Effect of Irrigation with Diluted Winery Wastewater on Cations and pH in Four Differently Textured Soils

Environmental legislation requires the South African wine industry to find solutions for winery wastewatertreatment or reuse. The feasibility of irrigation with diluted winery wastewater was assessed in a potexperiment under a rain shelter over four simulated irrigation seasons. Four soils varying in clay contentwere irrigated with winery wastewater diluted to 3 000 mg/L chemical oxygen demand (COD), whereas thecontrol received municipal water. The rate of K+ increase in the soil containing 20% clay was higher thanin soils containing 13% clay or less. This suggests that heavy soils will aggravate the risk of high K+ levels.The risk of Na+ accumulation increased linearly with clay content. Low Ca2+ and Mg2+ concentrations inthe diluted wastewater had no effect on the soil, irrespective of clay content. Irrigation with diluted winerywastewater increased soil pH(KCl) substantially in all the soils over the four simulated seasons. The soil pHincrease was attributed to the addition of organic/bicarbonate salts to the soil. It must be noted that theresults represent a worst case scenario, i.e. in the absence of rainfall or crops

Response of Soil Chemical Properties to Irrigation with Winery Wastewater on a Well-drained Sandy Soil

Most wineries in South Africa dispose of their wastewater through land application. This is carried out by irrigating small areas of cultivated pasture with the wastewater or ponding, with the former being the more general practice. Land application of winery wastewater results in the accumulation of potassium (K+) andsodium (Na+) in the soil and leaching of calcium (Ca2+) and magnesium  (Mg2+).This could lead to long term instability of soil structure. The objective of this study was to investigate the effect of irrigation with winery wastewater on chemical soil properties and potential environmental impacts. Therefore, an existinggrazing paddock at a winery near Rawsonville was selected where wastewater had been applied for many years. Due to the high volumes of wastewater irrigation plus rainfall, the inevitable over-irrigation leached large amounts of cations, particular K+ and Na+, beyond 90 cm soil depth at the selected study site. These leached elements are likely to end up in natural water resources in the long run. Irrigation with winery wastewater did not have a pronounced effect on soil pH(KCl). This was probably due to the decomposition of organic matter, and the fact that the applied salts were leached beyond 90 cm depth. The study confirmed that disposal of winery wastewater through land application can only be recommended where wastewaterapplication will not exceed the water requirement of the crop as well as the water holding capacity of the soil which is being irrigated

Annual Dynamics of Winery Wastewater Volumes and Quality and the Impact of Disposal on Poorly Drained Duplex Soils

The composition and volume of winery wastewater change throughout the year. Quality is usually at its worst when vintage operations are dominated by the production of red wines. The objective of this study was to investigate the annual dynamics of winery wastewater volumes and quality, as well as the effect of winery wastewater irrigation on the chemical soil properties of a poorly drained duplex soil. The study was conducted over two and half years. The wastewater contained a high concentration of potassium (K+) and low levels of sodium (Na+). The results of the study confirmed that winery wastewater did not complywith South African national legislation for wastewater irrigation with regard to chemical oxygen demand (COD) and pH throughout the study period, while some prominent spikes were observed in sodium adsorption ratio (SAR) and electrical conductivity (EC). Land application of winery wastewater resulted in the accumulation of high levels of K+ in the soil. It is important to note that this study represents the worst-case scenario, i.e. large amounts of wastewater were disposed of on a small surface, particularly during harvest and in winter. Due to the high volumes of wastewater irrigation plus rainfall, the inevitable over-irrigation leached large amounts of K+ beyond 90 cm soil depth. Unfortunately, the leached elements are bound to end up in natural water resources, resulting in the pollution of the environment

Effect of Irrigation with Diluted Winery Wastewater on Phosphorus in Four Differently Textured Soils

The wine industry needs solutions for wastewater treatment, as environmental legislation for its disposal isincreasingly being enforced due to non-compliance. The feasibility of re-using diluted winery wastewaterwas assessed in a pot experiment under a rain shelter over four simulated irrigation seasons. Four soilsvarying in parent material and clay content, viz. aeolic sand from Lutzville containing 0.4% clay, alluvialsand from Rawsonville containing 3.3% clay, granite-derived soil from Stellenbosch containing 13% clay,and shale-derived soil from Stellenbosch containing 20% clay, were irrigated with wastewater diluted to3 000 mg/L COD (chemical oxygen demand), whereas the control received municipal water. Irrigation withdiluted winery wastewater increased the pH(KCl) in the shale- and granite-derived soils into the optimumrange for P availability. Although pH(KCl) in the aeolic sand was initially above the optimum range, relativelyhigh Na+ levels also caused available P to increase as the pH(KCl) increased. The pH(KCl) in the alluvial sandincreased beyond the optimum range, thereby causing a reduction in the available P. This indicates thatirrigation with diluted winery wastewater may only enhance P absorption if the pH(KCl) shift is towards theoptimum. It must be noted that the results represent a worst-case scenario, i.e. in the absence of rainfallor crops

Vulnerability of Selected Soils in the Different Rainfall Areas to Degradation and Excessive Leaching after Winery Wastewater Application

A pot trial was conducted to assess the effect of simulated rainfall on six soils with different textures, irrigated with winery wastewater diluted to a chemical oxygen demand (COD) level of 3000 mg/L over one simulated irrigation season. Thereafter, simulated winter rainfall was applied to the pots. The rainfall was simulated according to the long term averages of the regions where the soils originated. Leaching of cations, particularly K+ and Na+ occurred only from four of the six soils when winter rainfall was simulated.  In one of the sandy soils, the simulated rainfall was too low to allow leaching. In another soil, high clay content of 35% in combination with low rainfall prevented leaching. In three soils that received the sameamount of rainfall, more cations leached from the duplex sandy soil compared to the two other soils. These trends indicated that leaching of cations was a function of soil texture and rainfall. The study showedthat in regions with low rainfall, irrigation with winery wastewater would lead to the accumulation of cations thereby increasing soil salinity. The study confirmed that for sustainable use of winery wastewaterirrigation in agriculture, different soil types will require individual management in order to avoid or minimize the negative environmental impact on natural resources by wastewater irrigation

Type II migration strikes back – an old paradigm for planet migration in discs

In this paper, we analyse giant gap-opening planet migration in proto-planetary discs, focusing on the type II migration regime. According to standard type II theory, planets migrate at the same rate as the gas in the disc, as they are coupled to the disc viscous evolution; however, recent studies questioned this paradigm, suggesting that planets migrate faster than the disc material. We study the problem through 2D long-time simulations of systems consistent with type II regime, using the hydrodynamical grid code FARGO3D. Even though our simulations confirm the presence of an initial phase characterized by fast migration, they also reveal that the migration velocity slows down and eventually reaches the theoretical prediction if we allow the system to evolve for enough time. We find the same tendency to evolve towards the theoretical predictions at later times when we analyse the mass flow through the gap and the torques acting on the planet. This transient is related to the initial conditions of our (and previous) simulations, and is due to the fact that the shape of the gap has to adjust to a new profile, once the planet is set into motion. Secondly, we test whether the type II theory expectation that giant planet migration is driven by viscosity is consistent with our simulation by comparing simulations with the same viscosity and different disc masses (or vice versa). We find a good agreement with the theory, since when the discs are characterized by the same viscosity, the migration properties are the same

Polariton Pattern Formation and Photon Statistics of the Associated Emission

We report on the formation of a diverse family of transverse spatial polygon patterns in a microcavity polariton fluid under coherent driving by a blue-detuned pump. Patterns emerge spontaneously as a result of energy-degenerate polariton-polariton scattering from the pump state to interfering high order vortex and antivortex modes, breaking azimuthal symmetry. The interplay between a multimode parametric instability and intrinsic optical bistability leads to a sharp spike in the value of second order coherence g (2)(0) of the emitted light, which we attribute to the strongly superlinear kinetics of the underlying scattering processes driving the formation of patterns. We show numerically by means of a linear stability analysis how the growth of parametric instabilities in our system can lead to spontaneous symmetry breaking, predicting the formation and competition of different pattern states in good agreement with experimental observations

Inward and outward migration of massive planets: moving towards a stalling radius

Stars and planetary system

Exciton-polaritons in a two-dimensional Lieb lattice with spin-orbit coupling

We study exciton-polaritons in a two-dimensional Lieb lattice of micropillars. The energy spectrum of the system features two flat bands formed from $S$ and $P_{x,y}$ photonic orbitals, into which we trigger bosonic condensation under high power excitation. The symmetry of the orbital wave functions combined with photonic spin-orbit coupling gives rise to emission patterns with pseudospin texture in the flat band condensates. Our work shows the potential of polariton lattices for emulating flat band Hamiltonians with spin-orbit coupling, orbital degrees of freedom and interactions

Healthcare-associated outbreak of meticillin-resistant Staphylococcus aureus bacteraemia: role of a cryptic variant of an epidemic clone

BACKGROUND New strains of meticillin-resistant Staphylococcus aureus (MRSA) may be associated with changes in rates of disease or clinical presentation. Conventional typing techniques may not detect new clonal variants that underlie changes in epidemiology or clinical phenotype. AIM To investigate the role of clonal variants of MRSA in an outbreak of MRSA bacteraemia at a hospital in England. METHODS Bacteraemia isolates of the major UK lineages (EMRSA-15 and -16) from before and after the outbreak were analysed by whole-genome sequencing in the context of epidemiological and clinical data. For comparison, EMRSA-15 and -16 isolates from another hospital in England were sequenced. A clonal variant of EMRSA-16 was identified at the outbreak hospital and a molecular signature test designed to distinguish variant isolates among further EMRSA-16 strains. FINDINGS By whole-genome sequencing, EMRSA-16 isolates during the outbreak showed strikingly low genetic diversity (P < 1 × 10(-6), Monte Carlo test), compared with EMRSA-15 and EMRSA-16 isolates from before the outbreak or the comparator hospital, demonstrating the emergence of a clonal variant. The variant was indistinguishable from the ancestral strain by conventional typing. This clonal variant accounted for 64/72 (89%) of EMRSA-16 bacteraemia isolates at the outbreak hospital from 2006. CONCLUSIONS Evolutionary changes in epidemic MRSA strains not detected by conventional typing may be associated with changes in disease epidemiology. Rapid and affordable technologies for whole-genome sequencing are becoming available with the potential to identify and track the emergence of variants of highly clonal organisms