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SIMPLE TWO-STEP PROCESS FOR MAKING AGRICULTURAL CULTIVATION SOLUTION FROM SEAWATER USING CALCINED HYDROTALCITE AND NATURAL ZEOLITE

2008; Volume: 14; Issue: 1 Linguagem: Inglês

0009-8574

Takaaki Wajima, Tomoe Shimizu, Takehiko Yamato, Yasuyuki Ikegami,

Wastewater Treatment and Nitrogen Removal

We attempted to make agricultural cultivation solution from seawater with a two-step process using calcined hydrotalcite and natural zeolite. Commercial calcined hydrotalcite was used in first step to reduce Cl - content in seawater. Two types of Japanese natural zeolite, mordenite-type zeolite (Iizaka mine, Fukushima prefecture) and clinoptilolite-type zeolite (Koriyama mine, Kagoshima prefecture) were used in second step to reduce Na + concentration. Cl - in seawater can be reduced by calcined hydrotalcite to obtain anion-reduced solution; Na + can be reduced by ion exchange with both types of natural zeolite. The obtained solution was neutral, and included the nutrients K + , Mg 2+ , and Ca 2+ , and low levels of Na + and Cl - . Higher concentrations of K + , Mg 2+ and Ca 2+ in the solution can be obtained by mordenite-type Iizaka natural zeolite than those by clinoptilolite-type Koriyama natural zeolite. Radish sprouts did not grow in seawater and anion-reduced solution, but they grew in both solutions after zeolite treatment.