Abstract: An experiment was conducted using two aeration
methods (water-into-air and air-into-water) and followed by filtration
processes using manganese greensand material. The properties of
groundwater such as pH, dissolved oxygen, turbidity and heavy metal
concentration (iron and manganese) will be assessed. The objectives
of this study are i) to determine the effective aeration method and ii)
to assess the effectiveness of manganese greensand as filter media in
removing iron and manganese concentration in groundwater. Results
showed that final pH for all samples after treatment are in range from
7.40 and 8.40. Both aeration methods increased the dissolved oxygen
content. Final turbidity for groundwater samples are between 3 NTU
to 29 NTU. Only three out of eight samples achieved iron
concentration of 0.3mg/L and less and all samples reach manganese
concentration of 0.1mg/L and less. Air-into-water aeration method
gives higher percentage of iron and manganese removal compare to
water-into-air method.
Abstract: An attempt was made for availability of wastewater reuse/reclamation for irrigation purposes using phytoremediation “the low cost and less technology", using six local aquatic macrophytes “e.g. T. angustifolia, B. maritimus, Ph. australis, A. donax, A. plantago-aquatica and M. longifolia (Linn)" as biological waste purifiers. Outdoor experiments/designs were conducted from May 03, 2007 till October 15, 2008, close to one of the main sewage channels of Sulaimani City/Iraq*. All processes were mainly based on conventional wastewater treatment processes, besides two further modifications were tested, the first was sand filtration pots, implanted by individual species of experimental macrophytes and the second was constructed wetlands implanted by experimental macrophytes all together. Untreated and treated wastewater samples were analyzed for their key physico-chemical properties (only heavy metals Fe, Mn, Zn and Cu with particular reference to removal efficiency by experimental macrophytes are highlighted in this paper). On the other hand, vertical contents of heavy metals were also evaluated from both pots and the cells of constructed wetland. After 135 days, macrophytes were harvested and heavy metals were analyzed in their biomass (roots/shoots) for removal efficiency assessment (i.e. uptake/ bioaccumulation rate). Results showed that; removal efficiency of all studied heavy metals was much higher in T. angustifolia followed by Ph. Australis, B. maritimus and A. donax in triple experiment sand pots. Constructed wetland experiments have revealed that; the more replicated constructed wetland cells the highest heavy metal removal efficiency was indicated.
Abstract: In this study, the ability of Aspergillus niger and
Penicillium simplicissimum to extract heavy metals from a spent
refinery catalyst was investigated. For the first step, a spent
processing catalyst from one of the oil refineries in Iran was
physically and chemically characterized. Aspergillus niger and
Penicillium simplicissimum were used to mobilize Al/Co/Mo/Ni from
hazardous spent catalysts. The fungi were adapted to the mixture of
metals at 100-800 mg L-1 with increments in concentration of 100 mg
L-1. Bioleaching experiments were carried out in batch cultures. To
investigate the production of organic acids in sucrose medium,
analyses of the culture medium by HPLC were performed at specific
time intervals after inoculation. The results obtained from Inductive
coupled plasma-optical emission spectrometry (ICP-OES) showed
that after the one-step bioleaching process using Aspergillus niger,
maximum removal efficiencies of 27%, 66%, 62% and 38% were
achieved for Al, Co, Mo and Ni, respectively. However, the highest
removal efficiencies using Penicillium simplicissimum were of 32%,
67%, 65% and 38% for Al, Co, Mo and Ni, respectively
Abstract: Many non-conventional adsorbent have been studied
as economic alternative to commercial activated carbon and mostly
agricultural waste have been introduced such as rubber leaf powder
and hazelnut shell. Microwave Incinerated Rice Husk Ash
(MIRHA), produced from the rice husk is one of the low-cost
materials that were used as adsorbent of heavy metal. The aim of
this research was to study the feasibility of using MIRHA500 and
MIRHA800 as adsorbent for the removal of Cu(II) metal ions from
aqueous solutions by the batch studies. The adsorption of Cu(II) into
MIRHA500 and MIRH800 favors Fruendlich isotherm and imply
pseudo – kinetic second order which applied chemisorptions
Abstract: A research project dealing with the phytoremediation
of a soil polluted by some heavy metals is currently running. The
case study is represented by a mining area in Hamedan province in
the central west part of Iran. The potential of phytoextraction and
phytostabilization of plants was evaluated considering the
concentration of heavy metals in the plant tissues and also the
bioconcentration factor (BCF) and the translocation factor (TF). Also
the several established criteria were applied to define
hyperaccumulator plants in the studied area. Results showed that
none of the collected plant species were suitable for phytoextraction
of Cu, Zn, Fe and Mn, but among the plants, Euphorbia macroclada
was the most efficient in phytostabilization of Cu and Fe, while,
Ziziphora clinopodioides, Cousinia sp. and Chenopodium botrys
were the most suitable for phytostabilization of Zn and Chondrila
juncea and Stipa barbata had the potential for phytostabilization of
Mn. Using the most common criterion, Euphorbia macroclada and
Verbascum speciosum were Fe hyperaccumulator plants. Present
study showed that native plant species growing on contaminated sites
may have the potential for phytoremediation.
Abstract: Water hyacinth has been used in aquatic systems for
wastewater purification in many years worldwide. The role of water
hyacinth (Eichhornia crassipes) species in polishing nitrate and
phosphorus concentration from municipal wastewater treatment plant
effluent by phytoremediation method was evaluated. The objective
of this project is to determine the removal efficiency of water
hyacinth in polishing nitrate and phosphorus, as well as chemical
oxygen demand (COD) and ammonia. Water hyacinth is considered
as the most efficient aquatic plant used in removing vast range of
pollutants such as organic matters, nutrients and heavy metals. Water
hyacinth, also referred as macrophytes, were cultivated in the
treatment house in a reactor tank of approximately 90(L) x 40(W) x
25(H) in dimension and built with three compartments. Three water
hyacinths were placed in each compartments and water sample in
each compartment were collected in every two days. The plant
observation was conducted by weight measurement, plant uptake and
new young shoot development. Water hyacinth effectively removed
approximately 49% of COD, 81% of ammonia, 67% of phosphorus
and 92% of nitrate. It also showed significant growth rate at starting
from day 6 with 0.33 shoot/day and they kept developing up to 0.38
shoot/day at the end of day 24. From the studies conducted, it was
proved that water hyacinth is capable of polishing the effluent of
municipal wastewater which contains undesirable amount of nitrate
and phosphorus concentration.
Abstract: Contamination of heavy metals represents one of the
most pressing threats to water and soil resources as well as human
health. Phytoremediation can be potentially used to remediate metalcontaminated
sites. A major step towards the development of
phytoremediation of heavy metal impacted soils is the discovery of
the heavy metal hyperaccumulation in plants. In this study, the
several established criteria to define a hyperaccumulator plant were
applied. The case study was represented by a mining area in
Hamedan province in the central west part of Iran. Obtained results
showed that the most of sampled species were able to grow on
heavily metal-contaminated soils and also were able to accumulate
extraordinarily high concentrations of some metals such as Zn, Mn,
Cu, Pb and Fe. Using the most common criteria, Euphorbia
macroclada and Centaurea virgata can be classified as
hyperaccumulators of some measured heavy metals and, therefore,
they have suitable potential for phytoremediation of contaminated
soils.
Abstract: Mercury adsorption on soil was investigated at
different ionic strengths using Ca(NO3)2 as a background electrolyte.
Results fitted the Langmuir equation and the adsorption isotherms
reached a plateau at higher equilibrium concentrations. Increasing
ionic strength decreased the sorption of mercury, due to the
competition of Ca ions for the sorption sites in the soils. The
influence of ionic strength was related to the mechanisms of heavy
metal sorption by the soil. These results can be of practical
importance both in the agriculture and contaminated soils since the
solubility of mercury in soils are strictly dependent on the adsorption
and release process.
Abstract: The objective of this study was to evaluate the
distribution patterns of Cd, Zn and Hg in groundwater by geospatial
interpolation. The study was performed at Rayong province in the
eastern part of Thailand, with high agricultural and industrial
activities. Groundwater samples were collected twice a year from 31
tubewells around this area. Inductively Coupled Plasma-Atomic
Emission Spectrometer (ICP-AES) was used to measure the
concentrations of Cd, Zn, and Hg in groundwater samples. The
results demonstrated that concentrations of Cd, Zn and Hg range
from 0.000-0.297 mg/L (x = 0.021±0.033 mg/L), 0.022-33.236 mg/L
(x = 4.214±4.766 mg/L) and 0.000-0.289 mg/L (x = 0.023±0.034
mg/L), respectively. Most of the heavy metals concentrations were
exceeded groundwater quality standards as specified in the Ministry
of Natural Resources and Environment, Thailand. The trend
distribution of heavy metals were high concentrations at the
southeastern part of the area that especially vulnerable to heavy
metals and other contaminants.
Abstract: Although oil-based drilling fluids are of paramount practical and economical interest, they represent a serious source of pollution, once released into the environment as drill cuttings. The aim of this study is to assess the capability of isolated microorganisms to degrade gasoil fuel. The commonly used physicochemical and biodegradation remediation techniques of petroleum contaminated soil were both investigated. The study revealed that natural biodegradation is favorable. Even though, the presence of heavy metals, the moisture level of (8.55%) and nutrient deficiencies put severe constrains on microorganisms- survival ranges inhibiting the biodegradation process. The selected strains were able to degrade the diesel fuel at significantly high rates (around 98%).
Abstract: In this study, the designed dual stage membrane
bioreactor (MBR) system was conceptualized for the treatment of
cyanide and heavy metals in electroplating wastewater. The design
consisted of a primary treatment stage to reduce the impact of
fluctuations and the secondary treatment stage to remove the residual
cyanide and heavy metal contaminants in the wastewater under
alkaline pH conditions. The primary treatment stage contained
hydrolyzed Citrus sinensis (C. sinensis) pomace and the secondary
treatment stage contained active Aspergillus awamori (A. awamori)
biomass, supplemented solely with C. sinensis pomace extract from
the hydrolysis process. An average of 76.37%, 95.37%, 93.26 and
94.76% and 99.55%, 99.91%, 99.92% and 99.92% degradation
efficiency for total cyanide (T-CN), including the sorption of nickel
(Ni), zinc (Zn) and copper (Cu) were observed after the first and
second treatment stages, respectively. Furthermore, cyanide
conversion by-products degradation was 99.81% and 99.75 for both
formate (CHOO-) and ammonium (NH4
+) after the second treatment
stage. After the first, second and third regeneration cycles of the C.
sinensis pomace in the first treatment stage, Ni, Zn and Cu removal
achieved was 99.13%, 99.12% and 99.04% (first regeneration cycle),
98.94%, 98.92% and 98.41% (second regeneration cycle) and 98.46
%, 98.44% and 97.91% (third regeneration cycle), respectively.
There was relatively insignificant standard deviation detected in all
the measured parameters in the system which indicated
reproducibility of the remediation efficiency in this continuous
system.
Abstract: The use of bioindicators plants (lichens, bryophytes
and Sphagnum....) in monitoring pollution by heavy metals has been
the subject of several works. However, few studies have addressed
the impact of specific type-s pollutants (fertilizers, pesticides.) on
these organisms.
We propose in this work to make the highlighting effect of NPKs
(NPK: nitrogen-phosphate-potassium-sulfate (NP2O5K2O) (15,15,15),
at concentrations of 10, 20, 30 , 40 and 50mM/L) on the activity of
detoxification enzymes (GSH/GST, CAT, APX and MDA) of plant
bioindicators (mosses and lichens) after treatment for 3 and 7 days.
This study shows the important role of the defense system in the
accumulation and tolerance to chemical pollutants through the
activation of enzymatic (GST (glutathione-S-transferase, APX
(ascorbat peroxidase), CAT (catalase)) and nonenzymatic biomarkers
(GSH (glutathione), MDA (malondialdehyde)) against oxidative
stress generated by the NPKs.
Abstract: Hexavalent chromium is highly toxic to most living organisms and a known human carcinogen by the inhalation route of exposure. Therefore, treatment of Cr(VI) contaminated wastewater is essential before their discharge to the natural water bodies. Cr(VI) reduction to Cr(III) can be beneficial because a more mobile and more toxic chromium species is converted to a less mobile and less toxic form. Zero-valence-state metals, such as scrap iron, can serve as electron donors for reducing Cr(VI) to Cr(III). The influence of pH on scrap iron capacity to reduce Cr(VI) was investigated in this study. Maximum reduction capacity of scrap iron was observed at the beginning of the column experiments; the lower the pH, the greater the experiment duration with maximum scrap iron reduction capacity. The experimental results showed that highest maximum reduction capacity of scrap iron was 12.5 mg Cr(VI)/g scrap iron, at pH 2.0, and decreased with increasing pH up to 1.9 mg Cr(VI)/g scrap iron at pH = 7.3.
Abstract: For more than 120 years, gold mining formed the
backbone the South Africa-s economy. The consequence of mine
closure was observed in large-scale land degradation and widespread
pollution of surface water and groundwater. This paper investigates
the feasibility of using natural zeolite in removing heavy metals
contaminating the Wonderfonteinspruit Catchment Area (WCA), a
water stream with high levels of heavy metals and radionuclide
pollution. Batch experiments were conducted to study the adsorption
behavior of natural zeolite with respect to Fe2+, Mn2+, Ni2+, and Zn2+.
The data was analysed using the Langmuir and Freudlich isotherms.
Langmuir was found to correlate the adsorption of Fe2+, Mn2+, Ni2+,
and Zn2+ better, with the adsorption capacity of 11.9 mg/g, 1.2 mg/g,
1.3 mg/g, and 14.7 mg/g, respectively. Two kinetic models namely,
pseudo-first order and pseudo second order were also tested to fit the
data. Pseudo-second order equation was found to be the best fit for
the adsorption of heavy metals by natural zeolite. Zeolite
functionalization with humic acid increased its uptake ability.
Abstract: Over a million tonnes of cigarette butts (CBs) are produced worldwide annually. These CBs accumulate in the environment due to the poor biodegradability of the cellulose acetate filters and pose a serious environmental risk. This paper presents some of the results from a continuing study on recycling CBs into fired clay bricks. Properties including compressive strength, flexural strength, density, water absorption and thermal conductivity of fired clay bricks are reported and discussed. Furthermore, leaching of heavy metals from the manufactured clay bricks was tested. The results show that the density of fired bricks was reduced by about 8 – 30 %, depending on the percentage of CBs incorporated into the raw materials. The compressive strength of bricks tested was 12.57, 5.22 and 3.00 MPa for 2.5, 5.0 and 10 % CB content respectively. Water absorption and initial rate of absorption values increased as density, and hence porosity, of bricks decreased with increasing CB volume. The leaching test results revealed trace amounts of heavy metals.