# Water Supply Systems for Settlements with Arsenic-Contaminated Groundwater--Making the Right Choice
###### Abstract
The use of bottled water places a large financial burden on the local residents; in addition, the water is distributed, for the most part, in single-use plastic water bottles, creating unnecessary  
Figure 1: Contents of As in the groundwaters used for water supply in Vojvodina (inset: municipalities of Kanjiza and Senta). plastic waste. According to [PERSON] et al. [9], expressed per person per year, Serbia uses approximately 1.6 times more PET bottles than Germany, and only 11% of those bottles are recycled, so the environmental consequences of the substitution of bottled water for tap water should not be underestimated. Generally, smaller settlements present a greater challenge for drinking water supply: the quality criteria for what constitutes safe water do not change with a decreasing population (although the legally required monitoring frequencies are often less stringent for small settlements [10]), but the available financial and human resources become significantly more limited [11]. Additional care must, therefore, be taken when assessing the feasibility of technically demanding solutions in small settlements. For small systems, the application of expensive and complex treatments to remove arsenic from groundwater is not usually feasible; in addition to the economic costs, the technical expertise required is often beyond the human resources of small settlements. A municipality's socioeconomic situation can, thus, significantly affect the infrastructure and operations of its water treatment facilities [12]. Research into the link between lower quality drinking water supply and the development of municipalities in Central Europe is a topical issue for multiple reasons. The socioeconomic status of a municipality can influence the quality of piped water supply. Municipalities with lower socioeconomic status may face challenges in maintaining and upgrading water supply infrastructure (e.g., scattered villages or insufficient capacity and quality of water supply). Additionally, lower socioeconomic status may be associated with a lack of awareness or knowledge of safe water practices, leading to further waterborne health risks. At the core of the problem, municipalities with lower levels of economic development may struggle to fund and maintain adequate water treatment facilities, leading to issues with water quality and safety. Finding technologically, economically, and environmentally viable solutions for water supply in regions with many small settlements and poor water quality resources is thus a significant challenge. The current and future water demands at each settlement must be taken into account, as well as the quantity and quality of the available water resources. In this context, the application of numerical models can be very helpful for long-term planning and to take into account all the factors influencing the long-term supply of safe drinking water [4]. The relative merits of centralisation and decentralisation in the provision of public infrastructure is the topic of much debate. [PERSON] and [PERSON] discuss the different drivers of centralisation versus decentralisation and note how different types of public infrastructure may benefit from various levels of governance hierarchy [13]. [PERSON] et al. argue that centralisation is the most cost-effective and also the safest strategy for arsenic-affected groundwater [14]. They note that best practice for drinking water supply requires a multiple barrier approach including not just source selection and protection and adequate treatment but also continuous monitoring of water quality and system maintenance. The last two, in particular, are difficult for decentralised systems to achieve. [PERSON] et al. also state that the digital transformation of the water treatment sector is greatly increasing the monitoring and maintenance capabilities of small decentralised systems.