Environmental Engineering and Management Journal [619787]

Environmental Engineering and Management Journal
June 2015, Vol.14, No. 6, 1295-1302
http://omicron.ch.tuiasi.ro/EEMJ/

“Gheorghe Asachi” Technical University of Iasi, Romania

EXPERIMENTAL INVESTIGATION ON THE HEAT OF COMBUSTION
FOR SOLID PLASTIC WASTE MIXTURES

Liviu Costiuc1, Mircea Tierean2, Liana Baltes2, Silvia Patachia3

1”Transilvania” University of Brasov, Mechanical Engineer ing Department, 29 Eroilor Bl vd., 500036 Brasov, Romania
2”Transilvania” University of Brasov, Materials Engineeri ng and Welding Department,
29 Eroilor Blvd., 500036 Brasov, Romania
3”Transilvania” University of Br asov, Product Design, Mechatroni cs and Environment Department,
29 Eroilor Blvd., 500036 Brasov, Romania

Abstract
The aim of this paper is to determine th e heat of combustion of plastic wastes resulted from municipal solid waste, automotive
shredder facility waste and building and constr uction waste. The plastic wastes have b een separated by flotation technique usin g
as flotation media: water, ethanol, their mi xtures and magnetic fluid. Re sulted fractions have been analyzed aiming to determin e
the most effective fraction from the heat of combustion point of view. The obtained results have been compared to those reporte d
in the literature, with those calculated by oxygen consumption method and th ose proposed in this paper and calculated by
weighted sum of combustion heat of compone nts, aiming to allow its approximation for different fractions of polymeric wastes
with known composition, avoiding the experimental measurements. Deviations of measured values of the heat of combustion
from those obtained by theoretical calculation have been explaine d by the polymer degradation during their life cycle. The most
effective fraction from calorific point of vi ew is that containing polyolefins, but this fraction could be mechanically recycle d. The
present study evidenced that the heat of combustion of the pl astic waste decreases after polyolefin extraction and the remainin g
density fractions can be effectively used for energy recovery of the plastic waste by incineration.

Key words: heat of combustion, oxygen bomb calorimetr y, polyolefins, polymers waste, recycling

Received: December, 2014; Revised fi nal: June, 2015; A ccepted: June, 2015

 Author to whom all correspondence should be addressed: e-mail: [anonimizat]; Phone: +[anonimizat]; Fax: [anonimizat] 1. Introduction

The main purpose of this paper is to determine
the heat of combustion of plastic wastes coming from
municipal solid waste, the automotive shredder facility and building and construction sector as
mixture of polymers. The heat of combustion can
decide the effectiveness of plastic wastes to be used
as fuel for energy recovery as reported (Banyai and
Fodor, 2014; Corabieru et al., 2014; EC-PWE, 2010; Ghinea et al., 2014; Hidalgo et al., 2014; Kocsis and
Kiss, 2014; Luca and Ioan, 2014; Orlescu et al.,
2013; Sarkady et al., 2013a, 2013b; Șchiopu and
Ghinea, 2013; Simion et al., 2013). The plastic wastes have been separated by
flotation technique using as flotation media: water, ethanol, their mixtures and magnetic density
separation (MDS) using a magnetic fluid (Rem et al.,
2013). Resulted fractions have been analyzed aiming to determine the most effective fraction from the heat
of combustion point of view. The results have been
compared to those reported in the literature by Van
Krevlen (1990), Walters et al. (2000) and Lechner
(2005), with those calculated by oxygen consumption method (Babrauskas, 1992; Van Krevlen, 1990;
Vîlcu and Leca, 1990) and those calculated by
weighted sum of combustion heat of components, aiming to allow its approximation for different

Costiuc et al./Environmental E ngineering and Management Journal 14 (2015), 6, 1295-1302

1296 fractions of polymeric wastes with known
composition, avoiding the experimental
measurements.
This study presents the effect of the
polyolefins extraction from the polymeric wastes on
the contaminants fractions heat of combustion, and it
evidenced that the density fractions resulted could be effectively used for energy recovery of the plastic
waste, by incineration.

2. Material and methodology

2.1. Material

The tested wastes investigated are covering
the municipal solid waste source (WS1), the
automotive shredder wa ste source (WS2) and
building and construction waste source (WS3) as major contributors to plastic waste production. The
source WS1 came from Romania, the source WS2
from Austria and source WS3 from France. Plastic wastes as were received as mixture of polymers are
presented in (Fig. 1).
The plastic wastes have been separated by
flotation technique using as flotation media: water,
ethanol, their mixtures and magnetic fluid to separate
different density fractions to extract polyolefins. The separation technique is presented in (Fig.2) and
details are reported by various authors (Moldovan et
al., 2012; Patachia et al., 2011; Vajna et al., 2010).
The flotation process separates the polymer mixture
in two fractions: float fraction with density smaller than 0.998 kg/m
3 and sink fraction with density
bigger than 0.998 kg/m3. The float fraction is processed with magnetic density separation and
results three density fractions: polyolefin fraction
with density between 0.880 and 0.964 kg/m3, light
fraction with density smaller than 0.880 kg/m3 and
heavy fraction with density between 0.964 and 0.998
kg/m3. The plastic wastes from WS2 and WS3 came
with polyolefin fraction already extracted. After
separation the resulted fractions are dried to remove
the moisture. Fractions composition has been
determined by a combination between the image
analysis, gravimetric method and FTIR spectroscopy
by using a Perkin-Elmer BXII Fourier transform infrared spectrometer, equipped with an attenuated
total reflectance (ATR). Polymer identification has
been made by using Essential FTIR software data base, (eFTIR, 2013). The composition results were
reported by Baltes et al. (2009, 2013), Patachia et al.
(2010, 2011) for WS1, Vajn a et al. (2010), Cazan et
al. (2013) for WS2 and EC-PWE (2010) for WS3.
Reported values for WS1 light fraction
composition was 17% polyethylene(PE) and 83% polypropilene(PP), for heavy fraction a composition
of 12% PE, 38%PP, 11%PS, 2%PET and 37%PVC.
For WS2 the light fraction contains 9%PP, 23% polyurethane foam, 5% STPe, 55% cellulose and 8%
epoxy adhesive, the heav y fraction contains 25%
polyethylene, 15% polypropylene, 11% PET, 5% polystyrene, 10% nylon, 15% cellulose, 5% PVC,
10% EPDT and 4% PC. The composition of WS3
light fraction is 15% PE, 23% poly(1buthene), 18%
LLDPE, 15% polymethylpentene, 26% ethylene
propylene rubber and 3% polyacril amide. The WS3
heavy composition is 56% PE, 24% PP, 14%
polybutadiene and 6% construction adhesive.

Romanian WS1 Austrian WS2 French WS3

Fig. 1. The test samples of plastic waste

Fig. 2. The separation scheme

Experimental investigation on the heat of combustion for solid plastic waste mixtures

1297Table 1. Polyolefin percent in plastic waste mixture

Polyolefin amount (%)
Light fraction Heavy fraction Waste source
PE PP PE PP
WS1 17 83 38 12
WS2 0 9 25 16
WS3 33 0 56 24

The size of shredded waste is about 4 mm or
bigger which is not suitable for heat of combustion
measurements. To determinate of the heat of combustion of solid fuels, maximum grain size of 1
mm according ECS (2006) and homogeneity of
mixture are necessary. The initial samples have been cooled with liquid nitrogen and grinded by using
ultra centrifugal mill (Retsch ZM200, Retsch GmbH,
Germany). The average sample size obtained after grinding was approximately of 0.5 mm. The samples
are prepared dry and ash free and sample heat of
combustion value has been measured in the absence of moisture and ash forming minerals. The tested
samples are: mixture of polymers from WS1, WS2
and WS3, and light and heavy fractions resulted after MDS separation of waste.
It could be noted that PP and PE as polyolefin
major fractions are present both also in lighter and heavier fraction of all the separated wastes as listed
Table 1.
The lighter fraction of WS1 coming from
urban plastic waste contains 100% polyolefins and
50% is found in the he avier fraction, the WS3
coming from building and construction waste
contains 33% polyolefins in lighter fraction and 80%
in heavier fraction and WS2 coming from automotive shredder waste contains 9% polyolefins in the lighter
fraction and 41% in the heavier fraction. The samples
WS2 and WS3 analyzed we re received with form
The polyolefin percent quantities in the light fraction
can be explained by the presence of the PP and PE
foam and bubble wrap and by the adherence of the air bubbles to PP and PE during the flotation process
and magnetic density separation.

2.2. Measurement of the heat of combustion

Both the initial waste samples and the
obtained fractions have been submitted to
calorimetric analysis. After drying, the samples were
weighed using precision analytical balance of 0.1 mg
(Kern & Sohn ABJ 220-4M model). Each sample
weight was at approximately 1 gram in order to get a accepted temperature rise of 2 liters of water in the
oxygen bomb jacket of 2.0-4.0°C for calorimetry
measurements according to standard (ECS, 2006) at
ambient temperature of 25°C.
The higher heat of combustion was measured
in an oxygen bomb calorimeter model XRY-1C, Plain Jacket Oxygen Bomb Calorimeter, Shanghai
Luheng Instrument co, with data acquisition
software. For each tested sample were measured the mass of probe and the ignition wire mass. The bath temperature was monitored and recorded during
burning process. The calculus is made using the
Regnault-Pfaundler method as described in (RNS, 1995; ECS, 2006; GNS, 2000) using recorded
temperature values.

2.3. Calculation of the heat of combustion

The following methods were considered in the
view of the calculation of the heat of combustion:
a) The oxygen consumption method (Walters et al.,
2000) considers that the wide range of organic compounds including polymers have the same heat of
combustion per gram of diatomic oxygen consumed.
The empirical quantity used is E=13.10±0.78 kJ/g-O
2
and authors have found that the estimation of the heat
of combustion for 49 pure polymers, using the Eq.
(1) is about ±4.4%, where Qc is the heat of complete
combustion of the sample with all products in
gaseous state, npolymer is the number of moles and
Mpolymer is the molecular weight of the polymer
repeating unit,
2Onis the number of moles of O2
consumed in balanced th ermochemical equation,
32
2OM g/mol is the molecular weight of diatomic
oxygen and the quantity r0 is the stoichiometric
oxygen-fuel mass ratio.

02 2rEM nMnE Q
polymer polymerO O
c 



 (1)

b) The proposed as second method to
calculate heat of combustion is described by the Eq.
(2) using literature data for polymers as a mass
weighted contribution of the heat of combustion of pure polymers that could be find in a density fraction,
where %
wpolymer is the mass ratio of each fraction
in the mixture and Qc,polymer is the heat of combustion
of each pure polymer.

 polymerc w mixc Q polymer Q, , %   (2)

The reported values from literature for the
heat of combustion of polymers are listed in Table 3.
The values used in Eq. (2) for the heat of combustion of pure polymers are represented as bold values in
Table 2, and were selected considering experimental
determination of them. The overall mixture heat of combustion was considered as a mass weighted
contribution of the heat of combustion of density
fractions, without considering the interaction between them.

Costiuc et al./Environmental E ngineering and Management Journal 14 (2015), 6, 1295-1302

1298
Table 2. Reported heat of combustion for pure polymers

Polymer Heat of combustion (J/g) References
44600 Babrauskas (1992)
47740 Walters et al. (2000)
46400 Lechner (2005) PE
47195 NIST (2013)
42660 Babrauskas (1992)
45800 Walters et al. (2000)
44000 Lechner (2005) PP
45799 NIST (2013)
42500 Babrauskas (1992)
43650 Walters et al. (2000) PS
41600 Lechner (2005)
PA 31400 Lechner (2005)
23220 Babrauskas (1992)
24130 Walters et al. (2000) PET
21600 Lechner (2005)
17950 Babrauskas (1992)
19000 Lechner (2005) PVC
18000-19000 NIST (2013)
PU foam 31600 RNS (2010)
32600 Smirnova et al. (2010) STPe 33900 RNS (2010)
Cellulose (wood) 17000- 20000 RNS (2010)
34930 Babrauskas (1992)
31370 Walters (2000) Epoxy adhesive
31700 RNS (2010)
Modified cellulose 20000 RNS (2010)
EPDT 40600 RNS (2010); Chuang (1997)
31000 Babrauskas (1992)
31300 Walters (2000) PC
30700 Lechner (2005)
45000 Lechner (2005) PB 45334 NIST (2013)
44600 Walters et al. (2000) LLDPE 46500 Lechner (2005)
PMP 47496 NIST (2013)
EPR 33900 RNS (2010)
22425 Vatani et al. (2007) PAM 21901 Smirnova et al. (2010)
44200 NIST (2013)
44213 CCD (2013) BR
44250 EPST (2005)
C&R adhesive 14000- 19500 RNS (2010)

2.4. Calibration

As is mentioned by Walters et al., (2000), and
described in (RNS, 2010; ECS, 2006; GNS, 2000),
before determining the calorific value of tested
samples the oxygen bomb calorimeter must be calibrated. For calibration a standardized benzoic
acid sample is used. The heat of combustion of
standard benzoic acid used is H
e = 26454 J/g as is
given by Parr Instrument CO. The weighted benzoic
acid mass of the sample is me =1.0018 g. To initiate
burning a 0.1 mm nickel chromium alloy wire is used as standardized fuse wire from Parr Instrument Co.
with a given heat of combustion of 5861.52 J/g. The
heat correction for the wire and cotton burning resulted is Q
wc =131.36 J. The final temperature
recorded during calibration from the main stage is tf = 20.453 °C, and the initial temperature from the main
stage is ti = 18.405 °C. The thermal capacitance of
the calorimeter, W, it is determined using Eq. (3).


KJttQ mHW
i fwc e e/ 12875 (3)

2.5. System setup

According to standard procedure the weighted
sample is placed inside a calibrated adiabatic bomb calorimeter with 1 mL of deionized water. The
ignition wire is connected to the electrodes in the
pressure vessel and placed in contact with the
sample. The bomb is then assembled, sealed and
purged twice by pressurizi ng to 0.4MPa with pure
oxygen to evacuate the air. Before determination it is

Experimental investigation on the heat of combustion for solid plastic waste mixtures

1299pressurized with pure oxy gen to 3.0MPa and placed
inside a bath containing 2 liters of water in an
insulated jacket. Temperature rise of the water is
measured by using a precision sensor with 10-3 K
temperature resolution. The equilibrium temperature
of the bath during to the test is recorded by the data
acquisition system at every 30 seconds. Three replicates are performed for each polymer mixture
sample. The results recorded during the experiment
are the values of temperatures for before period to
reach adiabatic conditions, main burning period and
after burning period.

3. Results and discussion of calorimetric analysis

The results obtained for mixed plastic waste
with standard deviation are presented in Table 3,
where Q
hi is higher heat of combustion and Qlo is
lower heat of combustion. Results of calorimetric
analysis of remained fractions after extraction of
polyolefins from samples are presented in Table 4. Each result is the av erage of at least 5
determinations.
As it can be seen in Table 3, the higher heat of
combustion of waste, before extraction of polyolefin
fraction, has a deviation of values of 2% for WS1
compared to WS3, of 6.4% variation for WS1 compared to WS2 and of 9. 1% for WS3 compared to
WS2. The higher heat of combustion after extraction
of polyolefin fraction from WS1 and WS3 waste
decreases with the increase of the fraction density for
sample (Table 4). For WS2, the light fraction density has a smaller heat of combustion than the heavier
fraction. That could be explained by considering the
reduced polyolefin percent identified in WS2 light fraction density of 9%.
The heat of combustion for the sample with
density smaller than 0.88 g/cm
3, coming from WS1,
calculated by using Eq. (2) with composition of
17%PE and 83%PP, taking into account the measured values reported by Walters et al. (2000) for
heat of combustion for PE and PP, respectively ( Q
c,PE
= 47740 J/g and Qc,PP = 45800 J/g) (Table 2), lead to
a mixture’s heat of combustion of Qc,mix = 45959.27
J/g. By using Eq. (1) for the same composition
sample, the resulting mixture heat of combustion from oxygen consumption method, with r
0 = 3.42193
is Qc,mix = 44683.4 J/g . The results obtained by using
the Eqs. (1-2) are in a good agreement with the
present study measured value of higher heat of
combustion of Qhi = 44824 J/g (Table 5), with an
absolute relative error of -0.32%, respectively of 2.53%. Table 5 presents th e measured values of the
heat combustion of the initial mixtures, calculated
with Eqs. (1 and 2) and relative errors reported to measured value in this research.

Table 3. Results of calorimetric analysis of the initial plastic waste

Source Q hi (J/g) Q lo (J/g) StDev (%)
WS1 45202 44649 ±0.24
WS2 40863 40323 ±2.38
WS3 44979 44427 ±1.37

Table 4. Results of calorimetric analysis of plastic waste fractions after extr action of polyolefins

Source Density fraction (g/cm3) Q hi (J/g) Q lo (J/g) StDev (%)
WS2 < 0.88 32257 31757 ± 1.39
WS2 0.964-0.998 35565 35051 ± 3.15
WS3 < 0.88 40161 39629 ± 0.96
WS3 0.964-0.998 38639 38110 ± 2.1
WS1 < 0.88 44824 44272 ± 2.50
WS1 0.964-0.998 35796 35281 ± 4.03
WS1 > 0.998 23257 22793 ± 4.09

Table 5. Calculated and experimental va lues of heat of combustion

Qhi (J/g) Q c,mix (J/g) Relative
error Qc,mix (J/g) Relative
error Source Density
Fraction
(g/cm3) Present study Eq. (1) % Eq. (2) %
WS2 mix 40863 38500.07 5.34 40749.48 -0.19
WS3 mix 44979 42494.98 5.52 45449.66 -1.05
WS1 mix 45202 43741.61 3.23 46608.96 -3.11
WS2 < 0.88 32257 27313.23 15.33 27582.01 14.49
WS2 0.964-0.998 35565 34599.49 2.71 36081.95 -1.45
WS3 < 0.88 40161 41678.76 -3.78 42732.39 -6.40
WS3 0.964-0.998 38639 36343.16 5.94 38852.96 -0.55
WS1 < 0.88 44824 44683.4 -0.32 45959.27 2.53
WS1 0.964-0.998 35796 33269.54 7.06 35366.40 1.20
WS1 > 0.998 23257 28209.07 -20.51 29479.13 -26.75

Costiuc et al./Environmental E ngineering and Management Journal 14 (2015), 6, 1295-1302

1300

Fig. 3. The heat of combustion (J/g) of test samples of plastic waste and the values calculated
by using Eq. (1) and Eq. (2) compared with 2 sorts of coal

For WS2 samples before and after extraction
of polyolefins it could be noted that the heat of
combustion of the plastic mixture is higher than the
heat of combustion of light fraction with 25% and higher than of heavy fraction with 15%. The relative
error resulted for WS2 by comparing to measured
and calculated values shows for mixture, an estimation of 5.34% with Eq. (1) and of -0.19% with
Eq. (2) and for heavier density fraction of 2.71% and
-1.45%. An interesting result is for WS2 lighter fraction which has relative errors of 15%. The
relative errors of 21-27% has found also on
estimation of WS1 density fraction bigger than 0.998 kg/m
3.
For WS3 samples results show that the
calorific power of the mixture is higher than calorific
power of light fraction with 10% and higher than
calorific power of heavy fraction with 15%. The absolute relative error for estimation of heat of
combustion of WS3 is of 6%. The best estimation is
made by the Eq. (2). For WS1 samples the calorific power of the mixture is higher than that of the light
fraction with 1% and higher than that of the heavy
fraction with 48%, That could be explained by considering the reduced polyolefin percent identified
in WS1 heavy fraction density of 50%, meanwhile
the light fraction have 100% polyolefins. The absolute relative error for estimation of heat of
combustion of WS1 is of 5%. The best estimation is
made by the Eq. (2) with 3% mean relative error.
The (Fig. 3) shows that the Eq. (2) estimates
very good the experimental values for heat of
combustion for WS1, WS2 and WS3 plastic mixtures, for WS1, WS2 and WS3 heavy fractions,
since Eq. (1) give a good estimation for WS1 light
fraction and closer values for the rest.
The lighter and heavier fractions of tested
plastic waste have a heat of combustion bigger than 35.0 MJ/kg for WS1, 32.0 MJ/kg for WS2 and 38.0
MJ/kg for WS3, and greater than anthracite coal heat
of combustion of 32.8 MJ/kg, or lignite coal heat of combustion of 28.0 MJ/kg, which assures their effectiveness to an energy recovery system (Kittle,
1993).
Regarding the method used to calculate heat
of combustion of plastic waste with known composition avoiding the experimental
measurements has found that the method of weighted
sum of combustion heat of components is a choice. This result is very useful in industrial management of
plastic waste to design a plastic incineration plant
which requires to calculate the estimated heat of combustion of waste and to evaluate the amount of
energy recovered considering the large variety of
polymers involved in plastic mixtures. Before incineration the plastic waste needs to be washed to
remove organic compounds, metals and ash, to be
dried to remove moisture, as additional steps. These
steps determine for real plas tic waste an increasing of
the energy recovered by incineration and a method to reduce the amount of plastic wastes from nature.

4. Conclusions

The calorimetric analys is shows that the
mixed plastic wastes can be used as fuel because of high heat of combustion comparing with coals. The
presence of polyolefins as th e PE and PP both in the
lighter and heavier fractions of wastes as composites, the heat of combustion of these fractions will be
higher, due to the higher polyolefinic heat of
combustion. The study show s that the extraction of
polyolefins from the mixed plastic waste the heat of
combustion decreases for all kinds of wastes. Even
after extraction of polyolefins, the heat of combustion of residues is still greater than those of
different sorts of coals and these wastes could be
effectively used for energy recovery from the plastic
waste, by incineration.
The weighted sum method proposed in this
paper for calculation of the heat of combustion with
known composition of polymers in the mixture has
found to be a good method to estimate the heat of combustion of the plastic waste without additional
experimental determinations.

Experimental investigation on the heat of combustion for solid plastic waste mixtures

1301Acknowledgements
This research was funded by FP7 Grant 212782, Magnetic
Sorting and Ultrasound Sensor Technologies for
Production of High Purity Se condary Polyolefins from
Waste, acronym W2Plastics.

References

Babrauskas V., (1992), Heat of Combustion and Potential
Heat , In: Heat Release in Fires , Babrauskas V.,
Grayson S.J. (Eds.), Else vier Applied Science,
London, 207-223.
Baltes L., Draghici C., Manea C., Ceausescu D., Tierean
M., (2009), Trends in Selective Collection of the
Household Waste, Environmental Engineering and
Management Journal , 8, 985-991.
Baltes L., Tierean M., Patachia S., (2013), Investigation on
the friction coefficient of the composite materials
obtained from plastics wastes and cellulosic fibers,
Journal of Optoelectronics and Advanced Materials,
15, 785-790.
Banyai O., Fodor L., (2014), Energy efficiency obligation
schemes in the energy efficiency directive – an
environmental assessment, Environmental
Engineering and Management Journal , 13, 2749-
2755.
Cazan C., Perniu D., Cosnita M., Duta A., (2013),
Polymeric wastes from automotives as second raw
materials for large scale products, Environmental
Engineering and Management Journal , 12, 1649-
1655.
CCD, (2013), Cameo Chemicals Database, Butadiene, On
line at http://cameo chemicals.noaa.gov/ chris/BDI.pdf.
Chuang T.H., Chern C.K., Guo W., (1997), The
Application of Expandable Graphite as a Flame
Retardant and Smoke-suppressing Additive for
Etylene-Propylene-Diene Terpolymer, Journal of
Polymer Research , 4, 153-158.
Corabieru P., Corabieru A., Vasilescu D.D., (2014), New
approaches in the design of plastic products for easy
recycling, Environmental Engineering and
Management Journal , 13, 1997-2004.
EC-PWE, (2010), European Commission DG ENV, Plastic
Waste in the Environment, Specific contract
07.0307/2009/545281/ETU/G2 under Framework
contract ENV.G.4/FRA/ 2008/0112, Final report.
ECS, (2006), European Comm ittee for Standardization,
Solid recovered fuels, Methods for the determination
of calorific value, DD CEN/TS 15400:2006.
eFTIR, (2013), Essential FTIR software TM, On line at:
http://www.essentialf tir.com/index.html.
EPST, (2005), Encyclopedia of Polymer Science and
Technology, Butadiene Polymers, V, John Wiley &
Sons, Inc., On line at: http://www.aspeak.net.
Kittle P.A., (1993), Alternate daily cover materials and
subtitle D-the selection technique , Rusmar
Incorporated West Chester, PA, On line at:
http://www.aquafoam.com /papers/selection.pdf.
Kocsis I., Kiss J.T., (2014), Energy efficiency obligation
schemes in the energy efficiency directive – an
environmental assessment, Environmental
Engineering and Management Journal , 13, 2825-
2830.
Ghinea C., Petraru M., Simion I.M., Sobariu D., Bressers
H.Th.A., Gavrilescu M., (2014), Life Cycle
Assessment of wa ste management a nd recycled paper
systems, Environmental Engineering and Management
Journal , 13, 2073-2085. GNS, (2000), German National Standard, DIN 51900-
1/2000, Determining the gross calorific value of solid
and liquid fuels using th e bomb calorimeter and
calculation of net calorific value, Part 1: General
information.
Hidalgo D., Corona F., Mar tín-Marroquín J.M., Gómez M.,
Aguado A., Antolín G., (2014), Integrated and
sustainable system for mu lti-waste valorization,
Environmental Engineeri ng and Management Journal ,
13, 2467-2475.
Lechner M.D., (2005), Polymers , In: Springer Handbook of
Condensed Matter and Materials Data , (Eds.)
Martiensen W., Warlimont H., On line at:
http://www.springer.com/978-3-540-44376-6, 477-
522.
Luca F.A., Ioan C.A., (2014) , Implementation of green
marketing in the analysis of municipal waste produced
in romania, correlated with environmental policy
management trends in selective collection of the
household waste, Environmental Engineering and
Management Journal , 13, 3131-3142.
Moldovan A., Patachia S., Vas ile C., Darie R., Manaila E.,
Tierean M., (2012), Natural Fibers / Polyolefins
Composites (I) UV and Electron Beam Irradiation,
Journal of Biobased Materials and Bioenergy , 6, 1–
22.
NIST, (2013), National Institute of Standards and
Technology, Material Measurement Laboratory, On
line at: http://webbook.ni st.gov/cgi/cbook.cgi.
Orlescu C.M., Costescu I.A., (2013), Solid waste
management in Romania: Cu rrent and future issues,
Environmental Engineeri ng and Management Journal ,
12, 891-899.
Patachia S., Moldovan A., Buic an R., Vasile C., Darie R.,
Tierean M., (2010), Composite Materials Based on
Polyolefins Wastes , 14th European Conference on
Composite Materials, Buda pest, Hungary Paper ID:
281-ECCM14.
Patachia S., Moldovan A., Tierean M., Baltes L., (2011),
Composition Determination of the Romanian Plastics
Municipal Wastes , Proc. of the 26th International
Conference on Solid Waste Technology and
Management, (2011) March 27-30, Philadelphia, PA
USA, 940.
Rem P., Di Maio F., Hu B., Houzeaux G., Baltes L.,
Tierean M., (2013), Magnetic fluid equipment for
sorting secondary polyolefins from waste,
Environmental Engineeri ng and Management Journal ,
12, 951-958.
RNS, (1995), Romanian National Standard, SR ISO
1928/95, Determining the gross calorific value of solid
fuels (in Romanian), Bucharest, Romania.
RNS, (2010), Romanian National Standard, SR EN ISO
1716, Fire standard for construction materials,
Determining the gross calorific value of solid fuels (in
Romanian).
Sarkady A., Dióssy L., Yuzhakova T., Kurdi R., Utasi A.,
Rédey A., (2013a), Industrial and communal
sustainable waste management in Hungary,
Environmental Engineeri ng and Management Journal ,
12, 1533-1540.
Sarkady A., Yuzhakova T., Diós sy L., Kurdi R., Rédey Á.,
(2013b), New trends in communal waste management
at the regional level: waste treatment plants in
Hungary and practic al applications, Environmental
Engineering and Management Journal , 12, 1691-
1698.
Simion I.M., Ghinea C., Maxineasa S.G., Taranu N.,
Bonoli A., Gavrilescu M., ( 2013), Ecological footprint

Costiuc et al./Environmental E ngineering and Management Journal 14 (2015), 6, 1295-1302

1302 applied in the assessment of construction and
demolition waste integrated management,
Environmental Engineeri ng and Management Journal ,
12, 779-788.
Șchiopu A.M., Ghinea C., (2013), Municipal solid waste
management and treatment of effluents resulting from
their landfilling, Environmental Engineering and
Management Journal , 12, 1699-1719.
Vajna B., Palásti K., Bodzay B., Toldy A., Patachia S.,
Buican R., Catalin C., Ti erean M., (2010), Complex
Analysis of Car Shredder Light Fraction, Open Waste
Management Journal , 3, 46-55.
van Krevlen D.W., (1990), Thermochemical Properties:
Calculation of the Free Enthalpy of Reaction from
Group Contributions , In: Properties of Polymers , 3rd
Edition, Elsevier, Amsterdam, 629-639. Vatani A., Mehrpooya M., Gharagheizi F., (2007),
Prediction of Standard Enthalpy of Formation by a
QSPR Model, International Journal of Molecular
Sciences , 8, 407-432.
Vîlcu R., Leca M., (1990), Polymer Thermodynamics by
Gas Chromatography (Studies in Polymer Science, 4),
Elsevier, Amsterdam.
Smirnova N.N., Bykova T.A., La rina V.N., Kulagina T.G.,
Pomogailo A.D., Dzhardimalieva G.I., (2010),
Thermodynamic Characteristics of Hydrated
Acrylamide and Polyacrylami de Complexes of Cobalt
Nitrate at T>0 to 380K, Polymer Science Series A , 52,
349-355.
Walters R.N., Hackett S.M., Lyon R.E., (2000), Heats of
combustion of high temperature polymers, Fire and
Materials Journal , 24, 245–252.