure within five years.

This article provides a technical evaluation of the requisite selection criteria for Archimedes screw pumps and an in-depth analysis of the top OEMs currently serving the market: Lakeside Equipment, Ebara, Huber, Spaans Babcock, and Landustrie. The analysis focuses on engineering specifications, maintenance profiles, and application suitability, devoid of marketing bias.

How to Select This Pump Type

Specifying an Archimedes screw pump requires a fundamental shift in thinking compared to centrifugal pump selection. Engineers must move away from Best Efficiency Point (BEP) curves and NPSH calculations and focus on geometric capacity, submergence levels, and structural integrity. The following criteria are essential for drafting robust specifications.

1. Hydraulic Performance and Efficiency

The efficiency of an Archimedes screw pump is largely a function of the gap between the flights (the screw blades) and the trough. This gap typically ranges from 3mm to 6mm depending on the pump diameter. Excessive gap width results in “slip” or backflow, drastically reducing volumetric efficiency.

• Variable Flow Handling: Screw pumps are self-regulating. As the influent level rises, the screw fills more completely, increasing output automatically without changing rotational speed. However, Variable Frequency Drives (VFDs) are now standard to optimize energy usage during low-flow periods and to provide soft starts that reduce torque stress on the drive train.
• Partial Load Efficiency: Unlike centrifugal pumps, which suffer efficiency penalties away from their curve, screw pumps maintain high efficiency (often 70-80%) across a wide range of flows, making them ideal for stormwater applications where flow rates fluctuate wildly.

2. Solids Handling and Non-Clogging Characteristics

The open design of the Archimedes screw prevents clogging. It does not rely on passing solids through a restricted volute.

• Large Solids: These pumps can lift any object that fits between the flights. This makes them the premier choice for raw sewage influent stations (headworks) where wipes, rags, wood, and debris are present before screening.
• Shear Sensitivity: The low rotational speed (typically 20 to 100 RPM) creates very low shear forces. In Return Activated Sludge (RAS) applications, this is vital as it prevents the breakup of biological floc, improving downstream settling in secondary clarifiers.

3. Lower Bearing Assemblies

The lower bearing is the “Achilles heel” of the Archimedes screw pump. It operates submerged in abrasive, corrosive wastewater. Selection here is critical.

• Grease-Lubricated: The traditional method. Requires continuous automatic grease injection to purge contaminants. Reliability is high if maintenance is maintained, but it presents environmental concerns regarding grease discharge.
• Oil-Bath/Sealed: Fully enclosed systems that do not purge grease into the water. These require less routine maintenance but catastrophic seal failure is harder to detect until damage occurs.
• Eco-Friendly/Water-Lubricated: Newer designs use water-lubricated polymer bearings or environmentally safe lubricants, eliminating the risk of water contamination.

4. Materials of Construction and Fatigue Life

The central torque tube undergoes massive cyclical stress. A common failure mode is fatigue cracking where the flights are welded to the tube.

• Tube Wall Thickness: Specifications should demand schedule calculations based on deflection limits (usually L/2000).
• Materials: Carbon steel is standard, usually coated with high-grade epoxy or coal tar epoxy. Stainless steel (304 or 316) is increasingly used for smaller screws or enclosed tube designs to eliminate corrosion and coating maintenance.
• Trough Construction: The trough can be concrete (screeded in situ by the screw itself) or a steel liner. Steel liners offer tighter tolerances but require precise installation.

5. Installation and Civil Considerations

Inclination Angle: Standard angles are 30°, 35°, and 38°.
Trade-off: Steeper angles reduce the footprint and civil costs but reduce the effective lifting capacity per rotation. Shallower angles increase capacity but require longer screws and larger footprints.

Comparison Table: Top Archimedes Screw Pump OEMs

The following table contrasts the five mandated OEMs based on their technical specialization, typical bearing configurations, and primary application strengths. Note that “Capacity” is a function of diameter and speed; all listed OEMs can engineer pumps for a wide range of flows.

OEM	Core Design Philosophy	Key Technologies	Primary Application Fit	Maintenance & Limitations
Lakeside Equipment	Robust, open-screw design focused on North American municipal standards.	Dual upper bearing design; Heavy-duty torque tubes; Open and enclosed options.	Municipal Headworks; Stormwater Lift Stations; RAS Pumping.	Strength: Extremely high domestic install base and parts availability. Note: Primarily carbon steel focus; requires coating maintenance.
Spaans Babcock	Pioneers of the modern screw pump; focus on bearing innovation.	ECO-bearing (grease-free lower bearing); Compact screw designs; Fish-friendly variants.	Large Scale Infrastructure; Environmentally Sensitive Areas; Retrofits.	Strength: The “ECO” bearing significantly reduces O&M costs regarding lubrication. Note: Premium pricing for proprietary bearing tech.
Landustrie	Renovation specialists with flexible bearing configurations.	“Landy” screws; Water-lubricated lower bearings; Retrofitting existing troughs of other brands.	System Rehabilitation; Polders/Flood Control; General Wastewater.	Strength: Excellent capability in re-engineering replacement screws for obsolete competitor installations. Note: Heavy reliance on European engineering standards (DIN/ISO).
Huber	Stainless steel fabrication and enclosed “tube” designs.	RoS 2/3 (Enclosed Screw); Integrated screening options; High-quality stainless fabrication.	Odor-sensitive plants; Industrial Pre-treatment; High-lift/low-flow applications.	Strength: Complete odor containment and zero-corrosion stainless construction. Note: Enclosed designs are harder to inspect visually during operation.
Ebara	Large-scale global infrastructure and custom engineering.	Custom large-diameter screws; Integrated station design; Global supply chain.	Mega-projects; Flood Control; Major Municipal Intakes.	Strength: Massive manufacturing capacity for very large scale projects. Note: Less focused on small standard municipal applications compared to others.

Top OEM Manufacturers: Detailed Analysis

The following analysis evaluates the mandated OEMs. These manufacturers have been selected based on their prevalence in the market, engineering history, and ability to support critical infrastructure.

Lakeside Equipment Corporation

Overview:
Lakeside Equipment is a dominant player in the North American market. For many US-based consulting engineers, Lakeside is the standard specification for open-channel Archimedes screw pumps. Their designs are conservative, prioritizing longevity and structural mass over lightweight cost-savings.

Technical Strengths:
Lakeside is renowned for its upper bearing assembly design. Unlike some competitors that use a simple pillow block, Lakeside often utilizes a dual-bearing configuration that separates radial and thrust loads, significantly extending the life of the assembly. Their torque tubes are typically engineered with substantial wall thickness to minimize deflection, ensuring the critical flight-to-trough gap is maintained over decades of service.

Best-Fit Scenarios:
Lakeside is the “go-to” for standard municipal wastewater treatment plant headworks. Their support network in the US is extensive, making them a low-risk choice for public works departments concerned about long-term parts availability and service support.

Ebara

Overview:
Ebara Corporation is a global heavyweight in fluid machinery. While often associated with submersible and centrifugal pumps, Ebara’s involvement in the Archimedes screw sector is defined by large-scale infrastructure projects. Their approach is one of total station engineering, often supplying pumps for massive flood control and drainage projects in Asia and globally.

Technical Strengths:
Ebara excels in the fabrication of large-diameter screws where manufacturing tolerances become incredibly difficult to manage. Their strength lies in their metallurgical capabilities and quality control processes (QA/QC) suitable for mega-projects. For municipalities planning massive stormwater diversion stations or regional lift stations, Ebara brings the capacity to handle high-volume custom fabrication that smaller boutique shops cannot.

Best-Fit Scenarios:
Large-scale flood control, raw water intake for desalination or power plants, and major metropolitan sewage lift stations where flow rates are extreme.

Huber Technology

Overview:
Huber is synonymous with high-quality stainless steel manufacturing. While they produce open screws, they have carved a unique niche with their enclosed screw pumps (Rotary Screw Pump RoS). Unlike the traditional open trough design, the Huber RoS features a rotating cylinder where the screw is welded to the drum, and the whole assembly rotates.

Technical Strengths:
The enclosed design eliminates the gap between the flight and the trough (as they are welded together), which eliminates backflow (slip) and maintains high efficiency even at low flows. Furthermore, the enclosed nature means zero odor emissions and no splash risk, allowing these pumps to be installed in urban areas or indoors without complex HVAC or covers. Huber also integrates screening technologies directly into their systems.

Best-Fit Scenarios:
Sites with strict odor control requirements, industrial applications requiring stainless steel (e.g., food and bev), or installations requiring steep angles of inclination (up to 45° is possible with enclosed designs).

Spaans Babcock

Overview:
Spaans Babcock is arguably the historical authority on the Archimedes screw pump. Having been instrumental in modernizing the technology in the 20th century, they boast perhaps the largest global install base. They are engineering-led, often pushing the boundaries of bearing technology and composite materials.

Technical Strengths:
The “ECO” bearing is their flagship differentiator. It is a completely enclosed, grease-free lower bearing assembly. This eliminates the need for automatic grease pumps and the associated maintenance/refill routes. It solves the primary environmental objection to screw pumps (grease in the water). Spaans also offers composite troughs, which are easier to install and replace than screeded concrete.

Best-Fit Scenarios:
Environmentally sensitive waterways (due to fish-friendly designs and no grease), remote stations where daily maintenance checks are impossible, and energy-conscious retrofits.

Landustrie

Overview:
Based in the Netherlands—a country that relies on screw pumps for its very existence—Landustrie combines heritage with pragmatic innovation. They market their pumps under the “Landy” brand. A significant portion of their business model is dedicated to the replacement market, engineering screws that fit into the civil constraints of defunct competitors.

Technical Strengths:
Landustrie is highly flexible regarding lower bearing options, offering stainless steel eco-bearings and heavy-duty cast iron variants. They have developed specific expertise in “screeding” techniques (forming the concrete trough), which is an art form essential to pump efficiency. Their renovation services are distinct; they can often replace a fatigued screw with a new design that offers higher capacity within the same footprint by optimizing flight geometry.

Best-Fit Scenarios:
Retrofit projects where an existing screw (from any brand) has failed. Applications requiring specialized lower bearings for abrasive grit environments.

Application Fit Guidance

Selecting the right OEM often depends on the specific sub-application within the treatment plant or collection system.

Municipal Wastewater Headworks

Preferred: Lakeside Equipment, Spaans Babcock, Landustrie.
Reasoning: These applications require maximum reliability and the ability to pass large, stringy solids (rags) without fouling. The open trough design allows operators to visually inspect the flow and easily remove large debris if necessary. Lakeside’s heavy-duty torque tubes are particularly valued here for their resistance to shock loads from large objects.

Industrial Wastewater & Odor Control

Preferred: Huber.
Reasoning: Industrial effluents can be corrosive or emit hazardous vapors. Huber’s enclosed stainless steel designs provide containment and material resistance that carbon steel open screws cannot match.

Stormwater and Flood Control

Preferred: Ebara, Spaans Babcock.
Reasoning: These applications involve massive volumes of water. Ebara’s capacity for large-scale fabrication allows for screws exceeding 3-4 meters in diameter. Spaans Babcock’s fish-friendly designs are also critical here, as stormwater intakes often interact with natural waterways.

Return Activated Sludge (RAS)

Preferred: Lakeside, Landustrie.
Reasoning: RAS pumping requires gentle handling to preserve floc structure. The traditional open screw design offers the lowest turbulence. Variable speed control is essential here to match the return rate to the plant’s hydraulic loading.

Engineer & Operator Considerations

Beyond the OEM nameplate, the long-term success of an Archimedes screw pump installation relies on specific operational and maintenance factors.

1. The Grouting (Screeding) Process

The most common cause of poor efficiency is not the pump itself, but the civil installation. The trough must be “screeded” to match the screw’s profile with a gap of only a few millimeters.

• Engineer Note: Specification documents must rigorously define the screeding method. Many OEMs (like Landustrie and Lakeside) prefer to supervise or perform this step themselves. Allowing a general civil contractor to pour the trough without OEM supervision often results in gaps that are too wide (loss of efficiency) or too narrow (screw rubbing and wearing).

2. Lubrication Management

For pumps with grease-lubricated lower bearings, the grease lines are the lifeline of the pump.

• Operator Note: Automated grease pumps are convenient but dangerous if they clog. A blocked line means the lower bearing is running dry underwater. Systems should include flow sensors on the grease lines, not just “pump on” status indicators.
• Spare Parts: Keep a spare lower bearing assembly in stock. Lead times for these specialized bronze or Babbitt bearings can be weeks or months.

3. Fatigue and Weld Inspections

The connection point between the helical flight and the central torque tube is a high-stress zone.

• Maintenance Note: Annual inspections should include cleaning the screw and inspecting flight welds for hairline cracks. Early detection allows for simple grind-and-weld repairs. Neglect leads to flight separation, which can jam the screw and catastrophically twist the torque tube.

4. Safety and Covers

While open screws are easy to inspect, they are hazardous rotating machinery.

• Engineer Note: Specifications should include aluminum or fiberglass covers that prevent accidental contact but feature easy-access hatches for inspection. Ideally, covers should be segmented to allow partial removal for maintenance without a crane.

Conclusion

The Archimedes screw pump is a testament to the idea that simple, robust engineering often outperforms complex high-speed technology in wastewater applications. When specifying these pumps, the focus must be on structural integrity, bearing technology, and the quality of civil integration.

Lakeside Equipment remains the benchmark for standard North American municipal applications, offering rugged reliability. Spaans Babcock and Landustrie offer deep European engineering expertise, particularly valuable for retrofits and advanced bearing requirements. Huber stands alone for enclosed, sanitary, and odor-controlled applications, while Ebara provides the industrial muscle for the world’s largest water infrastructure projects.

For the consulting engineer, the recommendation is to prioritize the lower bearing design and the trough construction method in the specification. For the operator, the focus must be on lubrication monitoring and annual weld inspections. By selecting the correct OEM and adhering to rigorous installation standards, a facility can expect 30+ years of reliable, high-efficiency service from these giants of hydraulic engineering.

source https://www.waterandwastewater.com/top-oems-for-archimedes-screw-pumps-in-wastewater-treatment-plants/