Cayman Brac — More Than a Year's Worth of Savings

LG Chem membrane elements result in a 16% energy reduction


Cayman Brac

Overview

Cayman Brac is a single train 2-pass SWRO plant with inland feed wells and cartridge filtration. It provides potable water to the Cayman Brac distribution system. The plant was expanded and upgraded in 2003 featuring ERI, new vessels and elements, and additional pre-filtration. The plant nameplate is 556 m3/d (146,880 USGPD). It uses five PX25 ERI’s, a Wheatley HP125 PD Pump, a Grundfos Booster pump, 36 (6×6) Filmtec™ SW30HR elements and 36 (6×6) FilmTec 4-inch BW30-4040 BWRO elements. The second pass is a 2-stage 4-into-2 design. There are three spare 8-inch 6-element vessels. Second pass pressure is 14.1 BAR (205 PSIG) and second pass feed is 6.6 m3/h (29 USGPM). Overall plant permeate quality is 50 TDS. First pass overall permeate quality is approximately 120 TDS.

Quick Facts

Location: Cayman Islands
Start-Up Date: July 1, 2011
Scale: 556 m3/d (146,880 GPD)
Product: Qfx SW 365 ES
Offering: Membrane Performance Contract
Client: Water Authority Cayman

Performance Results:

NanoH2O installed Qfx SW 365 ES elements and consequently saved Water Authority Cayman 0.98 kWh/m3 (3.7 kWh/1,000 USG), or 28%*, by lowering the pressure from 70.6 BAR (1,024 PSIG) to 44.8 BAR (650 PSIG) while exceeding their required permeate quality.  In addition, NanoH2O offered the client an opportunity to partner with NanoH2O through the company’s unique Membrane Performance Contracts offering.

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*28% reduction based on energy consumption prior to retrofit, 16% reduction when compared to new membranes