A water treatment plant built by AECI Water at Sea Harvest’s internationally accredited Saldanha fresh fish processing factories includes, Dissolved Air Floatation (DAF), Ultra Filtration (UF) and Sea Water Reverse Osmosis (SWRO) systems. These technologies are used to treat effluent or sea water, thereby providing the company with all the water it requires, said Sea Harvest operations director Terence Brown on Thursday at the launch.
“The most important deliverable of the plant is 1.15 Mℓ of potable water per day. This will ensure that there is no disruption to our business, we remain sustainable and profitable and, importantly, protect jobs.”
The quality of the water produced by the plant will conform to the South African National Standard (SANS 241-1:2015) as a minimum requirement for potable water.
Quality will be monitored continuously by the online plant instrumentation as well as AECI Water’s quality management system and Sea Harvest’s own quality management system.
Sea Harvest’s operation is National Regulator for Compulsory Specifications (NRCS) and European Union accredited and, to retain this accreditation, stringent food processing requirements include the use of water.
The fresh fish processing activities and factories, based at the Saldanha Bay Harbour, are dependent on municipal water to remain operational. Sea Harvest uses municipal water for factory hygiene, primary and secondary fish processing, human consumption, washing bins and tubs, the production of ice, and to supply vessels with water.
“This natural resource, therefore, is a key component of Sea Harvest’s operations,” added Brown.
The municipal potable feed to Sea Harvest was reduced by 35% between March 2016 and December 2017. Since the company is a large water user in the municipality the risks of a loss of water supply, and the associated jobs, prompted it to invest in the water treatment plant.
The SWRO will replace the municipal feed and will process factory effluent and sea water as a blended feed. With all process water now being self-supplied, water availability for Sea Harvest will now be limited to plant throughput, said AECI Water Engineered Solutions executive director Sepadi Mohlabeng.
“The first step of the process includes liquid-solid separation by means of mechanical screening followed by DAF. Further fine solids removal is carried out through UF. This filtration technology also ensures the removal of dissolved organic matter. Finally the dissolved solids (salts) are removed through the high pressure SWRO system to produce potable water.
“Give the high costs of energy associated with desalination, an Energy Recovery Device (ERD) has been installed in the system. This technology reduces power consumption in terms of kW/m3 by 30% - 50% depending on the feed source of the water, explains Sepadi Mohlabeng
The plant will supply water to all potable water areas in the factory, including fish processing, cleaning and sanitation, and general use. Although details costs of the project have not been disclosed, the expected return on investment is between 5 and 10 years based on the current municipal intake and discharge costs, he added.
“The desalination plant was designed, manufactured, constructed and commissioned within 16-week in support of AECI Water’s rapid deployment strategy. This involved careful planning, project management, setting up procurement goals and identifying critical path items early on in the project. This initiative was also supported through use of local suppliers said Mohlabeng.
“A desalination plant, if designed correctly, is sustainable and cost effective. Such engineered solutions can be built in any area with sea water supply. Further, all secondary waste from water works can be processed similarly. The Potsdam Waste water plant, which produces and supplies process quality water and is another of AECI Water’s clients in the Western Cape, is a prime example of this sustainability.