Wastewater treatment — screening to tertiary polishing
A municipal works drawn as the unit-process train it is: 6 mm screens and grit removal, primary settlement taking 60% of the suspended solids, an activated-sludge lane at 3000 mg L⁻¹ MLSS with return sludge holding the age at 10 days, nitrification and anoxic denitrification, and sludge to a 35 °C digester whose biogas runs the site.
Rendering…
Make it your own.
{
"nodes": [
{ "id": "influent", "type": "water-drop", "label": "Influent — BOD 300, SS 350 mg L⁻¹", "x": 40, "y": 40, "width": 150, "height": 104, "fill": "#ede9fe", "stroke": "#6d28d9", "bold": true },
{ "id": "screens", "type": "fence", "label": "6 mm screens take rag and gross solids", "x": 215, "y": 40, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "grit", "type": "funnel", "label": "Grit channel — sand out, organics on", "x": 390, "y": 40, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "primary", "type": "cylinder", "label": "Primary settlement — 2 h, 60% of SS", "x": 565, "y": 40, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "aeration", "type": "ocean-wave", "label": "Aeration lane — MLSS 3000 mg L⁻¹", "x": 740, "y": 40, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "clarifier", "type": "cylinder", "label": "Final clarifier — the sludge blanket", "x": 915, "y": 40, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "storm", "type": "valve", "label": "Storm overflow above 6× dry-weather flow", "x": 40, "y": 200, "width": 150, "height": 104, "fill": "#fee2e2", "stroke": "#b91c1c", "bold": true },
{ "id": "screenings", "type": "bucket", "label": "Screenings skipped to landfill", "x": 215, "y": 200, "width": 150, "height": 104, "fill": "#fce7f3", "stroke": "#be185d" },
{ "id": "blowers", "type": "motor", "label": "Blowers — half the works' electricity", "x": 390, "y": 200, "width": 150, "height": 104, "fill": "#e0f2fe", "stroke": "#0369a1", "bold": true },
{ "id": "primarysludge", "type": "layers", "label": "Primary sludge — about 5% dry solids", "x": 565, "y": 200, "width": 150, "height": 104, "fill": "#dbeafe", "stroke": "#1d4ed8", "bold": true },
{ "id": "biomass", "type": "petri-dish", "label": "Floc-forming bacteria and protozoa", "x": 740, "y": 200, "width": 150, "height": 104, "fill": "#dcfce7", "stroke": "#15803d", "bold": true },
{ "id": "ras", "type": "conveyor", "label": "Return sludge holds the age at 10 days", "x": 915, "y": 200, "width": 150, "height": 104, "fill": "#e0f2fe", "stroke": "#0369a1", "bold": true },
{ "id": "nitrification", "type": "gear", "label": "Nitrification NH₄⁺ → NO₃⁻ needs oxygen", "x": 40, "y": 360, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "denitrification", "type": "cloud", "label": "Anoxic zone returns NO₃⁻ as N₂ gas", "x": 215, "y": 360, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "phosphorus", "type": "test-tube", "label": "Ferric dosing takes phosphate to 1 mg L⁻¹", "x": 390, "y": 360, "width": 150, "height": 104, "fill": "#e0f2fe", "stroke": "#0369a1", "bold": true },
{ "id": "digester", "type": "cylinder", "label": "Digester — 35 °C, 20 days, 60% methane", "x": 565, "y": 360, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "chp", "type": "power-plug", "label": "Biogas to CHP — it powers the works", "x": 740, "y": 360, "width": 150, "height": 104, "fill": "#fce7f3", "stroke": "#be185d", "bold": true },
{ "id": "cake", "type": "truck", "label": "Digested cake to agricultural land", "x": 915, "y": 360, "width": 150, "height": 104, "fill": "#fce7f3", "stroke": "#be185d", "bold": true },
{ "id": "tertiary", "type": "funnel", "label": "Sand filter and UV before discharge", "x": 215, "y": 520, "width": 150, "height": 104, "fill": "#fef3c7", "stroke": "#b45309", "bold": true },
{ "id": "consent", "type": "clipboard", "label": "Consent 20:30 — BOD 20, SS 30 mg L⁻¹", "x": 565, "y": 520, "width": 150, "height": 104, "fill": "#ccfbf1", "stroke": "#0f766e", "bold": true },
{ "id": "river", "type": "ocean-wave", "label": "Discharge to river, sampled weekly", "x": 915, "y": 520, "width": 150, "height": 104, "fill": "#fce7f3", "stroke": "#be185d", "bold": true }
],
"edges": [
{ "id": "e1", "source": "influent", "target": "screens", "thickness": 2.5 },
{ "id": "e2", "source": "screens", "target": "screenings" },
{ "id": "e3", "source": "screens", "target": "grit", "thickness": 2.5 },
{ "id": "e4", "source": "grit", "target": "primary", "thickness": 2.5 },
{ "id": "e5", "source": "storm", "target": "influent", "label": "spills when the sewers surcharge", "style": "dashed" },
{ "id": "e6", "source": "primary", "target": "primarysludge" },
{ "id": "e7", "source": "primary", "target": "aeration", "label": "settled sewage, BOD down to 210", "thickness": 2.5 },
{ "id": "e8", "source": "blowers", "target": "aeration", "label": "2 mg L⁻¹ of dissolved oxygen", "style": "dashed" },
{ "id": "e9", "source": "aeration", "target": "biomass", "style": "dashed" },
{ "id": "e10", "source": "biomass", "target": "nitrification" },
{ "id": "e11", "source": "nitrification", "target": "denitrification", "thickness": 2.5 },
{ "id": "e12", "source": "aeration", "target": "clarifier", "thickness": 2.5 },
{ "id": "e13", "source": "clarifier", "target": "ras" },
{ "id": "e14", "source": "ras", "target": "aeration", "label": "the biomass is recycled, not grown", "thickness": 2.5 },
{ "id": "e15", "source": "clarifier", "target": "tertiary", "thickness": 2.5 },
{ "id": "e16", "source": "tertiary", "target": "river", "thickness": 2.5 },
{ "id": "e17", "source": "consent", "target": "river", "label": "what the discharge is judged against", "style": "dashed" },
{ "id": "e18", "source": "primarysludge", "target": "digester", "thickness": 2.5 },
{ "id": "e19", "source": "ras", "target": "digester", "label": "surplus activated sludge" },
{ "id": "e20", "source": "digester", "target": "chp", "thickness": 2.5 },
{ "id": "e21", "source": "digester", "target": "cake", "thickness": 2.5 },
{ "id": "e22", "source": "phosphorus", "target": "clarifier", "label": "floc settles with the sludge", "style": "dashed" },
{ "id": "e23", "source": "denitrification", "target": "clarifier", "style": "dashed" },
{ "id": "e24", "source": "tertiary", "target": "consent", "style": "dashed" }
]
}