Methodology
Screen headworks flow cases, channel hydraulics, rated screen/grit capacity, redundancy, and optional screenings/grit handling from explicit project and vendor data.
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Engineering Tool · Water Treatment
Wastewater Preliminary Treatment Designer
Screen headworks flow cases, channel hydraulics, rated screen/grit capacity, redundancy, and optional screenings/grit handling from explicit project and vendor data.
01 · PROJECT AND FLOW BASIS
Headworks design inputs
The peak-hour input is entered as a flow rate for one hour. Required hierarchy checks enforce Minimum ≤ Average Day ≤ Maximum Day and Peak Hour ≥ Average Day. Peak Hour below Maximum Day is a basis-review warning only; event flow is outside this hierarchy.
Required flow cases
Each flow includes source provenance.Bounded event / shock flow
Optional · requires a positive duration and source02 · SCREEN / CHANNEL EQUIPMENT
Installed and duty basis
Screen equipment ratings and channel hydraulics use separate counts. Each channel is modeled with the same entered width and operating depth, with equal flow split across channels in service.
03 · SCREENING DESIGN
Opening area, velocity criteria, and headloss basis
Effective open area
Geometry dimensions are projected normal to through-flow.Project velocity criteria
Calculated values are reported separately from declared criteria.Screen headloss
Basis and flow point stay visible in results and exports.EPA clean bar-screen method
hL = (V² − v²) / (2 × 0.7 × g)V = velocity through bar openings; v = approach velocity. Clean bar screens only. Fouled loss is not inferred.04 · CHANNEL HYDRAULICS
Minimum and design-flow channel checks
Approach velocity uses Q divided by the gross wetted area of the entered number of channels in service. Through-screen velocity uses effective opening area when the selected method supports it. Screen equipment capacity is evaluated from its separate duty count.
Velocity across explicit flow cases
| Flow case | Total flow | Approach velocity | Through-screen velocity | Calculated / rated loss | Headloss basis / provenance | Duty utilization |
|---|---|---|---|---|---|---|
| Calculate to populate these values. | ||||||
Capacity by flow case is available after calculation.
05 · GRIT REMOVAL
Technology-specific hydraulic and equipment basis
Horizontal-flow chamber velocity criteria are project inputs. Aerated and vortex/proprietary capacity is vendor/project-rated. No generic capture efficiency is predicted.
Geometry and hydraulic detention
Required rectangular active-channel geometry.Optional declared performance basis
Never labeled as an ATLAS prediction.06 · REDUNDANCY AND FAILURE CASES
Selected one-unit-out capacity and hydraulics
Failure scenarios use separate screen and channel counts: one screen out, one channel out, a paired screen-and-channel N−1 case, and all installed screens/channels. Vendor headloss curves are not extrapolated for failure cases.
Screen duty and failure-case checks
| Scenario | Available screens | Active channels | Hydraulic capacity | Utilization | Capacity margin | Actual shortfall | Approach velocity | Through-screen velocity | Headloss | Headloss method / basis |
|---|---|---|---|---|---|---|---|---|---|---|
| Calculate to populate these values. | ||||||||||
07 · OPTIONAL HANDLING BASIS
Screenings and grit quantities
Solids identity: influent TSS is not screenings and is not grit. Screenings and grit are separate from primary sludge and biological sludge. Quantities below require a declared measured/project/vendor rate.
Screenings handling basis
Grit handling basis
08 · DETAILED RESULTS
Engineering values and limitations
Calculate a valid input snapshot to populate detailed results. Infeasible inputs do not expose a normal design result.
Revision ww-headworks-1.1.0 · deterministic local calculation · explicit project/vendor assumptions
Vendor-rated screen/grit performance must be verified for the selected equipment. Generic hydraulic screening does not predict proprietary capture efficiency. Influent TSS is not screenings production and is not grit production. This preliminary check does not replace equipment supplier hydraulic curves or detailed civil/mechanical design.
01
Engineering Basis
Assumptions
- An integrated preliminary/headworks workbench. It does not predict proprietary capture efficiency, infer screenings or grit from influent TSS, or replace supplier curves and detailed civil/mechanical design.
Scope / Limitations
- An integrated preliminary/headworks workbench. It does not predict proprietary capture efficiency, infer screenings or grit from influent TSS, or replace supplier curves and detailed civil/mechanical design.
02
Engineering Path
Upstream Context
- Wastewater Influent Basis An integrated preliminary/headworks workbench. It does not predict proprietary capture efficiency, infer screenings or grit from influent TSS, or replace supplier curves and detailed civil/mechanical design.
Current Tool Decision
- Wastewater Preliminary Treatment Designer Screen headworks flow cases, channel hydraulics, rated screen/grit capacity, redundancy, and optional screenings/grit handling from explicit project and vendor data.
Downstream Engineering Step
- Wastewater Equalization Designer Review active equalization storage and operating inventory from an entered influent and controlled outlet schedule. Optional: use when declared flow variability supports equalization. Enter values manually; no automatic transfer occurs.
- Clarifier Designer An integrated preliminary/headworks workbench. It does not predict proprietary capture efficiency, infer screenings or grit from influent TSS, or replace supplier curves and detailed civil/mechanical design.