Biological wastewater treatment
Many municipal wastewater treatment works face challenges e.g. related to meeting new stricter discharge criteria and insufficient capacity but limited space for expansion. Others are looking into water reclamation for the benefit of the local community. Alfa Laval offers several innovative, flexible and highly efficient biological wastewater treatment technologies as alternatives to more traditional methods.
Alfa Laval technologies for biological wastewater treatment are ideal for removal of nutrients, organic matter, fats, oil and grease (FOG), and other undesirable micro particles and substances. They are characterized by high efficiency, flexibility and small footprint and have all steps in the same tank.
Where influent flow and organic loads vary and effluent requirements are stringent the Alfa Laval AS-H Sequencing Batch Reactor (SBR) with our patented floating decanter is a good choice for secondary biological treatment. Combine it with the Alfa Laval AS-H Iso-Disc® Cloth Media Filter for tertiary treatment to get effluent of water reuse quality (5-10 µm) and <5 mg/l suspended solids and <10 mg/l BOD at a rate of 10-15 m3/h/m2.
Alternatively, install the all-in-one Alfa Laval Membrane bioreactor (MBR) system, that combines secondary and tertiary wastewater treatment and delivers a superior effluent quality (effective filtration in sludge to 0.2 µm) suitable for reuse. It removes suspended 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; recreation lakes, wetlands, wildlife habitat and stream augmentation and ground water recharge.
Water treated with Alfa Laval MBR and AS-H Iso-Disc filtration systems can even be used as potable water if a final polishing step e.g. UV radiation, ultrafiltration, nanofiltration, reverse osmosis, active coal, ozone or chlorine is added.