Alternative Water Sources Research Articles

Optimal management of mixed hydraulic barriers in coastal aquifers using multi-objective Bayesian optimization

• Optimum mixed hydraulic barriers location and rate obtained by Bayesian optimization. • Constrained multi-objective Bayesian optimization solved coastal management problem. • BO with few evaluations outperforms NSGA-II with a large number of evaluations. • Injection barriers have higher control over the remediation system. • Abstraction barriers useful as an alternative source of water. Mixed hydraulic barriers is an effective method to control seawater intrusion (SWI), particularly in regions that suffer from water shortages. However, determining the optimal well locations and rates for injection and abstraction is challenging due to the computational burden resulting from the huge number of calls for the high-fidelity hydrogeological simulation model. To alleviate this issue, we utilized a constrained multi-objective Bayesian optimization (BO) approach to optimize rates and locations of the hydraulic barriers to minimize total cost, aquifer salinity, and salt-wedge intrusion length, while satisfying regional abstractions with acceptable salinity levels. BO is useful for optimizing computationally expensive problems in few iterations by using a surrogate model and an acquisition function. Despite being an efficient optimization tool, the use of BO in the field of coastal aquifer management has not been explored. The proposed framework was evaluated on an unconfined aquifer subjected to three management scenarios considering different physical and technical constraints and was benchmarked against the widely used robust NSGA-II (Non-dominated Sorting Genetic Algorithm II) method. The results proved the effectiveness of BO in achieving an optimum mixed hydraulic barriers design in much fewer runs of the variable density aquifer model. BO with 350 evaluations yielded comparable results to 4150 evaluations using NSGA-II. BO solutions were spatially well-distributed along the approximated Pareto front. For the same number of evaluations, the hypervolume obtained by BO was larger by 30%. Based on different scenarios, the average amount of water required for abstraction ranged from 1.5% to 25% of that for injection. The injection has a significant impact on SWI management, but the abstracted water provides an alternative source of water. A sensitivity analysis was conducted on the optimization problem to illustrate its efficiency by omitting the barriers one at a time and assessing impacts on objective and constraint functions.

(Un)Affordability of Informal Water Systems: Disparities in a Comparative Case Study in Beirut, Lebanon

Achieving affordable and equitable access to water for all remains a challenge worldwide. In areas suffering from chronic water shortages, communities pay high costs for alternative informal water sources (such as tanker trucks, bottled water, and wells) to meet their daily water needs. This study examines water costs of informal sources and overall affordability disparities for two communities of different socioeconomic status in Beirut, Lebanon. Water is often unaffordable for both of these communities. Overall, 6% of household income is spent on purchasing water (compared to an average global percentages of 3% to 5%). There are also significant disparities between the communities: lower income residents pay 2.2 times more of their income to secure water, and more than half of these residents (55% of households) spend more than 5% of their income on water. To overcome water shortages, these residents turn to informal water sources, but at significant additional cost. These costs and impacts on lower income residents are high and inequitable. We propose strategies to address cost, quality and quantity issues for informal sources.

Urban Wastewater Reuse for Citrus Irrigation in Algarve, Portugal—Environmental Benefits and Carbon Fluxes

Water scarcity is increasing in the Mediterranean and alternative sources of water are needed to meet food production needs, protect the environment and reduce the effects of climate change. Currently, many urban wastewater treatment plants (WWTP) produce high volumes of treated effluents which can be an alternative source of water for agriculture irrigation, since they fulfill the quality requirements for crops and the environment. This work analyzed the quantity and quality of a treated effluent produced by an urban WWTP in Algarve, and the environmental benefits of its use on the irrigation of a citrus orchard, as an alternative to groundwater. Carbon dioxide emissions related to orange production were quantified and the orchard’s potential to sequester CO2 was estimated. The reuse of this urban wastewater is revealed to be technologically feasible and environmentally advantageous, avoiding the overexploitation of the local aquifer and preventing the eutrophication of aquatic ecosystems, contributing to the improvement of soil characteristics and decreasing the carbon emissions in orange production. Furthermore, it was found that during the five-month experimental period, the citrus orchard sequestered 87.5% of the CO2e emitted by WWTP in the effluent treatment, converting 72,623 kg of sequestered CO2 into orange biomass.

Characteristics of dissolved organic matter in two alternative water sources: A comparative study between reclaimed water and stormwater

Reclaimed water and stormwater are two important alternative water sources to mitigate water resource shortage. They can be reused by discharging into drinking water sources. Due to different sources, characteristics of dissolved organic matter (DOM, a precursor of disinfection by-products, DBPs) present in reclaimed water and stormwater would be different. This study selected reclaimed water to compare with stormwater (including both stormwater runoff and rainwater) by investigating their DOM characteristics, including concentrations, aromaticity, molecular weight, hydrophobicity/hydrophilicity, composition and DBPs formation potential. The results showed that reclaimed water had higher dissolved organic carbon (DOC) concentrations (6.02–10.8 mg/L) than stormwater (3.62–5.48 mg/L) while SUVA254 values of stormwater runoff (1.92–2.53 L/(mg-C·m)) were higher than reclaimed water (1.11–1.24 L/(mg-C·m)). Additionally, reclaimed water is more hydrophobic while stormwater runoff and rainwater are more hydrophilic. Although all water types included the highest fraction of DOM with molecular weight <1 kDa (43.0 %–77.5 %), reclaimed water primarily contained soluble microbial products (SMPs)-like and humic acid-like substances while stormwater runoff primarily contained humic acid-like DOM. In terms of DBPs, reclaimed water showed relatively higher formation potential than stormwater runoff while rainwater had the lowest DBPs formation potential. These results can contribute to effective water resource management. Particularly, when reclaimed water or/and stormwater are discharged into drinking water sources, these outcomes can help on efficient drinking water treatment.

Changes in the Water Surface Area of Reservoirs of the Crimean Peninsula and Artificial Increases in Precipitation as One of the Possible Solutions to Water Shortages

The climatic conditions of Crimea are semiarid; therefore, alternative sources of fresh water are needed. A significant increase in water use and consumption (due to the intensification of construction, industry, tourism, and militarization), along with the cessation of fresh water supplies from mainland Ukraine, has reduced the water levels in some reservoirs to critical levels, and climate change has exacerbated this situation. There has been a significant decrease in precipitation by 10–15% on the Crimean Peninsula, accompanied by an increase in surface temperature by 0.8 ± 0.1 °C per 10 years during the period 1991–2020. The analysis of satellite-driven drought severity index reveals that the vast area of Crimean steppe is exposed to moderate–high drought risk. According to Landsat satellite imagery, there is a decreasing tendency for the water mirror area of all reservoirs, with a decrease of 34% on average in 2021 compared to 2015. The retrospective analysis of satellite images for 2015–2021 showed that the water surface area of the Simferopol reservoir had decreased on average by ~20% compared to 2015. To solve the problems associated with the shortage of fresh water, a series of works on the active influences on atmospheric processes was conducted, aimed at providing additional artificial precipitation. Two situations were considered, with mixed results: In the first case, on 30 October 2016, wet soil and standing water areas were detected by radar satellite imagery in agricultural fields within a radius of 40 km of the village of Petrovka, Krasnogvardiiskyi district, potentially related to the induction of precipitation by active influences on atmosphere. Meanwhile, in the second case, the realization of atmospheric precipitation occurred over Simferopol on 29–30 September 2020, leading to flooding in the city, but an increase in the water surface area of the Simferopol reservoir after active influences was not recorded.

Water Reuse: A Risk Assessment Model for Water Resources

The increasing demands for water for multiple purposes combined with climate change challenges are leading to water scarcity and quality deterioration. Portugal is vulnerable to the impacts of climate change and therefore, the use of reclaimed waters has been identified as a suitable alternative water source for non-potable uses, such as irrigation, to overcome water shortages. In the last two years, new policies for water reuse have been approved at the Portuguese and European levels. The legal frameworks are supported in the international guidelines developed by the International Organization for Standardization, namely for irrigation, urban uses and health risk assessment. In this way, all reuse projects must follow a fit-for-purpose approach, i.e., the water quality needs to meet the requirements of its specific end-uses without compromising public health or the surrounding environment, and all reuse projects must conduct a risk assessment for health and the environment. Quantitative, qualitative or semiquantitative models can be used. Although a quantitative assessment may be desirable, these models tend to be complex and present high uncertainty. Furthermore, these usually require extensive data which are often not available. Accordingly, this study intended to develop a conceptual model to deal with the risk assessment for water resources, namely surface and ground waters. A semi-quantitative approach was employed for the risk characterization, using empirical qualitative judgment to assess the relative importance of hazards, exposure routes, scenarios and barriers in place. The use of a strategic assessment allows the quality standards that meet the needs of each project to be validated. The developed model was applied to a case study to illustrate its applicability.&#x0D; Keywords: water reuse, water resources, risk assessment, semi-quantitative model, compounds of emerging concern

Performance Assessment for Increasing Connection Rates of Private Water Supply Operators in Cambodia

Private water supply operators (PWSOs) play an important role in extending piped water services in small cities in Cambodia. However, the connection rates to PWSOs are highly varied. Therefore, this study aimed to find the reasons for the low connection rates of PWSOs and to propose ways to increase the connection rates. The three PWSOs selected for this study supply water continuously, with sufficiently high pressure and good water quality except for the low concentration of residual chlorine, while the per capita supply volume varies significantly. Households with alternative water sources, namely rainwater and well water, consume less piped water than those without alternative water sources. Scattered service areas far away from water treatment plants had coverage rates that were lower than in compact service areas. The present connection costs and water tariffs are higher than those that non-connected households are willing to pay, though they pay high costs for bottled water. Due to the high variation in household income, connection fees and water tariffs are a financial burden for low-income households. Because the operating rates of the PWSOs are 21–47%, it is advised that PWSOs reduce their connection fees and water tariffs to obtain more connected households in their service areas.

Public perception of water re-use: building trust in alternative water sources in Malmesbury, South Africa

The recent drought in the Western Cape Province in South Africa has been marked as the worst since 1904. The drought impacted severely on the availability of bulk water supply in many parts of the Western Cape Province, particularly the Cape Town Metro and surrounding districts. In order to alleviate water scarcity, wastewater recycling (water reuse) has been identified to have the potential to augment water supplies in the province. This paper argues that although water recycling has the potential to contribute towards alleviating water scarcity, studies have shown that public perceptions greatly influence the outcome of any water recycling scheme. The study collected data using face-to-face interviews, focus group discussions, and the application of the Story with a Gap participatory exercise. One of the key findings is that residents have to trust the municipal competencies and systems, and this can be achieved through meaningful engagement between the municipality and residents. We argue that rolling out a water reuse scheme by starting with affluent areas increases the likelihood of acceptance among low-income communities.

Development of an Energy Efficient and Fully Autonomous Low-Cost IoT System for Irrigation Scheduling in Water-Scarce Areas Using Different Water Sources

Politicians and the general public are concerned about climate change, water scarcity, and the constant reduction in agricultural land. Water reserves are scarce in many regions in the world, negatively affecting agricultural productivity, which makes it a necessity to introduce sustainable water resource management. Nowadays, there is a number of commercial IoT systems for irrigation scheduling, helping farmers to manage and save water. However, these systems focus on using the available fresh water sources, without being able to manage alternative water sources. In this study, an Arduino-based low-cost IoT system for automated irrigation scheduling is developed and implemented, which can provide measurements of water parameters with high precision using low-cost sensors. The system used weather station data combined with the FAO56 model for computing the water requirements for various crops, and it was capable of handling and monitoring different water streams by supervising their quality and quantity. The developed IoT system was tested in several field trials, to evaluate its capabilities and functionalities, including the sensors’ accuracy, its autonomous controlling and operation, and its power consumption. The results of this study show that the system worked efficiently on the management and monitoring of different types of water sources (rainwater, groundwater, seawater, and wastewater) and on automating the irrigation scheduling. In addition, it was proved that the system is can be used for long periods of time without any power source, making it ideal for using it on annual crops.

Cysteine mitigates the effect of NaCl salt toxicity in flax (Linum usitatissimum L) plants by modulating antioxidant systems

Agriculture, the main water-consuming factor, faces a global water scarcity crisis. Saline water is an alternative water source, while excess NaCl decreases plant growth and productivity of crops. L-cysteine (Cys) is a promising thiol amino acid in plant growth and development. Flax; Linum usitatissimum L. is an economical plant with low salt tolerance. NaCl salt stress at 50 and 100 mM inhibited the growth parameters, the photosynthetic pigments, total soluble sugars, total phenols, and amino nitrogen in flax plants. Salt stress led to a marked rise in proline and lipid peroxidation and altered the protein profile. Foliar application of cysteine at 0.8 and 1.6 mM mitigates the unfriendly effects of NaCl stress on flax plants. Cysteine enhanced the growth traits, photosynthetic pigments, amino nitrogen, total phenols, and new polypeptides in NaCl-stressed plants. However, cysteine declined the total sugars, proline, the activity of peroxidase, and ascorbate peroxidase. The results confirmed that cysteine had reductant properties. Furthermore, it decreased the NaCl oxidative stress and maintained the stability of membranes by lowering lipid peroxidation. Overall, the redox capacity of L-cysteine is the cause behind its potential counteracting of the adverse effects of NaCl toxicity on the growth of flax plants.

Atmospheric Water Generator (AWG): New Innovative Technology to Overcome Global Water Scarcity

Freshwater scarcity is an ever-growing concern for human society. The atmosphere contains water in the form of water vapor; moisture etc., within that amount almost 35% of the water is wasted. Alternative new technologies are urgently needed to overcome the rapidly increasing global water scarcity. Atmospheric water is a potential source of potable water, as the earth’s atmosphere contains tons of fresh water (98% in a vapor state). The atmospheric water generator (AWG) converts water vapor into liquid water and is a capable solution for water scarcity. The major aim of this research work is to provide safe and clean drinking water to those areas which are facing water scarcity problems. In this research work we provide the comprehensive analysis of the chemical and biological profiles of water, produced for several months by three different AWG. Physical parameters, heavy metals and microbiological parameters were analyzed in the water. The main elements found were aluminum, calcium, magnesium, and potassium. The sampling site, likely affected the chemical composition of the produced atmospheric water. Nevertheless, the produced water nearly always met the WHO drinking water standards. In this research work, scientific evidence has been presented that supports, AWG can be an alternative potential source of water to cope up with water scarcity problem and provide safe drinking water throughout the year.

Water sustainability: A waterless life cycle for cosmetic products

Freshwater is a precious natural resource becoming scarce due to the expanding population, pollution, urbanization and economic development, and climate change. Industry accounts for about 20% of all water withdrawals, and companies and consumers are increasingly concerned about the environmental impact of the goods they produce and consume, respectively. The cosmetics industry has intensely relied on water as a key element for the formulation and manufacture of its products. Water is needed at all stages of the cosmetic product life cycle: it is one of the main ingredients in a cosmetics formulation, it is required to grow raw materials and for heating and cooling processes, equipment cleaning, and packaging production, which leads to high consumption and significant impacts in pollution. To save water and assure its sustainability, several companies are showing their commitment to reducing the water footprint of their systems. This approach includes sourcing sustainable raw materials, developing waterless, fast rinse-off or non-rinse formulas, finding alternative water sources, optimizing manufacturing processes including the adoption of circular water management in their facilities, using biodegradable, recyclable and reusable packaging, and improving transport infrastructure. The companies must also carry out consumers' education on how to responsibly use and dispose of products. Besides all the benefits to the planet, waterless products offer many advantages to consumers as they tend to be more concentrated, have richer formulations, are lighter, economical, and longer-lasting. To evaluate the product's impact, set improvement goals, report progress to society, and contribute to business transparency and informed consumption choices by consumers, it is crucial to define sustainability metrics based on water footprint assessment and achieve proper certification. Although there is still much to achieve, the collaboration between businesses, governments, regulators and communities will improve water management globally and safeguard water resources. This work aims to unravel the role of water in the cosmetic industry and strategies that can be used in each stage of a cosmetic product life cycle (conception, production, packaging, distribution, consumer use and disposal) to promote the sustainable use of water in this sector. Additionally, it shows the efforts and initiatives of some companies to raise awareness in this regard, such as waterless products of different categories already available on the market, and the publicity and information campaigns to encourage a change in cosmetics consumption and production patterns.

Assessment of the prospects for the use of treated wastewater for irrigation purposes in the Republic of Crimea

Treated sewage wastewater is a possible alternative water source for increasing the water supply to the agricultural industry of the Republic of Crimea. However, their use, according to the results of research by domestic and foreign scientists, is constrained by a combination of a number of factors that need to be taken into account and analyzed before implementing this direction. The purpose of the work is to assess the possibility of using treated wastewater for irrigation purposes in the Republic of Crimea in modern conditions. The main source of this water category is large sewage treatment plants (STP) serving the cities of Alushta, Dzhankoy, Yevpatoria, Kerch, Saki, Simferopol, Sudak, Feodosia, Yalta. They account for about 80% of the volume of wastewater, discharged into surface water bodies annually. Based on the salt composition of the treated wastewater, the most promising alternative water sources for irrigation purposes are the STP “Ukromnoye”.

Geospatial Assessment of The Potentials of Rooftop Rainwater Harvest at The Federal University of Technology, Akure, Nigeria

Recent reports reveal water shortage at the Federal University of Technology, Akure, (FUTA), Nigeria, with possibilities to worsen if adequate measures are not taken. This research focuses on the assessment of the potential of an alternative source of water supply the Roof Top Rainwater Harvest (RTRWH) at FUTA. This study goes beyond the determination of the potential volume of RTRWH by proposing a storage plan for the RTRWH based on geospatial analysis. Data collected for the study are rainfall data covering 19 years (2000-2018), High-Resolution Satellite Image (HRSI), Ground Control Point (GCP), attribute data, Landsat 8 and Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM). The rooftop areas were extracted by processing HRSI using ArcGIS software. The volumes of the RTRWH for each building were computed with the rooftop area, precipitation amount and roof's runoff coefficient of the rooftop material as variables. Suitable locations for siting the storage tanks were proposed based on Multi-Criteria Decision Making (MCDM) and geospatial analysis. Result obtained from the study reveals that the total area of rooftop catchment for all buildings considered is 164,246 m2. The study suggests 9 locations suitable for collecting and storing the harvested RTRW. The potential average daily, average monthly and total annual volumes of RTRWH are approximately 607 m3, 18,473 m3 and 221,681 m3 respectively, and thereby could potentially provide ~ 41% of water demand in addition to the existing water supply sources in FUTA. The RTRWH is therefore recommended as an alternative water source at FUTA.

Performance of rooftop rainwater harvesting system as a source of drinking water

Rainwater Harvesting Systems (RWHSs) are increasingly being used as an alternative or supplementary source of water to curb the water supply deficit in the Kathmandu valley. The harvested rainwater is primarily used for non-potable purposes like flushing toilets and irrigation, but the knowledge on the use of rainwater for potable purpose is remarkably sparse. This study assesses the suitability of rainwater in terms of quantity and quality in a public school that adopts Rooftop RWHS as the source of drinking water. In this study, we observed that the volume of rainwater being harvested is sufficient to address the current demand of drinking water, with a mean rainfall of 1664 mm on a catchment area of 372 m2. Storage capacity needs to be expanded if the demand increases. Physico-chemical and microbial analyses of water samples (before and after a series of treatments) were carried out for the winter, monsoon, and post-monsoon seasons. The values of physico-chemical parameters of the water samples, in all the seasons, were well within both the National Drinking Water Quality Standards (NDWQS, 2005) and the World Health Organisation (WHO, 2017) guidelines for drinking water, while fecal coliforms were detected in the storage tank, but were absent in tap water after the treatments. Based on the findings, we suggest that the harvested rainwater could be used for drinking purposes if properly treated. RWHS use at the institutional level, like in schools, on the one hand, curbs the increasing demand for water in water-deficit locations like Kathmandu, and on the other, encourages the adoption of such sustainable technologies for the water supply.

Optimizing textile dyeing wastewater for tomato irrigation through physiochemical, plant nutrient uses and pollution load index of irrigated soil

Reuse of wastewater for vegetable cultivation is becoming popular in order to augment the inadequate irrigation supplies and meet the growing demands of ground water for agriculture and industries production in different regions of the world. This study was investigated to optimize different stages of textile dyeing wastewater (TDW) for irrigation focusing on their effect on growth, yield and physiochemical attributes of tomato, plant nutrient use, heavy metals enrichment and pollution load of the irrigated soil. Textile wastewater were collected from the seven stages of (second wash after scouring and bleaching T2; enzyme treated water T3; second wash after bath drain T4; neutralization treatment T5; second wash after soaping T6; fixing treatment water T7; mixed effluent T8) of a dyeing process for physiochemical characterization and evaluation their irrigation feasibility for tomato cultivation in compare with the ground water (T1). The pot experiment consists of eight irrigation treatments was laid out following a completely randomized block design with three replications. Results showed the presence of plant nutrients and heavy metals in all the studied samples where T8 (mixed effluent) exceeded the limit of agricultural standard for almost all physiological parameters such as TDS, TSS, EC, BOD, COD affording the highest value. T8 also delivered the highest Cl- and heavy metals like Cd, Ni, Cr followed by T4 < T7. As a consequence, these provided comparatively higher enrichment factor (EF), pollution load index (PLI) and sodium absorption ratio (SAR) to transform fresh soil into the category of severe and slightly to moderate saline. Therefore, the yield and physiochemical attributes of tomato were dramatically reduced with T8 and T4 treatment. On the other hand, T2, T3 and T6 treatment had significant positive impact on growth and yield of tomato due to having higher N, P, K, S and lower heavy metals (Cu, Zn, Fe, Pb, Cd, Ni, Cr) than the recommended guideline. These features were contributed to cause minimum EF and PLI in the soil irrigated with T2, T3 and T6 stages of TDW. Correlation matrix demonstrated that EF and PLI of heavy metals (except Cd, Ni) were negatively related to yield, while positively related to SAR and fruit abortion. Although T6 (2nd wash after soaping) performed better in respect to growth, yield, yield attributes and nutrient use efficiency, principal component analysis revealed that T2 (2nd wash after scouring and bleaching) and T3 (enzyme treated water) were also belong to the same group of T6 and T1 (ground water). Thus, it may be suggested that T2, T3 and T6 stages of textile dyeing wastewater could be used profitably without ETP for vegetable cultivation and would effectively supplement not only the nutrient requirement of the crop but may also act as the alternate source of irrigation water. Although, further research is needed to sort out the health risk assessment through the heavy metals’ accumulation in the plant parts after irrigation with different stages of textile dyeing wastewater.

Location Characteristics of the New Country Capital in East Kalimantan Province

The relocation of the national capital has been carried out by several countries for various reasons. This study aimed to determine the characteristics of the location of the nation’s capital city in East Kalimantan Province. The research was conducted in two regencies, 3 sub-districts, and 4 sub-districts. Penajam Paser Utara District includes Babulu and Sepaku Districts, while Kutai Kartanegara District includes Muara Jawa District. The data used in this study is secondary data from the study literature. The findings from the study are that in West Babulu Village there is a network of arterial roads and local roads. Pemaluan Village, Sepaku Village, and Teluk Dalam Village have a network of local roads and other roads. North Panajam Paser Regency has 3 watersheds and Kutai Kartanegara Regency has 2 watersheds in total there are 5 watersheds. Meeting water needs apart from river water can also be from dams. In 2023, it is estimated that the Nation Capital's water needs will reach 16,500 liters/second, with the needs of surrounding districts in that year reaching 27,232 liters/second. In line with the development of the city and its facilities, the need for water will increase, so the nation’s capital city requires alternative sources of additional water. Topographic conditions seen from elevation, slope, and landform, there are several areas that need to be maintained as protected areas or city green open spaces (RTH), urban forests, which can also function as educational or tourism facilities for Capital cities in order to protect areas that are underneath

Experimenting with fog: Environmental infrastructures, infrastructuring environments, and the infrastructure of infrastructure

In coastal Peru, conservationists and scientists attend to fog as something that may be captured and transformed into water. This article draws on ethnographic fieldwork among Limeñan conservationists who tapped into this atmospheric phenomenon as an alternative water source for use in fog oasis ecosystem reforestation. As I demonstrate, experimental engagements with fog had reconfigured conservationists’ and other experimenters’ understanding about the connections between the atmosphere, vegetation, and the underground, thereby bringing into view a hitherto imperceptible environmental infrastructure of groundwater production. The infrastructural potentials of the landscape were in turn foregrounded by the conservationists through comparisons with other geographies well-known for their capacity to produce water. Against this backdrop, the article argues for renewed attention to the infrastructural as a comparative effect resulting from simultaneous fore/backgrounding. Rather than mere grounds for second-order processes, infrastructural relations can be understood as situated between foreground and background. As environmental calamities complicate the infrastructure–environment nexus, it is no longer clear what infrastructures consist of, nor what they are capable of doing. In this context, an understanding of infrastructures as comparative effects is useful for describing and speculatively amplifying potentially more sustainable infrastructural alternatives.

Recent insights into greywater treatment: a comprehensive review on characteristics, treatment technologies, and pollutant removal mechanisms.

With the rapid socio-economic and industrial development, the problem of water shortage is becoming increasingly serious. Seeking alternative water sources to reduce the need for freshwater resources is an increasing concern. Household greywater production is high and accounts for about 50-80% of domestic wastewater. In recent years, the in situ treatment and reuse of greywater have received widespread attention. Treated greywater can be used for non-potable purposes such as toilet flushing and irrigation, which can greatly reduce the pressure of freshwater resource shortage. This paper reviews the sources and characteristics of greywater and analyzes its quantity and quality. In addition, this paper outlines and summarizes various greywater treatment technologies commonly used, including physical, biological, and chemical treatment technologies, as well as combination technologies. Understanding the mechanisms of contaminant removal is essential for effective greywater treatment. While discussing different treatment technologies, we focus on the removal mechanisms of pollutants from greywater, including organics, nutrients, surfactants, and emerging contaminants. Finally, future perspectives on greywater management and reuse are presented. Through a comprehensive review, we expect that this review will help the reader to better understand the characteristics of greywater and to more rationally select the appropriate treatment technology based on the removal mechanism of pollutants.

Reclaimed Water Use in Agriculture: Effects on Soil Chemical and Biological Properties in a Long-Term Irrigated Citrus Farm

In Mediterranean regions, the scarcity of freshwater for agricultural purposes is leading to the use of alternative water sources. This study aimed to evaluate the effects of long-term irrigation with reclaimed water on chemical and biological soil properties. On a mandarin tree orchard (Citrus clementina, cv. Orogrande), freshwater (FW) and tertiary reclaimed water (RW) were supplied for irrigation. In spring 2017, a soil sampling was carried out, collecting from each experimental plot four samples at 0–0.20 m depth. Chemical and biochemical soil properties were determined on air dried and sieved soil and on fresh and field-moist soil, respectively. The irrigation with reclaimed water significantly increased the soil water extractable organic carbon (WEOC), available P, Mg, and Na content, and the electrical conductivity (EC). Although not significant, the respiration rates and enzymatic activities were higher in RW treatment. The results of this research highlighted that the irrigation with reclaimed water, providing organic carbon and other nutrients, could have, in the long-term, beneficial effects on soil microorganism and their activities. In any case, especially in arid and semi-arid environments, a proper management of wastewater should be recommended to avoid soil degradation due to salt accumulation in the rootzone.