Hicham Boulahfa, Mohamed Taky, Azzedine Elmidaoui

Desalination for the Environment: Clean Water and Energy 20–23 June 2022, Las Palmas de Gran Canaria, Spain

A reliable supply of these metals is crucial for a broad range of products, applications, and modern technologies. If a reliable and unhindered access to these metals in the European Union is limited, they are classified as so-called critical raw materials. The project contributes to the security of supply and aims to reduce the dependency on raw material imports by providing these elements to the market.

Since the application and use of elements recovered from brines is new in practice and unknown to existing markets, it is being investigated how these elements can enter the value chain. The highquality characteristics and requirements that the industries have set up, is also a key challenge to be addressed when it comes to market exploitation. The project will address supply and demand and give ideas, which strategies could be applied to benefit of the recovered materials.

Sea4Value has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N°869703 Keywords: Recovery of minerals and metals; Market uptake; Resources; Brines

LP 304

Coagulation-flocculation optimization prior to reverse osmosis: effect of sludge recirculation on residual aluminum concentration

Hicham Boulahfa a,*, Mohamed Takya,b, Azzedine Elmidaouia 1 Laboratory of Advanced Materials and Process Engineering, Faculty of Sciences, Ibn Tofail University, P.O. Box 1246, Kenitra, Morocco 2 International Water Research Institute, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, Ben Guerir 43150, Morocco *Corresponding Author e-mail: Boulahfa.hi@gmail.com Tel. +212 610527642

Coagulation–flocculation is considered as the most crucial method in surface water treatment, and it can be used as a pretreatment prior to reverse osmosis (RO). However, the addition of Aluminum (Al) based coagulants raised more concerns due to the increase of residual Al concentration prior to RO membranes. The plant studied includes conventional pretreatment and RO process. The aim of this study is the optimization of the coagulation-flocculation using Al sulfate in presence of settled sludge recirculation and its effect on residual Al concentration of pretreated water. The monitored parameters were turbidity, residual Al and silt density index (SDI). The results obtained illustrated that the settled sludge recirculation substantially increases the residual Al concentration of pretreated water and showed that the 5-micron cartridge filters contribute significantly to the reduction of the residual Al concentration.

Keywords: Reverse osmosis; Coagulation-flocculation; Coagulants; Residual aluminum; Sludge recirculation.