Effects of Zingiber officinale Roscoe. extracts in growth media on nitrate and phosphate removals for growths and accumulations by

Abstract

 The most effective measure for prevention and mitigation of water quality and ecological degradation from eutrophication is the minimization of NO3-N and PO4-P to the standards set out before discharging into waterways. Floating plants can absorb excessive NO3-N and PO4-P from sewage water effectively via their roots for growth. This mechanism supports ecological sustainability, as the result of their natural abundance, well-adaptation and aesthetics in water ecosystem. The experimental design was set up to achieve the objectives of comparing the growths of I. aquatica (water spinach) by fresh biomass experimented in 4 treatments of media growth (NO3-N and PO4-P concentrations at 20 mg-N/L and 1 mg-P/L) with the additions of Z. officinale (ginger rhizome) extracts at 0, 2,000, 4,000, and 6,000 ppm, respectively. Their efficacy of NO3-N and PO4-P removals (%) are analyzed. Analyses of variances (ANOVA) at a confidence level of 95% and Duncan Post Hoc Tests were performed to determine the differences among efficiency of NO3-N and PO4-P removals (%) and growths of I. aquatica. The results revealed that the application of the 4,000 ppm extract was appropriate for I. aquatica growth and the remediation of nutrient-rich waters. This is owing to the highest biomass of 130.08±25.33 g (sig=.015) which was mainly derived from the upper parts (leaves and stems) and the uttermost NO3-N at 67.9±6.20%, while the second most PO4-P at 95.55±3.98 % (95.75±3.22% in the controls) removals were found in 18 and 15 days. Moreover, the far below European Commission maximum levels for nitrate as contaminants in fresh vegetables (for fresh spinach) at 86.95± 4.40 mg-N/Kg may strengthen the safety for human and animal consumption.