%T Selection of Coagulant with Consideration of Sludge Characteristics for 
%T Treatment of Industrial Wastewater Containing High Strength Mixed Surfac
%T tants
%A Tongchai Sriwiriyarat
%A Rapeepan Wongvian
%A Sinchai Kuhakaew
%V An attempt was made in this study to compare the sludge characteristics 
%V between aluminum sulfate (alum) and polyaluminum chloride (PACl) in addi
%V tional to the optimum initial pH and dosage so the selection of the coag
%V ulant could be made for the coagulation-flocculation process treating sp
%V ecifically the wastewater containing high strength mixed surfactants gen
%V erated from the industry manufacturing soaps, detergents, and various co
%V nsumer-products. The sludge settling velocity, sludge volume index (SVI)
%V , and dewatering properties of each coagulant were evaluated to indicate
%V  the sludge characteristics. The optimum initial pH and chemical dosage 
%V of each coagulant were also conducted in a Jar Test apparatus for the si
%V multaneous removals of organic matters indicated as Total Chemical Oxyge
%V n Demand (TCOD), anionic surfactants indicated as Total Active Ingredien
%V ts (TAI), Total Suspended Solids (TSS), and turbidity. The experimental 
%V results indicated that the optimum pH value and dosage of alum were 8 an
%V d 600 mg/L, respectively, resulting in the TSS, turbidity, TCOD, and TAI
%V  removal efficiencies of 96.6, 90.4, 85.5, and 97.9%, respectively.  The
%V  same dosage of PACl at the concentration of 600 mg/L was required under
%V  the optimum pH of 6, providing the TSS, turbidity, TCOD, and TAI remova
%V l efficiencies of 99.2, 99.3, 83.3, and 97.9%, respectively.  The PACl p
%V rovided more TSS and turbidity removal efficiencies than the alum for th
%V e wastewater containing high strength mixed surfactants. For sludge char
%V acteristics, the alum sludge had higher settling rate, generated lower s
%V ludge volume, and was easier to be dewatered than the PACl sludge. The e
%V xplanation was that the destabilization mechanism of alum was sweep floc
%V culation resulting in compact aluminum hydroxide precipitates, but the m
%V echanism of PACl was interparticle bridging due to high concentration an
%V d aging providing less dense and loose structure of flocs. The PACl was 
%V superior to the alum for TSS and turbidity removals as a result of inter
%V particle bridging destabilization mechanism. In conclusion, the alum was
%V  suggested as the coagulant for this industrial wastewater as it provide
%V d approximately the same TSS, TCOD and TAI removal efficiencies as the P
%V ACl even though the turbidity removal efficiency was lower than about 9%
%V  because it generated better sludge characteristics.
%I Science Faculty of Chiang Mai University
%V http://it.science.cmu.ac.th/ejournal/dl.php?journal_id=8491;http://cmuir
%V .cmu.ac.th/jspui/handle/6653943832/63985
%D 2021
%V 0125-2526
%0 CMU e-Journals Article