Coagulation Process for Removing Algae and Algal Organic Matter—An Overview
Djamel Ghernaout, Noureddine Elboughdiri, Saad Ghareba, Alsamani A. M. Salih
Abstract
In drinking water sources, seasonal algal blooms have augmented greatly during the last decades following the elevated temperature and nutrient loading in surface water because of agricultural and surface runoff. More than 95% of algal cells may be retained via coagulation/flocculation techniques. Nevertheless, algal organic matter (AOM) stays not eliminated well throughout coagulation, therefore it provokes many working dares in potable water treatment. This work aims to discuss the performance of coagulation on AOM reduction. The main pathway of algae and AOM reduction stays charge neutralization (CN) at an optimum pH of about 6.0. More research has to follow the reduction of low-molecular weight AOM, reluctant to coagulate, with additional treatment methods to diminish its negative influence on water safety. As dissolved microcystins (MCs) are efficaciously eliminated via CN, enhanced coagulation (EC) would be more suitable for their elimination. On the other hand, some precautions must be followed to guarantee that the acid injection has not a secondary impact in the form of algaecide treatment to avert the dissolved MCs concentration augmentation. Consequently, both algae and dissolved MCs may be efficiently removed by EC when appropriate rapid mixing and acid/coagulant dosage are guaranteed.