Water Production Research Articles

Improving water flux distribution and energy efficiency in reverse osmosis for high-recovery water reuse

Reverse osmosis (RO) is widely accepted for water reuse because it ensures clean water production. However, innovation in the RO process is necessary for water reuse to enhance its recovery while mitigating membrane fouling and reducing the increase in specific energy consumption (SEC). Therefore, circle sequence reverse osmosis (CSRO) adopts a staged design with flow reversal (FR) and a semi-batch design with a jet pump to enhance water flux distribution and energy efficiency for high-recovery water reuse. This study examined the water flux distribution and SEC of CSRO. When the distribution of water flux was compared, CSRO demonstrated a 7.7 % reduction in water flux in the front element compared to semi-batch reverse osmosis (SBRO). This reduction was attributed to advanced designs in SBRO, such as the two-stage design and an FR operation. The SEC of RO systems was also compared under high-recovery conditions. While both SBRO and CSRO achieved SEC reduction of 20–25 % or 9–18 % compared to two-stage RO depending on the feed salinity, CSRO was slightly more energy-efficient for high-saline feed. It is expected that CSRO has excellent potential for high-recovery water reuse, considering the improvement in water flux distribution and energy efficiency.

Evaluation of Efficiency of a Finned Corrugation Basin in Inclined Basin-Type Solar Stills in Regulating the Water Supply of the CaspiCement Plant

The need for fresh water production is especially high in hot dry climates without any sources of drinking water but with an abundance of sea and underground water. The solution is water desalination with efficient solar-powered water treatment plants. This article proposes a new modification of a basin made of thin-finned corrugation with 43°-angle-inclined sides, equal to the region’s latitude, which provide strong heating. The experiments were carried out in the hot climate of Aktau city (43°49′ N, 51°1′ E). The study’s outcomes can be useful for regions with drinking water scarcity. To define the level of the corrugated basin’s efficiency, two versions (SS-1, SS-2) of experiments were carried out on a two-slope distiller, complete with two basins. In SS-1, basin-2 was heated by air. By 15:00, basin-2 had heated up to 98.5 °C, and the acrylic cover above had heated up to 101.6 °C, which led to its “deformation”. By 12.00 p.m., the temperature differentials between the glass (40.7 °C), the air–water mixture (57.3 °C), and basin-1 (61.1 °C) were 16.6 °C and 20.4 °C. This resulted from the wind speed increasing up to 5.9 m/s. The large temperature differential contributed to the condensate yield increasing from 0.128 kg at 11 o’clock to 0.293 kg at 12 o’clock. The throughput capability of basin-1 per day was equal to 2.094 kg. Basin-2’s input to the performance in SS-1 was only the thermal effect. In SS-2, basin-2 was used as a regular basin. The plexiglass temperature was lower than the temperatures of the water and basin-2. The temperature differential between the glass and air–water mixture at 10:00 a.m. was 20 °C; at 12:00 p.m. it was 30.6 °C; and a value of 30.6 °C was recorded at 3:00 p.m. The thermal differential between the glass and the air-water mixture provided the highest condensate yield of 1.114 kg at 3.00 p.m. The condensate yield from the basins in SS-2 was 8.72 kg, including 3.5 kg from basin-1, which is 1.7 times more than from basin-1 in SS-1. The experimental results are consistent with the equations coming from the models of Clark J.A. and Dunkle R.V. Tcondensation ≠ Tevaporation is an irreversible process. When the basins are heated, the heat is consumed; when the glass cools down, the heat is given off. Heat losses are minimized due to the “gap” and positive energy is provided. The still’s throughput capability can be made larger by increasing the basin’s area, reducing the water layer thickness, and regulating the flowrate of the desalinated water.

Polymer foam fabricated via surfactant foaming method enables high-performance solar interfacial evaporation

Solar interfacial evaporation is considered as a low energy consumption, low cost, and sustainable desalination technology. However, its practical application is still limited by complex preparation processes and low photothermal conversion efficiency. In this work, we report novel polymer foam (Agar/SA/GO-Ag composite foam). It is prepared by simple and convenient surfactant foaming and in-situ reduction methods and consists of graphene oxide (GO) and silver nanoparticles (Ag NPs) (photothermal conversion medium) as well as Agar and sodium alginate (SA) (basic skeleton) for use in solar-powered interfacial evaporation systems. The prepared foam has excellent wettability and achieves 96.7% light absorption in the full spectrum range. A high evaporation rate of 2.55 kg·m−2·h−1 and a high evaporation efficiency of 97.3% were obtained under the conditions of simulated sunlight (1.0 kW·m−2). Moreover, the foam exhibits good reusability in a 10-cycle test without obvious attenuation in evaporation performance. Foam is used for seawater desalination and wastewater purification, and the treated water meets the water quality standards of the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA). In short, this work demonstrates a sustainable strategy for low-cost and efficient solar-powered clean water production.

Distribution of antibiotic resistance genes and antibiotic residues in drinking water production facilities: Links to bacterial community.

There is a rapid spread of antibiotic resistance in the environment. However, the impact of antibiotic resistance in drinking water is relatively underexplored. Thus, this study aimed to quantify antibiotic resistance genes (ARGs) and antibiotic residues in two drinking water production facilities (NW-E and NW-C) in North West Province, South Africa and link these parameters to bacterial communities. Physicochemical and ARG levels were determined using standard procedures. Residues (antibiotics and fluconazole) and ARGs were quantified using ultra-high performance liquid chromatography (UHPLC) chemical analysis and real-time PCR, respectively. Bacterial community compositions were determined by high-throughput 16S rRNA sequencing. Data were analysed using redundancy analysis and pairwise correlation. Although some physicochemical levels were higher in treated than in raw water, drinking water in NW-E and NW-C was safe for human consumption using the South African Water Quality Guideline (SAWQG). ARGs were detected in raw and treated water. In NW-E, the concentrations of ARGs (sul1, intl1, EBC, FOX, ACC and DHA) were higher in treated water than in raw water. Regarding antimicrobial agents, antibiotic and fluconazole concentrations were higher in raw than in treated water. However, in NW-C, trimethoprim concentrations were higher in raw than in treated water. Redundancy analysis showed that bacterial communities were not significantly correlated (Monte Carlo simulations, p-value >0.05) with environmental factors. However, pairwise correlation showed significant differences (p-value <0.05) for Armatimonas, CL500-29 marine group, Clade III, Dickeya and Zymomonas genera with environmental factors. The presence of ARGs and antibiotic residues in the current study indicated that antibiotic resistance is not only a clinical phenomenon but also in environmental settings, particularly in drinking water niches. Consumption of NW-E and NW-C treated water may facilitate the spread of antibiotic resistance among consumers. Thus, regulating and monitoring ARGs and antibiotic residues in drinking water production facilities should be regarded as paramount.

Synergetic integration of machining metal scrap for enhanced evaporation in solar stills: A sustainable novel solution for potable water production

The global water crisis necessitates innovative solutions for sustainable potable water production. Solar stills represent a promising technology for harnessing solar energy to meet this demand. However, solar stills often face limitations regarding yield and cost-effectiveness. This research addresses the pressing need to augment the performance of solar stills by introducing amendments such as utilizing black-coated metal scrap as a photothermal absorber in the absorber basin. These modifications aim to boost the absorption of solar radiation, thereby increasing potable water yield and improving the system’s economic viability. The study explores the utilization of black-coated metal scrap as a photothermal absorber to modify the absorber basin. Experimental results demonstrate a significant improvement in potable water yield, with a 129.85 % increase on day 1 and 127.21 % on day 2, reaching 3080 mL/m2 and 3090 mL/m2, respectively. Compared to conventional solar stills, the newly developed double slope solar still with an absorber basin featuring metal scrap exhibits a remarkable economic advantage, with a payback period (PBP) of 5.4 months, as opposed to 9.45 months for the traditional system. Additionally, the cost per liter (CPL) of potable water generated by the innovative system is 75.53 % lower than that of the conventional solar still system.

Dual-mode harvest solar energy for photothermal Cu2-xSe biomineralization and seawater desalination by biotic-abiotic hybrid

Biotic-abiotic hybrid photocatalytic system is an innovative strategy to capture solar energy. Diversifying solar energy conversion products and balancing photoelectron generation and transduction are critical to unravel the potential of hybrid photocatalysis. Here, we harvest solar energy in a dual mode for Cu2-xSe nanoparticles biomineralization and seawater desalination by integrating the merits of Shewanella oneidensis MR-1 and biogenic nanoparticles. Photoelectrons generated by extracellular Se0 nanoparticles power Cu2-xSe synthesis through two pathways that either cross the outer membrane to activate periplasmic Cu(II) reduction or are directly delivered into the extracellular space for Cu(I) evolution. Meanwhile, photoelectrons drive periplasmic Cu(II) reduction by reversing MtrABC complexes in S. oneidensis. Moreover, the unique photothermal feature of the as-prepared Cu2-xSe nanoparticles, the natural hydrophilicity, and the linking properties of bacterium offer a convenient way to tailor photothermal membranes for solar water production. This study provides a paradigm for balancing the source and sink of photoelectrons and diversifying solar energy conversion products in biotic-abiotic hybrid platforms.

Oilfield Brine as a Source of Water and Valuable Raw Materials—Proof of Concept on a Laboratory Scale

Oilfield brine is the largest byproduct stream generated during the extraction of crude oil and natural gas and may be considered a resource for the production of potable water and valuable raw materials. The high salinity of such waters limits the application of typical membrane-based techniques. In most oilfields, waste cold energy from the process of the low-temperature separation of natural gas is available and may be used as a source of cold for the freezing desalination (FD) of brine. As a result of the FD process, two streams are obtained: partially desalinated water and concentrated brine. The partially desalinated water may be suitable for non-potable applications or as a feed for membrane desalination. The concentrated brine from the FD could be used as a feed for the recovery of selected chemicals. This paper focuses on verifying the above-described concept of the freezing desalination of oilfield brine on a laboratory scale. The brine from a Polish oilfield located in the Carpathian Foredeep was used as a feed. Four freezing–thawing stages were applied to obtain low-salinity water, which subsequently was treated by reverse osmosis. The obtained permeate meets the criteria recommended for irrigation and livestock watering. The concentrated brine enriched with iodine (48 mg/L) and lithium (14 mg/L) was subjected to recovery tests. Ion exchange resin Diaion NSA100 allowed us to recover 58% of iodine. Lithium recovery using Mn- and Ti-based sorbents varies from 52 to 93%.

Three-Dimensional evaporator for simultaneous VOC removal and clean water production

Interfacial solar steam generation (ISSG) is a promising and sustainable technology to product clean water, but most of current evaporators suffer the failure to remove volatile organic compounds (VOCs) from condensate water and prevent the production of concentrated water. Herein, we proposed a three-dimensional bi-functional evaporator integrating ISSG with heterogeneous Fenton technology, simultaneously to remove various organics from both condensate water and feed water. The evaporator (rGO-FeOOH@MF) was prepared by loading reduced graphene oxide (rGO) and hydroxy-ferric oxide (FeOOH) nanoparticles onto melamine foam (MF). The results manifested that rGO-FeOOH@MF exhibited an outstanding evaporation flux of 2.20 kg m-2h-1 under one sun irradiation. More importantly, the removal rate of VOC in condensate water reached 92.56 ± 0.11 % due to synergetic Fenton reaction, which was 4 times (23.1 %) than that of sole ISSG. Meanwhile, the VOC removal rate remained ∼92 % even after 7 times cycle tests, demonstrating the evaporator with a good stability. The rGO-FeOOH@MF was also proved to be able to remove VOCs from high saline wastewater (96.43 %). Besides, for the purification of concentrated water, the evaporator achieved ∼100 % removal rates for non-volatile organic compounds. To sum up, the prepared rGO-FeOOH@MF evaporator opens a new way to simultaneous removal of non-volatile and volatile contaminants in wastewater treatment field.

Benchmarking study of coal seam gas production from Brownfield to Greenfield wells in the Surat basin, Australia

Benchmarking coal seam gas (CSG) production from Brownfield to Greenfield is an important step for assessing the development plan for Greenfield. However, the observed Brownfield production data is impacted by many factors besides reservoir properties, e.g., well spacing, well efficiency factor (WEFAC), surface pipeline network. This paper presents a case study in the Surat Basin to discuss how to benchmark CSG production from Brownfield to Greenfield. The selected Brownfield study area includes 143 wells and the Greenfield 450 proposed wells. Various tools for static modelling, decline curve analysis, and dynamic modelling were used in this study. Results show that the peak gas rate decreases quickly and the time to peak gas rate increases quickly when the WEFAC is less than 0.65. The peak gas rate is reached when the cumulative water production is between 39% and 46% of water-in-place for the selected box model. After introducing the wells’ online time ratio or WEFAC from the daily production data and the ratio of the observed cumulative water production to the expected cumulative water production, gas production rates can be predicted based on the modified Morse potential energy equation. Artificial neural networks (ANN) can be used to estimate the peak gas rate, the time to peak gas rate and the decline rate based on the reservoir properties; while the ramp-up rate can be calculated from the time to peak gas rate.

A fully coupled compositional wellbore/reservoir model for predicting liquid loading in vertical and inclined gas wells

Liquid loading presents a formidable challenge for mature gas wells, often resulting in substantial economic losses. Traditional research has predominantly centered on the analysis of gas-liquid two-phase flow within the wellbore to predict critical gas velocity or rate, aiding in identifying the onset of liquid loading. This study introduces a fully coupled compositional wellbore-reservoir simulator designed to detect liquid loading in both vertical and inclined gas wells. Leveraging the drift-flux model to evaluate flow pattern transitions, this simulator employs pressure or rate constraints at the wellhead as boundary conditions. It comprehensively captures the flow dynamics in both the wellbore and reservoir, unveiling significant changes in gas production rate, water production rate, gas velocity, flow regime, and the reserved position of the liquid film under liquid-loaded conditions. Moreover, the accumulation of liquid at the bottom hole leads to increased reservoir pressure and gas saturation near the wellbore. The simulator predicts a typical unstable production period, emphasizing its crucial role in implementing effective strategies to mitigate liquid loading. This paper investigates the capability of the coupled wellbore-reservoir model to characterize transient liquid loading phenomena from a systematic perspective. The proposed model can function as a real-time tool for predicting the status of liquid loading in gas wells.

Effect of ten different physical parameters on solar still productivity: Theoretical modeling

AbstractSolar distillation using solar stills is widely recognized as a clean and cost‐effective method for producing freshwater. However, due to its straightforward design, solar still performance is greatly influenced by various physical characteristics. Many researches have evaluated solar still parameters, while only a few articles have concerned physical ones. Therefore, this article aims to investigate the effect of different physical parameters on solar still productivity through thermal modeling. The theoretical results were validated with those of a previous experimental model, showing a good agreement with each other. The results reveal that daily productivity experiences significant improvement with an increase in plate emissivity or insulation thickness. Conversely, an increase in water mass, glass absorptivity or insulation thermal conductivity leads to a substantial reduction in productivity. Notably, water transmissivity and plate absorptivity do not affect productivity. Modest enhancements in productivity can be achieved by reducing the effective emissivity between water and glass. While the initial temperature of water has a minor impact on productivity at low water mass, it exhibits a substantial improvement effect at high water mass. These results can be a good guidance for the designers and manufacturers to develop more efficient designs that maximize the production of clean water.

Analysis of the effectiveness of combining inorganic coagulants with chitosan and bentonite in the treatment of raw water

The production of drinking water often leads to the creation of a high residual concentration of aluminum when mineral salts are used. This concentration must be carefully monitored and controlled. A study was carried out at a drinking water production facility situated in Al Hoceima, Northern Morocco.Throughout this investigation, the treated water from the plant underwent comparative testing, evaluating the effectiveness of chitosan as a flocculant and bentonite as an adjuvant with inorganic coagulants (aluminum sulfate and ferric chloride). The objective was to reduce the residual aluminum concentration in the water after treatment while minimizing the use of inorganic coagulant. Coagulation-flocculation tests, employing a jar test, optimized coagulant dosage while enhancing turbidity and oxidability removal rates.The coagulation-flocculation tests showed that the combination of aluminum sulfate with 10 mg/L of chitosan and 140 mg/L of bentonite, proved to be significantly more effective. Compared to traditional treatment methods using aluminum sulfate alone, this combination reduced the residual aluminum concentration by 38.88%. The optimal parameters were as follows: aluminum sulfate dose of 10 mg/L, a pH of 7.83, an aluminum concentration of <0.07 mg/L, and a turbidity removal efficiency reaching 95.94% and oxidability removal of 42.70%.

Dual-Interface Solar Evaporator with Highly-Efficient Thermal Regulation via Suspended Multilayer Design.

Facing the increasing global shortage of freshwater resources, this study presents a suspended multilayer evaporator (SMLE), designed to tackle the principal issues plaguing current solar-driven interfacial evaporation technologies, specifically, substantial thermal losses and limited water production. This approach, through the implementation of a multilayer structural design, enables superior thermal regulation throughout the evaporation process. This evaporator consists of a radiation damping layer, a photothermal conversion layer, and a bottom layer that leverages radiation, wherein the bottom layer exhibits a notable infrared emissivity. The distinctive feature of the design effectively reduces radiative heat loss and facilitates dual-interface evaporation by heating the water surface through mid-infrared radiation. The refined design leads to a notable evaporation rate of 2.83kg m-2 h-1. Numerical simulations and practical performance evaluations validate the effectiveness of the multilayer evaporator in actual use scenarios. This energy-recycling and dual-interface evaporation multilayered approach propels the design of high-efficiency solar-driven interfacial evaporators forward, presenting new insights into developing effective water-energy transformation systems.

Predictive simulation of the water-energy-food nexus for the City of Cape Town

The City of Cape Town (CoCT), South Africa faced a critical situation between 2015 and 2018 in which the municipal water supply was almost completely exhausted. This situation, commonly referred to as Day Zero in South Africa emanated from a decline in rainfall, resulting in one of the most severe droughts in history. The crisis was also aggravated by rapid population growth and urbanization. CoCT was on the verge of becoming the first city in the past decade to experience a complete cessation of water supply for urban and agricultural purposes. In addition to the effects of low rainfall and population surge, urban energy consumption and increased food demand impacted directly the available water resources. To evaluate the interlinkages between water utilization, water production, energy supply and demand, and food production and demand, this study employed a system dynamics modeling (SDM) approach. The model was developed as a stock and flow diagram utilizing Stella Architect and encompassed five interconnected nodes: water, energy, food, land, and population. The findings revealed that by the end of the 20-year modeling period, the volume of accessible and stored water in all the major dams will be approximately 459 million cubic meters, with residential use accounting for about 85 % of urban water use and agriculture accounting for approximately30.37 % of total water demand. The model illustrates the impacts of precipitation rate, runoff, and evaporation on variables such as land-use change and population dynamics. It is anticipated that the outcomes of this study will serve as valuable inputs for decision-making processes, not only within the CoCT as it aims to mitigate or prevent the recurrence of Day Zero, but also for other cities facing similar challenges.

Techno-Economic Modelling of Bioclarified Water Recovery from Petroleum Wastewater Using ASPEN Software and Box-Behnken Design

Application and efficiency of bio-coagulants for petroleum wastewater biocoagulation, flocculation, and sedimentation (bioclarification) are still confined to laboratory proof-of-concept practice. The scale-up process design of bio-clarified water recovery from petroleum wastewater has been a major research lacuna. This paper presents ASPEN Base Case Scale-Up Simulation (BCSUS) using optimum laboratory experimental data and techno-economic predictive models for bioclarified water production from petroleum wastewater. The BCSUS, process design, and economics were performed in the ASPEN Batch Process Developer V10 environment. Predictive models for predicting and optimizing techno-economic parameters such as return on investment (ROI), payback time (PBT), and production rate (PR) were achieved in RSM via the Box-Behnken Design (BBD) technique of Design Expert V13. The base case techno-economic model gave batch size, annual production cost, Total Capital Investment (TCI), PBT, and ROI of 406kg, $9195, $631484, 5.18 years, and 17%, respectively, at the selling price of 2 $0.225. The regression models gave R values of 0.9984 for ROI and 0.9920 for PBT, while the production rate was 0.8867. This study shows that a petroleum wastewater bioclarification scale-up design is feasible.

Design and performance evaluation of Front glass-covered photovoltaics-thermal hybrid system for enhanced electrical output and hot water production

Proof of concept is established for the thermal management of PV modules for the simultaneous benefit of electrical and thermal efficiency. It was achieved by designing the controlled open-loop water-based hybrid PV-T system and demonstrated for thermal management of 150W photovoltaic panel at natural solar conditions. In this integrated front glass-covered PV-T hybrid (IFG-PV-T) system, the PV panel is clipped between the front glass and rear aluminium collector without causing any permanent changes in the existing panel. The flow of water from the source tank is controlled by automated solenoid valve assembly coupled with thermocouples. The solenoid operational temperature is fixed at 40°C to controlled the PV surface temperature at an optimum range to mitigate the adverse effect on voltage and current output. The water layer thickness in the front glass box is optimized to filter the maximum infrared radiations and the collector's toughened glass feature allows the maximum light transmittance with super safety. The performance of the IFG-PV-T system has been evaluated in terms of variation in open circuit voltage, short circuit current, maximum power output, electric and thermal efficiency under the natural solar insolation for a week. Experimental investigations revealed that the open-circuit voltage is increased by ∼16.1 % with IFG-PV-T as compared to conventional PV panel. The increment can be attributed to the synergy of the front glass collector and solenoid valve operation at 40oC that regulates PV surface temperature and boost the current output. These factors have ameliorated the electrical efficiency of IFG-PV-T compared to conventional PV panel. The average thermal efficiency was 39.4 ​% wherein the IFG-PV-T system provides ∼100 ​L of hot water (38–41 ​°C) per day. The present controlled loop operation system and collector configuration have proven their significance for electrical power increment and concomitantly able to deliver moderate hot water which can be useful for any household or commercial application.

At-sea distribution of marine predators around South Georgia during austral winter, with implications for fisheries management

The sub-Antarctic island of South Georgia is surrounded by highly productive waters, supporting dense aggregations of Antarctic krill (Euphausia superba), a vital food source for globally important seabird and marine mammal populations. These waters also support a commercial fishery for Antarctic krill. Regular monitoring of key krill predator species is undertaken at South Georgia to detect any changes in the ecosystem in response to harvesting activities. This monitoring provides essential data but is focused on land-breeding animals during the austral summer, whilst the krill fishery operates exclusively in winter. Here, we report the results of at-sea surveys to investigate abundance and distribution of krill-dependent predators from winter 2010 and 2011, which represented a “poor” krill year and “good” krill year, respectively. Correspondingly in 2011 higher numbers of krill predators were observed; notably Antarctic fur seals (Arctocephalus gazella) across the northern shelf. Spatial overlap between fur seals and the krill fishery occurred mainly within the krill fishery hotspot to the north-east, highlighting the potential for locally high levels of competition. Cetaceans were observed during both survey years, but in low numbers compared to recent studies. Gentoo penguins (Pygoscelis papua) were the most frequently observed penguin species, showing an inshore distribution and almost no overlap with the krill fishery. Diving-petrels (Pelecanoides spp.) were the most abundant flying seabirds, observed across all transects, with particularly high densities to the south in early winter 2010. In conclusion, this survey provides valuable baseline data on the distribution of South Georgia’s predators during the winter months.

Impact of formation conditions and well configurations on underground hydrogen storage

Converting surplus renewable energy into hydrogen is considered an efficient technique to balance renewable energy generation and demand, which necessitates large-scale underground hydrogen storage (UHS) in geological formations. While the H2 trapping mechanisms and fluid flow behavior have been rigorously reported in past studies, the performance of UHS is strongly influenced by the formation conditions and well configurations, which have not been explored thoroughly. To this end, this study investigated the sensitivity of UHS efficiency to variations in formation temperature, brine salinity, well placement, and well perforations. For each scenario, key aspects such as plume migration dynamics, residual trapping, dissolution trapping, structural trapping, H2 recovery factor, and water production were thoroughly analyzed. The results indicate that factors such as formation temperature, brine salinity, and well perforations have a negligible impact on the shape of the overall H2 plume. However, these significantly influence local H2 saturations. Formations with higher temperatures, central dome well placement, and production wells in the top layers exhibit a higher H2 recovery factor (as high as 69.93 %), whereas salinity plays a minor role in H2 trapping and withdrawal (maximum change observed is ∼1.7 % and ∼1.4 % for trapping and withdrawal respectively with a 20 wt % increase in salinity). In addition, brine production is strongly influenced by the formation conditions and well configurations (e.g., ∼3965 m3 brine produced under at 343 K and ∼26,000 m3 for non-central well placement), due to variations in H2/brine properties, such as density and viscosity, and the extent of H2 accumulation.

Intelligent fertigation improves tomato yield and quality and water and nutrient use efficiency in solar greenhouse production

Intelligent fertigation is a sustainable solution for optimising water and fertiliser input, thus minimising environmental pollution in vegetable cultivation facilities and reducing labour costs in agricultural practices. It is important to optimise irrigation scheduling parameters to specific crops to ensure water and nutrient use efficiency. A field experiment was conducted in Shouguang, Shandong Province, to investigate the effects of irrigation scheduling with different treatments (farmer drip irrigation FI, intelligent irrigation II1, and intelligent irrigation II2) on tomato growth, irrigation water and nutrient use efficiency over two growth seasons. Intelligent irrigation II1 and II2 utilised FDR sensors to control the moisture range within 80–95% and 80–85% field capacity (FC) for automatic irrigation scheduling, respectively. Intelligent irrigation (II1 and II2 treatments) reduced irrigation rate by 24.3–63.8% in comparison with FI treatment, significantly increasing total dry matter accumulation, nutrient uptake, yield and fruit quality of tomato. II2 treatment further reduced the irrigation rate by 31.6–32.3% compared to II1 treatment, with no significant difference in tomato yield and quality. Root dry matter, root-shoot ratio, 0–2 mm diameter root length and root surface area, 0–1.5 mm diameter root tips, and >3.5 mm diameter root volume were significantly increased under intelligent irrigation treatments. Positive correlations between irrigation water productivity; nitrogen, phosphorus, and potassium use efficiency; and the indices of length, surface area, tips, and volume of roots were highly significant. Intelligent fertigation system (IFS) maintained soil moisture within a suitable range through high-frequency irrigation scheduling, promoted the growth of 0–2 mm diameter roots, which were responsible for absorbing, acquiring, and transporting water and nutrients in the soil, and reduced water loss and nutrient leakage. Taken together, the intelligent fertigation system presented herein is an effective fertigation strategy to improve irrigation water and nutrient use efficiency.

Characteristics and Sources of CBM Well-Produced Water in the Shouyang Block, China

The Shouyang Block was selected as the research subject. Comprehensive analysis was conducted using coalbed methane (CBM) well production data, geochemical test data on water produced from the coalbed methane well, and fundamental geological information. The findings reveal the water dynamics in the Shouyang Block are characterized by weak groundwater runoff or retention in most areas. The groundwater head height exhibits a gradual decrease from the north to south, which is closely associated with the monoclinic structure of the Shouyang Block. Overall, water production is relatively high. As the average water production increases, the average gas production gradually decreases. A concentration of high water production wells is observed in the northern part of the Shouyang Block, which gradually increases towards the southeast direction. A comprehensive analysis was conducted on the factors influencing water production, including total water content of coal seams, coal seam porosity, groundwater stability index, groundwater sealing coefficient, D value of the fracture fractal dimension, fault fractal dimension, and sand–mud ratio. The correlation degree was calculated and ranked in order of magnitude through grey correlation analysis. The order of factors that influence water production, from strongest to weakest, is as follows: sand–mud ratio &gt; porosity &gt; fractal dimension of fault &gt; fracture fractal dimension D value &gt; groundwater sealing coefficient &gt; groundwater stability index &gt; total water content of coal seams. The dissolution amounts of carbonate and sulfate are both small, and the water source may mainly come from the sandstone aquifer. Attention should be paid to the distribution and lithological combination of sandstone aquifers in coal-bearing strata in the future exploration and development process of the Shouyang Block. This will help to avoid the potential influence of fault structures and enable the identification of favorable areas for low water and high gas production.