Case Study Detail

CWCO Expands Production Capacity with PX™ Devices
The Bahamas Water & Sewerage Corporation (BWSC) Plant in Blue Hills was first built in 2006 by Consolidated Water Co. (CWCO). The plant supplied 18,444 m³/day of water to the 300,000 inhabitants on the island of New Providence in Nassau County. At the time, CWCO selected a competing supplier of energy recovery devices for its reverse osmosis (RO) process.

After four years in operation, the plant has since increased its daily water production needs and expanded its capacity to produce 45,000 m3/day of potable water. This time,
rather than using the former piston-type isobaric energy recovery device (ERD), CWCO selected Energy Recovery Inc’s PX™ Pressure Exchanger energy recovery devices
and ERI AquaBold™ high pressure pumps for the plant’s expansion.

Why didn’t CWCO use their former supplier of energy recovery devices for the plant expansion? Simple. Every desalination plant contributes the largest part of its operating
cost to energy consumption, which accounts for as much as 30% of the overall cost of the RO process. The original piston-type isobaric ERD’s chosen from a competing
supplier were installed four years ago to conserve the most amount of energy possible at the plant. During the four years, the unreliability of the devices became problematic, primarily due to constant maintenance requirements. As a result, the total downtime of the ERD’s substantially minimized the availability of the plant, thus reducing water production.

The Crippling Cost of Downtime
Actual and empirical data from various desalination plants show that one day per year of unplanned downtime can cause a 20,000 m3/day plant to lose more than USD
117,000 in revenue*(* NPV over 25 year life, assumptions: energy cost 0.1$/kWh. Interest 8%.). Logically, the costs for unplanned downtime increase as failures increase. For example, when downtime increases to 15 days per year, the revenue loss
over the life of plant becomes USD 1.7 million, excluding any likely costs incurred for new parts and maintenance. The cost of unplanned downtime can truly be crippling. Selecting the proper type of ERD can save millions of dollars in operational and capital expenses. As such, the role that ERDs play is undeniably critical to the overall success or failure of a plant. With zero unplanned downtime, ERI PX™ devices offer the highest availability with guaranteed efficiency to ensure plants run smoothly and save money.

“CWCO selected Energy Recovery Inc’s PX devices because in our experience, they reliably reduce energy consumption, costs and the environmental impact generated by desalination without the need for regular maintenance or a large stock of spare parts. Much of the overall cost of desalination can be attributed to energy consumption, which is why CWCO is partnering with ERI to conserve as much energy as possible, ensuring that clean, safe drinking water is within reach for every resident on the island.”
– Ramjeet Jerrybandan, Vice President of Overseas Operations, Consolidated Water Co.

The Availability Advantage with PX™ Technology
Availability is crucial to a plant’s operating capabilities and economic decisions. Operating without disruptions due to unplanned downtime from SWRO equipment is essential.
This availability, or “uptime,” is a primary factor that should weigh heavily on the selection of ERDs when downtime has such a significant financial impact.

The advantage of PX devices lies in its redundant array system, offering plant owners and operators high availability. Medium to large sized arrays of ERI PX™ devices can
still operate acceptably with one or multiple stopped units, which a major reason why PX™ devices have no unplanned downtime. One unit failure in a competing ERD
system could shut down a plant’s operations—preventing valuable water production and risking financial ramifications. For expansion plants and mega-sized desalination
facilities looking for a solution that is highly reliable and durable enough to last a lifetime, PX™ technology is the optimal solution.

The Best Economic Solution in Energy Recovery
ERI PX™ technology offers an exceptional economic solution in energy recovery. The PX™ devices are highly reliable, quick to start up and will not cause unplanned
downtime. Plant operators can now focus on what matters most to them—producing water for the communities they operate in. With proven uptime of over 99.8% and a
constant high efficiency guarantee greater than 96.5%, ERI PX™ devices offer the best return on investment for a SWRO plant. For large plants producing over 100,000 m³/day it could mean a total savings of USD 15 million over the lifetime of a plant.

Availability is the key economic driver in deciding on the proper ERD system to implement in any plant. Other critical factors include installation, commissioning, efficiency and
durability. ERDs are typically 1-2% of the initial capital expenditure of the entire plant, but operating expenses from unplanned downtime and lack of production can be
significantly higher.

With ERI PX™ devices, system availability is an advantage that can save you millions of dollars over the lifetime of a plant. Get the PX™ Technology High Availability Advantage.
Need help improving your ERD system availability? Check out your plant’s availability by visiting our website to calculate your potential savings: www.energyrecovery.com/uptimecalculatorinv
and www.energyrecovery.com/uptimecalculatorop