Abstract:
Removal of the organochlorine compounds from industrial wastewater by sonochemical processes was performed in order to evaluate process’ efficiency. Sonochemical degradation of the following organochlorine compounds: 1,2dichloropropane, 1,1,2-trichloroethane, 2 ethylhexanol and , ’—dichlorodiisopropylether was carried out. The experiments was realized with two types of equipment: ultrasound bath UCD-150 and sonotrode UP 200 Ht. Experimental results showed high efficient removal for all compounds: 1,1,2- trichloroethane and ’ dichlorodiisopropyl ether 78.0%, 1,2 Dichloropropane 66.0%, 2 ethylhexanol 35.0 % in bath ultrasound treatment after 60 minutes. Degradation of ’-dichlorodiisopropyl ether, 1,1,2-trichloroethane, 1,2 dichloropropane and 2 ethylhexanol performed much better for sonotrode with 14 mm diameter (89.0%, 77.5%, 73.0%, respectively 73.0%) than for sonotrode with 40 mm diameter (64.0%, 64.0%, 53.0% and 48.0%). This difference between the two probes regarding removal efficiency can be explained by different amplitudes of equipment.
Abstract:
In Natural Reservation is very important to maintain the environmental, the equilibrium for the protected species, flora, and fauna. The paper presents a technological model perfect adapted to these conditions as not disturb the local equilibrium. In the first part are mentioned the topic importance and the new problems appeared into last decades, related to the environmental problems in Natural Reservation Lake Techirghiol. This new solution placed on a mobile pontoon uses renewable resources as to collect and partially dry the collected sludge from the lake. Some experimental measurements were done in 2015, as to determine the quality of water, the main parameters, and the conditions responsible for disturbing the ecosystem. The technological model intends to solve the local problem, to collect, compact and partially dry the active sludge. The extracted sludge can be in short time integrally consumed for agricultural purpose, as ecologic and nutritive fertilizer for the adjacent area, known as the Plover, with low potential for agriculture. The sludge, well known in the past for its human therapeutic utilization, more, then one hundred ago, nowadays-due ecological and biological changes lost his efficiency. The reconstruction of the local ecologic balance and for the sludge to recover its therapeutic properties, using renewable resources, without disturbing the environment are the main objectives of this research. Some conclusions, the acknowledgements, and references are also presented.
Abstract:
This study deals with the experimental evaluation of some relevant ash samples collected from the flue gas filters of a hazardous waste incinerator plant. The experimental analysis focuses on size, distribution and dielectric properties of the samples. The reported results reveal the presence of nanoparticles in the samples and the possibility to use dielectrophoresis for their handling. The study exploits also numerical simulations in order to investigate the behavior of nanoparticles with size range from 50 to 150 nm, which is fructified as a micro channel – working unit used as a particulate trap. Based on the experimental data and a proposed mathematical model, the concentration profile of nanoparticles suspension inside a micro fluidic separation device is calculated and the performance of the device is analyzed in terms of three new specific quantities of separation process, called Recovery, Purity and Separation Efficiency.
Abstract:
The kinetics of the oxidation process of the organic substances known as fuel gas (the alkanes class in general) deals with reactions whose mechanisms are analyzed in many theories and models. Irrespective of the nature and excess of the carburant, all partial combustion intermediates are revealed: alcohols, aldehydes, organic acids (that together with other derivatives from catalytic reforming reactions are characterized by the global parameter VOCs), carbon monoxide and carbon dioxide and finely divided carbon under the form of soot. The volume of oxidation intermediates increases when the carburant excess decreases monotonously to values below the stoichiometric ratio, so that when the limit is reached the carbon dioxide and water vapor volumes can be minimal. This paper puts forward a kinetic combustion model based on the parallel and consecutive reactions producing part of the chemical compounds that form the concentration of VOC, carbon monoxide and finely divided particles of the gas produced by fuel gas combustion.
Abstract:
Some natural adsorbents were evaluated for the advanced removal of pollutants from aqueous systems. The sorption capacity of walnut shells and volcanic zeolite tuff (from Mirsid-Cluj Romania) to remove the chrome and cadmium at different experimental conditions was studied. The concentration of metal ions in aqueous systems was evaluated with an inductively coupled plasma mass spectrometer (ICPMS) and an atomic absorption spectrometer. The effect of time, initial concentration of the metals and solution pH on the adsorption at room temperature was studied. pH of the solutions was found to influence the adsorption. Higher Cr(VI) adsorption was observed at lower pH and at low concentration of metal ions. The maximum efficiency of volcanic tuff in acidic media was 97.12% for chrome and 57.04% for cadmium, respectively, for 0.1 mg/L initial concentration. Moreover, in the same experimental conditions, the maximum efficiency of walnut shells was 61.24% and 44.51% for chrome and cadmium. The two low-cost natural sorbents were efficient for the remove of pollutants from aqueous systems.
Abstract:
In Romania, there are more than 200 dams realized during 1975-1990 from local materials, without any ulterior remediation or rehabilitations. Nowadays, many hydropower systems confront with infiltration through dams or lateral dikes, followed by unexpected erosions. In order to maintain the hydropower system active, the water level is drastically reduced, sometimes even with 10 m. Consequently, it means less water for the human necessities (water supply, irrigation), but mainly few resources to produce electric energy. The research paper starts by presenting the actual dams situation, structured on hydrographic basins. For the case study two hydropower lakes from Arges-Vedea hydrographic area that confront seepage through embankments were selected. In that area there are more than 100 lakes which confront with different functioning problems. The local geomorphologic structure and the water quality create an image of local functioning conditions. Further, there are briefly presented the mathematical and numerical models, elaborated as to establish the infiltration risk zones. The numerical model is tested and calibrated based on local conditions, showing the zone with erosion and infiltration risks. Finally, some conclusions, possibilities to extend the numerical model, the acknowledgements, and references are presented.
Abstract:
The development of new materials, with imposing properties – for environmental protection, represents a challenge for contemporary society. In this paper, we propose obtaining of new adsorbent materials from thermo plant ash and lime. The use of ash presents the advantage, because this waste is in great quantities, and it is a way for its capitalization. The new materials offer new scientific and technological perspectives due to the specific interesting physical properties of these materials. The utilization of adsorbents based on ash/lime, for waste water depletion, represents an alternative with ecological and economic implications. The authors present in this study the results of experimental researches on the adsorbents prepared in the laboratory using fly ash produced at CET Holboca Iasi and lime from Bicaz. The experimental conditions of obtaining new adsorbents were established and the characterization of synthesized materials was realized. Raw and synthesized materials were characterized by: SEM/EDAX (Quanta 3D – AL99/D8229), XRD (X’Pert PRO MRD X-ray diffractometer), BET (Quanta-chrome Instruments) and FT-IR analysis (DIGILAB FTS 2000). Experimental results demonstrated that the new materials can be successfully used for removal of lead from waste water. The removal rate was over 97%, after 60 minutes, and adsorption capacities were obtained of 21.25 mg/g. The resulted product is easy to separate and can be used as building material. On the other hand, the product is not polluted for the environment.
Abstract:
An experimental study has been carried out to assess sulphate precipitation via ettringite process from acid mine water (AMD) originating from closed non-ferrous Romanian mining areas. Such a treatment is required, because by conventional treatment of the AMD with calcium hydroxide, the conformity for sulphate will not be achieved, because the concentration correlated to gypsum solubility exceeds the limit value by roughly three times. Although sulphate is considered benign or with low toxicity, some countries have set limits for the wastewater discharged to natural receivers, from 500 to 1000 mg/L or 600 mg/L in Romania. The process of sulphate precipitation as ettringite using solid aluminium sources is known to be slow. Tests for sulphate precipitation, using monocalcium aluminate cement as source of reactive aluminium for the ettringite formation were done using continuous flow mixed flow reactors in series (or continuous stirred reactors, CSTR). This reaction system allows the direct determination of the apparent reaction rate versus sulphate concentration which can be used further for various design tasks. The reaction rate for sulphate concentration below 600 mg/L may be less than 5 mg/L/min, depending on working conditions. The mixed flow reactors series has a net advantage over single CSTR, the best choice for a full scale treatment plant is a mixed flow reactors series also, as the results indicate that a system with a single mixed flow reactor is to be much larger.
Abstract:
Short-term cavitational treatment (22 kHz, 1.65 W/cm3, 35 W) of the water showed an increase in the amounts of the cells of Bacillus cereus bacteria type that was explained by the process of cell disaggregation usage microscopical investigations. The duration of disaggregation process was 3-5 minutes with gas bubbling during sonication but 30 minutes without gas bubbling during sonication. It was shown an acceleration of disaggregation process under simultaneous action of gas and cavitation by 10 times (synergistic effect).
Abstract:
In this paper there are presented laboratory studies on the influence of additives in diesel fuels on accidental pollution of the soil. The additive used in the experiments was cyclohexanone ketal glycerol. The presence of hydroxyl groups in the structure of ketals of glycerol decreases the solubility of hydrocarbons. To solve this disadvantage and for improving other features, in order to use as additives/components for classic fuel, the hydroxyl group of glycerol ketal methyl ethyl ketone was block by transesterification with methyl esters of monocarboxylic acids. The results obtained were compared to the content of nutrients (N, P, K) in the soil polluted with diesel fuel additives and diesel oil without additives. It was performed the soils decontamination by applying the method of solvent extraction. For ecological reconstruction there were used unpolluted soil samples, samples contaminated with diesel oil with and without additives and the resulting samples after the extraction with the solvents.
Abstract:
2,4,6-Trinitrotoluene(TNT) is one of most common toxic pollutant identified in wastewater generated from ammunitions plants, due to its potential carcinogenic characteristics. Various treatment methods were investigated in order to remove such toxic pollutants and among them, photocatalysis was successfully applied. From various semiconductors, titanium was a widely studied photocatalyst, due to its chemical inertness, low cost, photo stability and nontoxic character. Since, TiO2 is only photoactive under UV irradiation, modification of semiconductor by metal doping, aimed to reduce photocatalyst band gape and increase its quantum efficiency in visible domain represents an important issue. Fe-TiO2 assisted photocatalytic degradation of TNT in aqueous media, under UV-VIS irradiation was studied. The effects of operating parameters such as catalyst loading and pollutant concentration were assessed. TNT degradation was found to follow a pseudo-first order kinetic. The main oxidative species responsible for pollutant degradation are the surface adsorbed hydroxyl radicals.
Abstract:
A mixture of grassland species Lolium perenne, Festuca arundinaceea, Medicago sativa and Ttrifolium pratense were used in situ phytoremediation of oil polluted soil, with 70.45-120.52 g/kg d.m. Total Petroleum Hydrocarbons (TPH). They were studied variants of phytoremediation of oil polluted soils and fertilized with 50 t/ha stabilized sewage sludge in absence / presence of 50 t/ha fly ash, waste from coal burning power plants. Lolium sperenne herbs formed on the surfaces sown exclusive bouquets, in first weeks. After six weeks of vegetation appear and develop leguminous species Medicago sativa and Trifolium pratense. After five months, was a balanced distribution of species of legumes and grasses species on the surfaces sown. The efficiency reducing the TPH from oil polluted soil was 48.7% in variant fertilized with stabilized sewage sludge and fly ash. Efficiency was with 15.3% higher than the reduction efficiency of petroleum products in fertilized variants in fly ash absence. The process efficiency of oil polluted soil treated with stabilized sewage sludge and fly ash was similarly with phytoremediation variant with fertilizer and indigenous volcanic tuff realized.
Abstract:
The influence of various dopant types like S, Fe, Co, Ni (5% wt.) in the photocatalytic degradation of cyclophosphamide under UV-VIS irradiation was investigated. The working conditions were as follows: irradiation time up to 270 minutes, photo catalyst dose 100 mg/L, initial pollutant concentration 19.15 mg/L. Pollutant degradation was found to follow a pseudo first order kinetic. CP degradation rate constants decreases in the following order kFe-TiO2 > kNi-TiO2 > kCo-TiO2 > kS-TiO2 > kTiO2, which was also in accordance with chlorine mineralization rate constants.
Abstract:
This study shows the wastewater efficient treatment process resulted with Fe-Al complex coagulation agent obtained from industrial waste. Coagulation agent prezented 24.5 – 28.0 g·L-1 Fe and 16.0 – 17.5 g·L-1 Al content. pH coagulation agent is in the range pH=1-2. The wastewater with high degree i.e. chemical oxygen demand (COD) = 25,000-30,000 mg O2·L-1, Total organic carbon (TOC) = 3,600 – 4,000mg C·L-1, dry matter = 9.55 – 10.45 g·L-1, etc. is resulted from printing house. Treated water samples with the optimal dose of coagulation agent based on iron-aluminium salts obtained from industrial waste prezented similar TOC and dry matter reduction efficiencies with samples treated with the optimal dose of ferric chloride. COD reduction efficiency in treated water samples with the optimal dose of coagulation agent based on iron-aluminium salts it was 10% greater vs. reduction efficiency obtained from samples water treated with classic coagulation agent, FeCl3. The advantage of the complex Fe-Al coagulation agent obtained from industrial waste was that it can be used for some wastewater of printing house in lower optimal dose, by 30%, vs. ferric chloride, coagulation agent. The complex Fe-Al coagulation agent obtained from industrial waste cost is much less than that of classical coagulation agents.