The Effect of The Fertilizer Water Cycle on The Water Quality of The Hydroponic System

Abstract

Water quality changes in the hydroponic planting system planted with curly kale (kailan) were examined by measuring physiochemical analysis over three planting cycles. The water quality parameters measured included temperature, pH, Electrical Conductivity (EC), Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). In this study we also measured 13 elements in water samples which are Ammoniacal Nitrogen (AN), Phosphate (PO₄), Sulphate (SO₄), Nitrate (NO₃), Boron (B), Calcium (Ca), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Phosphorus (P) and Zinc (Zn). The analysis results compare the observed values with those recommended by the National Water Quality Standards (NWQS) Class IV (water quality standard for irrigation purposes). Chemical analysis of AN, B, Cu, Mn, Zn, COD, and BOD obtained from water sampling cycles 1–3 remained within the acceptable range. The determination of minerals was also relatively low compared to the NWQS value. However, the water analysis results for cycle 3 showed that Nitrate and Fe levels exceeded the maximum limit set by NWQS. Phosphate and K demonstrated a similar pattern, even though no fixed value exists for these parameters in the NWQS. The results of the water quality analysis during the cultivation process demonstrate that the fertilizer water can still be recycled, contributing to water conservation and pollution control.