1,721,008 research outputs found
Rainwater in Wastewater Treatment Plants: a Case Study
No full textIn combined sewer rainwater is collected together with wastewater up to a hydraulic load which is multiple of average load, the remaining quantity is overflowed. Rainwater runs off roads and flushes sediments in sewer; so it increase hydraulic load and causes large variations in pollulants loads. Effects of rainwter on hydraulic and organic load were studied in a plant and are presented in this paper
Synthesis of a new class of fluorinated cationic surfactants: 3-perfluoro-n-alkyl-2-hydroxy-N,N,N-trialkylpropan-1-ammonium salts
No full text
Fluoro-alchil silossani idrosolubili per la formulazione di rivestimenti lapidei a bassissima emissione di COV
No full textPROCESS FOR THE MANUFACTURE OF FLUORINATED SURFACTANTS
No full textThe present invention relates to new fluorinated quaternary ammonium compounds of formula (1) and (5), to new fluorinated proteic hydrolisates, to processes for their preparation and to fire-fighting compositions that contain said compounds against fires originated from both apolar and polar hydrocarbon liquids
Small Wastewater Treatment Plants in Italy: Situation and Case Studies of Upgrading with Advanced Technologies
No full textThe choice between centralization and decentralization of wastewater treatment depends on
many factors and requires a case-specific approach. In Italy, 92% of plants have a potentiality
of less than 10,000 p.e., but altogether they treat 31% of total pollutant load. They must comply
with different local regulations and they have higher specific costs than larger plants.
This paper reports some examples of upgrading small overloaded plants with advanced
technologies such as lamellar settlers, dissolved air flotation (DAF), moving bed biofilm reactors
(MBBRs), and membrane biological reactors (MBRs). In plant nr. 1, nitrification was
improved by converting part of the aerated tanks into hybrid MBBRs. Plant nr. 2 was
upgraded by converting an out-of-use tank into a tertiary MBBR. Plant nr. 3 was upgraded
by introducing lamellae into the settler and converting a thickener into a tertiary MBBR. In
plant nr. 4, a DAF unit was installed as a primary treatment to remove Total Suspended
Solids and part of Chemical Oxygen Demand. In plant nr. 5, a DAF unit was installed as a
secondary treatment to work in parallel with the existing settler during rainy days. Plant nr.
6 is in a touristic locality and was upgraded with a new treatment line based on MBR
Synthesis and Surface Properties of Perfluoroalkylatedoligo(oxyethylene)glycols
No full textA series of perfluoroalkylated oligo(oxyethylene) glycols as non-ionic fluorinated surfactants was prepared. The synthesis was performed by adding a molecule of a oligo(oxyethylene)glycol of the general formula HO(CH(2)CH(2)O)(n)OH (n = 1, 2, 4, 6.4, 22.3) to 2-(perfluorooctylmethyl) oxirane in the presence of catalytic amounts of a Lewis acid. This procedure led to the formation of an amphiphilic molecule characterized by an hydrophobic lipophobic perfluorinated tail and hydrophilic non-ionic oligo(oxyethylene)chain. Infra red spectroscopy, mass spectroscopy and multinuclear NMR spectroscopy allowed the chemical characterization of the synthesized compounds to be made. Critical micellar concentration, surface tension, interfacial tension and cloud point measurements carries out on aqueous solutions allowed us to evaluate the surface and interfacial properties of the perfluoroalkylated oligo(oxyethylene)glycols. In addition, surface pressure-area (pi, A) diagrams allowed us to determine the principal parameters characterizing the state of their monolayers. The aim of the work was to investigate the effect of the hydrophilic chain length on physical and surface properties
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