FAQs: Sludge Dewatering

Or-Tec offers a complete range of proven mechanical dewatering solutions — including belt filter presses and the Rocker® Screw Press — so engineers can specify the right technology for any design scenario from a single vendor:

• Mark II: Ideal for small to medium municipal and industrial plants.
• xpress 2 and xpress 3: Double and triple belt configurations featuring independent gravity thickening zones.
• Gemini: A robust, full-capacity double belt system built for medium to large WWTPs.
• Rocker® Screw Press: The clear choice for enclosed operation, minimal footprint, or maximum cake dryness. It uses a wedgewire drum or rocking multi-disc filter with a variable back pressure plate to deliver dry cake with very low electrical, water, and polymer consumption.

All systems are available as complete turnkey packages — factory mounted, piped, wired, and skid-mounted in stainless steel — allowing your design documents to reference a single, fully integrated solution.

Or-Tec's application engineers have been sizing dewatering systems for municipal and industrial clients since 1980 and are ready to assist with equipment selection based on your design sludge volume, percent solids, biosolids disposal pathway, and solids capture requirements.

Or-Tec's dewatering systems are purpose-built to help facilities consistently meet the solids quality and volume reduction goals that underpin EPA 40 CFR Part 503 compliance and state-level regulatory requirements. The systems deliver the following key operational benefits:

• High Solids Capture: Keeps more suspended solids out of the press filtrate, which reduces internal recycle loads and protects effluent permit compliance.
• Drier, Consistent Cake: Lowers the overall weight and volume of biosolids, directly reducing land application, transport, and landfill disposal costs while mitigating environmental liability.
• Precise Polymer Dosing: Uses hydraulic energy instead of mechanical shear to mix polymer without damage, yielding better flocculation, lower polymer consumption, and cleaner filtrate streams.

Or-Tec's equipment consistently delivers high cake dryness and high solids capture rates across municipal, industrial, and food processing sludge applications - and we back that up with decades of real-world installations, not just laboratory projections.

The Rocker® Screw Press is specifically engineered to produce an exceptionally dry cake, making it the preferred choice for facilities where minimizing biosolids volume is a primary design objective. Belt press systems like the Gemini deliver large dry solids throughput combined with excellent final cake quality and high solids capture, ideal for higher-flow design scenarios.

For design documents and procurement specifications, Or-Tec's application engineering team can provide performance data by sludge type - including waste activated sludge, primary sludge, mixed sludge, and anaerobically digested sludge - to support defensible performance guarantees. We also recommend bench or pilot testing with site-specific sludge when projects require performance bonding, and we have the field experience to help interpret those results accurately.

Contact Or-Tec early in your design process - our team is a strong resource during preliminary engineering and can help you build specifications that protect the owner while remaining competitively biddable.

Absolutely. Or-Tec's dewatering systems are designed with energy and resource efficiency as core performance criteria — not afterthoughts.

The Rocker® Screw Press stands out in this regard, offering low electrical consumption, minimal wash water usage, and reduced polymer demand compared to centrifuges and many conventional belt press designs. Less wash water means a smaller internal recycle flow back to the treatment process — a real benefit for plants managing nutrient loads or operating near hydraulic capacity. The system's enclosed design also controls odor and aerosol emissions without requiring separate containment infrastructure.

For facilities pursuing energy-neutral or energy-positive operational goals, drier cake from Or-Tec's systems increases the energy value of biosolids directed toward co-digestion or thermal processing pathways. The xpress 2 and xpress 3 belt presses further support efficiency with an independent gravity thickening zone that pre-concentrates sludge before it reaches the dewatering belts, reducing the hydraulic and polymer load on the press itself.

All Or-Tec equipment is constructed entirely of stainless steel, supporting long service life, reduced replacement frequency, and a lower long-term environmental footprint. Or-Tec is a strong partner for green infrastructure, capital efficiency, and lifecycle cost goals in sustainable facility design.