Spirulina biomass accounts for 30% of the total algae biomass production globally. In conventional process of Spirulina biomass production, cultivation using chemical-based culture medium contributes 35% of the total production cost. Moreover, the environmental impact of cultivation stage is the highest among all the production stages which resulted from the extensive usage of chemicals and nutrients. Thus, various types of culture medium such as chemical-based, modified, and alternative culture medium with highlights on wastewater medium is reviewed on the recent advances of culture media for Spirulina cultivation. Further study is needed in modifying or exploring alternative culture media utilising waste, wastewater, or by-products from industrial processes to ensure the sustainability of environment and nutrients source for cultivation in the long term. Moreover, the current development of utilising wastewater medium only support the growth of Spirulina however it cannot eliminate the negative impacts of wastewater. In fact, the recent developments in coupling with wastewater treatment technology can eradicate the negative impacts of wastewater while supporting the growth of Spirulina. The application of Spirulina cultivation in wastewater able to resolve the global environmental pollution issues, produce value added product and even generate green electricity. This would benefit the society, business, and environment in achieving a sustainable circular bioeconomy.
While wetlands are the largest natural source of methane (CH4 ) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17 ± 11 days, and lagged air and soil temperature by median values of 8 ± 16 and 5 ± 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH4 . At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.
To understand the effects of fish predator’s kairomones on Aedes mosquitoes’
oviposition, we established an experiment using gravid Aedes females. Kairomones
concentrations were established using Hampala macrolepidota. One individual fish was
placed inside containers with varying water levels (1 L, 5 L, and 10 L of water). The fish
were kept in the containers for 24 hours and were removed immediately at the start of
each trial in order to have the kairomones remnants. Twenty gravid adult females of
Aedes aegypti and Aedes albopictus were allowed to lay eggs on oviposition site with
various treatments: (1) control without any kairomones; (2) kairomone remnant in 1 L of
water; (3) kairomone remnant in 5 L of water; and (4) kairomone remnant in 10 L of water.
There are significant differences between the numbers of eggs laid by both Aedes species
for each different treatment (F = 9.131, df = 16, p
Rapid urbanization and industrial development in the Langat Basin has disturbed the groundwater quality. The populations' reliance on groundwater sources may induce possible risks to human health such as cancer and endocrine dysfunction. This study aims to determine the groundwater quality of an urbanized basin through 24 studied hydrochemical parameters from 45 groundwater samples obtained from 15 different sampling stations by employing integrated multivariate analysis. The abundance of the major ions was in the following order: bicarbonate (HCO3-) > chloride (Cl-) > sodium (Na+) > sulphate (SO42-) > calcium (Ca2+) > potassium (K+) > magnesium (Mg2+). Heavy metal dominance was in the following order: Fe > Mn > Zn > As > Hg > Pb > Ni > Cu > Cd > Se > Sr. Classification of the groundwater facies indicated that the studied groundwater belongs to the Na-Cl with saline water type and Na-HCO3 with mix water type characteristics. The saline water type characteristics are derived from agricultural activities, while the mixed water types occur from water-rock interaction. Multivariate analysis performance suggests that industrial, agricultural, and weathering activities have contributed to groundwater contamination. The study will help in the understanding of the groundwater quality issue and serve as a reference for other basins with similar characteristics.
Online preconcentration using electrokinetic supercharging (EKS) was proposed to enhance the sensitivity of separation for endocrine disrupting chemical (methylparaben (MP)) and phenolic pollutants (2-nitrophenol (NP) and 4-chlorophenol (CP)) in water sample. Important EKS and separation conditions such as the concentration of BGE; the choice of terminating electrolyte (TE); and the injection time of leading electrolyte (LE), sample, and TE were optimized. The optimum EKS-CE conditions were as follows: BGE comprising of 12 mM sodium tetraborate pH 10.1, 100 mM sodium chloride as LE hydrodynamically injected at 50 mbar for 30 s, electrokinetic injection (EKI) of sample at -3 kV for 200 s, and 100 mM CHES as TE hydrodynamically injected at 50 mbar for 40 s. The separation was conducted at negative polarity mode and UV detection at 214 nm. Under these conditions, the sensitivity of analytes was enhanced from 100- to 737-fold as compared to normal CZE with hydrodynamic injection, giving LOD of 4.89, 5.29, and 53 μg/L for MP, NP and CP, respectively. The LODs were adequate for the analysis of NP and CP in environmental water sample having concentration at or lower than their maximum admissible concentration limit (240 and 2000 μg/L for NP and CP). The LOD of MP can be suitable for the analysis of MP exists at mid-microgram per liter level, even though the LOD was slightly higher than the concentration usually found in water samples (from ng/L to 1 μg/L). The method repeatabilities (%RSD) were in the range of 1.07-2.39% (migration time) and 8.28-14.0% (peak area).
Matched MeSH terms: Water Pollutants, Chemical/analysis; Water Pollutants, Chemical/isolation & purification*; Water Pollutants, Chemical/chemistry
Recently, deep eutectic solvents (DESs) have shown their new and interesting ability for chemistry through their involvement in variety of applications. This study introduces carbon nanotubes (CNTs) functionalized with DES as a novel adsorbent for Hg(2+) from water. Allyl triphenyl phosphonium bromide (ATPB) was combined with glycerol as the hydrogen bond donor (HBD) to form DES, which can act as a novel CNTs functionalization agent. The novel adsorbent was characterized using Raman, FTIR, XRD, FESEM, EDX, BET surface area, TGA, TEM and Zeta potential. Response surface methodology was used to optimize the removal conditions for Hg(2+). The optimum removal conditions were found to be pH 5.5, contact time 28 min, and an adsorbent dosage of 5 mg. Freundlich isotherm model described the adsorption isotherm of the novel adsorbent, and the maximum adsorption capacity obtained from the experimental data was 186.97 mg g(-1). Pseudo-second order kinetics describes the adsorption rate order.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Water Purification/methods
Total mercury (THg) and methylmercury (MeHg) concentrations were determined from sediment samples collected from thirty sampling stations in Port Klang, Malaysia. Three stations had THg concentrations exceeding the threshold effect level of the Florida Department of Environmental Protection and the Canadian interim sediment quality guidelines. THg and MeHg concentrations were found to be concentrated in the Lumut Strait where inputs from the two most urbanized rivers in the state converged (i.e. Klang River and Langat River). This suggests that Hg in the study area likely originated from the catchments of these rivers. MeHg made up 0.06-94.96% of the sediment's THg. There is significant positive correlation (p
Matched MeSH terms: Water Pollutants, Chemical/analysis; Water Purification/methods
The effect of filler content and storage conditions such as drying, storing in water and thermal cycling on linear dimensional changes were investigated and evaluated. The dimensional accuracy studies were performed using a specific designed mould and a coordinate measuring machine. The findings gave support to the view that tiller content is an important factor influencing the physical and mechanical properties of the composite inlay material. The higher tiller content gave less polymerization shrinkage. The greatest linear shrinkage recorded was 0.79 %. The average linear shrinkage (in air, water and thermal cycling) for 79 % filler Prisma AP.H was 0.33 %, for 65 % tiller Prisma AP.H was 0.35 % and for 50 % filler Prisma AP.H was 0.42 %. Generally, dimensional changes was greatest when stored dry. This was followed by materials which were thermal cycled. The least dimensional change recorded was when the materials were stored in water.
Increasing demands in palm oil industry hence resulting the production of palm oil to increase. It is then creating a major problem in disposing the waste to be treat in appropriate ways. The governments are forced to look for alternative technology for the palm oil mill effluent (POME) treatment because the demand of oil increases with the awareness on increasing environmental issue. Therefore, a new technology must be found in order to reduce energy consumption, to meet legal requirements on emission and for cost reduction and also increased quality of water treatment. Membrane Anaerobic System (MAS) is a promising alternative way to overcome these issues. In this study, the efficiency of the MAS performance increases to 99.03% in ten days operation. The application of Monod, Contois and Chen & Hashimoto models were used to analyze the performance of MAS for treating POME. The results from the experiment show the substrate removal model is well fits for estimation of kinetics membrane anaerobic system. Amongst them, the Contois and Monod models predicted the bio-kinetic reactions of the MAS very well with coefficient of determination (R2>97%) values. The MAS bioreactor was creating to be an improvement method as well as successful biological treatment since the graph shows linearized which is good agreement with reported in literature.
This paper presents the solution to a calculation of the pH of a very dilute solution of a weak acid, taking into account the effect of the hydroxonium ions generated from the ionization of the acid on the ionization of water, also a very weak acid. To be solved successfully, this calculation involves the concepts of conservation of charge, pH, equilibria and the application of the general solution to a cubic equation. Such an exercise requires the application of skills in algebra, and can provide a core of understanding that can prepare advanced students for many different sorts of calculations that represent real-life problems in the chemical sciences. A programme is presented in C++ which enables the work of students to be individualized so that each student in a class can work through a slightly different pH calculation, in such a way that a class supervisor can quickly check each student’s result for accuracy.This exercise is presented as a potential means of enabling students to undertake and master similar types of calculations involving the application of complex algebra to problems related to equilibria and solution dynamics.
Proper integrated management of a dam reservoir requires that all components of the water resource system be known. One of these components is the daily reservoir inflow which is the subject matter of this study, i.e. to establish predictions of what is coming in the next rainfall-runoff process over a catchment. The transformation of rainfall into runoff is an extremely complex, dynamic, and more of a non-linear process. The available six-year average daily rainfall data across the Sembrong dam catchment were computed using the well-known Theissen’s polygon method. Daily reservoir inflow data were extracted by applying the water balance model to the Sembrong dam reservoir. Modelling of relationship between rainfall and reservoir inflow data was done using feed-forward back-propagation neural networks. The final selected model has one hidden layer with 11 neurons in the hidden layer. The selected model was applied for an independent data series testing. Results in relation to specific climatic and hydrologic properties of a small tropical catchment suggested that the model is suitable to be used in forecasting the next day’s reservoir inflow. The efficiencies of the model Abtained indicated the validity of using the neural network for modelling reservoir inflow series.
The effects of soaking conditions on the quality characteristics of seaweed paste of Kappaphycus alverazii species were studied. Response Surface Methodology (RSM) with a 2-factor, 5-level central composite design (CCD) was conducted to determine the optimum soaking conditions. The interactive effect of dry seaweed: soaking water ratio (X1 = 1: 15-50) and soaking duration (X2 = 30-120 min) on the gel strength (g), whiteness, expansion (%), moisture content (%) and protein content (g/100 g) of the paste were determined. Results showed that the experimental data could be adequately fitted into a second-order polynomial model with multiple regression coefficients (R2) of 0.8141, 0.9245, 0.9118, 0.9113 and 0.9271 for the gel strength, whiteness, expansion, moisture content and protein content, respectively. The gel strength, whiteness, expansion, moisture content and protein content of seaweed paste were dependent on the ratio of dry seaweed to soaking water and also soaking duration. The proposed optimum soaking conditions for the production of seaweed paste is at a ratio of 1:15 (dry seaweed : soaking water) and soaking duration of 117.06 min. Based on the result obtained, the RSM demonstrated a suitable approach for the processing optimization of Kappaphycus alverazii paste.
A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a 'sine-like' function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.
The combination of irradiation and biological technique was chosen to study COD, BOD5 and colour removal from textiles effluent in the presence of food industry wastewater. Two biological treatments, the first consisting a mix of non irradiated textile and food industry wastewater and the second a mix of irradiated textiles wastewater and food industry wastewater were operated in parallel. Reduction percentage of COD in textiles wastewater increased from 29.4% after radiation to 62.4% after further undergoing biological treatment. After irradiation, the BOD5 of textiles wastewater was reduced by 22.1%, but reverted to the original value of 36mg/1 after undergoing biological treatment. Colour had decreased from 899.5 ADMI to 379.3 ADM1 after irradiation and continued to decrease to 109.3 ADMI after passing through biological treatment.
The emulsifying properties of extracted okra (Abelmoschus esculentus L.) mucilage at different maturity indices (1, 2 and 3) were studied. The okra mucilage was prepared using water extraction method and was determined their viscosity at different temperature (10, 30, 50 and 70°C), water holding capacity (WHC), oil holding capacity (OHC), as well as their emulsion capacity (EC) and emulsion stability (ES). Results found that okra with maturity index 2 produced the highest percentage yield of mucilage (1.46%) and followed by index 1 (1.10%) and index 3 (0.31%) (p
Thermal processing of green coconut water (GCW) caused non-enzymic browning and development of rancidity. Effect of the addition of several combinations of ascorbic acid (AA) (0 to 100 ppm) and sodium metabisulfite (SMB) (0 to 30 ppm) on brown discolouration and rancidity of GCW during elevated thermal processing (121°C for 5 min at 15 psi) was investigated. Addition of AA and/or SMB significantly (P
Heel Effect is the well known phenomena in x-ray production. It contributes the effect to image
formation and as well as scattered radiation. But there is paucity in the study related to heel effect.
This study is for mapping and profiling the dose on the surface of water phantom by using mobile
C-arm unit Toshiba SXT-1000A. Based on the result the dose profile is increasing up to at least
about 57% from anode to cathode bound of the irradiated area. This result and information can be
used as a guide to manipulate this phenomenon for better image quality and radiation safety for
this specific and dedicated fluoroscopy unit.
Studies of deep-sea benthic communities have largely focused on particular (macro) habitats in isolation, with few studies considering multiple habitats simultaneously in a comparable manner. Compared to mega-epifauna and macrofauna, much less is known about habitat-related variation in meiofaunal community attributes (abundance, diversity and community structure). Here, we investigated meiofaunal community attributes in slope, canyon, seamount, and seep habitats in two regions on the continental slope of New Zealand (Hikurangi Margin and Bay of Plenty) at four water depths (700, 1,000, 1,200 and 1,500 m). We found that patterns were not the same for each community attribute. Significant differences in abundance were consistent across regions, habitats, water and sediment depths, while diversity and community structure only differed between sediment depths. Abundance was higher in canyon and seep habitats compared with other habitats, while between sediment layer, abundance and diversity were higher at the sediment surface. Our findings suggest that meiofaunal community attributes are affected by environmental factors that operate on micro- (cm) to meso- (0.1-10 km), and regional scales (> 100 km). We also found a weak, but significant, correlation between trawling intensity and surface sediment diversity. Overall, our results indicate that variability in meiofaunal communities was greater at small scale than at habitat or regional scale. These findings provide new insights into the factors controlling meiofauna in these deep-sea habitats and their potential vulnerability to anthropogenic activities.
In this work a novel anode configuration consisting of an iron mesh double layer is proposed for the electrochemical treatment of wastewater. The removal of Reactive Black 5 dye (RB5) from synthetic contaminated water was used as a model system. At a constant anode surface area, identical process operating parameters and batch process mode, the iron mesh double layer electrode showed better performance compared to the conventional single layer iron mesh. The double layer electrode was characterized by RB5 and chemical oxygen demand (COD) removal efficiency of 98.2% and 97.7%, respectively, kinetic rate constant of 0.0385/min, diffusion coefficient of 4.9×10(-5)cm(2)/sec and electrical energy consumption of 20.53kWh/kgdye removed. In the continuous flow system, the optimum conditions suggested by Response Surface Methodology (RSM) are: initial solution pH of 6.29, current density of 1.6mA/cm(2), electrolyte dose of 0.15g/L and flow rate of 11.47mL/min which resulted in an RB5 removal efficiency of 81.62%.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Waste Water/chemistry
Fennel seed spent (FSS)-an inexpensive nutraceutical industrial spent has been used as an efficient biosorbent for the removal of Congo red (CR) from aqueous media. Results show that the conditions for maximum adsorption would be pH 2-4 and 30°C were ideal for maximum adsorption. Based on regression fitting of the data, it was determined that the Sips isotherm (R2 = 0.994, χ2 = 0.5) adequately described the mechanism of adsorption, suggesting that the adsorption occurs homogeneously with favorable interaction between layers with favorable interaction between layers. Thermodynamic analysis showed that the adsorption is favorable (negative values for ΔG°) and endothermic (ΔH° = 12-20 kJ mol-1) for initial dye concentrations of 25, 50, and 100 ppm. The low ΔH° value indicates that the adsorption is a physical process involving weak chemical interactions like hydrogen bonds and van der Waals interactions. The kinetics revealed that the adsorption process showed pseudo-second-order tendencies with the equal influence of intraparticle as well as film diffusion. The scanning electron microscopy images of FSS show a highly fibrous matrix with a hierarchical porous structure. The Fourier transform infrared spectroscopy analysis of the spent confirmed the presence of cellulosic and lignocellulosic matter, giving it both hydrophilic and hydrophobic properties. The investigations indicate that FSS is a cost-effective and efficient biosorbent for the remediation of toxic CR dye.
Matched MeSH terms: Water Pollutants, Chemical/chemistry*; Water Purification*