Evaluation of ammonium issues in Indonesian groundwater: Potential sources and removal methods

Elevated concentration of ammonium (NH4+) has been identified as one of the problems with groundwater because it indicates anthropogenic disturbance. In this study, we evaluated the NH4+ presence in Indonesian groundwater and the land-use conditions possibly related to the issues. In addition, this research presents practical strategies for reducing NH4+ concentrations in groundwater. The spatial distribution shows that high levels of NH4+ are found in densely populated areas. Furthermore, land-uses analysis reveals that considerable concentrations of NH4+ were found in several land-uses, including settlement, agricultural, fishpond, industrial, and garbage disposal, reaching 24.16, 7.73, 16.7, 7.42, and 84.9 mg/L, respectively. However, the statistical analysis shows that not all land-uses types significantly correlated with groundwater NH4+ contents. Based on the p-value and confidence interval of 95%, NH4+ concentrations are significantly correlated with settlements, brackishwater ponds, and garbage disposal. Similarly, industrial and agricultural land-uses have positive correlations with NH4+ concentrations, although these correlations are insignificant. Finally, the promising methods for NH4+ removal are the adsorption and ion exchange methods using zeolite or biochar, which could reduce NH4+ levels by 90% and more. Furthermore, these methods do not require complicated application procedures.