Showing 153 results for Waste
Mahdi Kargar, Amir Hossein Mahvi,
Volume 5, Issue 1 (4-2012)
Abstract
A
MicrosoftInternetExplorer4
Backgrounds and Objectives: Large quantities of sludge are produced in
biological wastewater treatment. Because this sludge is highly rotten, it
should be stabilized before its disposal. Aerobic and anaerobic digestion is
widely considered as stabilization techniques. Because of high retention time
and sludge dewatering difficulties, reduction in retention time, operation and
maintenance should be given into consideration. Ultrasonic process increases
the enzymatic activity, so decreases the hydrolysis time, a limiting factor in
digestion process, and contributes to the decrease of the detention time. The
objective of this investigation is to determine the effect of ultrasound in
improving dewatering and stabilization of aerobic and anaerobic digested
sludge. In addition, the impact of ultrasonic treatment on improvement of
sludge dewatering and aerobic and anaerobic digestion is compared.
Materials and Methods: In this survey, samples of aerobic and
anaerobic digestion were collected from local full-scale Garb Town
and Tehran South wastewater treatment plant, respectively. The grab samples
were collected for 4 month from July to October 2010. Total numbers of 20
samples were collected biweekly for each type of digestion. Each sample was
sonicated for 15, 30, 60, and 90 min under 35 and 131 kHz frequencies
separately. Total solids, volatile solids , pH, temperature , total COD,
dissolved COD and settle able solids were measured. Ultrasound bath of the
solution in a 300 mL glass reactor was performed as a bath reactor with power
of 500 W.
Result: The results showed that the application of ultrasonic
wave increased dissolved COD and temperature and decreased volatile solid, pH
and settle able solids. Application of ultrasonic wave with frequency of 131
kHz decreased the VS and increased the dewatering of sludge more effective than
the 35 kHz frequency and the highest performance was at 15 min of time and 131
kHz of frequency. Also sonication method showed better efficiency for anaerobic
sludge samples compared to the aerobic sludge samples.
Conclusion: The results obtained showed that digestion
and dewatering properties of sludge improved by ultrasonic application.
Therefore it can be used as an alternative method for the sludge treatment.
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Ali Almasi, Meghdad Pirsaheb, Abdollah Dargahi,
Volume 5, Issue 1 (4-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Phenol is one of the
aromatic compounds, which due to its high toxicity and its presence in the
industrial effluents, should be removed and prevented it, to the receiving water resources.
The natural biological plant has been accepted as one of the most feasible,
eco-friendly and cost-effective options for the treatment of pollutants such as
Phenol.
The aim of this study is efficiency evaluation of the anaerobic stabilization
pond performance in removing phenol and other organic compounds from Kermanshah oil refinery wastewater.
Materials and Methods: The method of study
was experimental and analytical, a laboratory scale anaerobic stabilization pond,
with dimensions of 1 × 1 × 0/2 m, using fiberglass sheet with a thickness of 6
mm was designed and built up. In this study The hydraulic retention time and
hydraulic loading rate were expected 2 days and 95 liters per day respectively.
Organic loading rate for anaerobic pond was 100 g/m
3. After
starting, seeding and biological stability, samples were taken. Initial phenol
concentration was added about of 100 mg/l to pilot input, then the parameters
such as NH
3, PO
4 and Phenol were measured by Varian
spectrophotometer model UV-120-02 in the wavelength 425, 690, 500 nm
respectively. TCOD, SCOD, TBOD, SBOD, pH
and ORP were measured according to the standard methods of water and
wastewater.
Results: The results showed that the removal efficiency of NH
3,
PO
4, phenol, TCOD, SCOD, TBOD, SBOD in the anaerobic pond were
obtained 91.51%, 64.34%, 89.82% 74.99 % 73.34% 71.75%, 68.9% respectively.
Conclusion: The results showed that the ability for phenol and other organic compounds
removal in anaerobic pond using petroleum refinery wastewater is higher than
the other systems which are expensive and complex.
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Ensieh Taheri, Mahdi Hajian Nejad, Mohammad Mahdi Amin, Hossein Farrokhzadeh, Maryam Hatamzadeh, Marzieh Vahid Dastjerdi,
Volume 5, Issue 1 (4-2012)
Abstract
AR-SA
MicrosoftInternetExplorer4
Background and Objectives: Aerobic sludge granulation is an
advanced phenomenonin which its mechanisms have not been understood.
Granulation can be a promising and novel biological wastewater treatment
technology to eliminate organic and inorganic materials in future. High
salinity is a parameter which leads to plasmolisatian and reduction of the cell
activity. This could be a problem for biological treatment of the saline
wastewater. Aerobic granule was formed and investigated during this study.
Materials and Methods:
This study is an intervention study on the treatment of wastewater with
500-10000 mg/L concentration of NaCl by sequencing batch reactor. Asynthesized
wastewater including nutrient required for microorganism's growth was prepared.
Input and output pH and EC were measured. Range of pH and DO varied between
7-8, and 2-5 mg/L, respectively. SEM technology was used to identify graduals
properties.
Results: In terms of color, granules divided
into two groups of light brown and black. Granule ranged in 3-7mm with the
sediment velocity of 0.9-1.35 m/s and density of 32-60 g/L.Properties of
granules were varied. Filamentous bacteria and fungi were dominant in some
granules. However non filamentous bacteria were dominant in others. EDX
analysis indicated the presence of Ca and PO
4.
Conclusion: Granules
with non filamentous bacterial were compact and settled faster. Presence of
different concentrations of salinity leaded to plasmolysis of the bacterial
cells and increased concentrations of EPS
in the system as a result of
which granulation accelerated
.
Mohammad Malakootian, Hassan Izanloo, Maryam Messerghany, Mohammad Mahdi Emamjomeh,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and
Objectives: leachate from municipal solid waste
landfill is a strong sewage having hazardous toxic substances. It should
be
treated
by
choosing a
simple,
economical,
and eco-friendly method. The aim of this study is reduction of COD
from the
Qom City landfill leachate using electrocoagulation process.
Materials
and Methods: The experimental study
was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0.7 liter
capacity, containing nine plate aluminum electrodes connected to a DC power supply (10-60V, 1-5A). Samples were
collected in the middle of cell at regular (every 10 minutes) time intervals.
The concentration of COD was determined using
a COD analyzer. The effects of different parameters
including current density (52.08, 69.44 mA/cm
2), electrolyte time (10, 20,30,40,50 and 60 min), and voltage range
(10, 20, 30, 40, 50 and 60 volt) were investigated.
Results: For a voltage of 60 V and electrolysis time 60 min, the COD removal
efficiency was increased from 48.7% for 52.08
mA/cm
2 to 77.4% for 69.44
mA/cm
2. The highest TSS removal
efficiency was obtained at the largest current input when the voltage and
electrolysis time were kept at 60V and 60 min respectively.
Conclusion: The results showed that the highest COD removal
efficiency (77.4%) was obtained when the current density was 69.44 Ma/cm
2 and the voltage and electrolysis time were kept at 60V and 60 min respectively. Power consumption for this removal level was measured to
be 431.26 kWh per kg COD removal. The results obtained revealed that the electrocoagulation
technology is an effective treatment process for landfill leachate.
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Ramin Nabizadeh Nodehi, Hassan Aslani, Mahmood Alomohammadi, Reza Nemati, Kazem Naddafi, Maryam Ghany,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Irrigation of agricultural crops using wastewater will
increase, in some cases, their growth by 40 to 60 percent. However, this has a
high risks for human health because of the presence of higher number of
pathogenic organisms. The main purpose of this study was to investigate the
feasibility use of Fenton and modified Fenton with copper for the disinfection
of raw wastewater.
Materials and Methods: After primarily laboratory physicochemical and biological analysis, the
disinfection process was performed in three different phases in each process.
First, the disinfectants were injected separately, then we performed
disinfection using Fe++ and cu++ ions combined with hydrogen peroxide in order
to determine synergistic effect of each catalyst. Direct method was used for
fecal coliforms counting.
Results: Hydrogen
peroxide maximum efficiency for inactivation of fecal coliforms was only
0.66log inactivation. Fenton and modified Fenton with copper ions showed a
remarkable effect on the bacterial inactivation so that Fenton and modified
Fenton with 1 and 2 mg/l of Cu++ inactivated coliforms by 4.73, 3.28, and 4.88
log respectively.
Conclusion: Application of HP alone for the disinfection of raw wastewater is not
practicable due to low observed efficiency. However, its combination with ions
such as Fe++ and Cu++ increases HP performance in disinfection and has a
notable synergistic effect on HP
disinfection power, where, in the presence of each catalyst, hydrogen
peroxide can reduce the fecal coliforms of raw wastewater to meet the Iranian
Environmental Protection Agency Standards.
Amir Bagheri, Gholamreza Moussavi, Ali Khavanin,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Formaldehyde is a toxic substance and harmful to human
beings and the environmental health. Therefore, the effluents containing
formaldehyde have to be efficiently treated before discharging into the
environment. This study was aimed at investigating the efficiency of
Electro-Fenton (EF) Process in pre-treating industrial wastewater containing
high concentrations of formaldehyde.
Materials and Methods: The effect of the important operational variables including pH, current
density, H
2O
2 dosage, and reaction time were evaluated on the degradation of
7500 mg/L formaldehyde using batch tests. The EFP batch reactor was consisted
of a cylindrical glass column with 5.20 cm in internal diameter and 34.50 cm in
height. Working volume of the reactor was 500 mL.
Results: The maximum
formaldehyde removal was obtained at alkaline pH of 10, H
2O
2 concentration of
10 mM/min, current intensity 8.5 mA/cm2, and the reaction time of 6 minute.
Furthermore, aerating the EFP cell could enhance the formaldehyde removal.
Complete removal of formaldehyde was obtained under the abovementioned
operational conditions.
Conclusion: This study
demonstrated that the EFP is capable of reducing high concentration of
formaldehyde (7500 mg/l) to the level suitable for biological post-treatment.
Edris Bazrafshan, Ferdos Kord Mostafapour, Mahdi Farzadkia, Kamaledin Ownagh, Hossein Jaafari Mansurian,
Volume 5, Issue 3 (10-2012)
Abstract
Background and Objectives: Slaughterhouse wastewater contains various and high amounts of organic
matter (e.g., proteins, blood, fat, and lard). In order to produce an effluent
suitable for stream discharge, chemical coagulation and electrocoagulation
techniques have been particularly explored at the laboratory pilot scale for
organic compounds removal from slaughterhouse effluent. The purpose of this
work was to investigate the feasibility of treating cattle-slaughterhouse
wastewater by combined chemical coagulation and electrocoagulation process to
achieve the required standards.
Materials and Methods:
At present study, slaughterhouse wastewater after initial analysis was tested
for survey of coagulation process using Poly aluminum chloride (PAC) at various
doses (25-100 mg/L). Then we measured the concentrations of wastewater
pollutants (BOD5, COD, TKN, TSS and fecal Coliforms). Later, we transferred the
effluent to the electrocoagulation unit and we evaluated the removal efficiency
of pollutants in the range 10 to 40 volts of electric potential during 60 min.
Results: It was found
that the efficiency of chemical coagulation process using poly-aluminum
chloride (PAC) as coagulant increases with increasing doses (from 25 to 100
mg/L) we achieved maximum removal efficiency during the chemical coagulation
for parameters of BOD5, COD, TSS, and TKN at 100 mg/L of PAC equivalent to
44.78%, 58.52%, 59.9%, and 39.58% respectively. Moreover, the results showed
that with increasing the electric potential and reaction time, the yield
increases linearly so that maximum removal efficiency at a dose of 100 mg/L
PAC, an electrical potential of 40 volts and a reaction time of 60 minutes for
the parameters BOD5, COD, TSS, and TKN was 99.18% 99.25%, 82.55%,
and 93.97% respectively.
Conclusion: The
experiments demonstrated the effectiveness of combined chemical coagulation and
electrocoagulation processes for pollutants removal from the slaughterhouse
wastewaters. Consequently, this combined process can produce effluent
compliance with the effluent discharge standards.
Akbar Eslami, Mohammad Reza Massoudinejad, Farshid Ghanbari, Mahsa Moradi,
Volume 5, Issue 3 (10-2012)
Abstract
Background and Objectives: Electro-Fenton process has been widely applied for dye removal from
aqueous solution lately. Fenton's reagent is formed in the electrolysis medium
through the simultaneous electrochemical reduction of O2 and Fe3+ to H2O2 and
Fe2+ respectively on the cathode surface. In this paper, COD reduction
potential and decolorization of real textile wastewater were evaluated by
electrochemically generated Fenton reagent process. This wastewater mainly
contains non-biodegradable acidic dyes, which are highly resistant against
conventional oxidizing agents.
Materials and Methods:
Electro-Fenton process was carried out in an open and undivided cell in order
to evaluate the removal of color and COD from real textile wastewater using
graphite felt (cathode) and Pt plate (anode) at room temperature. The effects
of current density, flow rate of air, electrolysis time, initial pH, and
ferrous ion concentration were investigated for real textile wastewater.
Results: The results
showed that the optimal experimental conditions obtained in electrochemical
studies were as follows: current density=4.8 mA cm-2, pH=3, flow rate of
air=1.5L/min, Fe2+=3mM and reaction time=160 min. Under these conditions, COD
removal and decolorization achieved were 63% and 77.2% respectively.
Conclusion: According
to the results achieved, electro-Fenton process can be used as a pretreatment
for degradation of colored wastewater and refractory pollutants. Moreover, this
feasible technology improves biodegradability of the textile wastewater.
Somayeh Golbaz, Ahmad Jonidi Jafari, Roshanak Rezaei Kalantari,
Volume 5, Issue 4 (2-2013)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Cyanide is a toxic pollutant existing in the various
industrial effluents such as iron and steel, coal mining, non-ferrous metals
manufacturing and metal plating. Its presence in water resources and
wastewater, as serious hazardous substances leads to undesirable effects on
both the environment and human. Thus, its concentration control is essential
for human health. The main goal of this study was to evaluate Fenton process
efficiency in cyanide removal from aqueous solution.
Materials and Methods: This
is an experimental study Conducted at Lab scale in a batch system. We
investigated effect of different variables including pH, mole ratio of Fe
2+/
H
2O
2, contact time, and initial concentration of cyanide.
Data were analyzed using Excel software.
Results: We found that
cyanide with initial concentrations of 0.4 mM/L was reduced by 92 %. This
removal result was related to oxidizing agent of hydroxyl radicals under
optimum conditions including pH = 4, molar ratio Fe
2+/ H
2O
2=
0.046 (Fe
2+=0.27 mM/L) after 6o min reaction time. An increase in
reaction time was not improved cyanide removal efficiency. Moreover, the Fenton
process efficiency in cyanide removal decreased from 92 to 60 %, by increasing
the initial cyanide concentration from 0.4 to 0.6 mM/L.
Conclusion: It can be
concluded that Fenton oxidation Process can be considered as a suitable
alternative for cyanide removal to achieve environmental standards.
Mahran Mohammadian Fazli , Jalil Nassiri , Ramin Nabizadeh, Mohammad Reza Mehrasbi,
Volume 6, Issue 1 (5-2013)
Abstract
Backgrounds and Objectives: Medical waste management is one of the important issues in solid waste managment in each community. This research was carried out to study the quantity, quality and the management practices of solid wastes of hospitals in Zanjan City in 2011.
Materials and Methods: In the present study, the hospital wastes were categoried and weighted into four main categories. Waste management pattern was studied based on a checklist extracted from national guidelines. Then, hospitals were ranked from very poor to excellent classes. For data analysis, Excel soft ware was used.
Results: Waste generation rate was on average 2.402± 0.163 Kg/bed.day in the studied hospitals. The generation rate of domestic waste, infectious waste, sharp wastes, and chemical - pharmacological waste was 1.432±0.059, 0.926±0.096, 0.029±0.0055, and 0.015±0.002 kg/day.bed respectively. The status of the waste management practices was determined as average.
Conclusion: Waste generation rate in the hospitals of Zanjan was lower compared with the expected average value in other cities (e.g. 2.71 Kg/bed.day in Tehran). The percentage of medical waste in Zanjan hospitals was 34, which is higher than W.H.O. recommendations. Therefore, it is strongly recommended to reform and monitor certain solid waste management practices in order to reduce health and environmental issues.
Mahdi Jahangiri, Masoud Neghab, Vahid Kahdemain, Reza Rostami, Ali Karimi, Mandana Aghabeigi, Abasali Kasayee Nasab,
Volume 6, Issue 1 (5-2013)
Abstract
Background and Objectives: Wastewater contains various pathogens including viruses, bacteria, fungi, etc. These microorganisms can easily become airborne during normal operations of wastewater treatment plant and contaminate the neighborhood environment. The aim of this study was to investigate the type and density of bioaerosols in a petrochemical wastewater treatment plant in Iran.
Materials and Methods: In this cross sectional study, bioaerosols density was measured in different units of a petrochemical wastewater treatment plant according to the NIOSH 0800 method and the values measured were compared with background level (control area). For this purpose, air samples were collected on blood agar and dextro agar in Andersen single-stage sampler with air flow of 28.3 l/min for 10 minutes. Samples collected were shipped to the laboratory immediately and were incubated for 48 hours. Then, incubated samples were counted for colonies concentration.
Results: Average concentration of bacteria and fungi bioaerosols measured were 731.70±185.49 and 28.43±10.58 (M±SD) CFU/m3 respectively throughout the wastewater treatment plant units. These values were 35 and 1.45 times higher than background level (Control area). The differences between average concentrations of bacteria in all units of wastewater treatment plant with control area were statistically significant.
Conclusions: Generally, it was found that the density of bioaerosols, especially bacteria was much higher than the background level. The maximum density was measured at aeration chamber, where the emission of bioaerosols could be reduced through replacing nozzle diffused aeration system.
Somayeh Alijani, Mohammad Vaez, Abdolsamad Zaringhalam Moghadam,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: The development a low-cost and high efficiency water treatment technology to decolorize the organic dye effluents is desirable due to overwhelming discharge of organic synthetic dyes into the natural water cycle during the dying process. In this study, the decolorization of Acid Black 26, as the model organic contaminant, was investigated using immobilized nano-sized TiO2 particles as the photocatalyst. Material and Methods: Sackcloth fiber was used as a support to immobilize TiO2 nanoparticles. The structural properties of the immobilized photocatalysts were characterized by XRD and SEM. UV-Vis absorption spectroscopy and the measurement of the chemical oxygen demand (COD) were also used for the process performance studies. Moreover, we investigated the effects of the oxidant H2O2, initial dye concentration, the presence of anion and pH on the photocatalytic degradation efficiency. Results: The XRD results did not show significant changes in the structure of TiO2 as a consequence of the immobilization procedure. The formation of titania crystallites in the sackcloth fiber was confirmed by SEM. Experimental results showed that after 60 min, the degradation percentage of Acid Black 26 with the immobilized TiO2 particles was about 60%, which was higher than that with TiO2 slurry. Based on the COD results, after 3 h, the TiO2-coated sackcloth fiber effectively decomposed 94% of the organic compounds presenting in dye solution during the degradation of Acid Black 26. Conclusion: The titania nanoparticles immobilized on the sackcloth fiber can be used as an effective and environmental friendly photocatalyst in the degradation of colored wastewater.
Ahmad Reza Yazdanbakhsh, Akbar Eslami, Akram Najafi,
Volume 6, Issue 2 (9-2013)
Abstract
Background and objectives: Formaldehyde is one of the compounds widely used in various industries hence, its discharge into the effluent is unavoidable. Exposure to formaldehyde has a significant health effects. To prevent these issues, treatment of wastewater containing formaldehyde is necessary. The purpose of this study was to determine the performance of aerobic sequencing batch reactor (SBR) in removing formaldehyde from wastewater. Methods: We used a SBR having a total volume of 6.15 liters and an effective volume of 4 liters. The formaldehyde and COD removal efficiency of SBR was evaluated by applying loading rate of 0.031 to 0.156 kgCOD/m3.h. Four cycles of 6, 8, 10, and 12 hours were considered to investigate retention time effect onto the reactor efficiency. Results: Acclimation of microorganism with formaldehyde was achieved after about 30 days. We found that a retention time lower than an hour is not enough for achieving an acceptable efficiency. The maximum removal efficiency (90.52% for COD and 95.32% for formaldehyde) was observed at organic loading rate of 0.031 kg COD/m3.h and 12 hour retention time. The removal efficiency decreased to 46.44% for COD and 69.12%, for formaldehyde with increasing the organic loading rate to 0.156 kg COD/m3.h. The maximum concentration of MLSS was measured 2863 mg / L at organic loading rate of 0.091 kg COD/m3.h. Conclusion: The results showed that SBR could be applied as a practical, effective, and reliable technology for treatment of wastewater containing formaldehyde.
Mostafa Leili, Gholamreza Moussavi, Kazem Nadafi, Rasoul Khosravi,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: Furfural with a chemical formula of C5H4O2 is a toxic and hazardous substance for human and environment. Furfural and its derivatives such as furfuryl alcohol, alone or in combination with phenol, acetone or urea are used mainly in the production of resin. The second major application of furfural is in the production of solvents such furan and tetrafuran frequently used as a selective solvent in the production, treatment, and refining lubricants from petroleum products. A few studies have recently been done in terms of removal or recovery of furfural. Due to advantages of biological methods, the uses of theses environmentally friendly methods are being investigated in this study.
Materials and Methods: We used cyclic biological reactor (CBR) and Fusarium culmorum granules to biologically degrade different concentration of furfural and equivalent of COD under different operating conditions. The analysis was based on the measurement of furfural degradation efficiency during operational period using spectrophotometer and measuring influent and effluent COD variations using a closed reflux method.
Results: cyclic biological reactor was operated in various flow rate (Q) of furfural-containing wastewater for a different period. For all of the flow rate used, furfural degradation and COD removal efficiency was over 99 and 90 percent respectively. Fusarium culmorum granules were also exposed to different concentrations of furfural at different incubation temperatures showing high furfural removal capacity. Conclusion: Under different operating conditions of biological systems, high removal efficiency of furfural was observed, but CBR in comparison with Fusarium culmorum granules reached the optimum and desired removal efficiency in shorter time. Therefore, these systems can be developed and replaced with chemical methods to treat furfural containing wastewater.
Mohammad Ali Baghapour, Babak Jahed, Gholam Hossein Joshani,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Objectives: Increasing waste tiers production has made the recycling of this solid waste a critical issue in the world. On the other hand, it seems contamination of groundwater to the petroleum pollutant like gasoline is a great threat to the health of societies in developing countries. The main objective of this study was gasoline removal from aquatic environment by waste tire derived activated carbon.
Materials and Methods: In this study for preparation of activated carbon from waste tires, KOH was used for chemical activation process. We used argon gas to prevent precursor oxidation . We applied N2 gas and BET isotherm for characterization of the prepared activated carbon texture. Isothermal and kinetic models were used for defining gasoline adsorption characteristic to adsorbent, and thermodynamic studies were used to determine the effect of temperature.
Results: Characterization results revealed that SBET and VTOTAL were 111.702m2/g and 0.124cc/g respectively. Langmuir and pseudo-second order models were the best isotherm and kinetic models for prediction of the adsorbent behaviors to adsorb gasoline. The Gibbs free energy changes were negative at all temperatures applied.
Conclusion: Produced activated carbon has desired surface area and adsorptive capacity for gasoline adsorption in aquatic environments and it seems preparation activated carbon from waste tiers is cheap, effective and environment friendly.
Afsaneh Alinezhadian, Ahmad Karimi, Jahangard Mohammadi, Farzaneh Nikookhah, Mathias Niuman. Anderson,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Objectives: In arid and semi-arid regions, wastewater reuse has become an important element in agriculture. However, irrigation with this resource can be either beneficial or harmful, depending on the wastewater characteristics. The aim of this research was to investigate the soil bacterial and crops quality irrigated with treated wastewater.
Material and Methods: This research was conducted on a maize field near the wastewater treatment plant in Shahr-e-kord in summer,2011. Plots were arranged in a randomized complete block design in 3 replications and 2 treatments, well water (W1) with fertilizer and effluent (W2).
Results: At the end of growth season, soil samples were collected from depth of 0-5 and 5-15 cm and plant samples consisting of old and new leaves and seeds were collected for bacteriological analysis. According to bacteriological analysis, total number of positive lactose bacteria, total and fecal coliforms in depth of 0-5 cm was 42% more than depth of 5-15 cm. In the case of old leaves, total number of coliform and fecal coliform was 88 and 40 MPN/100 mL respectively. Moreover, for new leaves, it was 38 and 2 MPN/100 ml respectively.
Conclusion: According the results, number of indicator bacteria in soil is decreased (about 35%) by passing time.
Marzieh Mahtabi Oghani, Akbar Najafi , Habiballah Yunesi,
Volume 6, Issue 3 (12-2013)
Abstract
Background and objectives: Nowadays, landfilling is most common method in many countries owing to lower cost and adaptation to wide range of solid waste. Site selection of landfill requires evaluating several parameters such as municipal government requirements, environmental regulations and a large number of quantitative and qualitative criteria. The aim of current study was to compare AHP and TOPSIS in landfill site selection. For this purpose, two mentioned methods were applied to select suitable site in Karaj. Materials and methods: In present study, 4 candidate sites in south of Karaj were selected for landfill by overlaying data layers (digital maps) and query functions in Arc GIS 9.2. Prioritizations between alternatives were conducted by AHP and TOPSIS technique according to the criteria mentioned. Eventually, we compared and evaluated the AHP results and TOPSIS results with each other. Result: According to AHP, site prioritization was 3,2,4,1 respectively whereas, in the case of TOPSIS, it was ranked 4,3,2,1, respectively. These results showed that both methods are suitable to determine site priority. Conclusion: As in AHP, alternatives are compared with respect to goal and criteria, consequently it has better precision and higher accuracy and confidence compared with TOPSIS.
Kamiar Yaghmaeian , Ali Akbar Roudbari, Saeeid Nazemi,
Volume 6, Issue 3 (12-2013)
Abstract
Background & Objectives: The aim of the study was to design and implement integrated solid wastes management pattern in Shahroud industrial area, to evaluate the results, and to determine possible performance problems.
Materials & Methods: This cross - sectional study was carried out for 4 years in Shahroud industrial area and the implementation process included: 1. qualitative and quantitative analysis of all solid wastes generated in the area, 2. determining the current state of solid waste management in the area and identifying programs conducted, 3. designing and implementation of integrated management pattern including design and implementation of training programs, laws, penalties and incentives, and illustrating and implementing programs for all factories, and 4. monitoring the implementation process and determining the results.
Results: Annually, 1,728 tons of solid waste is generated in the area including 1603 tons of industrial waste and 125 tons of municipal wastes. By implementing this pattern, two separated systems of collection and recycling of domestic and industrial waste were launched in this area. Moreover, consistent with the goals, the amount of solid waste generated and disposed in 2011 was 51.5 and 28.6 kg per 100 million Rials production respectively. In addition, 42 and 40% of the industrial waste and paper were recycled.
Conclusion: Results showed that implementation of this pattern, i.e. running source separation, training programs, capacity building, providing technical services, completing chain of industries and strengthening the cooperation between industrial estate management and industrial units could greatly reduce the waste management problems.
Gh Asgari, A. R. Rahmani, A. R. Dehghanian, A. R. Soltanian,
Volume 7, Issue 1 (7-2014)
Abstract
Background and Objectives: In this experimental study, we used Analytical Hierarchy Process method to determine the best wastewater treatment process for dairy products factories. That is a multi-criteria decision making techniques and is based on expert knowledge. Materials and Methods: First, we formed the hierarchical structure and defined the main criteria and indicators. Then, we investigated the current situation of the treatment process through field observations and conducting influent-effluent analysis. Later, we converted the results obtained into quantitative indices. Then we weighted the main criteria, and their related sub criteria, depending on existing conditions we performed the experiments required and considered the experts ideas. Finally, Evaluation and prioritization of the options was conducted using Expert choice software. Then the sensitivity analysis was performed for main criteria and we evaluated the influence of the parameters weight change on the options. Results: In comparison with the main criteria, environmental criteria were more important followed by engineering criteria, economic and management criteria. Conclusions: Due to the influence of various parameters in choosing optimal wastewater treatment, Multi-criteria decision-making methods are necessary. Finally, “UASB + Aeration” was found to be the first priority followed by “Anaerobic filter + Aeration”, “Anaerobic lagoon + Aeration (2) + Sedimentation (2)”,” Anaerobic filter + Aeration (2) + Sedimentation (2)”. “Septic tank + Trickling filter + Aeration” system was found to be less preferable than other options.
N Navidjouy, M Jalali, H Khorsandi, Hossein Movahedian,
Volume 7, Issue 1 (7-2014)
Abstract
Background & Objectives: Listeria bacterium resists to the sludge digestion conditions and Listeria monocytogenes is the most important of them. Sludge produced in the north Isfahan wastewater treatment plant is stabilized by anaerobic digesters and is used for fertilizing agricultural lands after drying in the sludge drying beds. Based on the importance of the subject, the objective of this study was evaluation of sludge processing units efficiency, particularly anaerobic sludge digestion for reduction or removal of Listeria. Materials and Methods: In this descriptive study, samples were collected weekly from sludge processing units 13 times in north Isfahan wastewater treatment plant according to standard methods over three months. Listeria bacteria were enumerated and isolated by triple-tube fermentation method and U.S Department of Agriculture method respectively. Isolated Listeria were confirmed by phenotypic method and then bacterial species were diagnosed differentially by biochemical carbohydrate fermentation and CAMP test. Results: Contamination of raw, stabilized and dried sludge at least to one of L. Monocytogenes, L. Innocua and L. Seeligeri species was 100, 92.3 and 53.8 percent respectively. Anaerobic sludge digesters efficiency to remove L. Monocytogenes, L. Innocua and L. Seeligeri species was determined 64.7, 39.72, and 100 percent while the efficiency of drying sludge beds for L. monocytogenes and L.innocua species removal was 73.4 and 96.68 percent respectively. Conclusion: Listeria monocytogenes is more resistant than other identified species against the sludge processing conditions. Thus, the use of sludge as fertilizer can cause the spread of this bacterium in the environment and agricultural products pollution.
