Alternative Water Research Articles

Evaluating the precise grapevine water stress detection using unmanned aerial vehicles and evapotranspiration-based metrics

AbstractPrecise irrigation management requires accurate knowledge of crop water demand to adequately optimize water use efficiency, especially relevant in arid and semi-arid regions. While unoccupied aerial vehicles (UAV) have shown great promise to improve the water management for crops such as vineyards, there still remains large uncertainties to accurately quantify vegetation water requirements, especially through physically-based methods. Notably, thermal remote sensing has been shown to be a promising tool to evaluate water stress at different scales, most commonly through the Crop Water Stress Index (CWSI). This work aimed to evaluate the potential of a UAV payload to estimate evapotranspiration (ET) and alternative ET-based crop water stress indices to better monitor and detect irrigation requirements in vineyards. As a case study, three irrigation treatments within a vineyard were implemented to impose weekly crop coefficient (Kc) of 0.2 (extreme deficit irrigation), 0.4 (typical deficit irrigation) and 0.8 (over-irrigated) of reference ET. Both the original Priestley-Taylor initialized two-source energy balance model (TSEB-PT) and the dual temperature TSEB (TSEB-2T), which takes advantage of high-resolution imagery to discriminate canopy and soil temperatures, were implemented to estimate ET. In a first step, both ET models were evaluated at the footprint level using an eddy covariance (EC) tower, with modelled fluxes comparing well against the EC measurements. Secondly, in-situ physiological measurements at vine level, such as stomatal conductance (gst), leaf (Ψleaf) and stem (Ψstem) water potential, were collected simultaneously to UAV overpasses as plant proxies of water stress. Different variants of the CWSI and alternative metrics that take advantage of the partitioned ET from TSEB, such as Crop Transpiration Stress Index (CTSI) and the Crop Stomatal Stress Index (CSSI), were also evaluated to test their statistical relationship against these in-situ physiological indicators using the Spearman correlation coefficient (ρ). Both TSEB-PT and TSEB-2T CWSI related similarly to in-situ measurements (Ψleaf: ρ ~ 0.4; Ψstem: ρ ~ 0.55). On the other hand, stress indicators using canopy fluxes (i.e. CTSI and CSSI) were much more effective when using TSEB-2 T (Ψleaf: ρ = 0.45; Ψstem: ρ = 0.62) compared to TSEB-PT (Ψleaf: ρ = 0.18; Ψstem: ρ = 0.49), revealing important differences in the ET partitioning between model variants. These results demonstrate the utility of physically-based models to estimate ET and partitioned canopy fluxes, which can enhance the detection of vine water stress and quantitatively assess vine water demand to better manage irrigation practices.

Impact of using stored treated municipal wastewater for irrigation on the microbial quality and safety of vegetable crops

Climate change is increasing the demand for alternative water sources, with treated municipal wastewater from a wastewater treatment plant (WWTP) standing out as a potential alternative. A field study was performed to examine the impact of storage on the microbial quality of water from a WWTP and the possible microbial transmission to three vegetable crops irrigated with (stored) water from a WWTP. The analysis consisted of 13 microbial indicators, hygiene and pathogenic parameters. Results showed that storing water from a WWTP up to 32 days can result in a decrease of 4.8 log CFU/100 ml E. coli and the absence of Salmonella spp. and Listeria monocytogenes. Additionally, integrating waiting periods of 7 days post-irrigation resulted in very limited microbial transmission to the irrigated crops. However, continuous research and monitoring are essential to apply this method in practice, due to the variability of crop type and type of bacteria. As of now, in order to meet European legislation (2020/741/EC) and depending on the impact of post-harvest processing, further water treatment (e.g. disinfection) is still needed to safely use stored WWTP water as an alternative water source for irrigation.

Addressing water scarcity in agricultural irrigation: By exploring alternative water resources for sustainable irrigated agriculture

AbstractThis review paper addresses challenges in the water sector, particularly in irrigated agriculture, aiming to propose solutions for meeting irrigation demands while promoting global food security and sustainable development, notably SDG 6. Structured around three facets: empowering farmers, strengthening conventional sources of irrigation water and harnessing non‐conventional water resources, it emphasizes the significance of exploring blue water resources due to precipitation variability. Many irrigation systems operate below efficiency, offering productivity enhancement opportunities. Water management in agriculture spans various levels, involving farmers as key stakeholders. In addition to surface water, alternative sources like rainwater, grey water, recycled wastewater and groundwater can meet irrigation needs. Rainfed agriculture, facing challenges from erratic rainfall, can benefit from rainwater harvesting and under‐irrigation practices. Wastewater emerges as a pivotal resource, particularly in periurban areas, necessitating appropriate safety measures. This paper presents the General Report of Congress Question 64 of the ICID Congress in Visakhapatnam. It provides a unique opportunity to focus on how alternative water resources might enhance the resilience of irrigation systems and bridge the gap between water supply and demand. The subdivision of the paper into three distinct subtopics guides research contributions, encouraging responses that delve into the specific themes of reinforcing, harnessing and empowering, all within the context of sustainable irrigated agriculture.

Domestic access to water in a decentralized truck-to-cistern system: a case study in the Northern Village of Kangiqsualujjuaq, Nunavik (Canada).

Municipal water supply through truck-to-cistern systems is common in northern Canada. Household satisfaction and concerns about water services likely impact user preferences and practices. This case study explores household perspectives and challenges with regard to domestic access to water in a decentralized truck-to-cistern system. A case study was conducted in the Northern Village of Kangiqsualujjuaq, Nunavik (Quebec, Canada). A paper-based questionnaire was completed by 65 households (one quarter of the population). Many households (37%) reported not drinking tap water from the truck-to-cistern system. Chlorine taste was a frequently reported concern, with those households being significantly less likely to drink water directly from the tap (p = 0.002). Similarly, households that reported a water shortage in the previous week (i.e., no water from the tap at least once) (33%) were more likely to express dissatisfaction with delivered water quantity (rs = 0.395, p = 0.004). Interestingly, 77% of households preferred using alternative drinking water sources for drinking purposes, such as public tap at the water treatment plant, natural sources or bottled water. The study underscores the importance of considering household perspectives to mitigate the risks associated with service disruptions and the use of alternative sources for drinking purposes.

Does snow storage affect the Palmer drought severity index? Revisiting PDSI drought indicator via conceptual model and large-scale information

Climate change and its impacts have significantly altered the hydro-climatological conditions worldwide. Accurate monitoring of drought is a crucial work for assessing water availability and environmental suitability. The Palmer Drought Severity Index (PDSI) is a key indicator used to measure hydrological drought. However, its application in mountainous and snow-covered regions is limited due to the indicator's inadequate representation of snow hydrology and its impact during spring and summer. In this research, the authors aimed to enhance the PDSI drought indicator by incorporating snow storage and snowmelt processes via conceptual approach and large-scale snow information. Four different scenarios were developed and tested in the Gheshlagh watershed, a mountainous basin in western Iran. To ensure a comprehensive analysis, the Standardized Precipitation Index (SPI) was also employed to evaluate the results. Additionally, an alternative water balance model, better suited for the watershed, was used in place of the Palmer two-soil-layer water balance model. While the simulated indicators showed good agreement with the benchmark PDSI model, the results revealed significant changes in drought indicators, particularly during summer and spring, when considering snow storage. Moreover, the impact of using a different water balance model was found to be more influential than incorporating snow storage in the PDSI framework. Based on the findings, the authors recommend revisiting the PDSI approach by incorporating region-specific water balance models and accounting for the effects of snow storage.

Accumulation of ions in soil fertigated with dilutions of dairy effluents in the Brazilian semi-arid region

Wastewater is an alternative water source with the potential to guarantee agricultural productivity in semi-arid regions, where quantitative and qualitative scarcity is a limiting factor. This study aimed to analyze the effects of the application of dairy effluent dilutions on the alterations of sodium, calcium, magnesium, and nitrogen contents along the profile of an Ultisol cultivated with Cereus hildmannianus in the semi-arid region of Brazil. The experimental design used was a 5 x 5 factorial randomized block design with five dilutions of dairy effluent (T1 - only well water (WW); T2 - 0.1 x annual loading rate according to EPA (1981) (LW) plus WW; T3 - 0.2 x LW plus WW; T4 - 0.3 x LW plus WW; and T5 - 0.4 x LW plus WW) and five depths (0 to 0.10 m; 0.10 to 0.20 m; 0.20 to 0.30 m; 0.30 to 0.40 m and 0.40 to 0.50 m), with five replicates. Cereus hildmannianus cultivation lasted 240 days, and after this period, soil samples were taken to determine the contents of sodium, calcium, magnesium, and nitrogen. Fertigation using dairy effluent with up to 40% of the annual loading rate in Ultisol poses no risk of water and soil contamination by nitrogen leaching. Fertigation using dairy effluent in proportions of up to 20% of the annual loading rate poses no risk of soil degradation due to excessive accumulation of ions.

Dynamics of Water-Soluble Metals in Soil Moistened with Citrus Wastewaters Depends on Soil Reaction and Organic Acids

The demand for water for civil and industrial use is diminishing the availability of such a valuable environmental resource for agricultural purposes. Thus, for the next generation, it is imperative to find alternative water sources for crop irrigation. The citrus agroindustry utilizes a large amount of water for processing fruit (e.g., essential oil extraction, fruit washing). Wastewaters produced by citrus industry (CWWs) are rich in organic matter and mineral nutrients, thus making them potentially usable for crop irrigation. Conversely, due to their high content of organic acids and low pH, they may increase the availability of soluble metals, in the form of both plant nutrients and contaminants. The aim of this study was to evaluate the effect of CWWs on the dynamics of soil water-soluble metals and pH. To this end, CWWs from the processing of lemons, oranges, and tangerines at three different doses were used. CWWs were analyzed to investigate type and amount of organic acids. Soil water-soluble metals (Na, Mg, Al, K, Ca, Fe, Co, Ni, Cu, Zn, and Cd) and pH were determined at days 1, 3, 7, 21, and 28 after the addition of CWWs. Citric, ascorbic, oxalic, tartaric, acetic, and malic acids were found in CWWs, with citric acid being two orders of magnitude more concentrated than the other acids. After the addition of CWWs, soil pH promptly decreased from 7.2 to at least 5.3 depending on the type and concentration of CWWs. Concurrently, the concentration of almost all investigated metals sharply increased within 7 days after the addition of CWWs. Then, it decreased, reaching values similar to that of the control. The increase in metals availability as a consequence of pH decrease was ascribed to different causes: the exchange reaction between H+ and cations adsorbed onto colloid surfaces, the addition of organic matter by CWWs that stimulated microbial activity, and the quantity and type of organic acids added via CWWs. In conclusion, the obtained results suggest that the use of citrus wastewater for irrigation purposes could be a valid solution, with them being rich in plant nutrients and easily mobilized elements such as Ca, Mg, K, and Na. Further research is needed to refine the understanding of the impact of CWWs in the long term and to develop targeted strategies for managing industrial wastewater in agriculture.

Question 65 What on‐farm techniques can increase water productivity? General report

AbstractTechnological interventions in tackling water scarcity in agriculture delve into the water productivity issue through available alternative water resources and on‐farm techniques including both structural measures and agronomic practices accompanied by a sound water management approach. On‐farm water management has been addressed under Congress Question 65 through deliberations on irrigation efficiency, soil moisture forecasts and hydrological predictions, efficient and timely distribution of water, controlling non‐beneficial evaporation and reducing non‐returnable losses of irrigation water at existing and state‐of‐the‐art levels using technologies such as SCADA (Supervisory Control and Data Acquisition) and sensor technology. A wide range of land, water and crop‐related important parameters such as soil degradation, soil moisture, zero tillage, conservation agriculture, water demand and supply, future irrigation demand, biologically degradable mulching materials, cost‐effective design of drip irrigation, water quality and cultivation practices through simulation for evaluating environmental impact and adaptation capacity of farmers were addressed. The major outcomes inferred increasing water productivity through optimizing agricultural water use that led to higher crop yields. IoT (Internet of Things) technologies can provide accurate and dynamic information of water consumption and rainfall in real time and have the potential of adapting to climate change scenarios.

How Does Irrigation with Wastewater Affect the Physical Soil Properties and the Root Growth of Sugarcane under Subsurface Drip?

Studies on the development of the root system can provide important information about responses to different management strategies, such as the use of lower quality water, also evaluating the interaction between plants and the physical properties of the soil. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) supplies the water needs of sugarcane plants, increasing root growth and improving the physical properties of the soil. We evaluated the effects of subsurface dripping with TSE or surface reservoir water (SRW) on the root development of first ratoon cane (Saccharum officinarum L.) and the physical properties of dystrophic red latosol. Irrigation treatments were applied at 20 and 40 cm and soil properties were evaluated at soil depth layers of 0–20, 20–40, 40–60, and 60–80 cm. We verified that under irrigation with TSE and SRW, shallower soil layers present better porosity, soil aggregation, and aggregate stability conditions, parameters that improve the root system development and plant growth. On the other hand, deeper soil layers have lower macroporosity and higher total clay volume, indicating the possibility of compaction and greater limitations for sugarcane root growth. These results are important for understanding soil quality and provide significant information for agricultural management and for the implementation of sustainable soil conservation practices. This study shows the efficiency of TSE as an alternative water source for sugarcane crops.

Upstream land use with microbial downstream consequences: Iron and humic substances link to Legionella spp.

Intensified land use can disturb water quality, potentially increasing the abundance of bacterial pathogens, threatening public access to clean water. This threat involves both direct contamination of faecal bacteria as well as indirect factors, such as disturbed water chemistry and microbiota, which can lead to contamination. While direct contamination has been well described, the impact of indirect factors is less explored, despite the potential of severe downstream consequences on water supply. To assess direct and indirect downstream effects of buildings, farms, pastures and fields on potential water sources, we studied five Swedish lakes and their inflows. We analysed a total of 160 samples in a gradient of anthropogenic activity spanning four time points, including faecal and water-quality indicators. Through species distribution modelling, Random Forest and network analysis using 16S rRNA amplicon sequencing data, our findings highlight that land use indirectly impacts lakes via inflows. Land use impacted approximately one third of inflow microbiota taxa, in turn impacting ∼20–50 % of lake taxa. Indirect effects via inflows were also suggested by causal links between e.g. water colour and lake bacterial taxa, where this influenced the abundance of several freshwater bacteria, such as Polynucleobacter and Limnohabitans. However, it was not possible to identify direct effects on the lakes based on analysis of physiochemical- or microbial parameters. To avoid potential downstream consequences on water supply, it is thus important to consider possible indirect effects from upstream land use and inflows, even when no direct effects can be observed on lakes. Legionella (a genus containing bacterial pathogens) illustrated potential consequences, since the genus was particularly abundant in inflows and was shown to increase by the presence of pastures, fields, and farms. The approach presented here could be used to assess the suitability of lakes as alternative raw water sources or help to mitigate contaminations in important water catchments. Continued broad investigations of stressors on the microbial network can identify indirect effects, avoid enrichment of pathogens, and help secure water accessibility.

Assessment of Greywater Reuse in a University Building in a Hyper-Arid Region: Quantity, Quality, and Social Acceptance

Since Tacna is a hyper-arid region, greywater is a potential alternative water source. This study aimed to quantify and characterize greywater in a university building with 732 students, as well as assess their perception of greywater reuse. Water meters were used to calculate greywater quantity. To assess untreated greywater quality, physical–chemical and microbiological parameters were analyzed. Questionnaires were used to measure students’ acceptance regarding greywater reuse using a Likert scale. The greywater quantity recorded in this study was 426.85 L/d, which is less than reported in previous global research. The greywater quality showed relatively low values regarding physical–chemical parameters; however, microbial contamination was higher compared to international permissible limits for wastewater reuse. Furthermore, it was found that the generated greywater has little biodegradability (0.38). Students disclosed a lower acceptance of reusing untreated greywater compared to a 77.05% acceptance of reusing treated greywater for green areas. According to the greywater characterization, biological treatment will not be enough to ensure environmental protection and user health; thus, physical–chemical treatment will also be needed. The produced greywater quantities would generate a 12.67% water saving if used for toilet flushing. The greywater volume fulfills the whole demand for watering green areas or green roofs. Students would assent to the reuse of treated greywater.

Rainwater Harvesting System Analysis for Semi-Arid Climate: A Daily Linear Programming Model

Rainwater harvesting has proven to be an alternative water supply scheme for sustainable water management of regions with limited water resources. In this paper, a linear programming (LP) model with daily time steps, which minimizes a rooftop rainwater harvesting system (RWHS) cost, is developed and used to calculate the optimum RWH tank size. The developed LP model is applied to the semi-arid Northern Cyprus in the Eastern Mediterranean. The analysis is carried out for 33 sites which receive average annual rainfall ranging from 292 mm to 548 mm to evaluate the spatial effect of rainfall characteristic and the water cost on the financial feasibility and performance of the RWHS. At 29 out of 33 sites, RWHS investments are found to be financially feasible with discounted payback periods ranging from 12 to 28 years. The optimum RWH tank sizes are determined to be between 2 m3 and 6 m3 resulting in up to 20 % reliability with more than 50 m3 of average annual water savings per house. It is observed that the cost of water is a critical factor that affects the financial feasibility and water savings of a RWHS, especially in regions with limited rainfall. The comparison of the developed daily LP model with an LP model with monthly time steps demonstrates that the financial feasibility and the optimum tank size can only be assessed realistically when daily time steps are used. Finally, the sensitivity analysis shows that the discounted payback period is highly sensitive to the collector area.

Sustainable development goal 6 and the challenge of pipe-borne water connectivity in a growing tropical city: a case study

Water dams have been constructed in various regions across the globe to enhance access to potable water. Among these, the Aiba water reservoir, commissioned in 1957, was envisioned as a pivotal source of treated water for Iwo and its environs. Unfortunately, despite its inauguration, the primary objective of ensuring a sustainable and reliable water supply to the community remains unrealized to date. This research seeks to evaluate the accessibility of the study area to pipe-borne water (PBW) and discern the driving forces through the administration of structured questionnaire across 480 respondents out of which 458 were retrieved for analysis. The study utilized both descriptive and inferential statistics, employing Statistical Product for Service Solutions (SPSS) version 23. The respondent demographic revealed that 83.6% were female, and 18.4% claimed paying water tariffs while 76.2% relied on groundwater as their principal source of water. The data showed revealed diverse factors hindering PBW connectivity namely: Administrative bottlenecks (12%), while 57% cited the availability of alternative water sources as a reason for not connecting to PBW; 9% reported poor infrastructure for PBW, and 18% highlighted the unreliability of water supply from Aiba Water Works (AWW). Further analysis through Factor Analysis (FA) pinpointed three salient variables significantly influencing PBW accessibility. These are proximity to the main network (42.557%); cost of connectivity (22.275%); and availability of other sources (14.480%). These findings underscored the critical importance of expanding the PBW network, given the prevalent non-proximity of most residences to the main water pipes. Moreover, the research suggests that capacity building initiatives should be implemented to enhance the economic well-being of citizens, thereby fostering an improved quality of life for the inhabitants of the studied area. In conclusion, this study provides valuable insights into the complexities surrounding water accessibility and offers practical recommendations to realise SDG 6 by 2030.Graphical

Virus surrogates throughout a full-scale advanced water reuse system

Water reuse as an alternative water supply is increasing throughout the world due to water stress and scarcity; however, there are no standard practices for monitoring virus pathogens in such systems. This study aimed to identify suitable surrogates for virus fate, transport, and removal throughout a water reuse scheme. Various microbial targets (11 viruses, two phage, and three bacteria) were monitored using molecular and culture methods across all treatment stages in a wastewater reclamation facility and advanced water treatment facility. Criteria were established for identifying suitable surrogates, which included reliable detection, observable fate and transport, calculable log-reduction values (LRVs), correlations with other targets, and various morphological types. In total, five viruses (PMMoV, AiV, GII NoV, AdV, FRNA GII) met these stringent criteria and were suggested as potential virus surrogates. These surrogates enabled successful comparison of assigned versus actual LRVs throughout a water reuse scheme. Results suggest that virus pathogens are effectively removed throughout water reuse treatment and the suggested surrogates can be utilized for monitoring treatment performance and ensuring public health safety. This study provides a framework that water utilities across the world can reference for establishing virus monitoring practices.

Suitability of treated wastewater for irrigation and its impact on groundwater resources in arid coastal regions: Insights for water resources sustainability

Water scarcity threatens agriculture and food security in arid regions like Saudi Arabia. The nation produces significant quantities of municipal wastewater, which, with adequate treatment, could serve as an alternative water source for irrigation, thereby reducing reliance on fossil and non-renewable groundwater. This study assessed the appropriateness of using treated wastewater (TWW) for irrigation in a dry coastal agricultural region in Eastern Saudi Arabia and its impact on groundwater resources. Field investigations were conducted in Qatif to collect water samples and field measurements. A multi-criteria approach was applied to evaluate the TWW's suitability for irrigation, including complying with Saudi Standards, the Irrigation Water Quality Index (IWQI), the National Sanitation Foundation water quality index (NSFWQI), and the individual irrigation indices. In addition, the impact of TWW on groundwater was assessed through hydrogeological and isotope approaches. The results indicate that the use of TWW in the study area complied with the Saudi reuse guidelines except for nitrate, aluminum, and molybdenum. However, irrigation water quality indices classify TWW as having limitations that necessitate the use for salt-tolerant crops on permeable and well-drained soils. Stable isotopic analysis (δ2H, δ18O) revealed that long-term irrigation with TWW affected the shallow aquifer, while deep aquifers were minimally impacted due to the presence of aquitard layer. The application of TWW irrigation has successfully maintained groundwater sustainability in the study area, as evidenced by increased groundwater levels up to 2.3 m. Although TWW contributes to crop productivity, long term agricultural sustainability could be enhanced by improving effluent quality, regulating irrigation practices, implementing buffer zones, and monitoring shallow groundwater. An integrated approach that combines advanced wastewater treatment methods, community involvement, regulatory oversight, and targeted monitoring is recommended to be implemented.

Exploring Factors Shaping Farmer Behavior in Wastewater Utilization for Agricultural Practices: A Rapid Review

In recent years, circular economy strategies have gained attention in agriculture, particularly regarding the utilization of wastewater as an alternative water source. This study employs a rapid review methodology to examine farmers’ attitudes toward wastewater use in agriculture. By analyzing studies in literature published from 2000 to 2023, this review identifies the key factors influencing farmers’ adoption of wastewater irrigation. These findings are valuable for policymakers seeking to develop targeted policies that support and encourage the adoption of wastewater irrigation, thereby contributing to sustainable water resource management.

Persistent microbial communities in hyperarid subsurface habitats of the Atacama Desert: Insights from intracellular DNA analysis.

Desert environments constitute one of the largest and yet most fragile ecosystems on Earth. Under the absence of regular precipitation, microorganisms are the main ecological component mediating nutrient fluxes by using soil components, like minerals and salts, and atmospheric gases as a source for energy and water. While most of the previous studies on microbial ecology of desert environments have focused on surface environments, little is known about microbial life in deeper sediment layers. Our study is extending the limited knowledge about microbial communities within the deeper subsurface of the hyperarid core of the Atacama Desert. By employing intracellular DNA extraction and subsequent 16S rRNA sequencing of samples collected from a soil pit in the Yungay region of the Atacama Desert, we unveiled a potentially viable microbial subsurface community residing at depths down to 4.20 m. In the upper 80 cm of the playa sediments, microbial communities were dominated by Firmicutes taxa showing a depth-related decrease in biomass correlating with increasing amounts of soluble salts. High salt concentrations are possibly causing microbial colonization to cease in the lower part of the playa sediments between 80 and 200 cm depth. In the underlying alluvial fan deposits, microbial communities reemerge, possibly due to gypsum providing an alternative water source. The discovery of this deeper subsurface community is reshaping our understanding of desert soils, emphasizing the need to consider subsurface environments in future explorations of arid ecosystems.

Hydraulic characterization of Pwales aquifer in Malta Island preparatory for planning managed aquifer recharge (MAR) pilot plant

Whitin the aim to reduce the water demand by increasing water use efficiency and providing alternative water resources, and mainly to meet the demand of good quality irrigation water for agriculture, the Energy and Water Agency of Malta is planning to develop a Managed Aquifer Recharge pilot plant in Pwales Valley to improve the quantitative and qualitative status of the groundwater body. For this reason a detailed hydraulic characterization of the valley was carried out. Specifically, hydraulic properties of the rocks that constitute strata atop of the Pwales aquifer were determined by means of both laboratory measurements on samples and field test carried out in the studied area. The water retention and hydraulic conductivity functions, which relate the matric potential, ψ, and hydraulic conductivity, K, to the water content, θ, respectively, were measured using three experimental methods because each of them allows to obtain data points in a specific wet range. The water retention and hydraulic conductivity functions were measured on samples extracted from blocks of Upper Coralline Limestone formation, that hosts the aquifer, collected in three different quarries: Ghian Tuffieha, Mellieha and San Martin areas. The measured water retention and hydraulic conductivity data were fitted with LABROS SoilView Analysis software that allows to describe the functions and obtain the parameters which are crucial for modelling the water flow and transport processes in the critical zone. In addition, large ring infiltrometer test was carried out to determine the field saturated hydraulic conductivity, Kfs, and the average infiltration rate. Knowledge of the hydraulic characteristics of the Upper Coralline Limestone, completely missing in the scientific literature, allows developing a local groundwater-flow numerical model in order to better describe and understand how the water flows from the soil to the groundwater of the valley and visualize different environmental scenarios such as the potential effects of Managed Aquifer Recharge plant in the Pwales Coastal Groundwater Body.

Filtration of Grey Water Using Herbs in a Columnar Evaluation

Filtration of Grey Water Using Herbs in a Columnar Evaluation

MAAP code analysis for the in-vessel phase of Fukushima-Daiichi Nuclear Power Station Unit 1 and comparison of the results among Units 1 to 3

The accident progression of the in-vessel phase of Fukushima Daiichi Nuclear Power Station Unit 1 was analyzed using the MAAP code. Although there is a large uncertainty in the initial stage of accident progression behavior in Unit 1 with little measurement data, it is presumed to have similarities to that of Unit 3. As a result, in Unit 1, since there was almost no alternative water injection during the in-vessel phase, cooling of the debris transferred to the lower plenum was small. It was likely that a large molten pool of metals had formed, and that the steam supply to the high-temperature core materials was suppressed and metal oxidation was relatively small. The analysis results for Unit 1 were compared with those for Units 2 and 3, and differences between units such as the thermal conditions of the debris that relocated to the pedestal and the degree of metal oxidation were shown.