VSEP Industries

Fish Meal Wastewater

VSEP® Applications for Fish Meal Plants

Recover more oil. Reduce your evaporator load. Supports permit compliance.

Fish meal processing creates some of the most challenging separation tasks in industry—stabilized oil‑in‑water emulsions, high‑protein stickwater, and nutrient‑rich wastewater with variable flow. VSEP® (Vibratory Shear Enhanced Process) uses high‑frequency shear at the membrane surface to prevent fouling, sustain flux, and deliver precise separations where biological and gravity methods struggle making it ideal for fish meal wastewater treatment. On this page, see four proven VSEP placements that increase oil yield, reduce evaporator energy, and improve compliance—without adding complex chemistries or oversized tanks.

A fish meal plant processes whole fish and fish‑processing by‑products into fish meal and fish oil, two high‑value ingredients used primarily in aquaculture, livestock feed, and pet food. The process cooks and presses the raw material to separate solids, oil, and water, then dries the protein‑rich solids into a stable meal while recovering oil as a co‑product. The remaining liquid, known as stickwater, contains soluble proteins, minerals, and residual oil that are typically concentrated and returned to the meal or treated as wastewater. Together, these operations convert perishable fish material into nutrient‑dense, shelf‑stable products with global agricultural value.

What VSEP is and how it works.

VSEP® (Vibratory Shear Enhanced Process) is a membrane filtration technology that uses high‑frequency, low‑amplitude vibration at the membrane surface to generate intense shear, preventing fouling and maintaining stable flux even on highly concentrated, oily, or protein‑rich streams. Unlike conventional crossflow systems that rely on high recirculation velocities, VSEP applies shear directly where fouling forms, enabling efficient separation with lower energy and minimal pretreatment. The VSEP can operate with microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) membranes, allowing the same system architecture to be tailored for particle removal, oil recovery, protein concentration, or dissolved solids and salt rejection depending on the application.

 

Illustration of VSEP vs Crossflow Filtration.

Where VSEP Fits in a Fish Meal Plant (Four Applications)

1) Polishing the Recovered Oil (Hydrophobic PTFE Microfiltration)

Clarify disc‑stack oil by removing colloids (protein/phospholipid haze) that degrade stability and price.

How it works:

VSEP can be used with hydrophobic PTFE 0.05 µm microfiltration membrane to filter hot fish oil to remove very high percentage of protein fines, colloids, and other suspended solids that slip past the disc‑stack.

Expected outcomes:

  • Lower MIU (moisture, impurities, unsaponifiables)
  • Clearer oil with improved storage stability
  • Higher sale price in premium aquafeed or refining streams
  • Minimal yield loss due to recoverable retentate

Design notes:

  • Typical operating temp: 80–95 °C (match your current oil handling)
  • Clean‑in‑place (CIP) compatible; short cycles due to VSEP’s anti‑fouling action
  • Retrofit inline after the polishing separator or hot‑settling tank

2) Stickwater Microfiltration to Recover Oil for Re‑separation

Some oil can bypass the disc stack oil separator or skimmer and remains in the stickwater. Recover this oil in the stickwater using VSEP microfiltration and return it to the disc‑stack oil separator for recovery.

How it works:

VSEP 0.05 micron microfiltration rejects and concentrates free and emulsified oil droplets carried by proteins/phospholipids. The MF retentate is a compact, oil‑rich stream; the permeate is lower‑FOG water rich in soluble proteins ready for evaporation or concentration using VSEP nanofiltration.

Expected outcomes:

  • Increase net oil yield—capture what DAF/centrifuges miss
  • Lower evaporator fouling (less FOG to vapor side)
  • Smaller chemical footprint vs. heavy demulsifier programs

Integration path:

  • Source: post‑disc‑stack stickwater or mixed wash waters
  • Retentate looped back to the disc‑stack feed (or hot settling)
  • Permeate proceeds to evaporation or to NF (Placement #3)

Image of filtration samples from VSEP pilot system treating fish meal wastewater.

VSEP Filtrates (left) with emulsified oil removed, Stickwater (right)

3) Nanofiltration of Stickwater to Reduce Evaporator Load

Offload your evaporator by concentrating proteins, peptides, minerals, and residual oil upfront sending a smaller volume to the evaporator.

How it works:

VSEP nanofiltration (NF) rejects and concentrates high‑molecular‑weight proteins/peptides, colloids, and multivalent minerals, producing a high‑solids retentate and a COD‑reduced permeate. Vibration shear controls gel‑layer formation—stable flux even on sticky, high‑FOG stickwater.

Expected outcomes:

  • Reduce evaporator duty and steam consumption
  • Increase evaporator uptime (less fouling, fewer CIP cycles)
  • Smaller footprint than adding evaporator surface area

Process options:

  • Combine with MF (Placement #2) to first skim oil then concentrate the remaining proteins and organics efficiently

Example PFD of MF VSEP removing oil and TSS.

Example PFD – MF Removing Oil & TSS and NF Concentrating Protein

4) Final Effluent Polishing Prior to Discharge

VSEP RO for Final Effluent Treatment in Fish Meal Plants

For fish meal plants seeking a compact, high‑performance alternative to conventional wastewater treatment, VSEP reverse osmosis (RO) can be deployed as a final effluent step once coarse solids (>100 microns) and free oil are removed. In this configuration, VSEP acts as a physical barrier that effectively removes dissolved organics, residual oil, suspended fines, nutrients, and salts, producing a high‑quality permeate suitable for discharge or reuse.

Unlike conventional membrane systems, VSEP’s vibratory shear mechanism prevents the buildup of protein, oil, and colloidal fouling layers that typically limit RO performance on food‑processing effluents. This allows stable operation on fish meal wastewater streams that are traditionally considered “too fouling” for RO.

How VSEP RO Works in This Application

After coarse screening (≥100 µm):

  • Effluent is fed directly to VSEP RO modules
  • High‑frequency membrane vibration suppresses fouling & scaling
  • RO membranes are designed to reject dissolved solids
  • Concentrate is minimized and managed separately
  • Capable of meeting stringent discharge requirements

This approach does not rely on biology, residence time, or microbial health to achieve performance.

Comparison: VSEP RO vs. Conventional DAF / Biological Treatment

Aspect Conventional DAF + Biological VSEP RO
Removal mechanism Flotation + microbial degradation Physical membrane separation
Footprint Large (tanks, basins, clarifiers) Compact skid‑mounted system
Load sensitivity High (shock loads, seasonality) Low (membrane is load‑agnostic)
Oil & emulsions Requires chemical optimization Physically rejected
COD/BOD removal High, but variable Very high and consistent
Nutrient removal Requires nitrification/denitrification Intrinsic rejection
Startup time Weeks to months Immediate
Odor generation Common (anaerobic zones) Minimal
Operator attention High (biology management) Low to moderate
Effluent quality Variable Predictable and stable

Actual performance depends on feed composition, operating conditions, and membrane selection.

How VSEP Complements (Not Always Replaces) Conventional Treatment

In many plants, VSEP RO is used to:

  • Polish biologically treated effluent to meet tighter limits
  • Replace aerobic polishing stages
  • Avoid expanding overloaded biological systems
  • Provide a compliance safety net during peak production

For smaller plants or sites with limited space, VSEP RO can function as a stand‑alone final treatment system, provided upstream solids and oil are reasonably controlled.

Case Study – Peru Fish Meal

In 2021, New Logic conducted bench testing on stickwater from a fish meal plant in Peru. The client wanted to remove fines and residual oil that decompose rapidly and negatively affect the evaporator. The permeate would be a cleaner protein stream that would allow more efficient evaporation. The VSEP test demonstrated an average flux rate of 43 gfd with a recovery rate of 80%.

Total Solids FOG %
Stickwater Feed 5.36% 1.33%
VSEP Permeate 3.48% 0.001%
VSEP Reject 13.87% 6.60%

What You’ll Get from a no cost VSEP Assessment

  • Separation characterization (FOG, COD, particle size, proteins)
  • Pilot test options for your actual stickwater/oil
  • Implementation roadmap with integration details and timeline
  • CAPEX and OPEX estimates

Talk to a Wastewater Expert

VSEP has decades of experience treating some of the most challenging industrial wastewaters in the world.

Contact us today to learn how VSEP can transform your meat processing wastewater treatment system.

Call: +775-783-7600

About VSEP and New Logic Research

  • More than 450 industrial VSEP systems installed globally
  • Technology covered by U.S. and international patents
  • Used in food, beverage, wastewater, and agricultural applications
  • Engineering team with chemical, metallurgical, and mechanical engineering backgrounds

This page was prepared by New Logic Research’s senior process engineers with backgrounds in membrane process engineering. Our team has over 30 years of direct experience designing, building, and piloting high‑shear membrane systems for industrial applications.