HMI symbols for water & wastewater treatment
Water and wastewater plants share a common process vocabulary: pumps, blowers, knife gates, decanter centrifuges, sludge presses, scrubbers, instrumentation. The HMI Library catalog covers every category you'll need from intake through discharge — under one consistent ISA-101 calm color palette.
The water/wastewater process train
Most plants follow a similar block diagram. The catalog has the canonical symbols for every block:
1 · Intake & pumping
Submersible pumps lift influent from the well into the headworks. Coarse screens remove solids upstream of the wet well.
- Submersible pumps — pump_submersible (9 states each)
- Self-priming pumps — pump_self_priming
- Sump pumps — pump_sump
- End-suction centrifugal — pump_end_suction (the workhorse)
2 · Headworks (screening & grit removal)
Bar screens, screen rakes, grit chambers. Reduces wear on downstream equipment.
- Knife gates (manual / pneumatic / electric) — gate category, P&ID canonical
- Slide gates (rectangular, bulk solids) — slide_gate_rect
- Apron / bucket conveyors for grit removal — conveyor category
3 · Primary clarification
Settles solids by gravity. The skimmer mechanism rotates a sweeper blade across the surface and bottom.
- Drive motors with VFD — motor_with_vfd_canon
- Sludge transfer screw conveyors — conv_screw
4 · Aeration / biological treatment
Diffused-air aeration in activated sludge plants. PD (positive-displacement) blowers feed the diffusers; dissolved oxygen probes close the loop.
- Positive-displacement blowers — blower_pd_canon (with silencers, the canonical wastewater symbol)
- Centrifugal blowers (high-efficiency) — blower_centrif
- Liquid-ring vacuum pumps — pump_lrv
- Reversible motors for clarifier sweepers — motor_reversible_canon
5 · Sludge dewatering
Concentrate biosolids before disposal. Belt presses and decanter centrifuges are the two mainstream technologies.
- Decanter centrifuges — centrifuge_dec
- Belt-press filters — belt_press
- Progressive cavity pumps for thickened sludge — pump_progcav
- Booster-pump skids — pump_booster_skid
6 · Odor control / scrubbers
Headworks and dewatering buildings need odor mitigation. Packed-bed scrubbers with caustic recirculation are common.
- Packed-bed scrubbers — scrubber_packed
- Cyclone separators — cyclone_canon
- Demister vessels — demister_canonical
7 · Disinfection & discharge
UV reactors, chlorine contact tanks, plus the effluent pumping station back to the receiving body.
- Bullet tanks (chlorine storage) — tank_bullet
- Multistage centrifugal pumps — pump_multistage
- Inline vertical pumps — pump_inline_vertical
Instrumentation (ISA-5.1)
Wastewater plants are instrumentation-heavy. The catalog includes every common bubble + tag combo:
Flow meters
Coriolis, magnetic, rotameter, orifice, ultrasonic
5Bubble shapes
Field, DCS, PLC, shared, logic — empty for tag overlay
15+Alarm badges
P1-P4, ESD trip, deviation, rate-of-change, predictive
6Connection lines
Pipe, electrical, pneumatic, hydraulic, capillary, fieldbus
Recommended PLC architecture for wastewater
Most plants we've worked with use the same canonical encoding regardless of PLC brand:
- 1 INT word per equipment, encoded 0-8 (Stopped → Fault). Maps directly to a Multi-state Lamp / Indicator / Image with no logic in the HMI.
- Alarm priorities aggregated from individual booleans into a single P1/P2/P3/P4 indicator on the screen.
- Operating mode separate from state: Manual / Auto / Local in a parallel BOOL set, displayed as a colored badge on the corner of the equipment block.
See the 9 motor states encoding for the full state table, and the integration guides for vendor-specific binding patterns.
Why ISA-101 matters for wastewater operators
Wastewater control rooms see equipment counts in the hundreds: every lift station, every blower, every actuator. With a non-standard color palette, operators struggle to spot the one motor that just tripped among 300 visual elements.
ISA-101's calm gray background, color reserved for action philosophy is exactly what high-element-count plants need. A single red badge on a gray panel is unmissable; the same red on a saturated screen disappears. Read more in the calm HMI color palette guide.
Wastewater pack
~140 hand-picked symbols specific to water/wastewater plants. Pumps, blowers, knife gates, decanter centrifuges, scrubbers, sludge press, instrumentation. PNG + SVG. Perpetual commercial license.
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