Antibacterial behavior of silver-modified clinoptilolite-heulandite rich tuff on coliform microorganisms from wastewater in a column system

The water disinfecting behavior of silver-modified clinoptilolite–heulandite rich tuff (ZSAg) as an antibacterial agent against coliform microorganisms from water in a continuous mode was investigated. Silver recovery from the disinfected effluents by the sodium-modified clinoptilolite–heulandite rich tuff (ZSNa) was also considered. Escherichia coli (ATCC 8739) and total coliform microorganisms, as indicators of microbiological contamination of water, were chosen to achieve the disinfection of synthetic wastewater or municipal wastewater. Ammonium (NH₄⁺) and chloride (Cl⁻) ions were added to the synthetic wastewater as an interfering chemical species on the disinfection processes. The antibacterial activity of the ZSAg as a bactericide was measured by the coliform concentration as evaluated by the APHA method. The amount of silver in the disinfected effluents was determined using atomic absorption spectroscopy. The inactivation of the ZSAg was calculated from the breakthrough curves based on the model reported by Gupta et al. It was found that when the silver concentration in the effluent is less than 0.6 μg/mL, the bacterial survival percentage increased and the volume of disinfected water diminished. The total silver amounts found in the effluent at the end of the disinfection processes varied depending on the water treated (synthetic or municipal wastewater). The presence of NH₄⁺ ions in synthetic wastewater influent notably improved the disinfected water volume (zero NVC/100 mL), in comparison to the disinfection of the same influent without NH₄⁺ ions. A contrary water disinfection behavior was observed in the presence of Cl⁻ ions. The silver recovery does not depend on the mass of the sodium zeolitic bed according with the wastewater to be treated (synthetic or municipal wastewater) and the presence of NH₄⁺ or Cl⁻ ions in the influent also influenced the silver recovery from wastewater. The ZSNa did not have antibacterial activity. Therefore the amount of bactericide agent (silver-modified natural zeolite), coliform microorganisms from water (E. coli or consort of coliform microorganisms) as well as the water quality (synthetic wastewater or municipal wastewater) influenced both the disinfection process and the silver recovery in a column system.     

Adsorption of basic dye from aqueous solution onto fly ash

The fly ash treated by H₂SO₄ was used as a low-cost adsorbent for the removal of a typical dye, methylene blue, from aqueous solution. An increase in the specific surface area and dye-adsorption capacity was observed after the acid treatment. The adsorption isotherm and kinetics of the treated fly ash were studied. The experimental results were fitted using Langmuir and Freundlich isotherms. It shows that the Freundlich isotherm is better in describing the adsorption process. Two kinetic models, pseudo-first order and pseudo-second order, were employed to analyze the kinetic data. It was found that the pseudo-second-order model is the better choice to describe the adsorption behavior. The thermodynamic study reveals that the enthalpy (ΔH⁰) value is positive (5.63 kJ/mol), suggesting an endothermic nature of the adsorption.     

How to Consider the Value of Farm Animals in Breeding Goals. A Review of Current Status and Future Challenges

The objective of this paper is to outline challenges associated with the inclusion of welfare issues in breeding goals for farm animals and to review the currently available methodologies and discuss their potential advantages and limitations to address these challenges. The methodology for weighing production traits with respect to cost efficiency and market prices are well developed and implemented in animal breeding goals. However, these methods are inadequate in terms of assessing proper values of traits with social and ethical values such as animal welfare, because such values are unlikely to be readily available from the product prices and costs in the market. Defining breeding goals that take animal welfare and ethical concerns into account, therefore, requires new approaches. In this paper we suggest a framework and an approach for defining breeding goals, including animal welfare. The definition of breeding goals including values related to animal welfare requires a multidisciplinary approach with a combination of different methods such as profit equations, stated preference techniques, and selection index theory. In addition, a participatory approach involving different stakeholders such as breeding organizations, food authorities, farmers, and animal welfare organizations should be applied. We conclude that even though these methods provide the necessary tools for considering welfare issues in the breeding goal, the practical application of these methods is yet to be achieved.     

Long-term effects of sustained beef feedlot manure application on soil nutrients, corn silage yield, and nutrient uptake

A field study was initiated in 1992 to investigate the long-term impacts of beef feedlot manure application (composted and uncomposted) on nutrient accumulation and movement in soil, corn silage yield, and nutrient uptake. Two application strategies were compared: providing the annual crop nitrogen (N) requirement (N-based rate) or crop phosphorus (P) removal (P-based rate), as well as a comparison to inorganic fertilizer. Additionally, effects of a winter cover crop were evaluated. Irrigated corn (Zea mays L.) was produced annually from 1993 through 2002. Average silage yield and crop nutrient removal were highest with N-based manure treatments, intermediate with P-based manure treatments, and least with inorganic N fertilizer. Use of a winter cover crop resulted in silage yield reductions in four of ten years, most likely due to soil moisture depletion in the spring by the cover crop. However, the cover crop did significantly reduce NO3-N accumulation in the shallow vadose zone, particularly in latter years of the study. The composted manure N-based treatment resulted in significantly greater soil profile NO3-N concentration and higher soil P concentration near the soil surface. The accounting procedure used to calculate N-based treatment application rates resulted in acceptable soil profile NO3-N concentrations over the short term. While repeated annual manure application to supply the total crop N requirement may be acceptable for this soil for several years, sustained application over many years carries the risk of unacceptable soil P concentrations.     

Global warming and environmental production efficiency ranking of the Kyoto Protocol nations

This paper analyzes the United Nations Organization's Kyoto Protocol nations to address two questions. First, what are the environmental production efficiency rankings of these nations? Second, is there a relationship between a nation's ratification status and its environmental production efficiency ranking? Our findings suggest that the nations that have ratified the Kyoto Protocol are more likely to be environmentally production efficient as compared to the nations that have not ratified the Protocol.