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L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
54
Waste management and their environmental impact: Challenges and opportunities at
national level
https://doi.org/10.21698/rjeec.2020.108 Review
LIDIA KIM, GEORGETA MADALINA ARAMA*, GHEORGHE BATRINESCU, MIHAI
BRATU, AGNES SERBANESCU, CAROL BLAZIU LEHR
National Research and Development Institute for Industrial Ecology - ECOIND, 71-73 Drumul Podul Dambovitei
Street, 060652, Bucharest, *madalina.arama@incdecoind.ro., Romania.
Abstract
Both nationally and globally, waste generation increases with increasing product consumption. Thus,
addressing the issue of waste is an ongoing challenge for researchers around the world. This challenge
derives from the fact that in many European countries, including Romania, the amount of waste generated is
very high compared to current technologies for treatment, recycle or recovery. Therefore, the most
convenient management methods remain storage and incineration. These methods generate significant
amounts of hazardous pollutants with a significant impact on the environment and human health. The paper
presents a series of results related to waste management obtained within National Research and
Development Institute for Industrial Ecology – ECOIND Bucharest in the last 10 years. The paper is focused
on four topics: analytical detection and monitoring of waste pollutants; environmental impact and risk
assessments; harmonized waste classification and management; waste treatment and recovery technologies.
The results obtained within these topics refers to optimal methods for detection and characterization of
complex waste matrices, methods for assessing the impact on the environment generated by non-compliant
landfills and risk prediction and reliable solutions and technologies for waste treatment and recovery. The
topics approached represent a challenge for starting the implementation of circular economy concept
promoted by EU and adopted by countries and governments all over the world.
Keywords: environment, management, monitoring, technologies, waste
INTRODUCTION
As a result of the increasing amount of
continuously generated waste, their management
is a challenge both at national and global level.
As a consequence, the European legislation
created a legal framework to start a harmonized
waste classification for their further efficient and
ecological management [1-6]. Industrial
symbioses and academic partnerships have been
encouraged to create the premises of
implementation of circular economy. Specialists
from different areas such as ecology,
engineering, chemistry, biology, regulatory/
governmental bodies and agencies started to
work together in order to find viable waste
management solutions. However, there are a lot
of uncertainties about how pollution on different
environment segments can evolve over time [7-
9]. Numerous ongoing research studies are being
conducted on how the limits for the discharged
environmental pollutants for air, soil and surface
water segments should be set. However, the
issue of waste management related to the
environmental and human health protection is
far from being resolved. [10-13]. Consequently,
the best protective practices direct actually
towards minimization of waste volumes to be
disposed. Research in recent years on waste
management has been carried out in accordance
with national and European waste environmental
legislation. Thus, in the context of sustainable
development, according with Law 211 of 2011
on waste management, they should be managed
applying the principle of waste hierarchy. First
of all, according to this principle, the generation
of waste should be avoided through good design
and manufacturing practices. Second, if
possible, any valuable component should be
recovered for energy or non-energy uses. Lastly,
there is the management of waste by disposal
after appropriate pre-treatment/treatment, if
necessary, in the context of maximum protection
of the environment and human health. These
represent ongoing challenges for the scientific
community and are the prerequisites for starting
to implement the concept of circular economy.
Another challenge in the waste management
field is the harmonized classification of waste
according to the presence/absence of substances
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
55
that confer hazardous properties to the waste.
For the classification of waste, special attention
shall be paid to the hazard statements of waste
components defined in accordance with EU
Regulation 1272/2008. Those components can
induce hazardous properties HP1÷HP15 to the
waste when exceeding certain limits of
concentrations as stated in the Directive 98/2008
Annex III with revisions, transposed in the
Romanian legislation by the law L 211/2011
with updates [3, 4, 14]. Based on those aspects,
our research activities in the last decade have
been dedicated to improvements of the analyses,
techniques, methods and methodologies linked
to the waste management and their
environmental impacts. In order to find good
practical management solutions, research studies
on the following topics have been developed:
waste pollutants analytical detection and
monitoring; environmental impact and risk
assessments; harmonized waste classification
and management; waste treatment and recovery
technologies (Figure 1).
Fig. 1. The topics presented in the paper
International and national trend of studies on waste - Web of Science Platform
According to the Clarivate ISI Web of
Knowledge - Web of Science Platform, more
than 13,000 publications approaching waste
topics waste have been identified in the last 10
years. Figures 2-7 show the evolution of the
number of articles published in the platform on
each topic. The search was made by keywords
present in the title of the article: "waste
management"; “waste detection”; “waste
monitoring”; “waste risk”; waste environmental
impact”; “waste classification”; “waste
symbiosis”; “waste treatment”; “waste
recovery”.
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
56
Fig. 2. Trend of waste management studies – Web of Science Platform
Fig. 3. Trend of waste detection & monitoring – Web of Science Platform
Fig. 4. Trend of waste risk & environmental impact – Web of Science Platform
Fig. 5. Trend of waste classification & symbiosis – Web of Science Platform
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
57
Fig. 6. Trend of waste treatment – Web of Science Platform
Fig. 7. Trend of waste recovery – Web of Science Platform
Figures 2-7 show an increase in the number of
publications in the last 10 years on each topic,
most articles being focused on waste
management, treatment and recovery.
At national level there are few studies conducted
in the field of waste, Romania being at the
bottom of the ranking among European
countries in this field (Figure 8). Thus, the need
to intensify studies in the field of waste becomes
an emergent necessity considering both the
rigorous impositions of European Directives and
the impact induced on the environment by the
quantities of waste that are constantly growing.
Fig. 8. Trend of studies on waste at national level – Web of Science Platform
RESULTS AND DISCUSSION
Waste pollutants analytical detection and monitoring
The composition of waste is changing rapidly
with new production technologies, from which
various waste matrices are generated. Analytical
detection and monitoring of pollutants from
waste have some specific issues linked among
others to the sample matrix complexity and
heterogeneity. These have a significant impact
on uncertainty of final detection results. Any
laboratory involved in such investigation
activities should have a clear methodology for
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
58
samples collection, preservation and processing
according to the waste characteristics [15]. The
indicators must to be analyzed by using
recommended/accepted standards and norms in
the field, in order to ensure reliable and
comparable test results. The established testing
program according to standards in the field, for
example SR EN 16457:2014, should ensure
good coordination of field and laboratory
activities [16]. The high heterogeneity of the
waste sample has consequences on mass
balances closures for analytical results reporting.
For liquid waste, the specialists in the field agree
for mass balance closure to be around 90 %
w/w not 100% w/w [17]. In the same idea, for
solid wastes, the sum of determined constituent
concentrations will be reported on dry matter in
a range of 90÷110% w/w. According to the
current law, in the analytical test reports, for
final classification decision purposes, the
concentration of wet wastes that includes the
water content will be used as computation
reference. Issues related to samples preparation
and processing of waste will be presented next.
Some practical solutions were found for accurate
determinations of different monitoring indicators
from different waste matrices. Among a variety
of environmental waste pollutants to be
determined, a special case is represented by
heavy metals. They are largely found in different
liquid, solid and gaseous waste flows and they
are not degraded in the environment but they
only transform [18]. That is exactly why a good
deal of the research in the pollutants detection
and monitoring area has been focused towards
monitoring heavy metals emissions from
different kind of waste types (class)/categories
(groups) to find the most adequate procedures
for preparation and processing of metal
containing waste samples. Starting from those
aspects, relevant results for assessment and
characterization of metal fractions in bottom and
filter ashes from medical waste incineration
using two different sequential extraction
methods were obtained [19]. To assess metal
toxicity in the leaching process it was used
TCLP test (Toxicity Characteristic Leaching
Procedure). In both types of ashes, the metals
are predominantly bounded in exchangeable and
iron and manganese oxides fractions. While in
bottom ash the metal concentrations are in the
range of tens to hundreds of mg/Kg (e.g. 180
mg/kg) in filtered ash, the concentrations are
found in the range from hundreds to thousands
of mg/Kg (1,300 mg/kg). In filter ash, due to
high concentrations of Cu, Cr, Pb and Zn in
exchangeable forms, a special attention should
be given when manage such waste, in order to
avoid heavy metals dispersion in environment
segments. Even if the wastes are classified under
the same harmonized code, the heavy metals
content is different from one matrix to another
depending on the generation process. Thus,
some research studies focused to set some
experimental models for the characterization and
analysis of waste samples coming from the same
type/class of waste [20]. The experimental
models were applied on the metals analysis in
four wastes coming from processing and
finishing activities of metal surfaces and other
materials. For organic matter decomposition
were used four digestion methods. Metal
concentrations have been analyzed by AAS
(Atomic Absorption Spectrometry) and XRF (X-
Ray Fluorescence Spectrometry) to show their
influence on the final analytical results. From
obtained results was found that, there are very
high differences in concentrations between the
matrices of wastes analyzed. Despite this fact,
the mineralization using method IV is the one
that responded well in both low and high levels
of metals. The proposed experimental models
can be successfully applied in the usual
laboratory practice to characterize different
groups/categories of wastes from European list
of waste. In the same context were developed
adequate digestion methods for metal
determination in biomass wastes coming from
agriculture, forestry, horticulture, and wine
industry [21]. For biomass waste mineralization
have been used two types of digestion methods.
The metals were analyzed by AAS (Atomic
Absorption Spectrometry) and ICP-MS
(Inductively Coupled Plasma-Mass
Spectrometry) in order to demonstrate the
quality of the obtained results in terms of
detection limits, precision, accuracy and
extended uncertainty. The authors concluded
that for the matrices of biomass waste,
reproducible results have been obtained by using
microwave digestion and metals determination
by ICP-MS. Another important parameter
besides the waste matrix is waste sample
homogeneity as we have already mentioned.
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
59
Other researchers reported results on the
statistical evaluation of experimental
determinations for gross calorific value and
carbon content indicators [22]. The research was
realized to set the necessary degree of samples
homogeneity prepared from mixed solid wastes
used in the current laboratory determinations. It
is known that the accuracy of those
determinations is directly involved in the safety
of combustion and environmental protection in
relation with gaseous emissions. In relation with
this topic another important parameter for the
environment and human health that should be
accurately determined from the waste/waste
mixture intended for incineration is Sulphur
content. Among other determination methods of
Sulphur from waste mixtures, one method of
choice might be ion-chromatography method
[23]. The research has been done on Refused
Derived Fuel resulting from municipal waste.
From experimental tests it is observed that “the
ion-chromatographic method gives similar
results with the more frequently used
gravimetric method. In addition, this method has
advantage of being faster and giving more
homogenous results.
Table 1. Waste - analytical detection and monitoring
Matrices
Analytical procedures
Analytes
Detection
technique
Aims
Ref.
Fly ash;
Bottom ash
Comparative
sequential extraction procedures
BCR – classic method: shaking time 16 h
followed by centrifugation;
BCR – modified
method: sonication
time 30 min followed
by centrifugation
Cr, Cu, Ni, Zn,
Pb, As, Cd
ICP-MS
Assessment mobile
fraction from ashes
[19]
Fly ash;
Bottom ash
Toxicity characteristic leaching procedure
test (TCLP)
Cr, Cu, Ni, Zn,
Pb, As, Cd
ICP-MS
TCLP test is using to
confirm toxicity for
metals in exchangeable
form
[19]
Soil and filter
cakes;
Powder
coating
waste;
Paint waste
For decomposition organic matter were
using four mineralization
methods: I. HNO3,
II. HNO3 + HCl;
III. HNO3 + H2O2;
IV. HNO3 + H2O2 + HCl
Cu, Zn, Ni, Pb
AAS
XRF
Characterization of
waste with complex
matrices
[20]
Biomass
waste
Comparative digestion methods
Closed system – microwave oven: 0,25 g
sample, 2 mL H2O2 + 8 mL of HNO3 for 15
minutes at 180°C;
Open system – sand bath: 1 g sample, 2 mL
H2O2 + 8 mL of HNO3 for 90 minutes at
120°C
Al, Mg, K, Ca,
Na, Fe
ICP-MS
AAS
Find an appropriate
method for
characterization the
biomass wastes
[21]
Solid waste
(mixture of
biomass,
textile and
plastic)
-Sample preparation by particles size
reduction:
Ash content and calorific value
determination – particles size below 1mm;
Carbon content determination –
particle size between
0.2 mm – 0.5 mm
-Samples homogenization
Gross calorific
Carbon
content
Calorimetry
Elemental
analysis
Influence of
homogeneity in
analytical
determinations
[22]
RDF
(Refuse-
Derived
Fuel);
Textiles and
paper;
Sewage-
sludge;
Oil-sludge
Comparative determination methods
Ion-Chromatographic – performance method
Gravimetric – classic method
Sulfur content
IC
technique
Find a faster method for
determination of sulfur
content
[23]
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
60
Environmental impact and risk assessments
The identification of pollution that leads to a
significant impact on the environment, is
followed by a risk assessment to take the
necessary measures to mitigate it. Monitoring
the pollution of air, soil, subsoil, surface water
and groundwater near municipal and industrial
landfills is a very important environmental topic.
The specialized literature presents numerous
studies in this field [24-26]. Air pollution can be
perceived in the vicinity of industrial pollutants
by unpleasant atmosphere and unpleasant odor.
There may also be many dangerous compounds
imperceptible in high concentrations [27].
Therefore, both perceived harmful odors and
imperceptible hazardous compounds should be
continuously monitored both at the source and in
neighboring areas. Nuisance odors control is
usually accomplished in industrial settings by
gas scrubbing with wet scrubbers or by
controlling conditions in anaerobic facilities in
such a way that hydrogen sulfide will not be
released [24-26]. In those conditions the air
monitoring pollutants is becoming a stringent
necessity. In many cities across Romania,
landfills are placed very close to settlements,
and in some cases even inside cities. Besides
landfill activities, other companies that deal with
waste sorting, recycling and treatment operates
nearby. Related to this topic, relevant results of
monitoring of odors near a landfill were
obtained [28]. The research was directed
towards monitoring of NH3, H2S and VOC in
order to impact assessment of landfill situated in
high urbanization area. Odor level was
determined according to SR EN 13725:2003
using dynamic olfactometry method. For the
impact assessment and annoyance level were
using FIDOL factors such as Frequency,
Intensity, Duration, Offensiveness and Location.
From obtained results, it is found that high
values were recorded both for chemical
measurements and odor level. The results
showed a significant impact on the air due to
landfill site and other connected activities. Next
are presented some relevant research related to
atmospheric pollution with gaseous emissions
near non-compliant landfills [29-30]. These
research studies were realized in the context of
future residential developments in the vicinity of
those landfills. Two municipal waste landfills
situated in the West of Bucharest and in Suceava
county have been investigated. Thus, several
campaigns of investigation have been running
for gases emissions from soil/subsoil areas
situated in their neighborhoods. In order to
estimate the risk components (probability and
severity of consequences) two specific
methodological approaches have been used. The
conclusions of the study show that for the
landfill located in the western part of Bucharest,
even after 20 years from the landfill works
closure there are different ways of migration of
gaseous emissions. These emissions are
influenced by anthropogenic factors such as
excavation activities, the position of pipelines
routes and cracks. For the landfill located in
Suceava County, low concentrations of methane
(0.4%) were found. However, the concentrations
cannot exclude the possibility of gas migration
in the vicinity of the deposit. For both evaluated
landfills, the sedimentary lithology of the area is
permeable, thus favoring the migration of gases
in the soil / subsoil. The ground and surface
waters pollution has been also the topic of
investigation in Bucharest - Giulesti Sarbi area
near a landfill site [31]. The research revealed
the existence of a pollution able to induce a high
risk for those environmental segments. Also,
another zone located near the municipal waste
landfill in Targu Neamt revealed the adverse
effects of landfill levigates on the quality of
groundwater [32]. Over last decades, in rainy
periods, the levigates from municipal waste
discharged directly in torrent valley generating
degradation of the Slatina river quality. These
discharges caused acute toxic effects on aquatic
ecosystem inducing a significant environmental
impact. Following those findings, adequate
mitigation measures have been recommended.
Another study referring to environmental risk
assessment for a landfill located in Region NW
of Romania in the vicinity of Cluj-Napoca was
performed [33]. To assess the environmental
risk, a conceptual assessment model was
proposed and sampling campaigns were
established for air, groundwater, soil and
leachate samples from both the landfill and its
immediate vicinity. Quantification of the risk
according to the results obtained indicates a
significant risk of environmental pollution even
after cessation of activity, a risk that requires
immediate mitigation actions. Another research
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
61
study refers to the characteristics of groundwater
in a mining area with an activity over 30 years.
The study focused on the spatial-temporal
evolution of heavy metal concentrations in
groundwater. The investigation area was
established next to a waterproofed pond located
next to two other sterile mining tailings ponds
[34]. The hydro-observation wells were
monitored in three seasonal investigation
campaigns. The obtained results showed that the
groundwater is contaminated with heavy metals,
the highest concentrations being recorded for Fe,
Cd, Mn and Pb. Regarding the investigation
period, for all hydro-observation wells, high
concentrations were registered in the spring
campaign. This may be due to the rich seasonal
precipitation that led to the dissolution of the
metals. A good environmental impact and risk
assessment requires good and reliable decision
methods. In this respect, in the latest years our
research have been also directed towards the
development of reliable multi-criterial decision
methods for environmental impact/risk
assessments based on Dempster-Shafer,
Evidential Reasoning algorithm, Rough Set
Theory, Fuzzy Set Theory and Analytical
Hierarchy Process [35-43]. Those methods are
useful instruments that help to structure high
volume of data and information encountered in
the practical applications. Those methods can be
useful also “when statistical data are missing or
are too costly”. Using subjective probability and
assessment with linguistic attributes can be
effectively used with them. These assessments
help evaluators to report much easier the
obtained risk assessment results to the interested
parties. A multicriterial method for
environmental risk assessment for the landfill
waste is proposed [44]. The method tries to
synthesize the most important criteria of interest
to predict possible pollution and its
consequences. Thus, the method offers a good
decision support instrument for environmental
risk mitigation measures. Good decision support
instruments are of particular importance to set a
sustainable development strategy. It is known
that, in last decades both at national and world
level there is a significant pollution due to waste
generation. Thus, a lot of research activities
have been focused on finding indicators that can
decouple the economic growth from the
excessive resources consumption especially
those that are non-renewable or hard renewable
ones. In this context, it was developed a
methodology that underlies a system of
statistical indicators that can be used to illustrate
the environmental pressure that comes from
economic development [45]. These indicators
are calculated by relating the amount of
hazardous / non-hazardous waste generated at
the level of an industrial economic activity to the
value of the obtained production. Statistically
indicators can be established both at the level of
a specific industrial activity and also at the
global level for a sector or an industrial branch.
By conducting this statistical study, it can be
shown that for a certain period of time the
increase of environmental pressure is less than
the increase of industrial economic activity.
Thus, the developed indicators are a useful tool
for central and local authorities, reflecting the
failure or success of national economic
development policies.
Harmonized waste classification and management
Harmonized waste classification is first step
for the future adequate waste management. In
this context, at the European level the waste
management has been regulated through EC
Waste Directive 98/2000 updated with EC
Regulation no. 1357/2014 and EC Decision
532/2000 updated with Decision Commission
955/2014, setting the rules regarding wastes
classification and wastes management [1, 3, 5].
This is done through a waste comprehensive
inventory named List of Waste organized by
chapters, sections and codes. Each wastes
producer/holder shall scan this inventory and
try to find a “best match” for the generated /
held wastes for an appropriately classification.
In Figure 9 is presented the general scheme for
identification one waste code.
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
62
Fig. 9. General scheme for waste classification
The classification can be done under three types
of wastes categories: absolute non-hazardous
waste (ANH), absolute hazardous waste (AH)
and mirror wastes – wastes that can be classified
under two different codes either as mirror non-
hazardous wastes (MNH) or mirror hazardous
wastes (MH). Their classification is based on the
absence or quantitative presence of substances
with intrinsic hazardous statement codes that
might impart to the wastes hazardous properties
of type HP1÷HP15. In this respect, it should
mention a set of published papers between 2013-
2018 revealing efforts done to find the best
methodological approaches including principles,
algorithms, and procedures in order to determine
hazardous properties of waste HP1÷HP15 for a
harmonized waste classification [41, 43, 46-49].
Waste classification and management represent
the first step to start realize transition from a
linear economy to a circular economy [8-10,
50]. The circular economy is defined as an
economic system which is based on extract,
produce, reuse, recycle and recovery of used
materials along the product life cycle going
towards the desiderate of zero waste disposal.
The concept of circular economy has been
promoted in recent years by the European
Community and extended to countries around
the world. In Romania, studies in this field are
still in their infancy, but there is a potential
interest in deepening the field of circular
economy and industrial symbiosis. Thus, within
a project financed by the European Union
(ECOREG project, LIFE + program) a
methodology was developed for the
implementation of industrial symbiosis in
several small communities in Suceava County
[51, 52]. Through industrial symbiosis, there is
the possibility to increase production for
economic units, without increasing the
consumption of raw materials and utilities. The
results showed that some 500,000 tons of
biomass waste from various landfills were
directed to a local chipboard producer. In
addition, some 150,000 m3 of biomass waste
from various landfills were directed to a local
wooden briquettes manufacturer. Thus, over 600
ha of virgin forest and fossil fuels were saved.
This project showed that financial, technical and
economic performance can be improved by
applying an industrial symbiosis.
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
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Waste pretreatment/treatment and recovery technologies
Waste treatment and recovery technologies are
used to find different ways for waste
management including recovery of useful non-
energetically and energetically components.
However, when such recovery technologies
cannot be applied the waste should be disposed
with maximum protection for the environment
and human health. Such an example is given in
the study realized for bottom and filter ashes
resulted from the incineration of medical waste
[53]. These ashes are contaminated with heavy
metals and other pollutants whose
concentrations exceed maximum admissible
values for the storage on hazardous waste
landfills. The research was aimed the treatment
of these ashes in order to dispose them on non-
hazardous waste landfills. Thus, two treatment
solutions were proposed: first solution was to
wash them under mixing with acid solution
followed by filtration and the second solution
was to mix them with sand and cement and to
incorporate them into concrete type matrices.
The obtained results after these treatments,
showed that the bottom and filter ashes can be
disposed on the non-hazardous waste landfills.
Also, in relation with ash type of waste one
could mention that, along the years ashes from
different thermal processes have been disposed
in different landfills, not only in Romania but all
over the world. Old landfills waste from thermal
power plants operating on fossil fuel (coal) are
usual in this category. The pollutants from those
ashes were dispersed by rainfalls that affected
environmental ecosystems. In those conditions,
Romania, following the examples from other
western countries targeted them for
phytoremediation. In the next section are
presented the possibility of reclamation of land
areas that were taken out from the agricultural
circuit as a result of storage of bottom and boiler
slag and fly ash [54-56]. Their reintegration can
be done by using a waste as biological material,
e.g. sewage sludge. In Table 2 are presented
some results of phytoremediation of such areas
using plants species and monitoring them for
bioaccumulation of heavy metals i.e. Cd, Cr, Cu,
Ni, Pb, Zn. The success of phytoremediation is
that metals particles are hampered to be spread
into the environment. The phytoremediation
proposes the alternative of concentrating metals
in some tolerant species that can grow in this
area transforming the landscape into more
pleasant one.
Table 2. Phytoremediation
Matrices
Fertilizer
Plant for
remediation
Accumulated metals
Ref.
Contaminated
soil
Sewage sludge
Lolium perenne
Cu, Cr, Ni, Zn - small amounts
Pb - large amount
[54]
Fly ash
Municipal
sewage sludge
Lolium Perenne
(LP)
Onobrychis
Viciifolia (OV)
Cu, Cr, Fe, Ni, Pb - the amount
accumulated by the two plants is similar
Mn - Onobrychis Viciifolia accumulates
twice as much as Lolium Perenne
Zn – Onobrychis Viciifolia accumulates
four times more than Lolium Perenne
[55]
Contaminated
soil
Biosolid
fertiliser
Festuca
Arundinacea (FA)
Onobrychis
Viciifolia (OV)
Festuca Arundinacea
Cr - 17,1%,
Ni, Cu, Zn between 29,4 – 39,1%
Fe - up to 61,2%
Onobrychis Viciifolia
Cu – 59,3%
Cr – 29,9%
Ni – 42,2%
[56]
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
64
As for the possibilities of using of the harvested
biomass enriched with the metals species, this is
for sure another very important research topic
[57]. In this respect, research was conducted
regarding the use of biomass in industrial
combustion process. Within the experiments
were used blends of biomass (sawdust) with
different other materials such as coal, clay, ash,
slag from various industrial power plants from
Romania. The role of biomass was to improve
the industrial combustion processes. The
obtained experimental results led to the
following main conclusions: a) when using of
biomass waste mixed with coal, the carbon
content and calorific values increased and the
ash and Sulphur content decreased; b) wastes
biomass added to coal and slag reduces the
amount of ash and decreases the Sulphur content
improving the process from the energetically
point of view. So, these results can be used for
further adjustments to the feed of some
combustion power plants in order to be able to
use biomass waste in their operations. Other
types of waste having cellulose content are also
subject to some new biotechnological solutions
for transforming them in useful products. Thus,
was studied the biogas production by using
paper and mill organic sludge in combination
with fermented municipal sludge and cattle
manure as inoculum [58]. The experimental
results showed that paper wastes can be used for
biogas production by thermophilic anaerobic
digestion (50°C) for a retention time of 28 days.
Even if biogas production is lower than in the
case of anaerobic digestion of municipal sludge,
this one is sufficient for biogas facility
maintenance. Also, the anaerobically stabilized
sludge can be used without any health risk, as
agricultural fertilizer because potential pathogen
bacteria are absent after digestion period. In the
same idea were reported the results obtained by
using anaerobically digested (stabilized) sewage
sludge as fertilizer for corn culture [59]. A
comparison between amounts of heavy metals
that have been accumulated in different parts of
the plant: grain, basal node, leaves, cobs and
corn husks was carried out. The results showed
that in the aerial parts of the harvested plants
from fertilized fields with the sewage sludge, the
toxic metals concentrations for Cd, Ni, Cr, have
been under the detection limits, and the amount
of Zn was according to the nutritional
requirements. In all studied cases, the heavy
metals amounts were mostly bioaccumulate in
the leaves of harvested plants. The heavy metals
accumulated in grains were always lower than in
aerial parts. This experimental research has been
done in order to show how sludge, might be
used as fertilizer on corn soil cultures in
comparison with unfertilized corn soil cultures.
Such, the anaerobically digested sewage sludge
can contribute to an increase of corn production
with 12 % comparing to the amount harvested
from the control field and with 5 % comparing
to the amount collected from a fertilized field
with 40 t/ha of manure.
In the same category of using waste in
agriculture, another example is to use the
stabilized sewage sludge for obtaining compost
type products [60]. In this respect, was
performed several composting experiments
using dewatered anaerobic digested sludge from
a municipal WWTP (Waste Water Treatment
Plant). As vegetal wastes, have been use vine
shoots, straws and wood chips in different
proportions and water for ensuring a 50-70%
humidity. The process of composting evolution
was verified during the whole period of three
months by controlling specifically parameters.
The quality of the obtained compost was similar
to the commercial products used for pot-flowers.
The heavy metal concentrations were below the
limits imposed by Order 344/2004, which makes
it possible soils fertilization with this
composting recipe. In the domain of waste
valorization, the composite materials have a
special attention in the latest years. Next, in a
series of papers are presented experimental
researches in order to obtain and characterize
new composite materials using different types of
waste [61-64, 65, 66]. The role of these
composite materials is to absorb and mitigate
noise from industry or extra urban and urban
areas. Thus, were established the specific
parameters and proposed wastes compatibilities
in order to obtained composite materials
according to the absorption coefficient which
recommends them from the point of view of
other necessary characteristics depending on
intended applications.
Different recipes for obtaining composite
materials were tried by using different types of
waste both as a binder matrix and as a
reinforcing agent. Wastes from technological
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
65
processes from different industries were used,
such as metallurgical industry - steel slag waste,
thermal power plants - ash, high temperature
sterilized municipal waste, wood processing
industries - wood waste of various sizes,
industry rubber or automobiles - crushed rubber
waste. The porosity of each material obtained is
the main property for the absorption of sound
waves but of course it is important and
mechanical strength.
The obtained results are presented in Table 3
with reference to each proposed composite
material related to the matrix binder and
reinforcement agents, a part of used material
being from processed waste.
Table 3. Waste derived composites, technical characteristics and possible uses
Composite material
Characteristics
Possible uses
Ref.
Binder matrix: fly ash;
Reinforcement agents: slag steelworks,
sterilized waste garbage, slag outbreak from
thermal power plant, seed shells burning ash
-Absorption coefficient of
0.98 in the frequency
range:400÷2600 Hz
-Material of Class A
absorbing panels
[61]
Binder matrix: polyester resin 50 %;
Reinforcement agents: rubber powder waste 50
% from used tires and from rubber formed
polymer processing (natural styrene butadiene
isoprene)
-Diffraction coefficient
decreases proportionally
with the increasing of the
operation frequency.
-A reduction of sound
pressure level due to
absorptive properties.
industrial sound-
absorbing barriers
[62]
Binder matrix: formaldehyde resin;
Reinforcement agents: waste slag, sterile
municipal waste and sawdust
absorption coefficient
between 0.8-0.9
panels for
industrial settings
or road
transportation
[63]
Binder matrix: formaldehyde resin 80%
Reinforcement agents: ground glass, wood and
polypropylene waste
absorption coefficient
between 0.8-0.9
panels for
industrial settings
[64]
Binder matrix: polymeric resins; Reinforcement
agents: solid organic or inorganic wastes
-good mechanical properties
(hardness, abrasion and
compressive strengths)
-good thermal stability at
high temperatures variation
and
-high stability in different
aggressive media
-good sound absorption
capacity depending on the
proportion and nature of
used waste.
panels for
industrial settings
[65]
Binder matrix: concrete mixes with different
water to cement ratio (0.45, 0.50 and 0.55)
Reinforcement agents: crumb rubber dosages
(0%, 5.0% and size ranging varied from 0.5 to 4
mm) and it was used a fine aggregate with size
ranging from 0.063 to 2 mm, and a coarse
aggregate with size ranging from 2 to 16 mm
-good mechanical properties
(hardness, abrasion and
compressive strengths)
-good sound absorption
capacity depending on the
compozit material porosity
obtain and pore size.
panels for
industrial settings
[66]
Other research studies were focused on
obtaining the plastics composite materials [67].
The used materials were mixtures of HDPE and
PP with different filler contents of crushed
postage envelope waste. The assessing
mechanical and morpho-structural
characteristics of these composite materials was
realized with SEM (Scanning Electron
Microscopy). The results shown that wastes of
mixtures of paper and plastic can be competitive
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
66
for obtaining plastic composite materials when
special mechanical and electrical characteristics
are not required.
Related to the same possible use, in another
paper are presented the results of an
investigation related to the assessment of the
environmental impact at disposal of the above-
mentioned composite materials [68]. Thus,
combined plastic and paper waste were subject
to the leaching test before being injected in the
matrices of composite materials and after
applying this recovery process.
It is known that, when a recovery process is
proposed, the new obtained products, besides
compliance to the quality standards for their
proposed use/application, should also meet the
standards for the environmental quality. The
results from leaching tests in accordance with
Order 95/2005 show that after the wastes
injection in the matrices of composite materials
the concentrations of indicators as DOC
(Dissolved Oxygen Carbon) and TDS (Total
Dissolved Solids) are smaller than limits
imposed comparing with wastes made of
mixtures of plastics and paper. Thus, the
obtained composite materials are recommended
also from the environmental point of view.
In addition to the recovery of energy
components from waste, energy recovery is
another option that needs to be investigated
before the final disposal of waste. For the
correct operation of a combustion plant, the
combustion characteristics of the fuel and fusion
characteristic of the produced ash are very
important. In this regard, the oxides composition
from residual ashes and its influence on the
slagging and fouling process was studied [69].
The slag process was evaluated on the basis of
indices such as: the basic oxides, the acid-base
ratio, the slag index and the fouling index. The
obtained results show that, depending on basic
oxides, sewage ash can cause a high to moderate
slagging tendency. Thus, the complete
characterization of the sludge has an important
role in the design of combustion plants for their
incineration or co-incineration.
And last but not least we should mention that
water quality is also vital for all the planet [70].
Consequently, in order to protect the good water
quality, its recovery from the treatment of
industrial liquid waste represent a necessity
governed by present accelerated economic
progress of the society. Thus, one study presents
how two types of different wastes can be
combined in order to clean an industrial
wastewater heavily polluted. The paper presents
the use of a coagulation agent obtained from
industrial waste containing as a major
component Cu, Mn, Al and Fe to treat
wastewater from printing industry, replacing this
way more costly usual used inorganic coagulants
like FeCl3 and AlCl3. The results show that very
heavily polluted liquid waste from printing
industry was brought to a much lower pollution
level, by a combined coagulation, precipitation
and co-precipitation processes. The quality of
the separated, filtrate can also be improved
according to the further water use (industrial
use) or for the discharge into a water body with
or without final wastewater treatment plant
according to the legally imposed limits.
CONCLUSIONS
The research studies result from the present
work, have been obtained within research
projects and have been materialized in:
pollutants detection and monitoring methods
from complex matrices wastes, environmental
impact and risk assessment methods,
methodologies and models, waste hazardousness
assessment and classification methodologies
according to the harmonized European list,
technological solutions for waste treatment,
recycling and valorization.
Those results were the basis to develop some
new environmental services for different
economic agents, represented the basis for
applying them in other research projects and
establishing the research partnerships with
entities in the field of environmental protection.
Waste management is a major and complex
issue both in Romania and all over the world.
All the research done in the past and the future
research will have as priority finding those best
solutions for minimizing the quantity of waste
generated, as well as the treatment and safe
disposal of hazardous waste. At the same time,
research on best practices for the application of
industrial symbiosis and the circular economy
remains relevant for the entire scientific
community.
L. Kim et al.: Waste management and their environmental impact: Challenges and opportunities at national level
Romanian Journal of Ecology & Environmental Chemistry ● Vol.2 ● No.1 ● 2020
67
ACKNOWLEDGEMENTS
National Research and Development Institute for Industrial Ecology performed these researches
with the financial support of the Romanian Research and Innovation Ministry and Union Europe in
the period of 2009 – 2019 (NUCLEU Program, CEEX Program, LIFE+ Program, POC Program).
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