STP Digital Twin — 100 KLD MBBR Sewage Plant

Follow the water, start to end

Raw sewage enters on the left. Scroll right to follow the same water as it gets progressively cleaner, stage by stage, until it comes back out as reuse water. The brown loop underneath is the sludge that's pulled out along the way.

Sewage / water — gets cleaner left → right Sludge — pulled out, dewatered, disposed Click any stop for the full operating card.

Utilities — support every stage above, mostly running 24×7

00:00

00h04h08h12h16h20h23h

Daily logs to keep at this hour and through the shift

DO · pH · SV30 · residual chlorine · flow · blower & pump run-hours · chemicals consumed · screenings removed · cake produced. In a healthy plant almost every selector on the MCC sits on AUTO — a selector on MANUAL means someone bypassed a fault and forgot.

All quantities scale linearly from the 100 KLD base with the capacity slider. scaled for 100 KLD

Chemical	Where	Purpose	Strength	Dose (scaled)	When

Sludge cake

kg wet cake / day @100 KLD

At 18–20% solids. A real 200-flat Bengaluru apartment reported 80–100 kg/day. Cake should crumble in your hand, not drip.

Dry solids

kg dry solids / day @100 KLD

~8–10 kg dry solids drives the poly dose (3–6 kg poly per tonne of dry solids).

Screenings

L wet screenings / day @100 KLD

Raked from the bar screen 2–3×/day. This is sanitary/reject waste — never into the OWC, compost, garden or storm drain.

Polymer

g poly powder / day @100 KLD

Made fresh daily as 0.1% solution (aged 30–60 min). Only dosed while the press runs.

Where the sludge cake goes

BEST — dried & stabilised → farmers/landscapers or the society garden REAL — KSPCB-authorised septage handler, co-compost / landfill (keep the manifest) NO DEWATERING — BWSSB honeysucker to a notified septage/FSTP point, with a receipt NEVER — wet-waste/OWC stream NEVER — storm drain / rajakaluve

Wet, stinking cake is what causes the fly problem and the resident complaints. Aerate the sludge holding tank and dewater before it sits more than a day in Bengaluru heat.

The 30% capacity trick

Decant the clear supernatant off the top of the sludge holding tank back to the equalisation tank. You get a ~30% capacity gain without building anything, then feed only the thickened sludge to the press.