All posts by simiecoind

Abstract:

It has been known the surfactants have been used to remove stains from leather,
clothes and household items, particularly from kitchens and bathrooms.
Our studies were carried out during eight months in order to include all the seasons
(July, August 2016 – Summer; September, October 2016 – Autumn; January,
February 2017 – Winter and March, April 2017 – Spring) to detect the variation of
anionic and nonionic surfactants concentration from industrial wastewaters. The
wastewater samples were taken from three sampling points belonging to a subway
maintenance company: Berceni, Militari and Pantelimon.
The total concentration of anionic surfactants in wastewaters was analyzed by
Methylene Blue Active Substances Method (MBAS), and the total concentration of
nonionic surfactants was detected by the method with Dragendorff reagent.
The results showed that anionic and nonionic surfactants concentrations detected in
wastewater samples were less than 0.1 mg/L (under the quantification limit) up to
2.03 mg/L for anionic surfactants and the nonionic surfactants had less than 0.15mg/L
(under the quantification limit) up to 1.72 mg/L. According to the national legislation
(HG 352/2005, NTPA 002, Annex 2/2005), the accepted value of surfactants (as sum
of anionic and nonionic) is less than 25 mg/L.
The results of the study revealed the highest concentration of both anionic and
nonionic surfactants during March, one of the possibilities of this variations could be
the lower level of maintenance in February than the other months. Furthermore, this
change of concentration may be the result of switching the type of organic compound
(detergent) using for the subways cleaning.

Abstract:

Red Mud from domestic alumina plant contains high excess alkaline components and
traces of many toxic heavy metals. The results showed that Red Mud contains as main
components hematite, goethite, residual aluminium oxide-hydroxides, desilication
products (DSP), TiO2 and does not contain radioactive elements such as Uranium (U),
Thorium (Th). U and Th in Red Mud are less than the average concentration values
of Uranium (4ppm) and Thorium (12 ppm) in the earth´s crust. Physical structural
composition of domestic Red mud can be classified by an equilateral triangle iron
oxide/hydroxide-sandy components-clays (23.2÷53.7% iron oxide/hydroxide;
34.1÷63.8% sandy components; 7.3÷34.1% clays). Chemical composition of red mud
is, by weight (%w/w): Fe2O3Tot in the range 31.02 to 47.04; Na2O: 2.45÷5.39; CaO:
3.01÷20.86; K2O: 0.02÷0.07; MgO: 0.05÷ 0.73; Al2O3: 10.97÷22.78; SiO2:
1.09÷8.28; TiO2: 2.59÷ 5.76; Loss of Ignition (LOI): 13.03÷ 38.75. Red Mud also
contains traces of some heavy metals and valuable metals (Cr, Mn, Zn, V, Ga, Gd,
Sc, etc.) and has the pH in the range 13.0 ÷ 11.9 (when it is fresh) and 9÷10 (when it
is aged) respectively. The search results are an important basis to select the proper
treatment and recovery this waste as secondary resources for ceramic materials
production (ceramic foams).

Abstract:

Sewage sludge from urban wastewater treatment plants come from different stages of
wastewater treatment and are considered as waste, falling under the waste regulations.
In order to reduce the negative environmental impacts, the removal of sewage sludge
on landfill is considered as the last waste management option.
One of the sludge management alternatives is to recover energy from the sewage
sludge by incineration in waste incinerators or co-combustion in cement or thermal
power plants.
The use of sewage sludge as a source of renewable energy is an ecologically and
economically efficient option, both in the EU and Romania sludge management
strategy.
Total organic carbon is a key environmental indicator for soil, sludge and sediment
and a parameter for characterizing sludge for energy recovery.
The paper presents the methodology for total organic carbon determination from
acidified sludge samples by dry combustion, in an oxygen atmosphere using FlashEA
1112 Series Analyser.
From the experimental laboratory researches the following aspects were highlighted:
the interdependence between the total organic carbon content and the heating value
of sludge samples, an important factor for energy recovery/elimination by
incineration, co-combustion and utilization as secondary raw materials in cement
plants.

Abstract:

One of the logical reasons for the study of nitrogen is the toxicity of its various forms.
Their effect on the natural aquatic environment is very different and depends on the
amount and structure of organic radicals associated with amine nitrogen. The
difference of the effect of amines of natural origin (diethylamine – DEA) and synthetic
origin (1 -naphtylamine – 1 -NA, diphenylamine – DPA and cetyltrimethylammonium
– CTMA) on the processes of ammonia oxidation has been investigated. The
maximum allowable concentration (MAC) for synthetic amines and for natural origin
amines differs by almost two orders of magnitude. Both natural and synthetic amines
affect oxidation-reduction processes caused by the activity of bacterial enzymes, even
within MAC values. In the case of 1 -NA, the inhibitory effect is associated with a
toxic effect, whereas for DEA this effect is doubled (due to a toxic effect, as well as
from the amine-bound carbon). CTMA also has an impact on the inhibition of
processes. But in the presence of anionic surfactants (egg, lauryl sulfate-LS) in an
aqueous medium, the effect of CTMA is clearly reduced. Conversely, the presence of
CaCO3 particles reduces the ability of anionic organic substances to decrease the
effect of cationic ones. Typically, the amines, arising from the decomposition of
organic materials of natural origin, have less toxicity and lower MAC than those of
synthetic origin. It is important to note here that laboratory models are sensitive even
at concentrations below the MAC. Because of this, MAC can not be perceived as
absolute values and only meaning within certain limits.

Abstract:

Soil is considered to be the most diverse microbiological ecosystem on Earth.
Microbial soil biodiversity is substantially influenced by animal husbandry, intensive
agricultural practices and soil cultivation (tillage, crop rotation, irrigation, organic and
inorganic fertilization, application of pesticides etc.). Soil mismanagement represents
a worldwide topic that impairs natural ecosystem sustainability as a first consequence.
In order to understand and correctly apply soil management practices a deep insight
in ecological processes is necessary.
Soil microbiota have a great impact on both natural processes (biogeochemical cycles)
as well as various other aspects that could influence human health and the quality of
life (micro- or macro-contaminants, pharmaceuticals, fertilizers, phytosanitary
products). Pharmaceuticals, especially antibiotics are intensively used in animal
husbandry either as therapeutic agents or for prophylactic measures. Antibiotics of
microbial, semi-synthetic or synthetic origin impact the metabolism of bacteria: at
subinhibitory concentrations they act as hormetic intercellular messengers stimulating
gene expression. Higher amounts have bacteriostatic or bactericidal effects according to
their mode of action. Both result in a profound modulation of bacterial community
structure and biodiversity by boosting genotypic and phenotypic variability and
induction of antibiotic resistance. They also pose an indirect effect on the communities
(generating different genotypic and phenotypic variability such as antibiotic resistance).
Agricultural management practices like application of organic fertilizers (e.g. manure)
expose soil microbiota to a variety of hazardous agents of anthropogenic origin
including antibiotics, antibiotic resistant bacteria and antibiotic resistance genes which
interact with the indigenous soil resistome.
This paper describes the impact of human land-use, especially the ecological effects
of antibiotics on natural ecosystems and the increase of antibiotic resistance in soil
communities.

Abstract:

All infections follow the basic epidemiological pattern that if recognized early helps
to apply the measures to prevent and control pathologies. The epidemiological process
cannot be triggered in the absence of the microorganism’s reservoir and therefore it
is very important to control the potential reservoirs involved in nosocomial infections.
The etiological structure of nosocomial infections varies and includes a wide variety
of potentially or strictly pathogenic bacteria that have native or acquired proprieties
of virulence and antibiotic resistance. The aim of this project was to monitor the
potential role of the environmental risk factors involved in outbreak nosocomial
infections. The microbiological studies from an emergency hospital from Bucharest
have been started in January 2016 and samples were quarterly collected from drilling
and tap water, waste water, air and surfaces. There were performed quantitative
analyzes of microbiological contamination level and qualitative analyzes for
pathogenic and resistant bacteria detection. Some pathogenic bacteria have been
identified in the waste water and drilling water, indicating their interference. The
antibiotic resistance properties were observed especially in bacteria from waste
waters. Bacteria from vegetables from food preparation were detected in air samples
and surfaces tests from kitchen. The results indicated that environmental factors from
a medical unit could constitute a reservoir of microorganisms that can trigger
nosocomial infections.

Abstract:

The aim of this work is to apply an ion – chromatography method which was initially
developed for the determination of sulfur content in fuels, on other classes of samples
as municipal waste and oil and sewage sludge.
With respect to their physical properties and texture, solid waste materials as
municipal waste, are typically strongly heterogeneous and thus, sample preparation
can be critical in obtaining reliable analysis results so that, particle size reduction and
homogenizing of the municipal waste was an important step in conducting the
experiments. The homogenization of the samples was performed by cutting and then
grinding the material in two steps: first a reduction of the particles to diameters
passing a 10-mm sieve and secondly to diameters passing a 2-mm sieve.
The sulfur extraction from the homogenized waste samples was carried out by the
combustion method in the calorimetric bomb. Sulfur as sulfate anion was then
analyzed by ion-chromatography and gravimetric techniques and the results were
compared. Depending on the nature and sulfur content of the sample, the repeatability
standard deviation sr and the relative repeatability standard deviation RSD of the
results were of the same order of magnitude for the both gravimetric and ion –
chromatography methods and they were in the range of about 0.01 – 0.05 % for sr and
in the range of about 3.23 – 6.25 % for RSD.

Abstract:

Sludges from urban wastewater treatment plants (WWTPs) were tested for the
presence of the following natural and synthetic estrogenic steroids: estrone, 17α-
estradiol, 17β-estradiol, estriol, 17α-ethinylestradiol and equiline. The method
involved ultrasonic extraction followed by solid phase extraction cleanup and liquid
chromatography tandem mass spectrometry coupled with electrospray ionization in
the negative mode. The steroids were identified and determined by internal standard
method in selected multiple reaction monitoring mode. All target compounds were
detected in the investigated sludge samples. The highest estrogen concentrations were
determined for estrone, which reached 164.4 ng/g in one sample. Synthetic estrogen
17α-ethinylestradiol was detected in 50% of the analyzed samples, in concentrations
ranging from 2.7 to 16.1 ng/g.