Coagulation of surface water: Observations on the significance of biopolymers

摘要: Although the treatment of natural surface waters by coagulation has been investigated extensively, detailed interaction between organic matter and alum is still not adequately understood or predictable, owing to complexity different components matrix conditions during coagulation. In this paper, we present results a novel approach study topic, which involved progressive separation according size, followed filtrate solution, in order expose influence particular fractions. Using two water sources, representative lake river waters, solutions content were obtained progressively filtering source using membranes decreasing pore size; viz. microfiltration (MF), ultrafiltration (UF), grades nanofiltration (NF). While MF had little impact on range organics present, UF was able separate biopolymers (MW > 100 kDa), NF substantially medium-high MW (1-10 kDa) substances. The tests showed that size flocs greater when suggesting their beneficial role bridging precipitated Al(OH)3 nanoparticles. For smaller fractions (<10 kDa), trend increasing floc with concentration, but minor may be explained charge effects. Very similar found both support main finding have an important formation.