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Groundwater nitrate remediation using plant-chip bioreactors under phosphorus-limited environment

Satake, Shunichi, Tang, Changyuan
Journal of contaminant hydrology 2018 v.209 pp. 42-50
Cryptomeria japonica, Lithocarpus, Phyllostachys edulis, bioreactors, denitrification, denitrifying microorganisms, detergents, dissolved organic carbon, equations, groundwater, nitrates, phosphorus, remediation
Groundwater denitrification bioreactors under limited phosphorus conditions were studied in column experiments using four types of plant-chips. When the phosphate-P concentration in the influent increased from 0.04mg/L to 0.4mg/L, the nitrate removal ratio increased from 61.6% to 86.1% in reed, from 7.2% to 12.6% in Japanese cedar, from 37.0% to 73.6% in Moso bamboo, and from 19.2% to 50.5% in Lithocarpus edulis. The carbon source of the denitrifiers' growth was indicated by the content of acid detergent soluble organic matter in the chips. Furthermore, according to the modified Michaelis–Menten-type equation proposed in the study, the denitrification rate was largely limited by the phosphate-P concentration in reed and L. eduilis, and by the dissolved organic carbon (DOC) in Japanese cedar. Denitrification in Moso bamboo was affected by both phosphate-P and DOC. Besides the DOC, phosphorus emerged as an important limiting element of denitrification in some bioreactor plant-chips.