Passive cylindrical wedge-wire (Johnson / T-) screens — low-velocity, fish-friendly fine screening with no moving parts, kept clear by periodic air-burst backwash. The benchmark for 316(b) intake protection.
Intake Screening for Water & Desalination Plants
A passive wedge-wire screen is a submerged cylinder of V-profile (“wedge”) wire with precise slot openings (typically 0.5–10 mm) and a very low through-slot velocity (under 0.15 m/s). With no moving parts, it relies on ambient cross-current and periodic air-burst backwash to stay clear. The small slots and low velocity make it the leading technology for excluding fish, eggs and larvae.
Wedge-wire (profile-wire) technology originates from water-well screens developed in the early twentieth century (notably Johnson Screens). Cylindrical passive intake screens rose to prominence from the 1990s–2000s as the “best technology available” for US EPA Clean Water Act §316(b) compliance, protecting aquatic life at cooling-water and desalination intakes.
Configurations in service
Horizontal cylinder(s) on a manifold, sized for low through-slot velocity.
Periodic compressed-air burst sheds accumulated debris from the slots.
90/10 Cu-Ni or coatings resist marine biofouling between cleans.
0.5–10 mm slots set the exclusion size for eggs, larvae and debris.
An honest engineering assessment
Typical applications
Passive wedge-wire screens are specified for offshore SWRO desalination intakes, 316(b)-driven cooling-water intakes and ecologically sensitive sites where fish protection and reliability are paramount.
The full intake-screen series
A companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreA companion intake-screen type — design, history and trade-offs.
Read MoreThe screening stage of the seawater intake series.
Read MoreIntake design integrated with SWRO pre-treatment.
Read MoreThe full seawater intake hub — structures, fouling, materials.
Read MoreBar, band and drum screens across our range.
Read MoreOur engineers select and size intake screening — wedge-wire (passive) and the full train — matched to your debris load, fish-protection duty and downstream process.
Our expertise spans multiple industries with sector-specific water treatment solutions.
Explore closely-related topics, equipment and guides
Send your influent analysis and our engineers assess your process and recommend a tailored treatment solution — free, confidential and no obligation.
Select the regulatory standard for your country — it sets which parameters we need for a compliance-aware process assessment.
Required parameters for the chosen standard are flagged on the sample form. You can still submit a partial set and we will advise what else to test.
Your sample is stored against your company so we can track the project. Provide a company name or email as a minimum.