1. Understanding High Suspended Solids in Screw Press Filtrate

A screw press dewatering machine is designed to separate liquid from wet materials by conveying and compressing the feed inside a screened chamber. The separated liquid passes through the screen, while the concentrated solids move toward the discharge outlet.

When the filtrate contains excessive suspended solids, the separation process may not be retaining particles as expected. This can affect downstream wastewater treatment, liquid reuse, or other processing stages.

It is important to distinguish between two different problems:

High filtrate volume: A wet feed may release a large amount of liquid even when separation is working properly.

High suspended solids: Fine particles are passing into the liquid stream, potentially indicating a screen, material, or operating issue.

Cloudy liquid can indicate suspended particles, but visual appearance alone is not a quantitative measurement.

2. Common Reasons for High Suspended Solids

Unsuitable Screen Opening

The screen opening must match the characteristics of the material being processed. If the openings are too large relative to the particles that need to be retained, more solids may enter the filtrate.

A smaller opening is not always the best solution. Fine openings can increase clogging risk and affect throughput, so selection requires balancing filtrate quality and stable operation.

Worn, Damaged, or Incorrectly Installed Screen

A screen may deteriorate through continuous operation and abrasive wear. Cracks, damaged sections, loose connections, or incorrect installation can create unintended pathways for solids.

If filtrate quality suddenly deteriorates after previously stable operation, screen inspection should be one of the first steps.

Excessive Fine Particles in the Feed

Raw materials differ in particle size and composition. Food waste, fruit and vegetable residues, fibrous materials, and other organic waste streams may contain fine particles that are difficult to retain mechanically.

Upstream grinding, mixing, or changes in raw material can increase the fine-particle fraction and affect separation results.

Unstable Feed Rate or Material Properties

A screw press may perform differently when the feed rate fluctuates or when moisture, fiber content, and consistency change. Feeding more material than the machine can handle under the current conditions may reduce effective separation.

Unsuitable Operating Conditions

Screw speed, discharge backpressure, and feed rate influence conveying and compression. Their appropriate settings depend on the equipment design and the characteristics of the material. Changes should be made within the manufacturer's recommended operating range.

3. A Practical Troubleshooting Process

A structured inspection can help identify the source of the problem without unnecessary adjustments.

Step 1: Establish a baseline. Record feed rate, material characteristics, operating settings, filtrate appearance, and discharged-solids condition.

Step 2: Inspect the screen. Check for damage, wear, blockage, and installation issues. Confirm that the screen specification is appropriate for the application.

Step 3: Test the filtrate. Collect a representative sample under stable operating conditions. Where the application requires a defined separation result, measure suspended solids using an appropriate test method.

Step 4: Review feeding and machine settings. Check whether feed rate and material consistency have changed. Review screw speed and discharge backpressure against the manufacturer's guidance.

Step 5: Make controlled adjustments. Change one variable at a time and compare results at similar feed conditions. Record filtrate quality, throughput, power consumption, and operating stability.

Avoid assuming that increasing backpressure, reducing feed rate, or changing the screen will always solve the issue. Each adjustment can have trade-offs.

4. Choosing the Right Dewatering Solution for Your Material

Troubleshooting performance begins with understanding the feed. A machine handling brewery spent grain may require a different configuration from one processing kitchen waste or fruit and vegetable residues.

Huatao provides equipment and application information for different waste streams, including:

Screw press dewatering equipment

Screw press selection for kitchen and organic waste

Kitchen waste dewatering before composting or anaerobic digestion

Fruit and vegetable waste dewatering

The right solution depends on material composition, particle size, required throughput, target filtrate quality, and the intended use of both liquid and solid outputs.

If high suspended solids persist after routine inspection and controlled adjustments, a material trial and technical assessment can help establish whether changes to the screen, equipment configuration, or upstream process are needed.

Contact HUATAO

Email: team12@huataogroup.com

Whatsapp: https//wa.me/8617732852675