Antiscalant & Chemical Dosing for RO Pre-treatment

Overview

Scale is the biggest operational threat to RO membranes in India. Hard water — high in calcium, magnesium, and bicarbonates — is the norm in Rajasthan, Gujarat, Maharashtra, and large parts of UP. Without antiscalant dosing upstream of the membrane, calcium carbonate, calcium sulphate, and silica scale build up on the membrane surface within days, cutting permeate flow, wrecking recovery, and forcing early replacement.

SEW's Vanguard Series triplex plunger pump meters antiscalant into the RO feed line at a precise dose rate — typically 5–20 ppm by volume. The pump's positive displacement mechanism delivers the same volume per stroke regardless of downstream pressure variation, which diaphragm metering pumps struggle with at higher system pressures.

How It Works

Antiscalant concentrate is stored in a PE or SS day tank upstream of the RO feed pump. The triplex dosing pump draws from the tank through a foot valve and injects into the feed line through a check valve injection quill — typically at a point 30–60 seconds upstream of the first membrane vessel.

Dose rate is set by adjusting pump stroke rate (via VFD or stroke counter) to maintain the target ppm relative to the RO system's feed flow rate. The positive-displacement mechanism ensures accurate dosing even if system pressure fluctuates.

Bare Unit Use

RO system operators and water treatment EPC contractors order the bare triplex dosing pump for new antiscalant skids or to replace failed diaphragm dosing pumps. Connects to existing day tank and injection quill. Flow: 0.5–10 LPM, pressure: up to 100 bar, depending on RO system feed pressure.

Skid Package Use

For complete antiscalant dosing systems, SEW supplies PE or SS day tanks (50–1000 litre) with level switch, triplex dosing pump, VFD speed control panel, discharge pressure gauge, suction strainer, injection quill, and flexible connections — all mounted on a common skid, ready to connect to the RO feed line. Used in: municipal water plants, industrial water treatment, pharma purified water, and food & beverage RO pre-treatment systems.

Why SEW

Positive displacement metering — same dose per stroke regardless of downstream pressure variation. More reliable than diaphragm pumps at high system pressures.

0.5–10 LPM dosing range — covers small 10 KLD RO systems to large 1 MLD industrial plants.

Indian manufacturer, Nashik — local spares and service. No waiting when a dosing pump fails and membranes are at risk of scaling.

Complete dosing skid supply — full antiscalant dosing stations designed and built to your RO system's feed flow and antiscalant dose rate.