Desalination & Reuse Handbook - Flipbook - Page 36
IDA
WATER SECURITY
HANDBOOK
DJERBA, TUNISIA
The Djerba desalination plant marks a significant step forward for desalination
in Tunisia. It constitutes the first stage of the country’s desalination programme
and creates an important new North African market for the technology.
The design and construction project, executed jointly by Aqualia and GS
Inima, also included the seawater and effluent capture systems, well-water iron
removal plant, product water pumping station, and the installation of pipes
to connect with the existing distribution network (23.7 km of pipelines). The
consortium’s contract with SONEDE also contemplates the commissioning of
the facilities and their management for a period of one year.
Water is drawn from the Mediterranean Sea through an intake located 2.9 km
offshore at a depth of 5 m, and is subjected to dual media and pressure filtration
pretreatment stages. The plant’s two-train RO system operates with a recovery
rate of 46%, using Dow membranes and an ERI energy recovery device. Carbon
dioxide and calcium hydroxide are added to the product water in the posttreatment stage.
Production capacity
12,000 m³/d
Order date
March 2017
Startup date
January 2018
Feedwater source
Mediterranean Sea
Feedwater TDS
41,000–43,000 ppm
Feedwater temperature
11–28°C
Intake type, location
350 m offshore
Intake depth
3m
Pretreatment system
Strainers (125 micron)
Dow UF
Number of UF trains
8
RO system description
Two-pass RO
RO recovery
35%
Number of RO trains
8+4
RO membrane supplier
Dow Filmtec
Post treatment
Dow EDI
Energy recovery supplier ERI, Inc.
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Energy consumption
≤ 3.5 kWh/m3
Product water quality
≤ 0.1 μS/cm
Concentrate disposal
Diffused outfall
Project delivery method
6-yr BOT
EPC contractor
Accionia Agua
Project cost
€22 million ($25.6 million)
System footprint
1,260 m2
Production capacity
50,000 m3/d
Order date
4th May 2015
Startup date
15th May 2018
Feedwater source
Mediterranean Sea
Feedwater TDS
41,210 ppm
Feedwater temperature
17–30°C
Intake type, location
2,900 m offshore
Intake depth
5m
Pretreatment system
Dual Media, Pressure filters
Desal system description
RO
RO recovery
46%
Number of RO trains
2
RO membrane supplier
Dow
Post treatment
CO2 + Ca(OH)2
Energy recovery supplier
Energy Recovery, Inc
Energy consumption
2.8 kW/m3
Product water quality
400 mg/l
Concentrate disposal
Diffused outfall
Project delivery method
EPC + 1 year O&M
EPC contractor
Aqualia-GS Inima consortium
Project cost
€62,347,086 ($72.6 million)
System footprint
7,300 m2
SARROCH REFINERY
SWRO, SARDINIA
In January 2018, Acciona Agua commissioned a 12,000 m3/d seawater reverse
osmosis (SWRO) plant at Sarlux’s Sarroch Refinery on the island of Sardinia. The
project was delivered under a BOT contract in which Acciona will operate and
maintain the plant for six years, with the option of a three-year extension. The
project takes screened seawater from a submerged, offshore intake. Pretreatment
includes 125-micron, self-cleaning strainers and UF membrane filtration, after
which seawater undergoes two-pass RO treatment followed by electrodeionisation
(EDI) to polish the water to meet boiler feedwater requirements. The system has
been designed with 97% availability as a modular and largely containerised plant.
