Innovative technology development approaches for organic removal in water treatment

Coagulation remains the most commonly used unit operation for dissolved organic carbon (DOC) removal in drinking water treatment. However, this process has been shown to have limitations in terms of removing large proportions of small molecular weight and hydrophilic fraction of natural organic matter (NOM) that has been linked to the formation of disinfection by-products (DBPs), and results in the generation of large volumes of sludge which require further processing and ultimate disposal. The occurrence of elevated DOC and color levels in surface water is a common problem faced by many water utilities in Canada. Additional spikes in organic loading linked to periods of high intensity rainfall or snow melt can lead to a number of operational problems within the treatment plant. In particular, under conditions of high organic loading or colder surface water temperatures typical in winter months, the performance of treatment plants can rapidly deteriorate with the formation of weak and easy to break flocs, leading to poor settling and floc carryover. There is a need to investigate the impact of elevated organic content waters on conventional and alternative treatment processes, to gain a better understanding of propensity for floc degradation and provide framework for the removal pathways of organic matter. The overall objective of this research program will be to develop an improved understanding and approach to the removal of natural organic matter (NOM) using physical/chemical removal technologies. Innovative design approaches for NOM removal and optimum floc characteristics at elevated organic loads will be investigated to identify conditions under which conventional and alternative processes are suitable for use in treatment. The removal of NOM in drinking water treatment is becoming increasingly more important as DBP regulations become more stringent. Similarly, the Canada Council of Ministers of Environment (CCME) standards under the Canada-wide Strategy for the Management of Municipal Wastewater for combined sewer overflows (CSO) will require new small footprint, high-rate solids removal systems. This study will address these emerging issues within the water treatment sectors.