Self-Cleaning Filter Proposal for Organic Waste Filtration Application

1. Client Background

This inquiry comes from a client at the U.S. Department of Agriculture. Following their initial purchase of wedge wire screens from us, they have now submitted a second requirement for a self-cleaning filter system to process water-based material from agricultural waste.

2. Application Overview

The client needs to filter a water-based material containing soil and manure solids. The goal is to remove soil and manure down to 0.1% while minimizing loss of pesticide content (less than 1/20 loss). The filtered solids (filter cake) will need to be washed with fresh water twice to reduce pesticide residue to below 0.3% in the final dried filter residue.

3. Key Operating Parameters

| Parameter | Value |
| --------- | ----- |
| Flow rate | 17 L/min (1,000 L/hr) |
| Total daily volume | 6,000 L per workday |
| Solids content (incoming) | ~2% |
| Solids to be removed | 10–20 kg/hr |
| Target filtration precision | 20 microns |
| pH level | 4 (acidic) |
| Material composition | 0.3% pesticide emulsion (0.5–2 μm particles), 0.1% monocalcium phosphate, up to 2% soil (clay & silt in 50–150 μm range), 0.2% manure (including 1–2 mm grass fibers & trace hair up to 25 mm long), up to 0.1% glycerol |

4. Material Recommendation

Given the pH of 4 (acidic condition), the filter housing and all wetted components should be constructed from Stainless Steel 316L. This grade offers excellent corrosion resistance in acidic environments and is suitable for agricultural wastewater containing organic acids and phosphate compounds.

5. Recommended Equipment – Model 219 Self-Cleaning Filter

Based on the client's requirements, we recommend our Model 219 Self-Cleaning Filter with the following configuration:

• Filtration precision: 20 μm (primary)
• Spare screen: 100 μm for flexible operation
• Inlet/Outlet connection: 1.5" bolt flange, Class 150 (ANSI B16.5)
• Drain/backwash outlet: 1.5" as per original design
• Flange standard: ANSI 16.5 Class 150 bolt hole pattern
• Customer plans to connect to matching PVC flanges

6. Feed Pump Recommendation

The client asked which type of pump is best suited for feeding this filter.
Recommendation: A 1.1 kW centrifugal pump is sufficient for this application. The soil and manure content is not exceptionally high, and the required flow rate is only 17 L/min. A centrifugal pump at this power rating will provide adequate pressure and flow while being cost-effective and easy to maintain.

7. Installation Details Required by Client

To facilitate installation, the client has requested the following detailed connection information for all piping:

• Inlet port: Flange dimensions, bolt hole pattern, gasket size, bolt size/length
• Outlet port: Same details as above
• Waste/Drain outlet: Same details as above

The client has confirmed they have received the drawings and attached the ANSI B16.5 Class 150 bolt hole specification for reference. They plan to connect to compatible PVC flanges.

8. Operational Notes

• The system needs to handle 5–10 kg of filtered solids per hour.
• Backwash water can be settled and the liquid returned through the filter.
• The customer is open to dilution (from 2% down to ~1% solids) to improve filtration efficiency.
• The filter cake will require washing with fresh water twice, followed by re-filtration of the wash water.

****Figure: Model 219 Self-Cleaning Filter with flanged connections as specified.

9. Video Reference

For a visual demonstration of the Model 219 self-cleaning filter, please refer to the following video link: