🧪 ASTM D4189 Silt Density Index (SDI_15 <3.0 Target for Thin-Film Membranes)

RO Silt Density Index (SDI) Calculator

Calculate colloidal particulate fouling propensity of feed water entering thin-film composite reverse osmosis membranes under ASTM D4189: calculate 15-minute Silt Density Index (SDI_15 = [1 - T0/T15] / 15 x 100 ensuring SDI <3.0 to prevent irreversible membrane fouling), size multimedia and cartridge pre-filters, and water audit profits.

1. Project & Operating Inputs

RO Membrane Skids Monitored (Skid Count e.g. 6 Multi-Stage Skids)

Initial 500mL Filter Time T0 (Seconds e.g. 28.5s through 0.45µm Pad)

Customer Bid Price for Annual SDI Monitoring & Filter PM ($ / Skid)

Manual/Auto SDI Testers, Millipore 0.45µm Membranes, Field Chemist ($)

2. Financial Breakdown & Yield

ASTM D4189 SILT DENSITY INDEX

Annual Membrane Health Audit Profit

Water Treatment Service Margin

0.0%

Gross Revenue / Bill

Total Project CapEx

Operating / Material Cost