Search results for "Wastewater treatment"
showing 10 items of 178 documents
Endophytes from Phragmites australis: their role in phytodepuration
Wastewater treatment is an alarming question and phytodepuration represents an efficient and cost-effective solution. Phragmites australis is generally used for phytodepuration and it excellently removes arsenic, iron and nickel from polluted water. The purification potential of its bacterial endophytic community has never been explored though. G.I.D.A. S.p.a uses P. australis for phytoremediation in a pilot plant, at Calice purifier, which treats the effluent from the Membrane Bioreactor plant. Endophytic bacterial strains were isolated from different P. australis compartments sampled before the activation of the Calice purifier and four additional times during a 18-months period, to analy…
Screening of microalgae and LED grow light spectra for effective removal of dissolved nutrients from cold-water recirculating aquaculture system (RAS…
2019
Popularity of recirculating aquaculture systems (RAS) is increasing. Because of the high water recirculation rate, dissolved nutrients originating from fish feed are concentrated enough in RAS wastewater (WW) to enable growth of primary producers, e.g. microalgae. This study evaluated nitrate-nitrogen (NO3-N) and phosphate-phosphorus (PO4-P) removal efficiency of ten temperate zone freshwater microalgae species during their exponential growth phase in unfiltered RAS WW at 17 ± 0.5 °C. Growth and nutrient uptake efficiency of six green and four non-green microalgae strains were compared between WW and reference growth medium in batch monocultures. The effect of three different LED grow light…
Electrochemical production and use of chlorinated oxidants for the treatment of wastewater contaminated by organic pollutants and disinfection
2021
Abstract In the last years, an increasing attention has been devoted to the use of electrogenerated chlorinated oxidants for the treatment of wastewater polluted by recalcitrant organics and/or for the disinfection of water contaminated by pathogen microorganisms. In this review, more recent and relevant findings were presented and critically discussed. The main advantages and disadvantages of this technique were commented, including the potential formation of toxic chlorinated organic specie and of chlorate and perchlorate or the difficult selection of proper operative parameters, as well as the key points that should be addressed to enhance the use on an applicative scale.
Effect of air pressure on the electro-generation of H2O2 and the abatement of organic pollutants in water by electro-Fenton process
2015
Abstract The electro-generation of H 2 O 2 and the abatement of the model organic pollutant Acid Orange 7 (AO7) in water by an electro-Fenton process were performed under moderate air pressures (up to 11 bar) for the first time to our knowledge. An increase of the pressure gave rise to a drastic enhancement of the concentration of hydrogen peroxide. In systems pressurized with air at 11 bar, the electro reduction of oxygen at a graphite cathode gave rise to a concentration of H 2 O 2 of about 12 mM, about one order of magnitude higher than that achieved at atmospheric pressure. This result is attributed to the mass transfer intensification induced by the higher local concentration of molecu…
Electro-generation of H2O2 and abatement of organic pollutant in water by an electro-Fenton process in a microfluidic reactor
2013
The electro-generation of H2O2 and the abatement of the model organic pollutant Acid Orange 7 (AO7) in water by an electro-Fenton process were performed both in a conventional undivided macro cell and, for the first time, in a microfluidic reactor. Under optimized operative conditions, the reduction of oxygen in the microdevice gave rise, using graphite cathode, to a concentration of H2O2 of about 6 mM, one order of magnitude higher than that achieved in conventional cells. Similarly, when electro-Fenton was performed in the microfluidic reactor a dramatic increase of the abatement of COD was achieved with respect to that obtained in a conventional cell. Keywords: Wastewater treatments, Mic…
Greenhouse gases from membrane bioreactors: New perspectives on monitoring and mathematical modeling
2020
Abstract The awareness that the wastewater sector represents a significant source of greenhouse gas emission has increased, and is the awareness is evident based on the numerous research papers published in technical literature in the last 10 years. This chapter is aimed at providing a timely overview on greenhouse gas production and emission from membrane bioreactors. Specifically, this chapter dedicates particular attention to nitrous oxide (N2O), considering both experimental and mathematical modeling approaches. Referring to the experimental data, the observed results highlighted the significant contribution of the aerated compartments toward nitrous oxide emission as well as the import…
Quality Standards for Recycled Water: Opuntia ficus-indica as Sorbent Material
2017
In recent years, increased industrial and agricultural activities and the correlated population growth led to overexploitation of natural resources and the increased generation of various types of pollutants. For these reasons, the hazardous pollution of wastewater is one of the most important environmental problems worldwide. A wide range of wastewater treatment technologies are available; however, some disadvantages are often reported. Hence, there is a constant need to search for an efficient, low-cost and alternative wastewater treatment. Recently, several biosolids have been considered for pollutant removal from wastewaters, including Opuntia ficus-indica. This chapter focuses on waste…
Analysing the efficiency of wastewater treatment plants: The problem of the definition of desirable outputs and its solution
2020
Abstract Evaluating the efficiency of wastewater treatment plants (WWTPs) is highly relevant to improve their performance from an economic and environmental perspective. The issue is even more critical in countries where WWTPs are benchmarked to regulate water companies and define WWTPs’ economic and environmental objectives. Despite the large number of previous studies on this topic, none has considered that the amount of outputs produced by the WWTPs is restricted by the concentration of pollutants in the effluent. To overcome this limitation, the study’s main objective was to propose a new variant of the Weighted Russell Directional Distance Model (WRDDM) that would solve problems regard…
Effect of air pressure on the electro-Fenton process at carbon felt electrodes
2018
Abstract The effect of air pressure on electro-Fenton (PrEF process) was evaluated using two organic substances (maleic acid and Acid Orange 7) as model organic pollutants. First experiments were performed using a conventional carbon felt (CF) cathode. At room pressure, a slow removal of maleic acid was obtained, together with the generation of formic acid. Conversely, using pressurized air, the removal of maleic acid was dramatically accelerated and the formation of formic acid was not detected. The utilization of a carbon felt modified by the deposition of carbon black + PTFE mixture (MCF) and of pressurized air allowed to achieve even faster and almost total (>95%) removal of total organ…
Case Studies of Macro-and Microplastics Pollution in Coastal Waters and Rivers: Is There a Solution With New Removal Technologies and Policy Actions?.
2020
This opinion paper on microplastics pollution has selected different aspects and case studies of micro and macro-plastic litter pollution in coastal waters, and rivers. We point out a discussion on this topic and ask ourselves if there is a solution to the global problem by developing new microplastics removal technologies as well as policy actions. The first two case studies are related with macroplastics marine litter in beaches, a third report describes a new simple sampling device for microplastics in coastal and nearshore areas, five case study assess microplastics pollution in worldwide coastal environments, sediments and catchments (India, Mexico, Australia, Europe and the Nordic Sea…