Impurities in Sewage
Key pollutants our STP systems treat and eliminate
Biochemical Oxygen Demand
Measures organic matter that consumes oxygen. High BOD kills aquatic life. Output target: BOD <20 mg/L.
Chemical Oxygen Demand
Measures all organic carbon. Captures non-biodegradable compounds. Target: >85% COD removal.
Total Suspended Solids
Particles suspended in water causing turbidity and carrying pathogens. Output: TSS <30 mg/L.
pH Balance
Sewage pH varies widely. Treated water maintained at 6.5–8.5 — safe for reuse.
PSTP Process Description
Influent sewage passes through bar screen — removes large objects (cans, rags, sticks, plastic) before further treatment.
First stage: oxygen-depleted zone. Anaerobic bacteria break down organic matter. Solids settle, scum floats.
Denitrification — nitrates converted to nitrogen gas. Reduces total nitrogen. Critical for discharge norm compliance.
Moving Bed Biofilm Reactor: plastic carriers provide high surface area for biofilm. Aerobic bacteria degrade BOD/COD rapidly.
Pressure Sand Filter + Activated Carbon Filter removes TSS, colour, odour. BOD <20, TSS <30 mg/L achieved.
Final disinfection. Treated water suitable for garden reuse, flushing, or discharge as per CPCB norms.
PSTP Process Flow Diagram
