Contact us

Your challenges

Your challenges

Removing settleable solids efficiently

Wastewater can contain sand, grit, starch, sediment and other particles that settle naturally but can cause problems further downstream. Effective gravity separation removes these solids before they can overload subsequent treatment steps or accumulate in tanks and piping.

Separating oils, fats and floating particles

Free oils and fats can be difficult to manage in industrial wastewater. Gravity oil-separators use density differences and plate-pack technology to separate floating oil droplets and collect them for further handling.

Managing different wastewater conditions

Every wastewater stream has its own flow, solids loading, particle characteristics and separation requirements. Our gravity separators can be configured and sized according to the wastewater characteristics and required removal performance.

Making the most of available space

Conventional settling processes can require significant tank volumes. Compact plate-pack designs increase the effective separation area and promote laminar flow, allowing efficient solids separation in a smaller footprint.

How can NSI meet your needs?

Gravity separation uses the natural difference in density between water and the contaminants that need to be removed. Depending on the application, we use settling, flotation or a combination of plate-pack technologies to increase the separation area and improve performance.

NSI has provided gravity separator units for over 40 years, based on the company expertise of Nijhuis, Unidro and Flootech to several industries like oil and gas/ tank farms, mining, food (potato, chips, vegetables), meat/poultry, wood & paper and cement & brick.

The NSI ‘Gravity Separation’ solutions portfolio consists of:

Nijhuis NTB (Sedimentation unit)
The Nijhuis NTB is a compact lamella settler designed to remove settling particles from wastewater. Applications include sand, starch, settleable solids, biosolids and solids from backwash water.

Nijhuis NSS (Sand Separator)

The Nijhuis NSS is designed to remove sand and sediment from water and wastewater. It provides a straightforward gravity-based solution for applications where heavy mineral particles need to be separated before downstream treatment.

Nijhuis API (gravity separator)

The Nijhuis API gravity separator is designed around Stokes’ law and uses differences in particle and water density to separate contaminants. It is suited to applications where reliable gravity separation is required for larger wastewaster flows.

Nijhuis CPI (Corrugated plate interceptor)

The Nijhuis CPI is a large-capacity oil-water separator designed for installation in a concrete basin. Its corrugated plate pack increases the separation area and improves the removal of smaller oil droplets.

Nijhuis CSS –  Counter-current separator

The CSS is a stainless steel oil-water separator for gravity separation of oil and fats. Its plate-pack design creates an induced laminar flow that support efficient separation while allowing heavy solids to settle in the inlet compartment.

Nijhuis PPA plate pack

The Nijhuis PPA is a standardized plate-pack module used to increase the effective separation area in gravity separation systems. It is integrated into CPI configurations and supports while allowing heavy solids to settle in the inlet compartment.

FlooClari

FlooClari is a robust high-performance clarifier engineered to reliable process both primary and secondary sludge. It is designed to provide the most economical solution for precipitation and clarification. The basic Clarifier design provides for coagulation, flocculation, solids recirculation, clarification and positive sludge removal in a single basin, eliminating the need for multiple tanks and associated piping.

Customer benefits

Our gravity separation solutions combine a simple separation principle with application-specific engineering. This helps you remove solids and free oils efficiently while reducing the load on downstream treatment.

Chemical-free separation

Gravity separation uses density differences rather than chemical addition as the core separation principle. This makes it a straightforward option for applications where settling or floating contaminants can be separated naturally.

Efficient solids removal

Lamella plate packs increase the available separation area and promote laminar flow. This allows compact systems such as the NTB to efficiently remove settling particles from wastewater.

Compact separation

Plate-pack technology increases the effective separation area without requiring the same footprint as conventional settling arrangements. This makes compact gravity separation suitable for applications where space is an important consideration.

Reliable integration

Gravity separators can be used as an individual treatment step or integrated into a larger wastewater treatment process. Treated water can be discharged or transferred to a subsequent treatment step, depending on the application.

Flexible configurations based on the long-term market expertise

Different separator designs are available for different wastewater streams and separation requirements. Materials, configurations and sizing can be adapted to project-specific conditions.

Applications

Our gravity separation solutions can be applied across a range of water and wastewater treatment processes, for oil and gas / tank farms, mining, food (potato, chips, vegetables), meat/poultry, wood & paper and cement & brick including:

  • Free oil and fat separation
  • Oil-water separation
  • Sand and grit removal
  • Starch removal
  • Settleable solids removal
  • Backwash water treatment
  • Primary wastewater treatment
  • Pretreatment for downstream processes

Contact our experts

Contact our experts

Frequently Asked Questions (FAQ)

Gravity separation uses differences in density to separate contaminants from water. Heavy particles settle, while lighter substances such as free oil and fats rise to the surface for removal.