Alkalinity Levels Research Articles

Physicochemical Analysis of Groundwater Quality of Some Selected Villages of Tosham Region

To evaluate the groundwater quality of the Tosham area of the Bhiwani district in the Indian state of Haryana, a comprehensive study has been conducted. Eleven physicochemical parameters, including pH, electrical conductivity, total alkalinity, total hardness, total dissolved solids, calcium, magnesium, fluoride, chloride, nitrate, and sulphate, were analysed on 600 groundwater samples that were collected over the course of different seasons from ten selected villages. Various physicochemical parameters, including pH, total alkalinity, total hardness, total dissolved solids, calcium, magnesium, fluoride, chloride, nitrate, and sulphate, are found to be higher than the desirable limits suggested by the ICMR, according to analytical data of some groundwater samples from the study areas. Groundwater quality parameters show that some sampling stations groundwater samples are highly unfit for human consumption due to high levels of total alkalinity, total hardness, total dissolved solids, calcium, magnesium, fluoride, and chloride. As a result, appropriate recommendations for improving the groundwater quality have been made

A four-season exploration of surface water quality and trophic status in the highly dynamic waters of Karun-4 Dam Lake, SW Iran

This study explores seasonal fluctuations in water quality and phytoplankton communities within Karun-4 Dam Lake, the largest double-arch dam in the Middle East situated in Iran. Employing a systematic approach, 26 sampling stations were strategically selected to collect surface water samples at a depth of 50 cm during the midpoints of each season throughout 2019. Significant seasonal variations in water quality parameters and phytoplankton composition were observed. Predominant species included Chrysophyceae (38%) and Bacillariophyceae (32%), indicative of nutrient-rich conditions, particularly during spring and summer, as evidenced by the eutrophic state (Carlson Trophic State Index: 59.43 and 53.96, respectively). Summer exhibited the highest diversity (Shannon–Wiener Index = 2.27) and lowest evenness (Pielou’s Evenness Index = 0.21). PCA and CCA analyses revealed season-specific preferences for nutrients and ions among phytoplankton species. Water temperature emerged as a crucial factor in spring and summer, while environments with elevated bicarbonate and alkalinity levels were less favorable during winter and fall. This study provides essential insights into Karun-4 Lake's dynamic ecological conditions, underscoring the necessity for ongoing monitoring to discern long-term trends and anthropogenic impacts for effective ecosystem management.

Ecological patterns of phytoplankton across lake cross-section: insights into co-evolution of physicochemical conditions in Chashma Lake on Indus River.

Physicochemical properties of water influence planktonic diversity and distribution, which is essential in obtaining basic knowledge of aquatic biodiversity. Thus current study aims to investigate the spatiotemporal diversity, abundance ratio, and distribution of phytoplankton species and their association with water quality parameters of Chashma Lake, Pakistan. During the study period from 2018 to 2019, we measured 13 physicochemical parameters across three selected sampling sites (S1, S2, and S3) in Chashma Lake, revealing both spatial and temporal variability. Dissolved oxygen (DO) was higher in S3, while S1 exhibited higher alkalinity levels, carbon dioxide, phosphorus, and chloride levels. The study identified 77 phytoplankton species grouped into five taxonomic categories, with Cyanobacteria dominating (39.90%), followed by Chlorophyta (33.4%) and Bacillariophyta (24.88%). Euglenozoa and Ochrophyta were less abundant (1.3% and 0.41%, respectively). Spatial variations in phytoplankton distribution were noted, with Chlorophyta being more abundant at S2, Bacillariophyta and Cyanobacteria at S1, and Euglenozoa dominating at S3. Canonical Correspondence Analysis (CCA) revealed the influence of various physicochemical parameters on phytoplankton distribution. This comprehensive study provides valuable insights for the ecological assessment and monitoring of water bodies. It is recommended that continuous monitoring is required to capture long-term trends, further explore the specific environmental drivers impacting phytoplankton dynamics, and consider management strategies for maintaining water quality and biodiversity in Chashma Lake.

Groundwater Hardness and Alkalinity As Risk Factors for Kidney Stone Disease in Alwar, India: An Ecological Study.

Rajasthan is a semi-arid state in India where people still use groundwater for drinking purposes. However, the quality of groundwater as compared to standards have not been studied in any details. This ecological study was done to study the groundwater quality parameters in the stone-belt states, compare the quality of groundwater in Alwar with the rest of Rajasthan, and study the morbidity profile of surgical in-patients in the same district, with special emphasis on kidney stone disease (KSDs). The morbidity profile of patients coming to the surgery department of a tertiary teaching hospital between January 2002 and June 2023 was obtained from the medical records department, and water quality data was obtained from the publicly available Water Resources Information System (WRIS) groundwater dataset for the year 2023. The dataset provided detailed information on the chemical parameters of water samples throughout the country that were evaluated to estimate the quality of groundwater. It was found that the groundwater in Alwar is non-potable due to the presence of iron, alkalinity, magnesium, and total dissolved solids (TDS). Iron was estimated to be much higher than the acceptable limit of the Bureau of Indian Standards (BIS) drinking-water quality guidelines (0.3 mg/L). Similarly, most of the chemical parameters in the groundwaters of Rajasthan significantly exceeded the national average. The median electrical conductivity, fluoride, magnesium, sodium, hardness, alkalinity, and turbidity were found to be 1680 μS/cm, 1.05 parts per million (PPM), 41 PPM, 233 PPM, 330 PPM, 310 PPM, 988 PPM, respectively, which are above the WHO recommendations for drinking water guidelines. The levels of iron and total alkalinity were significantly higher in the study district as compared to the rest of the state. Also, magnesium hardness and TDS levels were very high in the groundwater of the entire state of Rajasthan, making the population vulnerable to KSDs in the long run.

Assessment of biogas production potentials of palm oil mill effluent and cow dung substrates in anaerobic digester

The biogas production potentials of palm oil mill effluent (POME) and cow manure (CM) substrates were evaluated using anaerobic digester. The first two digesters (D1 and D2) were charged with POME and CM for mono-digestion respectively. However, co-substrates digestion was done in digesters D3 (60/40 % POME-CM), D4 (70/30 % POME-CM), and D5 (80/20 % POME-CM) and all the digestion lasted for 21 days. The biogas yield of the digesters and performance of the digestions were measured by the analysis of moisture content, pH, total suspended solids (TSS), total solids (TS), volatile solid (VS), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total organic carbon (TOC) using standard analytical methods. The results showed that D4 (70/30 % POME-CM) has the highest biogas yield (1875±0.11 mL) while D2 (100 % CM) gave the lowest biogas yield (443±0.15 mL). The BOD of D3, D4 and D5 were not detected. The concentrations of COD, TS, TSS and TOC showed a significant (p<0.05) decrease in D1, D3, D4 and D5 compared to D2. While D2, D3, D4 and D5 showed a significant (p<0.05) decrease in moisture content compared to D1. However, D1, D3, D4 and D5 showed increasing level of alkalinity compared to acidic level of D2. Therefore, this study suggests that co-substrates anaerobic digestion of palm oil mill effluent and CM are suitable for biogas production.

Silk Fibroin-Laponite Porous Microspheres as Cell Microcarriers for Osteogenic Differentiation.

Silk fibroin (SF) has garnered significant attention as a natural polymer for fabricating porous scaffolds in various engineering applications. However, the limited osteoinductive property of SF has hindered its efficacy in bone repair applications. In this study, we constructed an SF-based injectable porous microcarrier that is doped with laponite (LAP), containing magnesium ions (Mg2+). The influence of freezing temperatures and concentrations of SF and LAP on the structural parameters of SF-LAP microcarriers was investigated. The SF-LAP microcarrier exhibited a porosity of 76.7 ± 1.2% and a controlled pore size of 24.6 ± 4.0 μm. At the 6 weeks of in vitro degradation test, a mild alkaline level in culture medium containing SF-LAP microcarriers was detected. The release of Mg2+ from the SF-LAP microcarrier was maintained at a concentration within the range of 1.2-2.3 mM during the 6 weeks. The seeded human adipose-derived stem cells in the SF-LAP microcarrier demonstrated a significant enhancement in osteogenic differentiation compared with cells seeded in the pure SF microcarrier, as evidenced by quantitative alkaline phosphatase activity and the expression of osteogenic marker genes. These findings underscore the potential of the SF-LAP microcarrier as an ideal cell carrier in the treatment of bone defects.

Optimization of phosphorus wet acid extraction from sewage sludge ashes: Detailed process insight via multi-variate statistical techniques

To tackle the issue of phosphorus (P) supply, Sewage Sludge Ash (SSA) is a promising secondary source. The goal of this research is the optimization of the wet P extraction process in the view of providing valuable insights for the process scale-up. While most of the studies relied on the “one-variable-changed-at-a-time” approach, this work applied a statistical optimization model based on the Design of Experiments technique for investigating the influence of most relevant operating conditions of extraction process on Phosphorus Extraction Efficiency (PEE) with two types of SSA characterized by different levels of alkalinity. Experimental results highlighted the importance of ash characteristics, making some SSA not suitable for cost-effective phosphorus recovery due to the high acid dosage required in extraction process. Type of acid and contact time become significant factors only for Ca-rich ashes, especially when using H2SO4 as extracting agent. Optimal operating conditions (CH2SO4 = 1.3 N, L/S = 20, t = 2 h and CHCl = 2.0 N, L/S = 10, t = 2 h for Ash#1 and CH2SO4/HCl = 0.8 N, L/S = 10 for Ash#2) resulting in high PEE (80–94%) were identified for extraction performed with H2SO4 and HCl as a function of ash characteristics.

L-cysteine-coated magnetite nanoparticles as a platform for enzymes immobilization: Amplifying biocatalytic activity of Candida antarctica Lipase A

This study presents the synthesis of magnetite nanoparticles coated with L-cysteine (Fe3O4@LC) and their subsequent utilization as a support matrix for the immobilization of Candida antarctica Lipase A (CALA). The immobilization process involved physical interactions and covalent bonding mediated by glutaraldehyde. Comprehensive characterization was conducted using techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM), providing compelling evidence of a successful synthesis. Under optimized conditions, employing 1 mg of protein per gram of support, pH 7 in a 25 mM phosphate buffer, and a 5 h reaction at 25 °C, immobilization on glutaraldehyde-activated support achieved an impressive yield of 85.0 % ± 2.6, accompanied by a specific activity of 212.5 ± 1.3 U/g, outperforming the physical adsorption approach. Remarkably, the immobilized enzyme exhibited higher activity than the free enzyme at alkaline and acidic pH levels. Furthermore, thermal and pH inactivation studies revealed that the biocatalyst's half-life exceeded that of free CALA by more than 8 times at pH 10. These results underscore the potential of the Fe3O4@LC-GLU-CALA system as a robust biocatalytic matrix with promising applications in biodiesel production, ester synthesis, and pharmaceutical manufacturing.

Post-mining ecosystem reconstruction

The global decade of restoration brings into sharp focus the need to rehabilitate lands damaged by mining, to provide safe, stable, and productive landscapes. For the majority of mines, the required final land use is some form of natural, semi-natural or managed ecosystem, such as agriculture, aquaculture or forestry. Mining activities lead to new highly altered landscapes that require rehabilitation. These comprise various on-land stores of waste material and mined land itself. The repair of damaged ecosystems is described by many terms including restoration, rehabilitation, revegetation, ecological restoration, and reclamation. These terms overlap in meaning, have regional biases, and all fall short of what is really required: ecosystem reconstruction. This requires a highly multidisciplinary approach drawing on many disciplines including geotechnical engineering, social science, soil science, law, hydrology, botany, geology, pollination biology, financial planning, alongside ecology. Ideally, mine rehabilitation should be progressive, start early in the life of the mine, and employ a strict regime of characterising and tracking waste materials for use in creating safe and stable post-mining landscapes. These actions will limit risks and optimise outcomes, especially when waste materials contain toxic metals or have high levels of acidity, alkalinity or salinity. Some mine sites are appropriate for the restoration of native ecosystems and biodiversity that existed pre-mining, but many, including landscape features created from waste materials, are not. Criteria for successful land rehabilitation are complex, multivariate, and highly contingent on the agreed final land use. Future advances in mine rehabilitation include the use of geomorphic landscape design and emerging thinking on cradle-to-cradle mining. This primer will discuss the complex factors that need to be considered in ecosystem reconstruction after mining and outlines approaches for optimising land rehabilitation outcomes.

Turning alkalinity deficiency-induced metabolic disorder into an opportunity for promoting granulation and enhancing heat generation

Shortage of alkalinity is a common problem in treating low carbon/nitrogen (C/N) wastewater and industrial influents. It negatively affects system stability and efficiency, but its positive effects remain unclear. To address this issue, insufficient (R1: 400 mg CaCO3/L) and sufficient alkalinity (R2: 750 mg CaCO3/L) levels were established in our study, where R1 served as the experimental group and R2 as the control group. In the experimental group, alkalinity deficiency deteriorated the nitrification and phosphorus removal process by reducing the abundance of functional microbes (Nitrosomonas, genus ammonia-oxidizing bacteria, AOB, and Dechloromonas, genus polyphosphate-accumulating organisms, PAOs) and genes (hao). At the same time, the alkalinity deficiency enriched slow-growing functional microbes (Candidatus_Competibacter, genus glycogen-accumulating organisms, GAOs) and key genes (nirK, norB, nosZ, acnB, fumA, fumB) increased the content of extracellular polymeric substances (EPS) and the ratio of protein to polysaccharide (PN/PS). By day 113, over 87 % of the particles were larger than 200 μm, and complete granulation was achieved. Microbial energy metabolism further indicated that alkalinity deficiency diverted some energy to non-growth metabolism, thereby enhancing microbial heat generation. Our results highlight an innovative approach, using the setting of insufficient alkalinity conditions to improve heat recovery and address the challenges of WWTPs. These research findings are in favor of wastewater treatment plants seeking to meet multiple sustainable objectives, including improving water quality, saving footprint, and maximizing energy recovery.

Adaptation responses of different ecotypes of Leymus chinensis to saline–alkaline stress

IntroductionSoil salinity–alkalinity has emerged as a global problem affecting many ecosystems, including grassland. Plants evolve into different ecotypes to adapt to various environments. Leymus chinensis widely distributed in the eastern Eurasian steppe, has evolved into two main ecotypes: yellow–green(YG) and gray–green (GG). Studies on the adaption mechanisms of both ecotypes in response to saline–alkaline stress are limited.MethodsIn this study, the growth and physiological traits of ecotypes YG and GG in soils with different salinity–alkalinity levels—severe saline–alkaline soil (SS), moderate saline–alkaline soil (MS), and light saline–alkaline soil (LS)—were studied. After exposure to saline–alkaline stress for 15 months, the L. chinensis ecotypes exhibited significant differences in the growth characteristics.ResultsThe specific leaf area, individual tiller biomass, net photosynthetic rate, and potassium content of the two ecotypes under MS conditions were significantly higher than or similar to those under LS conditions. This indicates that L. chinensis showed a certain degree of tolerance to saline–alkaline environments under MS conditions. Saline–alkaline stress increased the tillers by 56% in GG and reduced them by 26% in YG, and did not alter the SLA and the number of individual tiller leaves of GG but reduced that of YG. Moreover, with increasing levels of saline–alkaline stress, ecotype GG exhibited an increase in net photosynthetic rate (Pn), while ecotype YG showed insignificant changes. Under SS, GG exhibited higher Pn and chlorophyll content than YG. Additionally, with the increase in the saline–alkaline stress level, the Na+ content increased, but GG exhibited a significantly lower Na+ content than YG. Conversely, the K+ and Ca2+ contents and the K+/Na+ and Ca2+/Na+ ratios decreased, but GG exhibited higher values than YG.DiscussionGG reduced Na+ by absorption by increasing tillers. Additionally, GG absorbed more K+ and Ca2+ ions, thereby maintaining higher K+/Na+ and Ca2+/Na+ ratios than YG under saline–alkaline stress. These adaptive strategies enable ecotype GG to grow and maintain normal physiological functions under high saline–alkaline stress. The findings of this study hold practical significance for enhancing the economic and ecological value of saline–alkaline grasslands.

Behavioral Assessment of Koi carp (Cyprinus carpio) Exposed to Acidic and Alkaline pH

This study presents qualitative and behavioral evaluations in Koi carp (Cyprinus carpio) exposed to acidic and alkaline pH. Renewal system maintained for 96 hours was observed intermittently every 12 hours from pH 4 to 10. Qualitative indicators evaluated were (1) Repeated movement (2) Abrupt swimming (3) Body fatigue (4) Loss of physical activity (5) Loss of appetite (6) Change in body colour (7) Burnt marks (8) Decolouration of muscles (9) Mucous discharge (10) Glossy gills (11) Shedding of scale and (12) Disintegrated body parts. There was no mortality throughout the study. Majority of behavioral aversions and irregularities were observed at acidic (4 and 5) and alkaline (9 and 10) levels. The study suggests that this species is best maintained between pH of 6 to 8 in a domesticated subsystem.

Study on enhancing groundwater quality in a coastal area of Saudi Arabia using a curved glass solar still

Due to the complex geological factors and their causes, it is essential to realize the saltiness and pollution of the groundwater in the arid shoreline aquifer. The intrusion of seawater into coastline aquifers is an increasingly significant issue due to urbanization, the exploitation of groundwater, and the global rise in temperature. The increasing salt concentration of groundwater in shoreline aquifers has emerged as a significant social and economic problem in Saudi Arabia. Consequently, groundwater alkalinity levels must be accurately determined to ensure the effective protection and preservation of water resources. A compilation of eight water samples was collected along the south-western coast of Saudi Arabia, and a comprehensive evaluation of the groundwater quality was conducted using a combination of indicators. The findings indicated that the intrusion of saltwater caused a significant increase in the salt concentration and damage to the groundwater quality near the coastline. In this work, a curved glass solar still (CGSS) has been deployed to process the groundwater, and the performance of the CGSS in improving the groundwater quality was assessed under clear sky conditions. The findings indicate that the desalination process executed using the CGSS resulted in a more substantial improvement in groundwater quality, with an average daily yield of 3513 ml/day achieved with the CGSS.

Nitzschiatranstagensis Morales, Novais, Wetzel, Morais & Ector (Bacillariophyceae) - the second record in the Mediterranean Region.

The Mediterranean Region holds significant ecological importance, characterised by its unique climate, biodiversity and the crucial role it plays in global ecosystems. Mediterranean streams are naturally highly-stressed environments mainly due to fluctuations in water quantity. River flow generally varies from perennial to ephemeral and temporary rivers constitute significant water resources. Streams that flow through Balearic Islands are subjected to these conditions. The majority of these streams sustain water flow for 4-5 months annually, with exceptions noted for streams associated with springs, which typically maintain water throughout most of the year.Benthic diatoms are widely recognised as reliable bioindicators of water quality, used in many aquatic ecosystems. Analysing diatom communities and their biodiversity serves as a valuable tool to ensure the ecological and sustainable utilisation of water resources as well as the accurate development of guidelines for their conservation.The field of diatom taxonomy and distribution plays a crucial role in advancing our understanding of aquatic ecosystems and their biodiversity. Species of the genus Nitzschia are extensively found throughout the Mediterranean Region, including the Balearic Islands. However, they have rarely been investigated in temporary streams. This study presents the first record of Nitzschiatranstagensis Morales, Novais, Wetzel, Morais & Ector, outside the type locality and being the second record in Europe. In this study, the authors found this taxon in one temporary stream of Majorca Island, Torrent des Castellot in November 2005 (Balearic Islands). Nitzschiatranstagensis occurred at 2.6% abundance in this stream with oligotrophic waters (0.052 mg∙l-1 of nitrate), slightly alkaline pH values (7.8) and water conductivity levels of 626.5 µS cm-1. This species was recorded in the biofilm of the stones together with other taxa such as Achnanthidiumminutissimum (Kützing) Czarnecki (39.2%), Gomphonemarosenstockianum Lange-Bertalot & Reichardt (28.9%) and Halamphoraoligotraphenta (Lange-Bertalot) Levkov (20.4%). The Nitzschiatranstagensis frustules found in the examined material have similar dimensions and a higher fibulae count (8-11 in 10 μm vs. 6-10 in 10 μm) compared to the type material of Nitzschiatranstagensis. The habitat characteristics in which this species was found are described, together with LM micrographs of this taxon.

Sulfur enhances iron plaque formation and stress resistance to reduce the transfer of Cd and As in the soil-rice system

Sulfur plays an essential role in agricultural production, but few studies have been reported on how sulfur simultaneously impacts the transformation of cadmium (Cd) and arsenic (As) in the soil-rice system. This research selected two soils co-contaminated with both Cd and As, varying in acidity and alkalinity levels, to study the impacts of elemental sulfur (S) and calcium sulfate (CaSO4) on the migration and accumulation of Cd and As by rice. Results indicated that two types of sulfur had a substantial (P < 0.05) impact on decreasing the contents of Cd (28.3–50.4 %) and As (20.1–38.6 %) in brown rice in acidic and alkaline soils. They also increased rice biomass (29.3–112.8 %) and reduced Cd transport coefficient (27.2–45.6 %) significantly (P < 0.05). Notably, sulfur augmented the generation of iron plaque on rice root surfaces, which increased the fixation of Cd (17.6–61.0 %) and As (14.0–45.9 %). SEM-EDS results also indicated that the rice root surface exhibited significant enrichment of Fe, Cd, and As. The mechanism of simultaneous Cd and As immobilization by sulfur application was mainly ascribed to the contribution of iron plaque. Additionally, sulfur reduced the contents of Cd and As in soil porewater and promoted the transformation of As(III) to As(V) to reduce the toxicity of As. The K-edge XAFS of As in iron plaque also confirmed that sulfur application significantly promoted As(III) oxidation. Sulfur also promoted the activities of antioxidant enzymes and the contents of NPT, GSH, and PCs in rice plants. In general, this study establishes a foundation for sulfur to lower As and Cd bioavailability in paddy soils, enhance iron plaque and rice resistance, and reduce heavy metal accumulation.

Land suitability studies for paddy cultivation in Dadahup Swampy Irrigation Area

The Dadahup Swampy Irrigation Area is crucial in the government’s Food Estate initiative to enhance food security in Indonesia. Following extensive infrastructure improvements, including network rehabilitation and gate construction between 2020 and 2022, a pilot project was initiated in block A5. However, rice yields in this area still need to improve, primarily due to inadequate land management practices. This study evaluates and maps land suitability for paddy cultivation in the Dadahup Swamp Irrigation Area, employing a combination of laboratory data and field research integrated with geographic information system (GIS) technology. Various parameters were considered, such as climate factors (temperature and water availability), soil characteristics (drainage, texture, depth), peatland attributes (thickness, maturity), nutrient content (CEC, base saturation, pH, C-organic), available nutrients (nitrogen, phosphorus, potassium), salinity, alkalinity, pyrite depth, and inundation levels during planting. Then, thematic raster mapping was conducted using the Inverse Distance Weighted (IDW) method, followed by reclassification based on Food and Agriculture Organization (FAO) standards for land evaluation. The result categorized Block A5 into three suitability classes: S1 (highly suitable), S2 (moderately suitable), and S3 (marginally suitable). Approximately 22.5% of Block A5 is highly suitable (S1), 39.5% is moderately suitable (S2), and around 38% is marginally suitable (S3).

Effect of waste dumpsite on the surface and groundwater supplies using water quality index in Afikpo south local government area, Ebonyi state

The research examined the effect of waste dumpsite on the surface and groundwater supplies using water quality index (WQI) in Afikpo South Local Government Area of Ebonyi State. Fifteen samples were drawn from fifteen locations. The samples were analyzed using standard methods. The results of the analyses were compared with the World Health Organization (WHO) drinking water standard. The WQI of the water samples were calculated and compared with the classification of water quality status. The results showed that the pH of the water samples ranged 4.6±0.047 – 6.70±0.090, EC 7.26±1.63 – 2450±4.32, Turbidity 0.50±0.082 – 2.00±0.094, TDS 23.10±0.047 - 1830±17.00, Alkalinity 45±0.47 - 2080±4.71, Total Hardness 4±0.47 – 170±0.94, DO 5.07±0.012 – 7.72±0.016, BOD 0.4±0.047 – 12.8±0.082, NO3 - 1.14±0.009 – 32.69±0.047 and 0.09±0.00 – 15.6±0.028. The results showed that the pH, Turbidity, Total Hardness, NO3 - were all below the WHO drinking water standard. All the locations of the water samples showed some levels of acidity. Apart from location MB that recorded high levels of TDS and Alkalinity every other location was below the WHO permissible limit of drinking water standard. The results of the analysis also revealed that the WQI value of the water was 57.92 and this was below the critical value of 100. From the findings, all the water samples need to be treated with alkali to reduce the low pH while the water samples generally need to be given comprehensive treatment before usage.

Black Soils in the Eastern Mediterranean: Genesis and Properties

This study investigates the distribution, morphology, and properties of these soils, focusing on areas such as littoral plains, high hilly areas, and rift depression valleys. Black soils occur in the eastern Mediterranean with a limited distribution, and some of them meet the requirements for black soils according to the INBS (International Network of Black Soils), while others do not. Black soils can be categorized into three types based on their genesis and evolution: calcareous black soils (mainly raw rocky rendzina), hydromorphic black soils, and black soil on basalt. While black soils were found in various bioclimatic stages and parent materials, their presence was notably limited in certain areas, contrary to prior indications. A soil morphology analysis revealed distinct color variations and depths, influenced by the accumulation of organic matter for hydromorphic and calcareous black soils and basaltic parent material for black soils on basalt. A particle size analysis indicated texture variations from clay to loam, with no clear indication of illuviation. A chemical analysis showed alkaline pH levels, except in basalt-derived soils, which exhibited a slight acidity. Hydromorphic black soil is the most important in terms of expansion and agricultural use and is only found in limestone marl deposits and lakes in depressions emerging from Dead Sea rifts under conditions of saturation or poor drainage. These soils have a thick, dark moly horizon and a high organic matter content.

Post-Consumer Carpet Fibers in Concrete: Fiber Behavior in Alkaline Environments and Concrete Durability.

The widespread use of carpets in residential and commercial buildings and their relatively short life span result in large volumes of carpet being landfilled. A potential solution to this problem is the use of post-consumer carpet fibers in concrete. To this end, this paper systematically identifies the common fiber types in a typical post-consumer carpet fiber bale and evaluates their durability under exposure to varying levels of alkalinity. The tensile strengths and toughness of the fibers belonging to the nylon and polyethylene terephthalate (PET) families (the dominant fibers in most post-consumer carpets) are reduced by up to 50% following exposure to extreme alkalinity, the reasons for which are determined using spectroscopic and microscopic evaluations. The chloride ion transport resistance of concretes (~40 MPa strength) containing 2.5% carpet fibers by volume (~25 kg of fibers per cubic meter of concrete) is comparable to that of the control mixture, while mortar mixtures containing the same volume fraction of carpet fibers demonstrate negligible enhancement in expansion and loss of strength when exposed to 1 N NaOH. This study shows that moderate-strength concretes (~40 MPa) for conventional building and infrastructure applications can be proportioned using the chosen volume of carpet fibers without an appreciable loss of performance. Consideration of low volume fractions of carpet fibers in low-to-moderate-strength concretes thus provides a sustainable avenue for the use of these otherwise landfilled materials in construction applications.

Assessing alkali activation of waste stone wool from greenhouses combined with direct foaming or granulation to obtain recycled plant substrate.

Stone wool is commonly used as a plant substrate in soilless cultivation and discarded after one growing season. Stone wool waste is difficult to recycle, and thus it is typically landfilled. Alkali-activation of stone wool (i.e., milling and mixing with an alkaline solution) has been shown to be a feasible way to upcycle this waste fraction into, for example, construction products. In this study, the aim was to develop recycled plant substrate from stone wool waste from greenhouses via alkali activation. Waste stone wool from greenhouses was characterized by X-ray fluorescence (XRF) and mixed with sodium silicate solution either directly or after ball milling. The alkali-activation process was combined with the addition of H 2O 2, pre-made foam, or granulation to obtain suitable porous material for the plant substrate application. Preliminary greenhouse cultivation experiments of pea ( Pisum sativum) were conducted with alkali-activated stone wool mixed with peat (a weight ratio of 1:1) and fertility analysis of the mixture were conducted. The results indicated that the most feasible production method was to use ball-milled stone wool and to combine alkali activation with granulation. The obtained granules could reach 2.7 MPa as compressive strength while the other methods resulted in very fragile material. The preliminary greenhouse cultivation experiments revealed that there were significant levels of nutrients (Ca, P, K, and S) and alkalinity leached from the granules which hindered the growth of pea. The high P and S amounts were also confirmed by the XRF results of stone wool. It can be concluded that the developed granules did not function well as a plant substrate for pea but could enable the re-utilization of the nutrients contained in the greenhouse stone wool waste. Moreover, their application to acidic sulfate soils could be feasible as it would utilize the alkalinity of granules.