This paper summarizes results from a half-year sampling campaign in Budapest, when Danube River water and bank filtrate were analyzed for 36 emerging micropollutants. Twelve micropollutants were detected regularly in both river water and bank filtrate. Bisphenol A, carbamazepine, and sulfamethoxazole showed low removal (<20%) during bank filtration on Szentendre Island and Csepel island, whereas 1H-benzotriazole, tolyltriazole, diclofenac, cefepime, iomeprol, metazachlor, and acesulfame showed medium to high removal rates of up to 78%. The concentration range in bank filtrate was much lower compared to river water, proving the equilibration effect of bank filtration for water quality.
Increasing food demand has resulted in an ever increasing demand for nitrogen fertilizers. Ammonium is the main constituent of these fertilizers and is a threat to aquatic environments around the world. With a focus on the treatment of drinking water, the scope of this study was to investigate the influence of key parameters on the suitability of granular natural zeolites as adsorbents for ammonium. Sorption experiments were performed in artificial matrices by varying the grain size, contact time, ammonium concentration, pH, content of competing ions, and regeneration solutions used. Additionally, natural matrices and the point of zero charge (pzc) were investigated. With an initial ammonium concentration of 10 mgN/L, the grain size was shown to have no significant effect on the sorption efficiency (97–98%). The experimental data obtained was best described by the Langmuir adsorption model (R2 = 0.99). Minor effects on sorption were observed at different pH values and in the presence of competing anions. In addition, the pHPZC was determined to be between pH 6.24 and pH 6.47. Potassium ions were shown to be better than sodium ions for the regeneration of previously loaded zeolites, potassium is also the main competitor to ammonium sorption. The use of tap, bank filtrate, river, and groundwater matrices decreased the ammonium sorption capacity of granular natural zeolites by up to 8%. Based on our results, granular natural zeolites are promising cost-effective adsorbents for drinking water treatment, especially in threshold and developing countries.
The study presents results of five sampling campaigns at riverbank filtration sites at the Yamuna and Ganges Rivers in Uttarakhand, Uttar Pradesh and New Delhi 2015–2018. Samples were analyzed for organic micropollutants and general water quality parameters. In New Delhi and Uttar Pradesh, 17 micropollutants were detected frequently at relevant concentrations. Out of the detected micropollutants, 1H-benzotriazole, caffeine, cotinine, diclofenac, diuron, gabapentin and paracetamol were frequently detected with concentrations exceeding 1000 ng/L. Sites in Uttarakhand showed only infrequent occurrence of organic micropollutants. The mean concentration of micropollutants in the well water was lower compared to the river water. For all sites, removal rates for all micropollutants were calculated from the obtained data. Thereby, the capacity of riverbank filtration for the removal of organic micropollutants is highlighted, even for extremely polluted rivers such as the Yamuna.
There is a nationwide need among policy and decision makers and drinking water supply engineers in India to obtain an initial assessment of water quality parameters for the selection and subsequent development of new riverbank filtration (RBF) sites. Consequently, a snapshot screening of organic and inorganic water quality parameters, including major ions, inorganic trace elements, dissolved organic carbon (DOC), and 49 mainly polar organic micropollutants (OMPs) was conducted at 21 different locations across India during the monsoon in June–July 2013 and the dry non-monsoon period in May–June 2014. At most existing RBF sites in Uttarakhand, Jammu, Jharkhand, Andhra Pradesh, and Bihar, surface and RBF water quality was generally good with respect to most inorganic parameters and organic parameters when compared to Indian and World Health Organization drinking water standards. Although the surface water quality of the Yamuna River in and downstream of Delhi was poor, removals of DOC and OMPs of 50% and 13%–99%, respectively, were observed by RBF, thereby rendering it a vital pre-treatment step for drinking water production. The data provided a forecast of the water quality for subsequent investigations, expected environmental and human health risks, and the planning of new RBF systems in India.
The excessive use of ammonium fertilizer and its associated leakage threatens aquatic environments around the world. With a focus on the treatment of drinking water, the scope of this study was to evaluate and model the breakthrough curves for NH4+ in zeolite-filled, fixed-bed columns. Breakthrough experiments were performed in single- and multi-sorbate systems with the initial K+ and NH4+ concentrations set to 0.7 mmol/L. Breakthrough curves were successfully modeled by applying the linear driving force (LDF) and Thomas models. Batch experiments revealed that a good description of NH4+ sorption was provided by the Freundlich sorption model (R2 = 0.99), while unfavorable sorption was determined for K+ (nF = 2.19). Intraparticle diffusion was identified as the rate limiting step for NH4+ and K+ during breakthrough. Compared to ultrapure water, the use of tap, river, and groundwater matrices decreased the treated bed volumes by between 25% and 69%—as measured at a NH4+ breakthrough level of 50%. The concentrations of K+ and of dissolved organic carbon (DOC) were identified as the main parameters that determine NH4+ sorption in zeolite-filled, fixed-bed columns. Based on our results, the LDF and Thomas models are promising tools to predict the breakthrough curves of NH4+ in zeolite-filled, fixed-bed columns.
1 September 2004 in Acta Hydrochimica et Hydrobiologica