New inorganic coagulant, econite, composed of fossil shell and gypsum-ultra-purification of polluted water with high settling velocity
1996
Tamaura, Yutaka | Hasegawa, Noriko | Watanabe, Hiroyuki | Yamamoto, Takashi | Azis, Triant | Sales, Candelaria L. | Kiryu, Takashi | O-Hashi, Katsumi (Tokyo Institute of Technology, Tokyo (Japan). Environmental Protection Center. Research Center for Carbon Recycling and Utilization)
ECONITE is the inorganic coagulant composed of fossil shell and gypsum, which has been newly developed in recent years. ECONITE gives a significant difference in the setting velocity compared with PAC and LAS for the suspended solution of pond sediment and industrial waste water, Since ECONITE gives a high setting velocity compared to the PAC and LAS, we could treat a larger volume of polluted water. Also, this inorganic coagulant can remove almost completely the fine colloidal particles from the polluted water. This enables us to make a ultra-purified water from the highly polluted water. In the field experiment carried out in Hohrai pond in Japan (water volume = 300 cubic m), 60kg of ECONITE was used. This corresponds to about 0.02 percent of the total water weight. SS removal of about 98 percent was achieved, and the transparency of the Hohrai pond water after the treatment was about 70 cm. Chlorophyll content, which represents the amount of algae in the pond water, was reduced to 4 percent. Furthermore, it was observed that the pH after addition of the coagulant was around 7.2, indicating that the coagulant is friendly to fish. It was also confirmed that the effect of ECONITE of 1)high settling velocity, and 2)ultra-purification by sedimentation of fine colloidal particles, can act in a similar manner on the waste water from food production company (Sakeless waste water).
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