Evides (Netherlands)

• Single-variable based approach for water demand forecasting overlooks the future complexity • Water pricing, population growth and climatic condition are crucial in determining the demand • Forecasted models shows that by 2028 the study area would face drinking water shortage • Under worst-case scenarios, demand could reach 4454 MLD, creating a significant supply-demand gap • Scenario-based forecasting would be useful in diversifying the water extraction sources

Per- and polyfluoroalkyl substances (PFAS) are persistent micropollutants subject to strict drinking water regulations. Although granular activated carbon treatment can effectively remove PFAS from water, early breakthrough, especially for short-chain PFAS, requires frequent regeneration and increases treatment costs. While many studies have related the presence of natural organic matter (NOM) to early breakthrough, the mechanisms affecting PFAS adsorption remain unclear. In this study, we used resin and membrane fractionation to isolate distinct NOM fractions based on chemical characteristics and molecular size. Batch isotherm, kinetic, and column experiments showed that the presence of the <3 kDa fraction significantly reduced short-chain PFAS adsorption. As low molecular weight compounds (<3 kDa) are consistently detected in source waters at concentrations comparable to or higher than those included in the present study, their removal is crucial to improving short-chain PFAS removal during drinking water treatment. Conversely, long-chain PFAS adsorption was not notably affected by molecular weight fractions but was significantly reduced in the presence of the hydrophobic neutral (HON) fraction. The HON fraction consists of compounds with similar molecular characteristics as long-chain PFAS, leading to direct competition for adsorption sites. The HON fraction is typically present at lower concentrations compared to other NOM fractions in natural waters. This low concentration of the HON fraction helps explain the delayed breakthrough observed for long-chain PFAS, in contrast to short-chain PFAS, whose breakthrough is rapid due to the high concentration of the <3 kDa fraction. We found that the presence of specific NOM fractions can indicate reduced PFAS removal, suggesting that NOM fractionation techniques could be integrated into monitoring procedures at drinking water facilities, as the presence of specific fractions can indicate reduced PFAS removal.

Aeromonas is included in the Dutch Drinking Water Decree as an indicator for elevated microbial regrowth in non-chlorinated drinking water distribution systems (DWDS). The temporal and spatial diversity of Aeromonas species in ten DWDS and their planktonic growth characteristics for different carbon sources was investigated. Genotyping of the gyrB gene of isolates showed a non-systematic temporal and spatial variable prevalence of seven different Aeromonas species in these DWDS and no correlation with AOC-P17/NOX and Aeromonas concentrations. Pure cultures of these seven species showed a high affinity to low concentrations (μg/L) of individual amino acids and fatty acids, compounds associated with biomass. Growth occurred at 0.5 μg-C/L of an amino acid mixture. Growth of a mixed community of A. rivuli, A. salmonicida, A. sobria and A. veronii in drinking water occurred in pasteurized samples, however, no growth and decay occurred in competition with the autochthonous bacteria (non-pasteurized samples). This community also failed to grow in non-pasteurized distribution samples from a location with clear increase in planktonic Aeromonas concentrations in the transported drinking water. For competitive planktonic growth of Aeromonas an amino acid concentration of ≥5 μg-C/L is required. AOC-P17/NOX concentrations showed that such concentrations are not expected in Dutch drinking water. Therefore, we suspect that competitive planktonic growth is not the major cause of the observed non-compliance with the Aeromonas standard in non-chlorinated DWSD.Importance The occurrence of the bacterial genus Aeromonas in non-chlorinated drinking water in the Netherlands is regarded as an indication for elevated microbial regrowth in the distribution system. Identification of the prevalent species in ten distribution systems by genotyping yielded seven different species, with A. rivuli, A. veronii and A. sobria as the most dominant ones. Planktonic growth experiments of pure cultures confirmed former published affinity of Aeromonas for certain biomass compounds (amino and fatty acids). In competition with the autochthonous microflora, however, planktonic growth was not observed, only after addition of a threshold amino acid concentration of 5 μg-C/L. Based on our results and further observations we deduced that planktonic growth of Aeromonas in the DWDS is not very likely. Benthic growth in loose deposits and planktonic release is a more plausible explanation for the observed planktonic increase of Aeromonas.

In the Netherlands, central softening of drinking water is widely applied for reasons of public health, client comfort, economic and environmental benefits. Currently, the detrimental contributions of softening, in particular the use of chemicals and energy, are taken into account in the carbon footprint of the Dutch drinking water companies. The beneficial contributions have, however, until now not been included in the carbon footprint. Here, we present an attributional life cycle assessment (LCA) for the softening of drinking water, including effects at the household level and several sensitivity analyses. Five central softening methods were included (pellet reactor (PR), water storage reservoir (WSR), reverse osmosis (RO), nanofiltration (NF) and ion exchange (IEX)). Domestic softening by IEX is represented as well. Central softening, except RO, is shown to reduce the carbon footprint when effects at the household level are included. The main detrimental contributions are caused by the consumption of chemicals and energy in the softening process. The main beneficial contributions of softened water with respect to the carbon footprint are at the household level. Decreases in water hardness result in reduced scaling and give rise to a prolonged lifespan of appliances in which water is heated, reduced energy use of those appliances and less required cleaning agents. For PR and WSR a new beneficial effect was identified; carbon capture in the crystallized calcite and dissolution of CO2 into the softened water. We show that for the Dutch water companies Evides and Waternet approximately 20% and 60%, respectively, of their total carbon footprint is compensated by the net carbon benefit of softening. The net total carbon footprint of drinking water softening in the Netherlands is estimated to be −0.11 Mtonne CO2 eq./yr.

Abstract This paper gives an overview of the asset management landscape on drinking water in the Netherlands and twenty years of research on this topic executed by KWR in close collaboration with water companies. A description is given of research questions and the international developments in the field of asset management. This is followed by the developments on asset management at the Dutch water company Evides. Twenty years of asset management research at KWR is presented in five phases, showing a transition from the question of how can the concepts of asset management help to better plan the replacement of distribution networks, towards integrated decision making on the asset system as a whole. A focal point for research could be how research can contribute to creating value for water companies. More formal information and improved modelling will continue to play a central role; however, attention is required for making use of expert knowledge, scenario building, data quality and the integration of information of technical, financial and societal origin.

Because of their shared backgrounds, community health workers' (CHWs) care of patients/program participants (PAPAs) is assumed to be acceptable, and often not evaluated empirically. Using PRISMA guidelines, we reviewed 9560 articles from 5 databases, selected 37 articles for full-text review, and developed a 5-dimensional depth analysis (focus, context, meaning, range, and voices) to characterize quality/quantity of PAPA feedback. Depth analyses clarified a spectrum of PAPA responses from extremely positive to ambivalence to outright distrust and frustration with perceived CHW limitations. Designing evaluations with 5-dimensional depth analysis can enhance PAPA feedback quality and improve evidence-based, patient-centered, CHW care delivery.