As part of the process design and development phase of a typical ACWA Clear project, the feasibility of using a number of advanced unit processes will be investigated by our engineers.
Advanced computer modeling techniques are used to calculate outputs from each stage. By using a combination of specification information and water analysis data, the overall process design is built from a series of these unit process 'building blocks'.
Process selection
In almost all cases, it will be necessary to combine two or more unit processes to achieve the required results economically. Every project is studied thoroughly to balance capital and running costs to achieve optimum whole-life cost. The final water quality requirement will generally determine the 'prime technology' selection. The raw water quality and project economics will determine the 'pre-treatment technology' selection required.
For example, every reverse osmosis plant has a minimum pretreatment of 5-micron cartridge filtration and in many cases, pressurized sand filtration would be used to pre-treat the cartridge filter to minimize running costs.
Through partnerships with equipment suppliers, advanced technology manufacturers and other engineering companies, ACWA Clear is able to design systems to meet the stringent demands of any municipal or industrial water or wastewater treatment project.
Membrane technology
Various types of microfiltration (MF) and ultrafiltration (UF) membrane technology systems can be provided for water treatment applications from manually cleaned and self-backwashing strainers, thru disposable bag and cartridge filters to full engineered systems containing arrays of modular tubular, flat sheet or hollow fiber membranes. MF and UF systems typically remove particles from 0,01 to 1000 microns in size.
Nanofiltration (NF) systems remove dissolved components typically greater than 1000 microns in size. At this degree of filtration, some dissolved ions are removed - generally the larger and more highly charged ions such calcium and magnesium. Another application of nanofiltration membranes is color removal due to the ability to exclude the shortest chain organic molecules which pass though the 'MF and UF membranes.
Reverse osmosis (RO) membranes are sourced from our partner manufacturers in tubular, hollow fiber and spiral wound configurations. RO membranes typically remove in excess of 95% of dissolved ions and other components, and up to 90% of the treated water can be recovered to produce high purity RO permeate.
Advanced water treatment
Ion Exchange is utilized by ACWA Clear in the industrial field to produce high and ultra-high purity water.
Other technologies are engineered into ACWA Clear's systems where appropriate and can comprise pressure filters, gravity filters, chemical treatment systems and granular activated carbon (GAC) units. For example, GAC filtration is used to ensure water supplies are free of organics taste, odor, color and pesticides. Also, ozonation and/or ultraviolet sterilization can be employed to achieve disinfection/sterilization of water or wastewater.
Environmental responsibility
With demands on our environment increasing and regulatory limits tightening, ACWA Clear can work with you to provide the optimum solution that balances increasing energy costs, increasing solid waste disposal costs and water scarcity issues, while satisfying the demands of ever-increasing environmental legislation.
Advanced wastewater treatment
Our abilities in wastewater treatment are comprehensive and employ both conventional and advanced technologies, aerobic and anaerobic treatment solutions for sewage treatment and sludge and membrane bioreactor technology for water re-use.
Preliminary wastewater treatment processes employed by ACWA Clear include coarse and fine screening systems, grit removal, balancing and calamity systems, pH correction systems, nutrient addition and polymer systems. Primary treatment systems include conventional settlement, swirl-flow clarifiers, high-rate systems including bio-filters and lamella separators, dissolved air flotation (DAF) systems and a range of fat, oil and grease removal systems.
Biological aerobic treatment can comprise conventional secondary bio filters, low and high rate bio towers, activated sludge processes (using coarse or fine bubble diffused air or pure oxygen), sequencing batch reactors (SBRs), membrane bioreactors (MBRs), nutrient removal systems and high-rate ammonia removal systems.
ACWA Clear's hybrid anaerobic reactor combines the benefits of an up flow anaerobic sludge blanket (UASB) and anaerobic filter (AF) systems, and can typically remove 80% of the feed organic load. The hybrid anaerobic process produces biogas which can be used for on-site heating or electricity generation via a combined heat and power (CHP) system.
To meet stringent discharge standards, ACWA Clear provides a range of tertiary treatment process, including continuous up flow, rapid gravity and moving bed sand filters and nutrient removal systems.