How SUEZ’s membrane bioreactor (MBR) technology gives a second life to prevent plant closure
A Portuguese facility that makes Bleached Eucalyptus Kraft Pulp (capacity over 200 000Mt per year), mostly suited for tissue production, was facing increasing pressure through stringent environmental regulations (European BREF) impacting effluent discharge. The facility needed to revamp its wastewater treatment plant while reducing its water footprint. The plant is located near the river, so it was very important for the pulp company to select the right technical solutions to provide the best water quality effluents and comply with the more demanding discharge parameters.
With its long-term objective to increase its pulp produc-tion capacity it was also essential for the company to expand the water treatment capacity from 37,000 m3/day to 50,000 m3/day over 5 to 10 years while com-plying with the local/European enforced and coming regulations. In other words, the plant was faced with the task of increasing the amount of process related water consumption while decreasing the amount of wastewater generated.
SUEZ worked with the customer to identify the most cost-effective solution to address the water chal-lenge and position the pulp producer for expansion and growth. By installing a new MBR, SUEZ was able to comply with the more restrictive discharge requirements thanks to the physical barrier of UF membranes, minimize wastewater discharge and al-low for an increase in capacity.
To develop the solution, a pilot was used to define the achievable effluent water quality and evaluate tech-nology combinations to best meet customer require-ments. Based on the results of this pilot, combined with field expertise, SUEZ recommended MBR tech-nology.
Indeed, the secondary treatment consists of a biore-actor system equipped with the ZeeWeed* 500 MBR membrane filtration technology.
The ZeeWeed MBR system is comprised of two major functions: a biological reactor and an ultrafiltration system which separates biological solids from the final effluent. Its reinforced hollow-fiber membranes and unique design achieve superior effluent quality while reducing energy consumption with an increasing mem-brane lifespan. Advanced COD, color and lignin removal could be achieved by the addition of inorganic and organic SUEZ coagulants.
To avoid taxing the river water supply during the dry season, the ZeeWeed Ultrafiltration membranes deliver a water quality that is further processed by a temporary reverse osmosis (RO) unit which allows reusing water back into the pulp mill as process water. SUEZ antiscalants and membrane cleaning chemicals ensure the optimal operation of RO elements and consistency of effluent quality.
SUEZ’s technologies (MBR, ZeeWeed 500D membranes and chemicals) allowed the client to rapidly, effectively and safely start their new wastewater plant, while meeting environmental constraints and regula-tions.
The main operation and economic advantages of the membrane bioreactor are as follows:
By incorporating SUEZ’s membrane technology, MBR systems eliminate the need for secondary clarifiers, tertiary treatment and reduce the civils works. Its robustness and cost-effective treatment systems al-lowed the client to secure high-quality water supply, lower raw water intake and energy consumption and minimize environmental impact.
To overcome the challenge of water scarcity and dis-charge in the river, SUEZ is now working closely with the client to optimize the newly installed MBR plant reuse scheme. With implementation of this solution, reuse will be maximized to limit water discharge to 10,000 to 15,000 m³/d depending on the season.
In addition, SUEZ implemented InSight*, an Asset Performance Management (APM) solution that com-bines advanced data and analytics, to ensure consistent operation and asset reliability. The tool enables SUEZ and the customer to ensure that the system is operating as per design and provides a sys-tem view of the entire treatment plant.
As a global supplier of equipment, chemicals, ser-vices and digital solutions, SUEZ was able to ensure consistent treated water quality while being fully compliant with the BREF European and local regula-tions. In fact, European legislation recommends MBR as a technology of choice for pulp wastewater treat-ment. The full package allowed our client to continue operating its pulp production while respecting the surroundings and the environment, thereby enhanc-ing its positive image.
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