Effect of clariflocculator and pulsator based sedimentation technology and poly-aluminium chloride coagulant type on the efficiency of the water treatment plant

Polyaluminium chloride (PAC) with different basicity is used as a coagulant in most drinking water treatment plants (WTP). The aluminium concentration in PAC and its hydrolysis mechanism varied with the basicity of PAC. Incremental addition of PAC changes various Physico-chemical properties and turbidity removal mechanisms in water. Water treatment plants use the PAC concentration beyond its optimum dose without considering other aspects, including residual aluminium concentration. In the present work, the effect of high and medium basicity of PAC on different Physico-chemical properties like pH, zeta potential, and residual aluminium concentration of water was investigated. The pH of treated water decreases with the incremental addition of PAC, and an increase in zeta potential and residual aluminium concentration in treated water was evidenced. The change in pH after PAC addition is responsible for deciding the coagulation mechanism and efficiency of the coagulation process. pH reduction is comparatively more in high basicity PAC than medium basicity. PAC hydrolysis mechanism is controlled by the zeta potential of water and can be used as an alternative method to decide the optimum coagulant dose. The performance of clariflocculator and pulsator-based WTP was also evaluated for raw water from the same source. To reduce down the turbidity below the acceptable level, the coagulant requirement for clariflocculator based WTP is comparatively less than pulsator based WTP. The floc blanket in the pulsator gets disturbed with a slight change in the coagulant chemistry and quantity.

Development and validation of an analytical methodology for quantification of Al in alumina-based materials by 27Al Solid-state nmr

In this work, a simple protocol for counting the Al spins present in diamagnetic materials used as carriers and catalysts based on 27Al solid-state nuclear magnetic resonance using routine 4 mm rotors was developed and validated. The acquisition parameters were optimized, and validation tests were performed using a standard sample of γ-alumina with a known aluminium concentration. The validation results indicated that solid-state NMR can be used for the quantification of quadrupolar aluminium (mmol Al.g-1 material) in diamagnetic materials by employing non-special tools with satisfactory results, similar to the NMR quantitative analysis of dipolar nuclei in solids.

High Aluminium Concentration and Soil Acid Saturation Reduce Germination, Emergence and Seedling Establishment of Groundnut

Studies on crop responses to soil acidity have largely neglected the germination and seedling establishment stages. The objective of this study was to determine the effect of soil acidity, including aluminium per se and acid saturation, on germination, emergence and establishment of groundnut seeds. Germination was carried out on groundnut cultivars Harts, Jasper and Rambo under 0, 50, 100 and 200 μM Al applied as Al2 (SO4)3.18H2O at pH between 4.2 and 4.5. Seedling emergence and establishment were examined in 0, 3 and 6 g of dolomitic lime per kg of soil, representing control, 50% lime requirement and 100% lime requirement, respectively. High Al concentration of 200 μM reduced germination, germination velocity index and seminal root length but had no influence on mean germination time of all groundnut cultivars. There were highly significant differences (P<0.001) in seedling emergence between non-limed and limed soils. Root length and mass were significantly (P<0.05) reduced at high soil acidity but the cultivar Rambo was least susceptible. We conclude that the germination, emergence and establishment stages were negatively affected by high Al levels and acid saturation but the cultivars showed different tolerance levels to high acid saturation, and proper liming can ameliorate the problems associated with these growth stages. Key words: acid saturation, aluminium, establishment, peanuts, tolerance

Suspected alimentary poisoning by aluminium phosphide in horses – a case report

In November 2018, a horse owner from the Czech Republic experienced the loss of two of his stallions in consequence of probable poisoning. The affected animals were kept in the stable only. The mares, which were grazing on pasture during the day, were not affected. All the animals were fed the same type of feed. The day before the animals became sick, between 15:00 to 19:00 h the stable was not secured against the entry of strangers. When the mares were brought back to the stable and all animals were closed and locked for the night, no signs of health issues were observed. In the following morning, the two stallions were found in lateral recumbency with seizure attacks. Despite symptomatic treatment (infusion with saline, flunixine meglumine, activated charcoal) and applications of myorelaxants, the symptoms persisted until the afternoon, and the owner agreed with euthanasia. Based on the clinical signs and pathological examination, poisoning by pesticides was suspected. The results of toxicological analyses revealed that carbofuran, metaldehyde, and strychnine were not responsible for the poisoning as they were not detected in the samples. The only positive finding was a high aluminium concentration in the stomach content, liver and kidney samples. Based on the observed symptoms and the high aluminium concentration, it was presumed that aluminium phosphide could be the source of poisoning. As there was no evidence of the possession of such product by the horse breeder and the stable stayed unsupervised for a few hours, intentional poisoning cannot be excluded.

Bioaccumulation and Effects of Aluminium on Plant Growth in Three Culture Plants Species

Aluminium toxicity is one of the major factors that limit plant growth and development in many acid soils, by multiple, and still poorly understood mechanisms. In this paper, the aluminium content determinations were done through atomic absorption spectrometry method, on seedlings of three culture plants, Helianthus annuus L. (sunflower), Sinapis alba L. (white mustard) and Triticum aestivum L. (wheat), grown in hydroponic conditions with different aluminium concentrations (50, 100 and 250 mg/kg) expose. AAS data were correlated with biometrical determinations (shoot length and dry biomass) and leaf pigments concentration assessment. Results emphasize that none of the selected species accumulates aluminium in aboveground organs such as shoots and leaves, indicating that root exclusion and/or sequestration are the strategies employed by all three species for limiting aluminium toxicity. In all three studied species, both average shoot length and dry biomass tended to be lower at higher aluminium concentration. Due to high variations among seedlings grown at the same aluminium concentration expose, these differences are not statistically significant. In sunflower seedlings, chlorophyll a and carotenoids had maximum values at the highest aluminium concentration (250 mg/kg), while chlorophyll b was more abundant at 100 mg/kg. In mustard, all pigments had their maximum concentrations at 100 mg/kg, while in wheat, an aluminium concentration increase progressively lead to a drop in pigments concentration.