All posts by simiecoind

Abstract:
Sludge obtained in the tertiary stage of wastewater treatment can become a source of potential fuels. Up to now, the methods applied for making the best use of such sources have aimed at obtaining energy through indirect processes and using sludge for agricultural land improvement. However, most conversion methods applied on a national scale have major technical and economic disadvantages, as well as a negative impact on the environment. The present paper summarizes the research work performed by the authors for the direct use of sludge under the form of solid fuel, as well as the optimisation of the disposal of sludge resulted from biological wastewater treatment.

Abstract:
In situ chemical oxidation (ISCO) is one of promising remediation technologies applied within the Central and Eastern Europe. Type and extent of contamination, as well as treated matrix and an application method are driving parameters for determining, which of oxidation agents or their combinations are the best choice for set site conditions. Laboratory experiments of Fenton’s reagent, potassium permanganate and sodium persulphate (activated and nonactivated) plus conclusions of selected pilot-scale tests are discussed. Information on a possible combination of ISCO with surfactants is further given. Biologically enhanced reductive dechlorination (bio-ERD) offers a potential for destruction of chlorinated ethenes by an addition of a suitable electron donor directly to a contaminated ground. Organic by-products or processing waste of a food industry (e.g. beet molasses, stillage, whey) represent suitable as well as low-cost alternative electron donors for boosting this process. Results of laboratory experiments and a pilot-scale test performed on site heavily contaminated by chloroethylenes are presented. Nano zero-valent iron (nZVI) has 20 to 30-times higher reactivity then conventional ZVI, and thus this aspect is often stated as a main advantage of its usage (as a contrariety to its high price). Stoichiometry and passivation of nZVI active surface by reaction by-products are closely associated together and this fact directly influences practical efficacy this material. Experimental testing of various nZVI reactivity on Cr(VI+) and results of a pilot-scale on a site polluted by chlorinated hydrocarbons and petroleum substances are discussed. Moreover, bio-ERD and nZVI can be successfully combined in order to speed up remedial process, stabilise its performance and to cut clean-up financial costs. During this remedial train, nZVI generally accelerates establishment of anaerobic conditions in the ground and makes the first decomposition step (chemical reduction) of targeted pollutants. Later, the bio-ERD process finishes contamination treatment and, in general, returns back natural conditions onto a remediated site.

Abstract:
Combined sorbents based on cotton fiber and copper-potassium ferrocyanide were obtained. The influence of the main technological parameters of modification process on the inorganic component content in the final product and sorption properties was investigated. The sorption properties of new combined sorbents toward microamounts of 137Cs were found out. The structure of obtained sorbents was studied by methods of X-Ray diffraction and the decrease in degree of crystallinity of the modified sample was shown. A comparative analysis of the thermal characteristics of the initial and the modified fiber was done. It was found out that the thermal degradation of bleached cotton fiber modified by copper-potassium ferrocyanide occurs at higher activation energy than the initial fiber.

Abstract:
The biotechnological principle of using combined microalgae – activated sludge system for wastewater treatment consists in bidirectional metabolic fluxes that can be established between the photoautotrophic microalgae and heterotrophic bacteria. Thereby, the oxygen released during the photosynthesis process by the microalgae species is used by bacteria to degrade organic matter, the resulted degradation products (mainly CO2) being used in turn as nutrients by the microalgae for cell development. Since the microalgae biotechnology has been recognized as a viable solution for wastewater treatment, it was used mainly in tertiary treatment processes. However, during the last decade, several researchers focused their studies on using the microalgae for secondary wastewater treatment, high treatment performances for domestic and industrial wastewater being attained. The main drawback of this biotechnology is represented by the poor microalgae cells recovery. The currently applied methods (centrifugation, filtration, flocculation/coagulation etc.) are involving high costs, contamination with heavy metals, filter clogging etc. In order to solve this problem, several researches were conducted in this field and, until now, bio-flocculation method seems to be the most feasible solution.

Abstract:
A necessary condition for proper functioning of the economically optimal biological reactor is the correlation between the flow rates of introduced oxygen with the consumed in the metabolic degradation of organic materials. Modeling of physical, chemical and biological processes of aeration tanks in leachate treatment plants is difficult because they are very complex. In the aerobic biological reactor, the oxygen consumption varies over time and space due to the unevenness of the influent load of biodegradable organic substances or change the kinetic relationship between the growth rates of biomass and elimination rates of the substrate. Biological reactors for the treatment of leachate considered, provided with two types of air dispersion devices placed at the bottom of the basin(perforated pipe in the first bioreactor and porous diffusers in second bioreactor), was created using Flex PDE, two models. Modeling the dissolved oxygen concentration in the leachate, was aimed to optimize the process of mass transfer of oxygen from air into water, having an important role in minimizing the operating costs of facilities, energetic optimization of aeration systems and an improving on performances for leachate treatment. The models were designed for a two-dimensional domain, and to appreciate the distribution of oxygen concentration for both bioreactors equipped with different lenses (perforated pipes and porous diffusers). Numerical integration of the dispersion equation for the analyzed case was adapted by running a program written by the user using Flex PDE software package. The phenomenon of mass transfer at the interface was found by a continuous flow conditions required in the surface pores through which compressed air is blown. The results shows that the use of air insufflation made from porous diffusers is more efficient, compared to the system made from perforated pipes, the required value of the concentration of dissolved oxygen reached in a time period much lower, similar to that encountered in practice.

Abstract:
Domestic wastewater treatment plants have high energy loads for a good development of treatment processes. The organic load of sludge resulting from wastewater treatment is an inexhaustible source of potential energy to the treatment plant, if used in an efficient process of anaerobic digestion (AD). Since AD is also a major consumer of energy, then to get a larger amount of energy than necessary for the process, it is necessary to optimize the anaerobic digester, both in terms of hydraulic and in terms of heat, so that the heat loss is minimal and the temperature distribution to be uniform.

Abstract:
In order for the biological processes in wastewater treatment systems to develop optimally a good contact between the microorganisms and the substrate has to be realized. The reactors homogeneity can be achieved by applying intensive mixing systems that have high energy consumption. This paper has the aim of determining the optimal system that can assure the close contact while maintaining the energy need as low as possible.

Abstract:
Water is an essential substance for living systems as it allows the transport of nutrients and waste products in living systems. Research shows a clear correlation between diseases and the amount and types of fluids consumed, health-promoting properties of nutrients which can be added to water, optimal intake levels, and consumption patterns. Although three quarters of the Earth’s surface is covered with water, most of that water is not suitable for human consumption. Today, hundreds of millions of people in vast regions of the world do not have access to water to meet their basic needs. Natural disasters also create conditions which limit the availability of water that is suitable for human consumption. Industrial processes use significant amounts of water which require treatment before discharging to surface water systems. Municipal wastewater treatment systems discharge their effluents which often impact the aquatic organisms. This paper provides a survey of new developments and innovations relative to water treatment for drinking purposes and wastewater treatment during the last few years. For drinking water treatment, the recent technological advancements relate to primarily filtration (media filtration and membrane systems), disinfection processes, ion exchange, and carbon adsorption processes. For wastewater treatment, a significant majority of recent developments relate to biological processes and advanced treatment technologies such as adsorption. A review of the recent patents show innovative designs for treatment units, efficient approaches for water quality, as well as nanotechnology applications for removing impurities and disinfection purposes.

Abstract:
The dangerous radiation like ultraviolet, ionized, gamma and x have been studied in order to evaluate their impact to the public health. Especially the atmospheric ultraviolet radiation, due to the ozone hole, became more and more important for the public health particularly in summer time. This research has been focused to ultraviolet radiation (outdoor) in various seasons, in different regions. Also, various types of lamps of varied power have been investigated regarding their ultraviolet radiation production (indoor). The significant conclusion is that the highest values of ultraviolet radiation are observed in summer time and specifically at noon. The milky lamps are produced less ultraviolet radiation than the transparent lamps due to absorption. Similarly is between lamp- projector without mirror with those with mirror. As more broad the spectrum of ultraviolet as the absorption from the atmosphere is more weedy.

Abstract:
A pilot plant for the treatment of acid mine drainage was tested in the Apuseni Mountains on behalf of the Rosia Montana Gold Corporation. A containerised mobile unit was developed and built by a team of WISUTEC, G.E.O.S. and BAUER Water and operated for a period of 7 months. The plant allowed testing of two innovative treatment technologies, a two-stage precipitation process, and nano-filtration including optional solution pre-treatment and concentrate neutralisation, both of which proved their reliability in relation to durability and compliance to the stringent Romanian discharge limits (NTPA 001/2005). Valuable operating and cost data for future process design were obtained.

Abstract:
The aim of this paper was to apply the electrochemical oxidation on Dimensionally Stable Anodes (DSA) to remove pharmaceuticals at low concentrations from wastewaters. Two anodic compositions were used: Ti/RuO2-TiO2 and Ti/RuO2/SnO2-Sb2O5-RuO2 and diclofenac (DCF), a nonsteroidal anti-inflammatory drug, which is recalcitrant to biological degradation, was chosen as a model of pharmaceuticals. The experiments were carried out by using simulated solutions of DCF of 1 mg/L in 0.1 M Na2SO4 as supporting electrolyte and spiked effluent of a wastewater treatment plant (DCF-EWWTP). The applied current densities were 100, 200 and 300 A/m2 and pH of 5.8 and 11. The process was followed by recording the UV spectra and assessing the DCF concentration in the electrolysed solutions by high-performance liquid chromatography (HPLC) with ultraviolet-visible (UV-VIS) detection. The best results were obtained by using Ti/RuO2/SnO2-Sb2O5-RuO2.

Abstract:
Chlorinated aniline belongs to the anilines family, which are common pollutants, being frequently used as intermediates for the chemical synthesis in polymer, rubber, pesticide, pharmaceutical and dye industries. Due to their high toxicity and persistence in aquatic environments, they are classified by European Water Framework Directive 2000/60/EC as the priority pollutants and are strictly regulated in EU countries. Since their presence in water bodies is risky for human health and aquatic life, developing powerful, modern treatment methods like advanced oxidation processes (AOP`s) are needed in order to assures pollution mitigation. If properly applied, TiO2-based photocatalysis can be regarded as an environmentally friendly and cheap treatment option. In the present study, solutions with (0.14-14.2) x 10-4 M 4-CLA content were photo-oxidized in the following working conditions: pH=4; [TiO2] = 50-500 mg/L; [H2O2] = (0.1-10)x10-3M; τirr = 5 – 180 minutes. Pollutant degradation pathway by three possible routes was proposed, according to organic intermediates identified by gas-chromatography coupled with mass spectrometry-screening method. The first route consists of OH radical attack on target pollutants with amino group substitution and 4- chlorophenol (4-CP) formation. The second degradation route represents OH radical attack on aromatic ring by hydrogen abstraction with aniline-radical formation, that is subsequently stabilized by dimerization to 4,4’- dichloroazobenzene (DCAB), which is further oxidized to 4-chloronitrobenzene (4-NCB). The third route of pollutant degradation takes place by a heterolytic mechanism consisting of hydrogen and chloride atoms release as HCl, and aniline (A) formation, which is oxidized to 4-aminophenol (4-AP) by OH radicals addition to the aromatic ring. The secondary intermediates (4-CP, 4-AP, 4-NCB) are subsequently hydroxilated to hydroquinone that is also oxidized to benzoquinone leading to carboxylic acids by its ring cleavage under OH radical attack. Based on experimental results can be concluded that after 90 minutes of irradiation, 4-CLA was complete degraded. Mineralization yields of organic chlorine and nitrogen were around 81% and 85%, respectively for prolonged irradiation (180 min.). These results are consistent with presented degradation pathway that proposed as intermediates, aromatic compound like 4-CP, A, 4- NCB and 4-AP. The presence of these intermediates in irradiated samples is also supported by 82.4% TOC removal yield obtained at prolonged irradiation.

Abstract:
Environmental relationships with socio-economic activities has become a concern since the last decade of the last century and has evolved in complexity and shapes according to evolutionary laws and interest in environmental compliance requirements and demands. The work reviews synthetically the scientific fundaments of the compulsory provisions and regulations for obtaining the environment permit, agreements and authorizations from the habilitated environment institutions and of the voluntary procedures for the ISO14001 certification and the registration with the EMAS register.

Abstract:
This paper presents trichloroethylene (TCE) removal efficiencies from soilpolluted matrix based on batch oxidation experiments with potassium permanganate, at laboratory scale. The influence of KMnO4 dose and the reaction time on TCE degradation were evaluated, taking into account: chloride ions generated and residual TCE in aqueous phase. The soil sample was CAHfree topsoil having the following main characteristics: pH = 7.5, humus 3.3% d.w., 2 g TCE/ kg d.w. (addition of TCE analytical reagent), 58 mg Cl- /kg d.w., 55 g Fe/kg d.w., 29 mg Pb/kg d.w. Batch tests were performed in slurry system (soil:distilled water weight ratio of 1:10), continuous stirring. Solid oxidant KMnO4 was added in the range of 4.75 g/kg d.w. (stoichiometric amount) – 220 g/ kg d.w. and reaction times were two hours, 2 days and 4 days each of them corresponding to at least two different oxidant doses. Potassium permanganate reacts with both soil organic matrix and TCE. Trichloroethylene oxidation efficiency depends on the oxidant dose and oxidation/solubilization of soil organic matrix. The conversion of organic chlorine from TCE to ionic form increased with oxidant dose. Over 60 g KMnO4/kg d.w. soil is need to obtain TCE degradation efficiency higher than 90%. At the same time, the organic load (COD, TOC) in aqueous phase increases due the solubilization of humic mater. MnO2 generated in the oxidation-reduction processes remains in the soil bulk.

Abstract:
The study presents experimental data on phytostabilization/ phytoremediation of 5.57% total petroleum hydrocarbons contaminated soils, using plants of the Achillea millefolium species. Studies have been conducted on pots placed in outdoors in three experimental variants in the absence/presence of an additional treatment: 1.contaminated soil; 2. contaminated soil treated with fertilizer agent, stabilized sewage sludge; 3. contaminated soil treated with fertilizer and amendment based on indigenous volcanic tuff with clinoptilolite. After five months of growth the plant roots have formed a strong twinned network throughout the vegetation soils of volume pots. The content reduction of the total petroleum products in the contaminated soil was 45.4% and 65.4% for the variant of contaminated soil treated with fertilizer agents, anaerobically stabilized sewage sludge from the municipal treatment plant in the absence/presence of the amendment with indigenous volcanic tuff.

Abstract:
The granulated slag resulting from the pyrometallurgical processing of lead-rich concentrates was chemically analysed quantitatively by X-ray fluorescent spectometry, microstructurally by scanning electron microscopy (SEM), and microcompositionally by energy dispersive X-ray analysis (EDAX).The compositional phases were determined using the qualitative analysis by X-ray diffraction (XRD). A leachate test was carried out in order to asses the constituents which can be leached from the slag and to determine if these are in accordance with the specific reference figures. The preliminary assessment of the acid draining of slag was carried out using the modified static ABA test by acid-base analysis. In order to determine the possibility of valorisation of slag as a construction material for embankments, road foundations, and sub-base and base layers, the granulated lead slag was analysed by determining the chemical, physico-mechanical (granulometric analysis, compaction characteristics, California bearing capacity index, permeability) and geotechnical (direct undrained, unconsolidated shearing strength) characteristics and comparing these characteristics with those of sand.

Abstract:
Removing of oil spills from solid surfaces, sea, rivers and lakes formed as a result of accidental spillage during transport or storage is of great concern. Such ecological accidents have created a great need to find more efficient and lowcost materials for oil spill cleanup. The methods commonly used to remove oil involve the use of dispersants, skimmers, sorbents etc. The main limitations of some of these techniques are their high cost. Removal of oil by sorption has been observed to be one of the most effective techniques for removal of spilled oil under ambient conditions. In this work, indigenous oligotrophic peat was prepared using several methods and tested (according to ASTM F726-12 Standard Test Method for Sorbent Performance of Adsorbents) as a low cost sorbent in order to determine their potential for oil spill cleanup in terms of adsorption capacity, floatability and leachability. In order to cover the most common oil products causing accidental spills, for this study were used: gas, diesel and motor oil. The peat sample prepared by drying, chopping and sieving had highest adsorption capacities (expressed as g pollutant/g sorbent), depending on the contact time and pollutant properties, of 4.13 – 5.02 for gas, 5.44 – 6.81 for diesel oil and 15.13- 15.17 for motor oil. The adsorption capacity of indigenous peat sample increases along with the viscosity and density of the pollutants as follows: gas

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Abstract:
This paper describes the benchmarking of municipal sewing sludge dewatering technology with traditional geotube technology and air drying beds. The use of geotube dehydration technology process occurs faster due to reagents that provide clogging sludge. Applying the technology of dehydrating the sludge in geotube leads to reducing: the time required for dehydration from 18 months up to one month; the surface of land required for the dehydration from 6.0 to 1.25 ha, and respectively, for storage, from 27.7 to 3.65 ha. Removal of toxic gases into the atmosphere is reduced from 1.4 to 6.2 times. Compared with the traditional technology of air drying beds, the dehydrated sludge in geotubes contains 2 times more carbon and total nitrogen. Total phosphorus content had a slight tendency to decrease, total potassium concentration increases with 1.76 times. One tonne of dried sewage sludge stored in geotube and stocked for one year has the humidity of 65% and contains 151 kg of organic matter, 9.0 kg N, 10 kg P2O5 and 2.9 kg K2O. Heavy metal content is below the maximum that is allowed by national legislation from 2008. The application of sewage sludge as a fertilizer provided a specific increase of the total yield over the two years of 100.5 kg per ton of grain units at the dose of 18 t/ha and 45.5 kg per ton of grain units at the dose of 36 t/ha .

Abstract:
Chlorinated ethenes such as 1,2-dichloroethylene (1,2DCE), trichloroethylene (TCE), tetrachloroethylene (PCE) were identified in some groundwater sources used for potable purpose. Contamination of groundwater can occur from many sources, the most important of which being leachates from waste disposal sites. Analysis of contaminated groundwater has shown high concentration level of halogenated volatile organics (1,2DCE = 14-18 mg/L, TCE = 80-130 mg/L, PCE = 198-258 µg/L), over the current limits imposed by enforced legislation (L 458(r1)/2011: MACTCE + PCE = 10 µg/L). The main treatment technique used by individual water consumers is based on GAC adsorption in one or two steps (ηTCE = 99.4%, ηPCE = 99.8%, ηDCE = 46%), which can’t assure the required quality for drinking water, the residual concentrations being higher than MAC value (1,2DCE ≤ 10 mg/L; TCE ≤ 500 µg/L; PCE ≤ 0,5 µg/L). The applied treatment processes for advanced degradation of chlorinated ethenes are based on oxidation using photolysis or ozonation in different systems: UV alone, UV/H2O2, UV/O3, O3 alone, O3/ H2O2. Also, air stripping can be used for pollutants removal. The paper presents the experimental results obtained for the advanced removal of halogenated compounds by coupling air stripping with chemical oxidation, which can provide drinking water quality in compliance with legislation requirements.

Abstract:
The existence of drugs, hormones, toxic substances, synthetic polymers, etc in wastewaters is a great problem for environment. In this research the technologies for obtaining biodegradable “Core-Shell” composites with shell from natural biopolymers (collagen, casein or their combination) and immobilized in core drugs (ampicillin or gentamicin) in the smallest amount were developed.

Abstract:
The European Water Framework Directive (WFD-2000/60/EC) was implemented in order to improve and protect water quality (for surface water, coastal water, and groundwater) and to prevent further deterioration across Europe by the year 2015. Also, this directive stipulated that Priority Hazardous Substances are a subset of Priority Substances considered extremely harmful. Heavy metals are listed in the first category as they may accumulate to very high toxic levels and cause severe impact on the aquatic organisms without any visible signs. During the period 2008-2010 National Research and Development Institute for Environmental Protection was involved in the project SAFAR. One of the main objectives of this project was the determination of heavy metals content (Pb, Cd, Hg, Ni) and risk assessment for water and sediments. Another objective of the project was to establish the variation of environmental factors in respect to the heavy metal content upstream and downstream from the Moara Domneasca Lake. This paper presents part of the most relevant results concerning the heavy metals content and the hazard of the heavy metals in the water samples. The results obtained were interpreted according with the Romanian quality standards Order 2006/161 and Governmental Decision 2010/1038 based on the 2008/105/EC Directive with the W.F.D. amendment.

Abstract:
In the quest for efficient and economical water use and the optimization of land footprint needed in water production, membrane bioreactors (MBR) are leading the way. In this article, we look at how the membranes in a MBR work, and show some construction developments in this sector of water industry. Secondly the article discusses a completely new and extremely environmentally friendly module cleaning technology. This technology has meanwhile been successfully tested in different pilot units for example in cooperation with Darmstadt University of Technology.

Abstract:
Plant cell wall has the composition, structure and properties that make it suitable for many uses, such as composite and paper manufacture. Cell wall has many active sites on its surface which are involved in interaction with its environment (solvent). We investigate its capacity for purification of water pollutants. In this study, we investigated capacity of plant cell walls isolated from milled maize stem to remove different concentrations of nickel from polluted water. By combining fluorescence technique with spectrophotometry, complementary results were obtained. Autoflorescence spectra of plant cell walls were recorded and their spectral changes during interaction between cell wall and pollutants were examined. Emission spectra were analyzed by fitting with multiple log-normal distribution curves, whose form resembles to real experimental spectra of individual fluorophores