2. REACHED GOALS AND RESULTS
P.S.: DFormer PhD students with theses associated to the project authors of scientific
papers published during the period.
2.1 RESULTS ACHIEVED FOR CLEANING/WASHING WASTEWATER
STREAMS
With the purpose of minimizing the negative impacts of wood-based industries on the
environment and municipal sewage treatment plants in a cost-effective way, the
research has focused on the treatment of cleaning/washing wastewater using low-cost
nature-based strategies to remove organics and metals such as:
For wastewater streams (initial COD varying from 15,000 to 66,000 mg/L) after
sedimentation step to remove more than 50% of the pollutants, the investigations
included: unconventional adsorbents (wood fly ash, sawdust), commercial activated
carbon, electrocoagulation; Anaerobic-aerobic biological treatment associated to
chemical precipitation; AOPs such photo-Fenton with nano-scale Fe and Ozone-UV
associated to biological treatment.
2.1.1 Toxicity posed by cleaning/washing wastewater, even after high dilution rate
1. Toxicicity of wastewater on aquatic organisms even after high dilution: The
effects of two cleaning wastewater streams generated by different wood floor
production lines on Desmodesmus subspicatus were investigated. The microalgae
was exposed to different wastewater concentrations (100, 50, 25, 12.5 and 6.25%
v:v) and the algae growth evaluation was based on in vivo chlorophyll
fluorescence, cell density, cell size (number of cells/colony) and cell ratio
(length/width). Inhibitory effects of the tested wastewaters on the microalgae were
positively related to concentration and negatively related to exposure time. The
EC50,24 h of blade cleaning wastewater (BCW) and floor cleaning wastewater
(FCW) were 3.36 and 5.87% (v:v), respectively. No negative effect on cell colony
formation was caused by BCW, whereas an increase of 90% unicellular cells was
observed in FCW concentrations below 50% (v:v). At the lowest concentration
(3.13% v:v) where no growth inhibition was observed, both wastewater streams
caused changes in cell dimensions by increasing cell length and width. To
conclude, wastewaters generated during cleaning procedures in the wood floor
industries can pose severe environmental impacts on aquatic organisms, even after
high dilution. Therefore, these wastewaters must be treated before being
discharged into the sewerage system or water bodies. Conclusion: Wastewaters
generated during cleaning procedures in the wood floor industries pose severe
toxic effects on aquatic organisms such as microalgae, even after high dilution.
Sawanya LaohaprapanonD, Fabio KaczalaD, Paulo S. Salomon, Marcia
Marques and William Hogland. Wastewater generated during
cleaning/washing procedures in a wood-floor industry: toxicity on the
microalgae Desmodesmus subspicatus. Environmental Technology Vol. 33, No.
21, Nov 2012, 2439–2446.
2.1.2 Unconventional
adsorbents
biomass/waste-based
adsorbents
and
commercial
2. Sawdust as adsorbent for further removal of toxic metals from wastewater: The
experiments started with settling /sedimentation phase, which removed 85% and
93% of Vanadium and Lead reduction after 24 h from the real industrial
wastewater generated after cleaning of floor and machinery at a wood-laminate
floor industry. After that, batch sorption were conducted with untreated Pinus
sylvestris sawdust (particles ≤ 2 mm) using different adsorbent doses, initial pH,
and contact time for further removal of remaining toxic metals. The development
of pH along the sorption test and a parallel investigation of metals release from
sawdust in distilled water were carried out. In order to evaluate kinetic parameters
and equilibrium isotherms, Lagergren first-order, pseudo second-order, intraparticle diffusion and Freundlich models were explored. When the initial pH was
reduced from 7.4 to 4.0, the sorption efficiency increased from 32 % to 99 % for
Pb and from 43 % to 95 % for V. Whereas V removal was positively correlated
with the adsorbent dose, Pb removal was not. The sorption process was best
described by pseudo-second-order kinetics. According to Freundlich parameters
(Kf and n) sawdust presented unfavourable intensity for sorption of V. Such
excellent performance in removing metals at low cost shall be considered when
building up the train treatment plant. Conclusion: Metals such as vanadium and
lead are removed in high percentages from cleaning/washing wastewaters
generated by the wood-floor industry using untreated sawdust as adsorbent.
Fabio KaczalaD, Marcia Marques, William Hogland. Lead and vanadium
removal from a real industrial wastewater by gravitational
settling/sedimentation and sorption onto Pinus sylvestris sawdust.
Bioresource Technology 100 (2009) 235–243.
3. On-site treatment of a real industrial wastewater with “green” adsorbent
(sawdust): Treatment systems based on sorption mechanisms are flexible, easy to
operate and generate less sludge and several low-cost sorbents generated by
forestry activities have advantageous physico-chemical characteristics. The
current paper presents the preliminary results from a pilot treatment system
consisting of an equalization tank, settling/sedimentation and two sorption
reactors in parallel using Pinus sylvestris sawdust as sorbent implemented as part
of an integrated water management plan in a wood-floor industry. The simple to
operate and cost-effective pilot treatment system performs satisfactorily during an
initial period of operation. The study shows an average 39% - 54% reduction of
TPH; 17% - 38% reduction of oil; 2% - 15% of reduction of COD and; 11% 74% reduction of most toxic metals but for Co, Ni and Zn in the system B. Based
on these results, Pinus sylvestris sawdust is a potential low-cost and abundant
material to be considered for industrial wastewater treatment plants. Therefore, a
pilot plant based on setting/sedimentation followed by sorption with sawdust
removed TPH (39-54%), COD (2-15%), Toxic metals (11-74%) from a mixture of
different wastewater streams from the wood-floor industry. Conclusion: Metals
and organic pollutants are removed to some extent and in different percentages
from cleaning/washing wastewaters generated by the wood-floor industry using
untreated sawdust as adsorbent.
Fabio KaczalaD, Marcia Marques, William Hogland. Settling/sedimentation
followed by sorption with Pinus sylvestris sawdust as “green” sorbent: Onsite treatment of a real industrial wastewater. Journal of Environmental
Protection, 2014, 5, 368-375. http://dx.doi.org/10.4236/jep.2014.55040
4. Removal of Organic Pollutants from Wastewater Using Wood Fly Ash as a
Low-Cost Sorbent: In this study, untreated and treated wood fly ash (WA) was
used as a low-cost sorbent in batch sorption tests to investigate the removal of
organic pollutants from a real wastewater generated by cleaning/washing of
machinery. The experiments focused on the effect of the WA dosage and particle
size on the removal efficiency for organic compounds. With a WA dosage of 160
g L_1 and a particle size less than 1mm, the reductions of chemical oxygen
demand (COD), biologic oxygen demand, and total organic carbon were
37±0.4%, 24±0.4%, and 30±0.3%, respectively. Pre-treatment of WA with hot
water improved the COD removal efficiency by absorption from 37±0.4% to
42±1.6% when the same dosage (160 g L_1) was applied. Sorption isotherm and
sorption kinetics for COD using untreated WA can be explained by Freundlich
isotherm and pseudo-second-order kinetic models. Intra-particle diffusion model
indicates that pore diffusion is not the rate-limiting step for COD removal. Based
on the experimental data, WA could be used as an alternative low-cost sorption
media/filter for removal of organic compounds from real industrial wastewater.
However, leaching tests with wood fly ashes resulted in release of high
concentrations of Cr, which makes the fly ash unsuitable for the treatment.
Conclusion: although fly can be used in sorption tests for reduction of organic
load from cleaning/washing wastewaters generated by the wood-floor industry,
leaching tests with this unconventional low-cost adsorbent show release of toxic
metals to the water phase, which makes it unsuitable for wastewater treatment.
Sawanya LaohaprapanonD, Marcia Marques, William Hogland. Removal of
organic pollutants from wastewater using wood fly ash as a low-cost sorbent.
Clean – Soil, Air, Water 2010, 38 (11), 1055–1061.
5. Coal activated carbon (CAC) and wood activated carbon (WAC) for reduction of
COD from wastewater: In the present study, chemical oxygen demand (COD)
removal by packed-columns of activated carbon (AC) derived from two different
materials (coal activated carbon, CAC and wood activated carbon, WAC) is
reported as part of an on-site wastewater treatment system for handling small
volumes of wastewater generated at wood-floor industries for which there are no
proper on-site treatment options available in the market. The performance of the
sorbents, the effect of bed depth (0.19 and 0.57 m) and volumetric load (0.10 and
0.24m h_1) on the breakthrough curve of sorption systems were studied. The
results indicated the feasibility of using both ACs to treat these wastewaters. At
the bed depth (0.57 m), volumetric load (0.24m h_1), and 30% breakthrough, CAC
and WAC showed treatment capacity of 40.5 L kg_1 in 250 h and 23.8 L kg_1 in 63
h, respectively. This indicated that CAC requires longer retention times to reach a
performance similar to WAC. The experimental data was fit into the bed depthservice time model showing that under the same conditions CAC had higher
maximum sorption capacity (N0) than WAC. Moreover, thermal regeneration at
500 oC temperature could be a cost-effective procedure since the reuse of spent
AC through such regeneration process for further treatment could still achieve
90% of the initial sorption capacity, reducing then costs for the use of new
sorbents and also the need for waste disposal. Conclusion: Both coal and wood
activated carbon are potential adsorbents for removal of organic load from
cleaning/washing wastewaters generated by the wood-floor industry and thermal
regeneration could be used to reduce costs and solid waste generation.
Sawanya LaohaprapanonD, Marcia Marques, William Hogland. PackedColumn of Granular Activated Carbons for Removal of Chemical Oxygen
Demand from Industrial. Clean – Soil, Air, Water 2013, 41 (3), 244–250.
6. Iron mineral adsorbent for removal of inorganic anions from water: A number
of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate)
have been reported in alarming concentrations in numerous drinking water
sources around the world. Their presence even in very low concentrations may
cause serious environmental and health related problems. Due to the presence and
significance of iron minerals in the natural aquatic environment and increasing
application of iron in water treatment, the knowledge of the structure of iron and
iron minerals and their interactions with aquatic pollutants, especially inorganic
anions in water are of great importance. Iron minerals have been known since
long as potential adsorbents for the removal of inorganic anions from aqueous
phase. The chemistry of iron and iron minerals reactions in water is complex. The
adsorption ability of iron and iron minerals towards inorganic anions is influenced
by several factors such as, surface characteristics of the adsorbent (surface area,
density, pore volume, porosity, pore size distribution, pHpzc, purity), pH of the
solution, and ionic strength. Furthermore, the physico-chemical properties of
inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also
significantly influence the adsorption process. The aim of this paper is to provide
an overview of the properties of iron and iron minerals and their reactivity with
some important inorganic anionic contaminants present in water. It also
summarizes the usage of iron and iron minerals in water treatment technology.
Conclusion: The literature review focuses on iron minerals as potential
adsorbents for removal of inorganic anions such as nitrate, fluoride, bromate,
phosphate and perchlorate from water and properties that enhances the sorption
capacity.
Eva KumarD, Amit Bhatnagar, William Hogland, Marcia Marques, Mika
Sillanpää. Interaction of inorganic anions with iron-mineral adsorbents in
aqueous media - A review. Advances in Colloid and Interface Science 203
(2014) 11–21.
7. Aluminium-based adsorbents for removal of anionic pollutants from water:
Many anionic pollutants (e.g., fluoride, nitrate and nitrite, bromate, phosphate,
arsenate and arsenite, selenite and selenite, perchlorate) have been detected in
surface and groundwater in different parts of the world and strict measures are
being taken to minimize their concentrations and to control their mobility in
aqueous media. Mineral surfaces, in general, have shown enhanced uptake of
many anionic pollutants. Various phases of aluminum (Al) oxides, hydroxides and
oxyhydroxide are increasingly being employed as adsorbents for the
detoxification of water and wastewater contaminated with anionic pollutants.
Understanding the structural properties and morphology of adsorbents is
important in order to gain knowledge about the governing mechanism behind the
adsorption of anions by these adsorbents. The adsorption ability of aluminum
oxides, hydroxides and oxyhydroxide depends on several key factors including
properties of the adsorbent (surface area, pore size, pHpzc, porosity) and that of
the adsorbates. This paper provides an overview of the physical and chemical
properties of various aluminum oxides, hydroxides and oxyhydroxides and their
application in water and wastewater treatment with the focus on the removal of
anionic pollutants. Furthermore, the performance of these minerals and that of the
synthetically prepared hybrid adsorbents (containing Al-minerals) for the
adsorption of various anions has been reviewed with an emphasis on the behavior
of adsorbent-water interface in presence of the anionic pollutants. Conclusion:
The review focuses on aluminium (Al) oxides, hydroxides and oxyhydroxide
which are employed as adsorbents to remove anionic pollutants from water such
as fluoride, nitrate and nitrite, bromate, phosphate, arsenate and arsenite, selenite
and selenite, perchlorate.
Eva KumarD, Amit Bhatnagar, William Hogland, Marcia Marques, Mika
Sillanpää. Interaction of anionic pollutants with Al-based adsorbents in
aqueous media - A review. Chemical Engineering Journal 241 (2014) 443–456.
8. Modification methods applied to activated carbon – Review: Activated carbon
has been recognized as one of the oldest and widely used adsorbent for the water
and wastewater treatment for removing organic and inorganic pollutants. The
application of activated carbon in adsorption process is mainly dependent on the
surface chemistry and pore structure of porous carbons. The method of activation
and the nature of precursor used greatly influences surface functional groups and
pore structure of the activated carbon. Therefore, the main focus of researchers is
to develop or modifies the activation/treatment techniques in an optimal manner
using appropriate precursors for specific pollutants. In recent years, emphasis is
given to prepare the surface modified carbons using different procedures to
enhance the potential of activated carbon for specific contaminants. Various
methods such as, acid treatment, base treatment, impregnation treatment, ozone
treatment, surfactant treatment, plasma treatment and microwave treatment have
been studied to develop surface modified activated carbons. In this paper, these
modification methods have been reviewed and the potential of surface modified
activated carbons towards water treatment has been discussed. This review article
is aimed at providing precise information on efforts made by various researchers
in the field of surface modification of activated carbon for water pollution control.
Conclusion; The review discusses techniques applied to modify surface chemistry
and porous structures enhance adsorption capacity of activated carbons, such as
acid or basic treatment, impregnation, ozone treatment, surfactant and plasma and
microwave treatment.
Amit Bhatnagar, William Hogland, Marcia Marques, Mika Sillanpää. An
overview of the modification methods of activated carbon for its water
treatment applications. Chemical Engineering Journal 219 (2013) 499–511.
9. Solid waste generated by the olive oil industry as adsorbent for wastewater
treatment – Review: The global olive oil production for 2010 is estimated to be
2,881,500 metric tons. The European Union countries produce 78.5% of the total
olive oil, which stands for an average production of 2,136,000 tons. The
worldwide consumption of olive oil increased of 78 % between 1990 and 2010.
The increase in olive oil production implies a proportional increase in olive mill
wastes. As a consequence of such increasing trend, olive mills are facing severe
environmental problems due to lack of feasible and/or cost-effective solutions to
olive-mill waste management. Therefore, immediate attention is required to find a
proper way of management to deal with olive mill waste materials in order to
minimize environmental pollution and associated health risks. One of the
interesting uses of solid wastes generated from olive mills is to convert them as
inexpensive adsorbents for water pollution control. In this review paper, an
extensive list of adsorbents (prepared by utilizing different types of olive mill
solid waste materials) from vast literature has been compiled, and their adsorption
capacities for various aquatic pollutants removal are presented. Different
physicochemical methods that have been used to convert olive mill solid wastes
into efficient adsorbents have also been discussed. Characterization of olive-based
adsorbents and adsorption mechanisms of various aquatic pollutants on these
developed olive-based adsorbents have also been discussed in detail. Conclusions
have been drawn from the literature reviewed, and suggestions for future research
are proposed. Conclusion: The review focuses on olive mil waste as a problem
that increased with the increase of the olive oil production in the EU and its
potential for conversion in an inexpensive adsorbent for wastewater treatment.
Amit Bhatnagar, Fabio KaczalaD, William Hogland, Marcia Marques,
Christakis A. Paraskeva, Vagelis G. Papadakis, Mika Sillanpää. Valorization
of solid waste products from olive oil industry as potential adsorbents for
water pollution control—a review. Environ Sci Pollut Res (2014) 21:268–298
DOI:10.1007/s11356-013-2135-6.
2.1.3 Biological wastewater treatment
10. Anaerobic/intermittently aerated bioreactor for the treatment of wastewater with
focus on reduction of COD, formaldehyde and nitrogen: The treatment was
applied to wastewater generated after cleaning and washing of machinery used to
apply urea–formaldehyde resins onto wood-fibre boards. The biological system
consisted of an anaerobic – intermittently aerated reactor in lab-scale. Since the
investigated wastewater is intermittently generated, the system was designed to
operate in batch mode. The treatment focused on removal of formaldehyde and
COD, as well as the efficiency of nitrification–denitrification. The proposed cheap
and relatively simple-to operate biological system achieved COD and
formaldehyde removal rates of 65±11% and 93±4% respectively. In spite of
anaerobic ammonium removal and denitrification, the intermittently-aerated
reactor showed poor performance for nitrification. Therefore, a better
understanding of constraints for the process improvement is necessary. Regardless
the constraints faced during the investigation, the proposed system can be
considered feasible to partially reduce a great amount of biodegradable
compounds in urea–formaldehyde-based wastewaters. However, to comply with
strict threshold limits for industrial effluent discharges, the use of biological
treatment combined with more advanced processes is needed to achieve a better
quality of the final effluent. Conclusion:
Urea-formaldehyde-based wastewater (COD 11,235 mg/L and formaldehyde 730
mg/L) treated in batch mode in anaerobic-intermittently aerated reactor reduces
COD 65±11% and fomaldehyde 93±4% but poor nitrification in the intermittently
aerated reactor was achieved. More advanced processes must be combined with
biological treatment.
Fabio KaczalaD, Marcia Marques, William Hogland. Biotreatability of
wastewater generated during machinery washing in a wood-based industry:
COD, formaldehyde and nitrogen removal. Bioresource Technology,
101(2010):8975-8983.
http://dx.doi.org/10.1016/j.biortech.2010.06.122
11. Anaerobic Baffled Reactor (ABR) coupled to chemical precipitation: Reduction
of soluble chemical oxygen demand (CODs) and removal of dissolved organic
carbon (DOC), formaldehyde (FA) and nitrogen was achieved with a laboratoryscale biological anaerobic baffled reactor followed by chemical precipitation
using MgCl2 ·6H2O + Na2HPO4. By increasing the hydraulic retention time from
2.5 to 3.7 and 5 days, the reduction rates of FA, DOC and CODs of nearly 100%,
90% and 83%, respectively, were achieved. When the Mg:N:P molar ratio in the
chemical treatment was changed from 1:1:1 to 1.3:1:1.3 at pH 8, the NH+ 4
removal rate increased from 80% to 98%. Biologically and chemically treated
wastewater had no toxic effects on Vibrio fischeri and Artemia salina whereas
chemically treated wastewater inhibited germination of Lactuca sativa owing to a
high salt content. Regardless of the high conductivity of the treated wastewater,
combined biological and chemical treatment was found to be effective for the
removal of the organic load and nitrogen, and to be simple to operate and to
maintain. A combined process such as that investigated could be useful for on-site
treatment of low volumes of highly polluted wastewater generated by the wood
floor and wood furniture industries, for which there is no suitable on-site
treatment option available today. Conclusion: Treatment of wastewater (initial
average COD = 4155 mg/L; DOC = 2207 mg/L; FA = 208 mg/L and initial pH =
2.08) with a biological anaerobic baffled reactor in 5 days of HRT reduced COD,
DOC and FA in 83%, 90% and 100% respectively. A second step included
precipitation with MgCl2 ·6H2O + Na2HPO4, pH (8) and Mg:N:P molar ratio
(1.3:1.0:1.3) for NH+4 reduction of 98%.
Sawanya LaohaprapanonD, Marcia Marquesa and William Hogland.
Anaerobic baffled reactor coupled with chemical precipitation for treatment
and toxicity reduction of industrial wastewater. Environmental Technology,
2014 Vol. 35, No. 2, 154–162. http://dx.doi.org/10.1080/09593330.2013.821142
2.1.4 Electrocoagulation (EC) and different Advanced Oxidation Processes
(AOPs)
12. Association of electrocoagulation (EC) and sorption/filtration by coal-based
activated carbon (CAC): Both sequences (EC-CAC and CAC-EC) were tested to
treat five highly polluted wastewater streams and to evaluate, how different
sequencing of these treatment units affects the overall system efficiency regarding
COD reduction. On the basis of preliminary studies, an EC reactor (1.0 L) was
constructed with monopolar electrodes in parallel connection in an array of four
Al electrodes with surface area of 93.2 cm2 and an applied current density of 161
Am–2. This reactor was coupled to a sorption/filtration (CAC) unit with coal
activated carbon. The EC reactor was tested in two different sequences (before
and after the CAC unit). The overall COD reduction varied from 2 ± 0.5% to 77 ±
2.9%, depending on the sequence and the type of wastewater stream. The best
result from efficiency and operational viewpoints was obtained with the EC
reactor placed after the CAC unit. The increase in efficiency is likely to be due to
the removal by sorption in the activated carbon of compounds that interfere with
EC. Additionally, as desired, the use of EC before the sorption unit extended the
activated carbon lifetime. Conclusion: Electrocoagulation (EC) combined with
sorption/filtration (coal-based activated carbon CAC) treated 4 of 5 streams of
cleaning/washing wastewaters from the wood-floor industry. The best result was
obtained when EC reactor was placed after sorption/filtration column. It seems
that sorption/filtration removed compounds which interfere with the EC.
Henrik HanssonD, Marcia Marques, Sawanya LaohaprapanonD and William
Hogland. Electrocoagulation coupled to activated carbon sorption/filtration
for treatment of cleaning wastewaters from wood-based industry.
Desalination and Water Treatment, 52 (2014) 5243–5251 doi:
10.1080/19443994.2013.808582
13. Use of Nanoscale zero-valent iron (nZVI) in advanced oxidation by Fenton and
photo-Fenton: There is a need for the development of on-site wastewater
treatment technologies suitable for “dry-process industries,” such as the woodfloor sector. Due to the nature of their activities, these industries generate lower
volumes of highly polluted wastewaters after cleaning activities. Advanced
oxidation processes such as Fenton and photo-Fenton, are potentially feasible
options for treatment of these wastewaters. One of the disadvantages of the Fenton
process is the formation of large amounts of ferrous iron sludge, a constraint that
might be overcome with the use of nanoscale zero-valent iron (nZVI) powder.
Wastewater from a wood-floor industry with initial COD of 4956 mg/L and TOC
of 2730 mg/L was treated with dark-Fenton (nZVI/H2O2) and photo-Fenton
(nZVI/H2O2/UV) applying a 2-level full-factorial experimental design. The
highest removal of COD and TOC (80% and 60%, resp.) was achieved using
photo-Fenton. The supply of the reactants in more than one dose during the
reaction time had significant and positive effects on the treatment efficiency.
According to the results, Fenton and mostly photo-Fenton are promising treatment
options for these highly recalcitrant wastewaters. Future investigations should
focus on optimizing treatment processes and assessing toxic effects that residual
pollutants and the nZVI might have. The feasibility of combining advanced
oxidation processes with biological treatment is also recommended. Conclusion:
After the sedimentation/settling tank with a mixture of wastewater streams COD
was 4956 mg/L and TOC was 4956 mg/L at pH = 2.2. With treatment with photoFenton using nanoscale zero-valent Fe, COD and TOC were reduced in 80% and
60% respectively. Supply of reactants in more than one dose along reaction time
had a significant increase in the treatment efficiency.
Henrik HanssonD, Fabio KaczalaD, Marcia Marques and William Hogland.
Photo-Fenton and Fenton Oxidation of Recalcitrant Industrial Wastewater
Using Nanoscale Zero-Valent Iron. International Journal of Photoenergy Vol
2012, Article ID 531076, 11p. doi:10.1155/2012/531076
14. Ozone and ozone-based advanced oxidation processes: The wastewater with
initial chemical oxygen demand (COD) varying between 3,400 and 4,000 mg/L,
was treated using a tubular ozone reactor combined with an UV reactor designed
for different hydraulic retention times. The dependent variables addressed to
evaluate the treatment efficiency were the reduction of COD and total organic
carbon (TOC) and the biodegradability of the treated effluent based on
respirometric studies using activated sludge from a wastewater treatment. The
results showed that even though ozonation alone at acid pH promoted COD and
TOC reductions of 65% and 31% respectively, a decrease in the biodegradability
was observed. The most effective treatment (COD and TOC reductions of 93%
and 43%, respectively) was obtained when applying ozone combined with UV
light at basic pH. The ozone-UV combination was capable of increasing the
amount of readily available COD by 75% with an additional reduction of TOC by
60%. In conclusion, ozonation at low pH effectively reduces the COD content in
wastewater generated by the wood-based industry; however, in order to combine
advanced oxidation with biological process, ozone combined with UV is
recommended. Conclusion: The most effective ozone-UV treatment achieved
93% and 43% or reduction in COD and TOC respectively with initial basic pH.
The biodegradability of remaining organic load was increased, which suggest a
potential positive combination with biological treatment.
Henrik HanssonD, Fabio KaczalaD, Alexandre AmaroM, Marcia Marques,
William Hogland. Advanced Oxidation Treatment of Recalcitrant
Wastewater from a Wood-Based Industry: a Comparative Study of O3 and
O3/UV. Water Air Soil Pollution (2015) 226:229 DOI 10.1007/s11270-0152468-5
2.2 RESULTS ACHIEVED FOR RUNOFF DUE TO STORMWATER,
PRECIPITATION AND IRRIGATION OF LOG YARDS
For stormwater runoff generated at log yards, the project conducted
characterization of leachate from different tree species, including ecotoxicity
assessments and treatability studies using biomass-based adsorbents/filters, ozone as
pre-treatment to biological treatment; mesocosms of constructed wetlands/tanks with
aeration and/or vegetation in different hydraulic retention times.
2.2.1 Characterization and toxicity posed to aquatic organisms
15. Characterization of stormwater generated at log yards: The stormwater run-off
generated in an industrial log yard during 8 runoff events was studied with the
main focus on the transport of toxic metals. Associations between water quality
constituents and potential surrogates were evaluated by correlation analysis. The
first-flush phenomenon was verified by normalized M(V) curves. The results have
shown that, whereas some metals such as Zn, Ba, Cd, As and Fe were always
detected in these waters, others (Cr, Pb, Cu, Ni, V, Co) were not. Large variations
in the water constituents’ concentrations were observed, with Fe, Pb and V being
the most variable ones. Concentrations of Zn and Cu in the run-off waters
exceeded the values established by the Swedish environmental authorities in
100% and 97% of samples, respectively. The correlation analyses indicated, as a
potential surrogate of Pb, V, Co, Ni, As, Ba, Cr and COD (0.949 > R > 0.808),
making it reasonable to state that a treatment system with focus on TSS removal
would also reduce toxic metals from these waters. The first-flush phenomenon
was evident for most of the constituents. Significant differences (p < 0.05) in the
first-flush magnitude of different run-off events were observed confirming that
hydro-meteorological variables such as dry period, precipitation duration and
average intensity play important roles. Metal loads originating from the log yard
were mainly composed of Zn, Cu and Ba. Knowledge of the physicochemical
characteristics, discharge dynamics and the storm variables involved in the
process is a crucial step for the proposal and implementation of a stormwater
management programme. Conclusion: Stormwater runoffs from eight events were
characterized with focus on toxic metals. Metals Cr, Pb, Cu, Ni, V, Co were
detected in some events and Zn, Ba, Cd, As, Fe in all events. Concentrations of Zn
and Cu exceeded the threshold limits by the Swedish environmental authorities in
100% and 97% of samples. TSS was a good surrogate (0.949 > R > 0.808) to
indicate the presence of Pb, Co, Ni, As, Ba, Cr and COD.
Fabio KaczalaD, Marcia Marques, Eva Vinrot and William Hogland.
Stormwater run-off from an industrial log yard: characterization,
contaminant correlation and first-flush phenomenon. Environmental
Technology Vol. 33, No. 14, July 2012, 1615–1628.
16. Toxicity posed by the irrigation/stormwater runoff from log yards (log storage
areas) to aquatic organisms: The effects on the microalgae S. subspicatus of
stormwater runoff sampled during two rain events were addressed. The effects
were measured as the percentage change in growth rates in relation to a control
culture after exposure times of 24, 48, 72 and 96 h and different stormwater
concentrations. The runoff from the first rain event had induced growth
stimulation in S. subspicatus, whereas the runoff from the second rain event
inhibited algae growth. Differences in runoff physico-chemical characteristics
combined with the hydrological factors of each rain event explained these
opposite effects. The hypothesis of toxic first flush phenomenon was confirmed in
the second rain event on the basis of normalized inhibitory effects and runoff
volume. It was found that 42, 51 and 50% of the inhibitory effects during
exposures of 24, 48 and 72 h were associated with the initial 4% of the total
discharged volume. The fact that negative effects were observed in the two runoff
events analysed, raises concern about the potential environmental threats posed by
runoff originated from wood-based industrial areas during the entire hydrological
year. Conclusion: Stormwater runoff from log yards was toxic to microalgae S.
subspicatus. One event stimulated algae growth, the other inhibited algae growth.
Growth inhibition was associated to the initial 4% of the total discharged volume
and differences in runoff physico-chemical characteristics and hydrological
factors of each rain event explained these opposite effects.
Fabio KaczalaD, Paulo S. Salomon, Marcia Marques, Edna Granéli, William
Hogland. Effects from log-yard stormwater runoff on the microalgae
Scenedesmus subspicatus: Intra-storm magnitude and variability. Journal of
Hazardous Materials 185 (2011) 732–739.
17. Leaching tests with wood residues from five tree species to simulate stormwater
generation and toxicity posed to aquatic organisms: Leaching tests carried out
with sawdust from five tree species were investigated. The species were:
Pedunculate oak (Quercus robur), Scots pine (Pinus sylvestris), European larch
(Larix decidua), Norway spruce (Picea abies) and European beech (Fagus
sylvatica). The analyses included chemical parameters such as pH, TOC and
phenolic compounds (reported as total polyphenols) and acute toxicity posed to
aquatic organisms. The leachate generated by sawdust and bark from different tree
species showed great variation regarding amounts of different phenolic
compounds and acute toxicity posed to the microcrustacean Artemia salina and
the bacteria Vibrio fischeri (Microtox®), being the bacteria more sensitive than
the microcrustacean. The results showed that bark is one component of the tree
anatomy that needs to be handled as a potential hazardous material to the aquatic
environment. The large variation in toxicity presented by different tree species
need to be taken into account when considering the potential impacts to water
bodies, when constructing facilities to treat stormwater from irrigated log yards
and storage areas. Conclusion: Leachates from sawdust of five different tree
species were characterized for pH, TOC and total polyphenols. Acute toxicity
tests carried out with two bioindicators a bacteria and a micro-crustaceous,
showed differences according to the tree species.
Henric SvenssonD, Britt-Marie Svensson, William Hogland and Marcia
Marques. Acute Toxic Effects Caused by Leachate from Five Different Tree
Species on Artemia salina and Vibro fischeri. Journal of Biobased Materials
and Bioenergy Vol. 6, 214–220, 2012.
18. Water quality after leaching tests with different wood trees and implications for
the treatment: Batch tests were carried out with sawdust obtained from oak
(Quercus robur), maple (Acer platanoides), pine (Pinus sylvestris), beech (Fagus
sylvatica) and wood chips from oak and pine. Leaching of organic compounds
expressed as dissolved organic carbon (DOC) in mg/kg of dry mass took place
during the first 24 h. The following variables were also analysed: pH,
conductivity, colour, total phenols, tannins and lignin, and biochemical oxygen
demand (BOD7). When leachates generated by oak and pine wood chips were
compared, no significant difference was observed. However, in batch tests with
sawdust, DOC released by oak (90 000 mg/kg) was significantly higher (P =
0.0001) than DOC released by pine (30 000 mg/kg). Regarding BOD, colour
[platinum-cobalt (Pt-Co)], phenols, tannins and lignin, the leaching patterns
differed among species, and oak was the species with the highest released values.
Conclusion: Not only the particle size but also the tree species determine the
leachate quality with consequences for the treatment to be applied and potential
for environmental impact.
Henric SvenssonD, Marcia Marques, Fabio Kaczala & William Hogland.
Leaching patterns from wood of different tree species and environmental
implications related to wood storage areas. Water and Environment Journal
28 (2014) 277–284.
19. Oak wood leachate: organic contamination and toxicity associated to different
particle sizes: Oak wood leachate obtained from two storage facilities (storage
pound and ditch) in a wood-based industry, and leachate generated by a laboratory
leaching test, were characterized in seven categories regarding particle size
distribution (PSD) (raw leachate, ≤ 20 μm, ≤ 10 μm, ≤ 1.2 μm, ≤ 13 nm, ≤ 5 nm
and ≤ 2 nm). The PSD followed a normal distribution model with a correlation
coefficient (r) varying from 82 to 88. Each fraction was analysed regarding
chemical oxygen demand (COD), polyphenols and acute toxicity to
microcrustacean Artemia salina, bacteria Vibrio fischeri and the vegetable lettuce
Lactuca sativa. Fractions with particles >1.2 μm were more toxic to A. salina and
V. fischeri than fractions with particles ≤ 1.2 μm. No toxic effect was observed
with L. sativa. During particle size fractionation of wood, as soon as the large
particle sizes were removed, a tendency for reduction in the PP/COD ratio. Due to
that, as expected, larger particles generated leachate more toxic to aquatic
organisms than small particles. No toxicity was found to germination of L. sativa.
The explanation for the fractionation pattern is that tannins and/or lignin with size
>100 kDa are present; or, it is possible that during storage, further polymerization
of polyphenols might have occurred. Different models have been formulated since
the late 90s to show how humic substances aggregate or form supra-molecules.
Aggregated molecules are held together by planar-π-door-planar-π*-accepter or
by cation bridges. Therefore, the differences in particle sizes between field
samples and laboratory leachate could also be due to the higher amount of cations
found in the field samples compared to the laboratory samples. Another
possibility is that the charge in polarity might affect the retention in the filter,
which could affect the results. Conclusion: Polyphenols are probably the main
toxic compounds in oak wood leachate. A conspicuous difference was found
between field and laboratory samples, probably due to the aging processes and
degradation of organic contaminants in the first one.
Henric SvenssonD, Yahya Jani, William Hogland and Marcia Marques.
Particle size characterization of oak wood leachate: chemical oxygen demand
and toxicity distribution within different fractions. Water Science &
Technology 2014:502-509 DOI: 10.2166/wst.2014.252
20. Treatment of stormwater applying packed columns with peat and peat + fly ash
as filter/adsorbent: In the present study, two combinations of filter materials in
packed columns were examined for removal of total organic carbon (TOC) and
polyphenols (PP) present in stormwater runoff generated at wood storage areas.
One column was packed with peat mixed with carbon-containing fly ash, while
another one was packed only with peat. The mixture of peat and ash has shown
faster and higher removal capacity for TOC and faster removal with the same final
removal capacity for PP (in grams of pollutant per kg of sorbent) at the saturation
point. The superiority observed for the combined peat-ash filter is presumably due
to the unique characteristics of peat and ash, which enhanced the treatment
efficiency when applied together. Based on results, filters formed by peat and
carbon-containing ashes proved to be a potentially cost effective option for the
treatment of storm water generated at storage areas of wood materials such as
logs, sawdust and wood chips.
Conclusion: Two types of filters were built up in packed columns to treat wood
leachate: (i) peat mixed with carbon-containing fly ash: (ii) only peat. Peat + fly
ash removed faster and higher percentage of TOC and faster but the same final PP
(in g/kg) at the saturation point. However the release of metals by fly ash
previously reported is a limiting factor.
Henric SvenssonD, Marcia Marques, Britt-Marie Svensson, Lennart
Mårtensson, Amit Bhatnagar & William Hogland. Treatment of wood
leachate with high polyphenols content by peat and carbon-containing fly ash
filters. Desalination and Water Treatment 53 (2015) 2041–2048.
21. Nutrients addition to enhance biological treatment of irrigation
wastewater/stormwater treatment: The efficiency of biological treatment in
degrading organic matter is affected by both the available nutrients and the
efficiency of the microbial organisms. The investigation assessed whether a
constructed wetland treating stormwater generated at a wood industrial site faces
nutrients deficiency or lacked efficient microbes, and whether addressing these
possible problems could enhance the treatment efficiency. Stormwater, irrigation
wastewater and leachate from woodchip piles in an industry that processes mainly
pedunculate oak (leachate with high content of polyphenols) was treated in a
pilot-scale wetland system and an aerated lagoon. To assess the potential
enhancement of biological treatment though addition of nutrients (phosphorus,
nitrogen, micronutrients), headspace respirometry was used. The effect of adding
microbes from a paper mill activated sludge was also evaluated. The results
showed that all nutrients additions had a positive effect on the biological
treatability of the stormwater. In particular, the addition of nitrogen showed a 12%
rise in chemical oxygen demand reduction over 336 h. However, addition of paper
mill activated sludge did not enhance the degradation of organic matter; instead, a
toxic effect of the stormwater was shown. Conclusion: Stormwater runoff formed
by precipitation, log irrigation water and leachate from woodchip piles was treated
in a constructed wetland. Adjustment of nutrients enhanced the biodegradation of
organic compounds, according a respirometry tests.
Henric SvenssonD, Henrik HanssonD, William Hogland. Determination of
nutrient deficiency in stormwater from the wood industry for biological
treatment. CLEAN - Soil Air Water 43(1):38-43, 2015.
DOI:
10.1002/clen.201300621
22. Ozone as pre-treatment to facilitate biological treatment of stormwater from log
yards: The possibility of treating oak wood leachate with a combination of ozone
and biological treatment was investigated. Wood leachate was previously
characterized by high organic carbon content and toxicity to aquatic organisms.
Ozone was used as a pre-treatment before aerobic biodegradation. The biological
treatment was applied for seven days and evaluated using head-space
respirometry. The target pollutants investigated were chemical oxygen demand
(COD), total organic carbon (TOC) and colour and polyphenols. A custom made
bubble column ozone reactor was used and 1.5 L of wood leachate was exposed to
0–4 g/L of O3, corresponding to a specific ozone dose between 0.7–7 g/L O3 per
gram of initial COD. Oak wood leachate was found to be treatable by ozone, with
reduction >90% of polyphenols. COD was reduced by 73%, TOC by 61% and
colour by 97% with ozone. Furthermore, a positive correlation between
biodegradation and ozone pre-treatment was found. Conclusion: Oak wood
leachate was pre-treated with ozone before checking aerobic biodegradation.
Target pollutant indicators Polyphenols, COD, TOC and colour were reduced in
90%, 73%, 61% and 97% respectively. Biodegradation was increased after pretreatment with ozone.
Henrik HanssonD, Henric SvenssonD, William Hogland. Combined Ozone
and Biological Treatment of Oak Wood Leachate. CLEAN - Soil Air Water
43(4):598-604, 2015. DOI: 10.1002/clen.201400141
23. The effect of aeration and/or vegetation in constructed wetlands mesocosms three years of operation: This study investigated the effects of aeration and/or
vegetation in experimental constructed wetlands (CWs) as mesocosms on the
removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms,
with randomized replicated treatment combinations of vegetation (Phragmites
australis) and aeration was monitored during the second and third year after
construction. The investigation included control tanks with no aeration and no
vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen
demand (COD) and water colour. The reduction of COD after 28 days was
approx. 50% and more than 50% of PPs, whereas only 40% of the water colour
was removed. Aeration increased the effect of both COD and PP removal. The
vegetation treatment had a small but significant effect on removal of COD. The
vegetation plus aeration treatment, as well as aeration alone, increased the
removal efficiency of COD from 9.5 g m_3 d_1 in the control to 11 g m_3 d_1. The
results suggest that CWs can be used to treat stormwater contaminated by oak
wood leachate. Further, it is suggested that the main processes for removal of
pollutants in the leachate occur in the open-water habitat and that the hydraulic
retention time is more important for removal than aeration and vegetation related
processes. Conclusion: Based on two-years of monitoring, it was concluded that
aeration improved significantly COD and PP reduction and vegetation had a
significant but small effect on COD reduction. The main processes for removal of
organic pollutants occurred in the open-water habitat and hydraulic retention time
was more important for the treatment than aeration and vegetation related
processes.
Henric SvenssonD, Börje Ekstam, Marcia Marques, William Hogland.
Removal of organic pollutants from oak leachate in pilot scale wetland
systems: How efficient are aeration and vegetation treatments? Water
Research 84 (2015) 120-126.
Impact on research carried out in other parts of the world
A research project was started few years ago at Rio de Janeiro State University
(UERJ), Brazil using the same approach and lessons learned during the experience in
Kalmar region. The paper below illustrates who the knowledge was applied
24. Unconventional adsorbent based on exoskeleton of sun coral: Two exotic
species introduced during the 90 s known as sun coral currently spread along 2000
km of the Brazilian coast pose a severe threat to the marine biodiversity. Since
they have exoskeletons with high concentration of calcium carbonate, the present
investigation focused on the removal of phosphorus from wastewater, using
exoskeleton’s powder in three forms: raw (RSC); physically modified (SCA) and
chemically modified (SCC). A Central Composite Design with Response Surface
Methodology was applied to the assays along to studies of kinetics,
thermodynamics and equilibrium and sorbent’s characterisation by FTIR, XRD
and SEM-EDX techniques. The maximum P removal capacities of RSC, SCA and
SCC were 6826, 7062 and 9597 mg P kg−1, respectively. In all cases, the
adsorption followed the Langmuir’s pseudo-second-order kinetic model being the
process thermodynamically appropriate. The sun coral-based adsorbent is an
attractive option for wastewater treatment and may contribute to the control of the
sun coral population. Conclusion: The best efficiency in removing phosphorus
from wastewater using exoskeleton´s powder from sun coral as adsorbent was
achieved with chemically modified sun coral powder. Compared to other low-cost
adsorbents in the literature, the tested material showed a good to excellent
performance.
Marco Tadeu Gomes Vianna, Marcia Marques, Luiz Carlos Bertolino. Sun
coral powder as adsorbent: Evaluation of phosphorus removal in synthetic
and real wastewater. Ecological Engineering, 97 (2016) 13–22.