Search results for "Environmental engineering"
showing 10 items of 2674 documents
The dynamics of Italian competitive positioning in the Mediterranean Bluefin tuna industry
2020
The bluefin tuna or Thunnus thynnus is one of the widely recognised fish species since ancient times. Italy is the most important players in the international arena, however, the introduction of a system of total allowable catches and other measures established by the International Commission for the Conservation of Atlantic Tunas, has deeply changed the competitive positioning of Italy. The aim of this study is to perform an analysis of the comparative advantage of Italy by using the relative trade advantage index. Findings reveal that Italy has gained a competitive advantage in the Maltese market and has suffered a loss of the historical competitive advantage in the Japanese one. Results …
Improving soil and water conservation and ecosystem services by sustainable soil management practices: From a global to an Italian soil partnership
2020
The UN Sustainable Development Goals (SDGs) identify the need to restore degraded soils in order to improve productivity and the provision of ecosystem services. The aim is to support food production, store and supply clean water, conserve biodiversity, sequester carbon, and improve soil resilience in a context of climate change. Within this framework, in order to achieve the SDGs and to correct land management in the long-term, soil management is considered mandatory. The reduction of land degradation should be based on various sustainable soil management practices that improve and maintain soil organic matter levels, increase water infiltration, and improve soil water management. This tec…
Effect of Mg2+ ions on competitive metal ions adsorption/desorption on magnesium ferrite: Mechanism, reusability and stability studies
2021
Abstract The adsorption behavior of magnesium ferrite in single- and multicomponent metal ions solutions in the presence of Mg2+ ions were studied. A dramatic decrease in the adsorption capacity of magnesium ferrite towards Mn2+, Co2+, and Ni2+ ions for comparison study of single- and multicomponent solutions was established. The affinity of the sorbent in accordance with the maximum sorption capacities increases in the following order Cu2+ > Co2+ > Ni2+ > Mn2+. High efficiency of magnesium ferrite regeneration (~100%) with aqueous solutions of magnesium chloride in the concentration range of 0.001–0.1 M was shown. The low degree of toxic metal ions desorption combined with XRD, IR spectros…
Effects of NH3 and alkaline metals on the formation of particulate sulfate and nitrate in wintertime Beijing
2020
Sulfate and nitrate from secondary reactions remain as the most abundant inorganic species in atmospheric particle matter (PM). Their formation is initiated by oxidation (either in gas phase or particle phase), followed by neutralization reaction primarily by NH3, or by other alkaline species such as alkaline metal ions if available. The different roles of NH3 and metal ions in neutralizing H2SO4 or HNO3, however, are seldom investigated. Here we conducted semi-continuous measurements of SO4 2−, NO3 −, NH4 +, and their gaseous precursors, as well as alkaline metal ions (Na+, K+, Ca2+, and Mg2+) in wintertime Beijing. Analysis of aerosol acidity (estimated from a thermodynamic model) indicat…
Ammonium adsorption, desorption and recovery by acid and alkaline treated zeolite
2021
In this study, the suitability of zeolite as a possible medium for ammonium adsorption, desorption and recovery from wastewater was investigated. Specifically, batch adsorption and desorption studies with solutions enriched in NH$_4^+$ were conducted employing zeolite to evaluate how the chemical treatment and contact time affect adsorption and desorption. Several experimental tests were carried out considering both untreated and treated zeolite. Untreated and HCl-Na treated zeolite adsorbed up to 11.8 mg NH$_4^+$ g$^{-1}$ and showed the highest efficiency in recovering NH$_4^+$ from aqueous solution. Regardless of pre-treatment, treatments with NaCl resulted in higher and faster adsorption…
A comparative study of advanced oxidative processes: Degradation of chlorinated organic compounds in ultrafiltration fractions of kraft pulp bleachin…
2016
Oxidative pre-treatment methods such as the Fenton oxidation, ozonation, and photocatalytic treatment have been compared in reducing adsorbable organic halogens (AOX) and chlorophenolic compounds in untreated kraft pulp bleaching effluent. Their efficiency was also studied on effluent ultrafiltration fractions. The Fenton treatment removed all analyzed chlorophenolic compounds from the effluent. Ozonation and photocatalysis appeared to be much less effective methods. The efficiency of the Fenton oxidation appeared to be more pronounced in higher molecular weight effluent fractions. This suggests a novel design, where the filtration stage can be placed after the oxidation, and the high- -mol…
Diagnosis of boron, fluorine, lead, nickel and zinc toxicity in citrus plantations in Villarreal, Spain
1997
In the late 1980s, citrus plantations in the area of Villarreal (Spain) showed injuries similar to those previously reported for boron and fluorine toxicity. The area was affected by the disposal of industrial wastewater, mainly from ceramic industries. Conjunctive uses of surface water, groundwater and wastewater for irrigation had taken place. A survey was conducted at 25 orchards to assess leaves and soil for their boron, fluorine, lead, nickel and zinc contents. Wastewater and groundwater were also analyzed to corroborate the presence of these pollutants. The results showed that both boron and fluorine contents were greater than those reported as excess at the most part of the orchards …
Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons
2016
The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10 gNaCl L−1 to 20 gNaCl L−1 (Phase I); ii. hydrocarbons dosing at 20 mg L−1 with a constant salt concentration of 20 gNaCl L−1 (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The r…
Nitrate removal microbiology in woodchip bioreactors : a case-study with full-scale bioreactors treating aquaculture effluents
2020
Woodchip bioreactors are viable low-cost nitrate (NO3−) removal applications for treating agricultural and aquaculture discharges. The active microbial biofilms growing on woodchips are conducting nitrogen (N) removal, reducing NO3− while oxidizing the carbon (C) from woodchips. However, bioreactor age, and changes in the operating conditions or in the microbial community might affect the NO3− removal as well as potentially promote nitrous oxide (N2O) production through either incomplete denitrification or dissimilatory NO3− reduction to ammonium (DNRA). Here, we combined stable isotope approach, amplicon sequencing, and captured metagenomics for studying the potential NO3− removal rates, a…
Comparison between a detailed and a simplified integrated model for the assessment of urban drainage environmental impact on an ephemeral river
2008
The benefit of integrated analysis has been demonstrated in technical literature and it is also required by the EU Water Framework Directive 60/2000, which proposes a water-quality-orientated view of the whole urban drainage system and oversees new ways of assessing its performance. Integrated models, such as any complex modelling approach, often have prohibitive data availability requirements that reduce their applicability. Moreover, widely different approaches can be applied, ranging from simple conceptual models to complex physically based ones. In the present paper, two approaches have been compared using data from an experimental catchment in Bologna ( Italy), which consists of a part…