A review: Potential and challenges of biologically activated carbon to remove natural organic matter in drinking water purification process

• Published in: Chemosphere (Oxford) 2017-01, Vol.167, p.120-138
• Main Authors: Korotta-Gamage, Shashika Madushi, Sathasivan, Arumugam
• Format: Article
• Language: English
• Subjects: Bacterial Adhesion; Bacterial regrowth; Biodegradable organic matter; Biologically activated carbon; Biostability; Carbon - chemistry; Disinfectant by product; Disinfection - methods; Drinking Water - chemistry; Natural organic matter; Organic Chemicals - chemistry; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.09.097

The use of biologically activated carbon (BAC) in drinking water purification is reviewed. In the past BAC is seen mostly as a polishing treatment. However, BAC has the potential to provide solution to recent challenges faced by water utilities arising from change in natural organic matter (NOM) composition in drinking water sources - increased NOM concentration with a larger fraction of hydrophilic compounds and ever increasing trace level organic pollutants. Hydrophilic NOM is not removed by traditional coagulation process and causes bacterial regrowth and increases disinfection by-products (DBPs) formation during disinfection. BAC can offer many advantages by removing hydrophilic fraction and many toxic and endocrine compounds which are not otherwise removed. BAC can also aid the other downstream processes if used as a pre-treatment. Major drawback of BAC was longer empty bed contact time (EBCT) required for an effective NOM removal. This critical review analyses the strategies that have been adopted to enhance the biological activity of the carbon by operational means and summarises the surface modification methods. To maximize the benefit of the BAC, a rethink of current treatment plant configuration is proposed. If the process can be expedited and adopted appropriately, BAC can solve many of the current problems. •BAC removes low molecular weight NOM and trace level organics.•BAC treatment is slow and effluent can contain soluble microbial products and microbes.•Surface modification adopted elsewhere may expedite the removal of organics.•Issues arising from effluent quality could be solved, if used as a pre-treatment.•Some BAC regeneration techniques are promising but need further development.