Most often some form of tertiary treatment is necessary after industrial and municipal wastewater treatment to achieve an effluent quality good enough for discharge to a nearby recipient (sea, lake, etc.). And it is a must if treated wastewater is to be reused. Alfa Laval offers two types of tertiary treatment that produce effluent clean enough to meet strict discharge criteria or for water reuse.
Alfa Laval’s methods for tertiary treatment of municipal and industrial wastewater are both based on filtration and ideal for low effluent limits. They are very compact, highly efficient and turn wastewater into clean water that can safely be either discharged or reused.
- The gravity-driven continuous Alfa Laval AS-H Iso-Disc Cloth Media filter with outside-in filtration removes residual solids e.g. <5 mg/l suspended solids and <10 mg/l BOD from wastewater to a high final effluent quality (down to 5-10 µm) suitable for reuse. It handles 10-15 m3/h/m2 filtration area, and is a flexible, high capacity and cost-effective alternative to traditional sand filters.
- The all-in-one Alfa Laval Membrane bioreactor (MBR) system, that combines secondary and tertiary treatment of municipal and industrial wastewater, delivers a superior effluent quality with effective filtration in sludge to 0.01 µm. It removes suspended solids down to <1 mg/l, BOD down to <5 mg/l and handles 5-40 liter/h/m2 filtration area. The gravity driven, pump free and energy efficient design with compact membrane filtration modules (MFM) is based on our patented hollow sheet technology. Compared to other MBR solutions it offers improved safety, simplicity of operation, plus low operation and maintenance costs.
Wastewater - an untapped water resource
More and more realise that wastewater can also be a valuable water resource. There are many good reasons to consider reusing biologically treated municipal and industrial wastewater: Increase water resources, reduce intake of new water and limit effluent flow loads to sewers.
Reclaimed water can be used for numerous applications e.g. industrial process water, cooling towers and wash water; surface irrigation of crops, vineyards and golf courses; recreational lakes, wetlands, wildlife habitat and stream augmentation and ground water recharge.
Water treated with Alfa Laval MBR and Alfa Laval AS-H Iso-Disc filtration systems can even reach potable water quality if a final polishing step combining e.g. UV radiation, ultrafiltration, nanofiltration, reverse osmosis, active coal, ozone or chlorine is added.