Domestic wastewater (sewage) has been used for irrigation and aquaculture since the Bronze Age (ca. 3,200-1,100 BC) by prehistoric civilizations (e.g. Chinese, Egyptian, Indus Valley, Mesopotamian, ...and Minoan). In historic times (ca. 1,000 BC-330 AD), wastewater was disposed of or used for irrigation and fertilization purposes by the Greek civilization and later by the Romans in areas surrounding cities (e.g. Athens and Rome). In more recent history, the practice of land application of wastewater for disposal and agricultural use was utilized first in European cities and later in USA. Today, the planning and implementation of water reclamation and reuse projects is occurring throughout the world. Recycled water is now used for almost any purpose including potable use. This paper provides a brief overview of the evolution of water reuse over the last ca. 5,000 years. Understanding the practices and solutions of the past, provides a lens with which to view present and future challenges in a highly-urbanized world.
New industrial and urban developments in water-scarce regions are often inhibited by their high demand for water from natural resources. In addition, there often is a lack of water for purposes that ...contribute to an improved quality of life, such as urban green spaces. Therefore, the integrated industrial-urban water-reuse concept presents a strategy by linking and reusing treated industrial and municipal wastewater flows to increase urban water-reuse potentials. The concept of combining different reuse water flows, from wastewater treatment plants from industrial parks, aims at significantly increasing the water-saving potentials compared to a separate consideration of the industrial wastewater flows.
Urbanization and industrialization are increasing extreme weather events, causing water quantity and quality reduction. Global water scarcity impacts 32.5 % of the urban population and is growing. ...Brazil has also witnessed water scarcity, notably in the southeast (2014–2015) and south (2019–2020), with reservoirs dropping below 20 % capacity. Water reuse is vital for mitigating scarcity, though it presents risks due to contaminants. Risk analysis studies are crucial for evaluating contamination sources, pathways, and exposure scenarios in water reuse practices. Various methodologies, including quantitative, semi-quantitative, and qualitative analyses, can be employed. Given the uncertainty and diverse factors, qualitative methods are recommended for non-potable water reuse risk analysis. This work presents a qualitative risk analysis methodology that allows to evaluate non-potable water reuse categories. It assesses factors affecting human health and the environment, considering exposure scenarios, characteristics of the receptors, and sources of reused water. The risk analysis of water reuse was carried out focusing on agricultural reuse, considering as alternatives the irrigation of soybean and sugarcane crops. By reviewing literature, the probability of occurrence and the magnitude of impact of the risk factors were identified and rated, using an increasing relative numeric scale. This process resulted in an overall risk value for comparing agricultural irrigation alternatives. The obtained results indicate a promising risk analysis model that can be adjusted and applied to various water reuse modalities and key factors. This adaptable risk analysis model is mainly related to water treatment methods, prompting the proposal of risk control measures.
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•The risk assessment methodology is applied for scenarios and non-potable water reuse.•Risks are evaluated, considering factors affecting human health and the environment.•Case studies of risk assessments are presented, focusing on agricultural use.•Adaptation to water reuse categories, sites, and controls are highlighted.
With increasing water scarcity, many utilities are considering the potable reuse of wastewater as a source of drinking water. However, not all chemicals are removed in conventional wastewater ...treatment, and disinfection byproducts (DBPs) can form from these contaminants when disinfectants are applied during or after reuse treatment, especially if applied upstream of advanced treatment processes to control biofouling. We investigated the chlorination of seven priority emerging contaminants (17β-estradiol, estrone, 17α-ethinylestradiol, bisphenol A (BPA), diclofenac, p-nonylphenol, and triclosan) in ultrapure water, and we also investigated the impact of chlorination on real samples from different treatment stages of an advanced reuse plant to evaluate the role of chlorination on the associated cytotoxicity and estrogenicity. Many DBPs were tentatively identified via liquid chromatography (LC)- and gas chromatography (GC)-high resolution mass spectrometry, including 28 not previously reported. These encompassed chlorinated, brominated, and oxidized analogs of the parent compounds as well as smaller halogenated molecules. Chlorinated BPA was the least cytotoxic of the DBPs formed but was highly estrogenic, whereas chlorinated hormones were highly cytotoxic. Estrogenicity decreased by ∼4–6 orders of magnitude for 17β-estradiol and estrone following chlorination but increased 2 orders of magnitude for diclofenac. Estrogenicity of chlorinated BPA and p-nonylphenol were ∼50% of the natural/synthetic hormones. Potential seasonal differences in estrogen activity of unreacted vs reacted advanced wastewater treatment field samples were observed.
Water reuse is considered a technologically viable option to meet the increasing demands of the domestic, industrial and agricultural sectors. Alongside challenges such as environmental health, ...infrastructure and regulations, water reuse is often hindered by lack of acceptance and dismissive attitudes. This paper seeks to structure knowledge about acceptance of water use. It provides a systematic look at the overall reuse challenges and social attitudes towards water reuse considering the three integrative elements of water reuse, namely the water source, the technology, and the end use. It first maps the challenges and common insights that constitute the enigma of water reuse acceptance. Later, it conceptualizes acceptance as a social process consisting of the interdependent components of public perception, politicization, individual acceptance, and use adaptation. Using this conceptual framework, solutions to increasing water acceptance stemming from different bodies of acceptance studies are reviewed. The paper reiterates the need for a nuanced view on water reuse acceptance that incorporates spatio-temporal considerations as well as knowledge from different disciplines.
Water is essential in all aspects of life, being the defining characteristic of our planet and even our body. Regrettably, water pollution is increasingly becoming a challenge due to novel ...anthropogenic pollutants. Of particular concern are emerging organic contaminants (EOCs), the term used not only to cover newly developed compounds but also compounds newly discovered as contaminants in the environment. Aside from anthropogenic contamination, higher temperature and more extreme and less predictable weather conditions are projected to affect water availability and distribution. Therefore, wastewater treatment has to become a valuable water resource and its reuse is an important issue that must be carried out efficiently. Among the novel technologies considered in water remediation processes, metal–organic frameworks (MOFs) are regarded as promising materials for the elimination of EOCs since they present many properties that commend them in water treatment: large surface area, easy functionalizable cavities, some are stable in water, and synthesized at large scale, etc. This review highlights the advances in the use of MOFs in the elimination (adsorption and/or degradation) of EOCs from water, classifying them by the nature of the contaminant.
Population growth and climate change are leading to global water scarcity. Water shortages are thus hindering rural, urban and industrial development. These days, approximately half of the world’s ...population is affected temporarily by water scarcity. To enable a secure water supply, alternative water sources must be generated to tackle the challenge of water scarcity. An important alternative resource is the reuse of treated wastewater. Water reuse processes are rarely considered and implemented. In contrast to the storage and use of rainwater, treated wastewater is a valuable resource, as it is available daily. Certain wastewater treatment processes are required to produce the new resource “reused water”. The treatment processes depend on the quality of the wastewater since industrial and municipal wastewater flows are characterized by different concentrations. Moreover, water reuse methods must be developed in order to use the treated wastewater as efficiently as possible. Ideally, the reused water can be provided according to the "fit for purpose" principle and applied directly in areas such as irrigation, street cleaning, toilet flushing or make-up water for cooling systems.The Special Issue brings together new wastewater treatment technologies and water reuse concepts to tackle the challenges of climate change with the aim of bringing the resource “reused water” according to the “fit for purpose” principle to the user. This issue aims to draw on global experiences, approaches and solutions.
Wastewater treatment and reuse has passed through different development stages with time. This study reviews the most essential changes in water reclamation and reuses over millennia, focusing on ...initial approaches in the Hellenic world and discussing the current situation. Based on archeological evidence and time records, the awareness of the Greeks regarding land disposal, irrigation, and water reuse is highlighted. The latter has evolved into a plethora of applications, with Direct Potable Reuse (DPR) representing one of the last modern frontiers. Currently, advances in wastewater treatment and the spreading of wastewater treatment plants producing large amounts of treated effluents increase the potential for water reuse. This is regarded as a critical option for the continuing protection of water resources and human health, while concurrently satisfying water demand, particularly in areas subject to increased water scarcity. The main constraints in the expansion of water reuse practices are discussed, focusing on wastewater treatment efficiency and quality effluent standards issues, as well as on the lack of motivations related to the acceptability of this practice by final users. Against these challenges, the need for a transition from an “issue-by-issue” approach to a broader integrated water management framework is highlighted.
Organic matter (OM) is a ubiquitous constituent of natural waters quantifiable at very low levels using fluorescence spectroscopy. This technique has recognized potential in a range of applications ...where the ability to monitor water quality in real time is desirable, such as in water treatment systems. This study used PARAFAC to characterize a large (n = 1479) and diverse excitation emission matrix (EEM) data set from six recycled water treatment plants in Australia, for which sources of variability included geography, season, treatment processes, pH and fluorometer settings. Five components were identified independently in four or more plants, none of which were generated during the treatment process nor were typically entirely removed. PARAFAC scores could be obtained from EEMs by simple regression. The results have important implications for online monitoring of OM fluorescence in treatment plants, affecting choices regarding experimental design, instrumentation and the optimal wavelengths for tracking fluorescent organic matter through the treatment process. While the multimodel comparisons provide a compelling demonstration of PARAFAC’s ability to distill chemical information from EEMs, deficiencies identified through this process have broad implications for interpreting and reusing (D)OM-PARAFAC models.
When urban areas expand without concomitant increases in wastewater treatment capacity, vast quantities of wastewater are released to surface waters with little or no treatment. Downstream of many ...urban areas are large areas of irrigated croplands reliant on these same surface water sources. Case studies document the widespread use of untreated wastewater in irrigated agriculture, but due to the practical and political challenges of conducting a true census of this practice, its global extent is not well known except where reuse has been planned. This study used GIS-based modeling methods to develop the first spatially-explicit estimate of the global extent of irrigated croplands influenced by urban wastewater flows, including indirect wastewater use. These croplands were further classified by their likelihood of using poor quality water based on the spatial proximity of croplands to urban areas, urban wastewater return flow ratios, and proportion of wastewater treated. This study found that 65% (35.9 Mha) of downstream irrigated croplands were located in catchments with high levels of dependence on urban wastewater flows. These same catchments were home to 1.37 billion urban residents. Of these croplands, 29.3 Mha were located in countries with low levels of wastewater treatment and home to 885 million urban residents. These figures provide insight into the key role that water reuse plays in meeting the water and food needs of people around the world, and the need to invest in wastewater treatment to protect public health.
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