Heerema Marine Contractors (HMC) is a world leading marine contractor in the offshore oil and gas industry. HMC transports, installs and removes all types of offshore facilities. These include fixed structures, complex infrastructures and floating facilities, in shallow water, deepwater and ultra deepwater.
For the Project Porto Ambiom Angola we are pleased to develop and produce a water maker plant with a capacity of 160m³ per day.
For a reliability and good performance, top quality components are used, such as high retention sea water membranes, ASME certified and FDA approved pressure vessels and slow running high pressure plunger.
Before the raw seawater is being fed to the water maker it must be conditioned to maintain a reliable and maintenance free system.
To prevent scale by debris, biological growth or scaling the system has an extensive pre treatment.
This pre treatment is divided in the following steps:
- Multi media filter
- Micro biological protection: Demitec-UV® disinfection
- Cartridge filters
- Anti scalant dosing
First the water is being filtered by a multi media filtration unit which removes particles up to 25 microns. The debris free water will be stored in a buffer/flush tank of 60m³.
Periodically these MMF must be backwashed with water and air to clean the filter bed. Micro biological protection, a medium pressure UV system, is added to the system to minimise the risk of biological fouling of the membranes.
Cartridge filtration is working as a polishing filter and to remove fine particles passing the multi media filters.
To avoid precipitation of hardness components on the membranes (called scaling), an automatic dosing unit for anti-scalant is included.
After the pre-treatment, the seawater is pressurised up to 65 bars and fed through the membranes. The fresh water can pas trough the membranes and the concentrated salts will be returned to the sea.
The produced water will be neutralised with lime to make the water suitable for human consumption according to WHO guidelines.
To produce 1m³ potable water you need approximately 2.5m³ of seawater.
The potable water is stored in a fresh water tank of 100m³. To keep the water safe the fresh water tank is equipped with a Hadex® circulation dosing system which will dose Hadex on basis of free available chlorine. Heerema is always secured of the right amount of disinfectant in their potable water system.