The transition to a circular economy with an emphasis on eco-innovation is just beginning both in Europe and in Romania, as a member country of the European Union. The whole economic system in which people operate must be circular, which means that it must eliminate conflicting aspects related to regulation, collaboration, governance, supply chain dynamics, and data transparency. However, the barriers to the transition to a circular economy are substantial, and it is up to states to work together to find innovative solutions to society’s problems. This article focuses on aspects related to eco-innovation in the field of drinking water quality in all administrative regions of Romania. In this regard, a study was undertaken, and the main objective pursued in was to identify and highlight the degree of eco-innovation of drinking water suppliers in seven underdeveloped regions of Romania. Starting from an analysis of the water management framework through the OECD Principles on Water Governance, it was possible to develop a study on drinking water supply companies in Romania. This study was performed based on specific indicators grouped by categories, and it aimed in two directions: on the one hand, the identification of drinking water distributors with a high degree of eco-innovation, which leads to quality certification of the drinking water supplied and which has the impact of encouraging household consumers to mainly use this type of supplied water to the detriment of PET bottled water (which has well-known major disadvantages in relation to environmental pollution and user health); on the other hand, the identification of drinking water supply companies with a low degree of eco-innovation, which is proof of the need for mandatory measures to improve drinking water quality, measures that can be taken at the supplier level but especially with support from the administrative and political environment.

This paper presents research conducted in the direction of analyzing the efficiency of filters used for drinking water intended for domestic consumption, with effects on the water quality gained from the public distribution network. A basic method that uses accessible techniques, such as optical microscopy and tests that involve the use of existing products on the consumer market, was developed regarding the filtration capacities of the main filters existing on the market—a method that has advantages, such as speed and ease of application, a unitary character in obtaining samples, low costs, and high efficiency. The technique approached is that of microscopy, and the samples used were taken from the laboratory tests made on the mentioned filters, using a specific experimental stand designed to support laboratory tests by using chosen filter cartridges. The research results obtained were analyzed to make a classification from the perspective of filtration efficiency, in terms of using statistical analysis tools (mathematical models and methods processed in MATLAB software). Moreover, by using a certain type of application based on specific mathematical algorithms, which takes into account some influential factors with a decisive role on household consumers, it was aimed to identify the optimal filter element for acquisition and use in its own regime. The aim of the study was to identify the optimal filter cartridge from the perspective of quality–price ratio.

The quality of water and its impact on consumers’ health has been studied extensively, along with concerns surrounding the use of polyethylene terephthalate (PET) packaging. This research aimed to analyze consumer behavior regarding water consumption patterns, with a focus on sustainability, packaging preferences, and perceptions of drinking water quality. Two surveys, conducted in 2019 and 2024, used a 23-question structured questionnaire to assess the public willingness to prevent water waste in the context of the circular economy. The surveys addressed consumer identification, drinking water preferences, the awareness of alternative consumption methods, and the openness to sustainable solutions such as water filters. Key quantitative findings showed a 10.4% increase in the amount of bottled water purchased in a single trip and a 12.1% rise in the frequency of weekly purchases, particularly among women and younger consumers. Simultaneously, a 4% increase in the preference for PET packaging over glass raised concerns about environmental sustainability, while the preference for tap water dropped by 5%, correlated with a 4.2% decline in the perceived tap water quality. The brand preference also shifted notably, with Aqua Carpatica rising to 38% and Borsec declining from 37% to 16%, reflecting the influence of purity-focused marketing. The novelty of the approach lay in identifying emerging trends related to sustainability, health, and circular economy principles. A comparative analysis of Romanian citizens’ responses over time highlighted changing perceptions of water use and waste reduction. To support the analysis, 13 statistical indicators were evaluated, a Spearman correlation test was applied to 13 criteria, descriptive statistics were computed, and a t-test was conducted across eight hypotheses.

The purpose of this paper was to develop a testing infrastructure, under laboratory conditions, for the drinking water filters used in the household. The mechanical filtration of existing nanoparticles in drinking water distributed to the large public is a very important aspect of ensuring a high level of drinking water quality, at the final consumer-the household user, regardless of the conditions of supply or its distribution. Moreover, the importance of increasing the quality of domestic drinking water is reflected by the need to encourage its consumption, to the detriment of bottled PET packaging (polyethylene terephthalate), which confers a number of disadvantages in relation to environmental protection and consumer’s health. In order to achieve the proposed goal, a computer aided design (CAD) was developed and an experimental stand was designed and built to allow different categories of constructive and structural filters to be tested. The filters were chosen according to well established criteria. Their testing was aimed at identifying the potential and characteristics of mechanical filtration of existing nanoparticles in drinking water. Finally, using the atomic force microscopy technology (AFM), it was possible to microscopically investigate the nanofiltration results performed using the sample of tested filter elements and their classification according to the quality of the filtration obtained.

The study shows the findings of a microscopic examination of samples of filtered water obtained using five different types of filters. The novelty of the approach to the research carried out in this paper consisted in using of a statistical mathematical model that confers increased accuracy on the resulting values, with the aim of characterizing the efficiency and quality of drinking water filters intended for the general public for domestic consumption at the national level. Atomic force microscopy was used to carry out the analysis, and particular mathematical models were used to statistically evaluate the findings. The paper explains the methodology used, including details on the laboratory setup, the steps finished, and the tools used to accomplish the suggested goals. With an emphasis on the three dimensions of the particles—height, diameter, and arithmetic roughness—the findings from the microscopic analysis of the particle deposits on the filtered water samples are given and tabular indexed. As a result, it was feasible to use a computational mathematical model to identify the statistical indicators of the values recorded in the samples that underwent microscopical analysis. Following the application of the mathematical model, the findings were centralized, and their correlation was analyzed using graphical representations. The results led to the concrete identification of the impurity degree of drinking water filtered by consumer means.