IRAN - WASTEWATER TREATMENT CITY OF MARAGHEH

In the Name of God
Date:
Energy Science & Technology in Tarasht Ref:
Reg.: 450534 – Tehran –Iran E-Mail: info@se3tco.ir
Energy Science & Technology in Tarasht Co. (SE3
T) Tel: +98-21-66083178
Unit 25, Floor 3, No. 69, Habibzadeghan Ave., Teymouri St., Sip Phone: 40663015
Tarasht, Tehran, Islamic Republic of Iran, Post Code: 1459996600 Web: www.se3tco.ir
Preliminary Information on
DEVELOPMENT OF ANAEROBIC DIGESTION FOR
WASTEWATER TREATMENT IN THE CITY OF
MARAGHEH
IR Iran
Energy Science & Technology in Tarasht Co.
SE3
T
March 2018

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Table of Contents
1-1- Introduction to Maragheh ……………………………………………………………...1
1-1- Maragheh wastewater treatment plant 6
1-2- Development programs 8
2- Products of wastewater treatment units and their applications …………………………...5
2-1- efficiency increase solutions -anaerobic digester technology 10
2-1-1- Solid state anaerobic digestion 10
2-1-2- Increase amount of organic material in digester 10
3- Estimation of local biomass sources to use in anaerobic digester ……………………….7
3-1- Sewage sludge potential in nearby cities 11
3-2- Agricultural wastes potential 11
3-3- Challenges and uncertainties of agricultural wastes 11
3-4- Other resources available for increasing the organic material of digester 11
4- Products from anaerobic digestion……………………………………………………….8
4-1- integrated production plants and value maximization 12
4-2- Estimated potential for wastewater treatment sludge 13
4-3- Estimated potential for organic solid waste 13
5- Compost quality improvement ………………………………………………………….10
5-1- Reduce heavy metals by using vermicomposting 14
5-2- Product standards 14
5-3- The Potential of Maragheh University in analyzes of standards 15
6- Economic Analysis 12
7- Conclusion 14

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List of Figures
Figure 1: geographical location of Maragheh .............................................................................................................. 1
Figure 2:location of Maragheh waste water treatment plant...................................................................................... 2
Figure 3: Maragheh wastewater treatment plant and its vicinity............................................................................... 3
Figure 4: top view of Maragheh wastewater treatment plant..................................................................................... 3
Figure 5: schematic reference flow of wastewater ...................................................................................................... 4
Figure 6: probable heat application sites....................................................................................................................... 6

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List of Tables
Table 1: guaranteed purchase price for electricity....................................................................................................... 5
Table 2: summery of main agricultural products in Maragheh.................................................................................. 7
Table 3: estimated products form anaerobic digester.................................................................................................. 8
Table 4: statistics of Pectin import in April – August 2016....................................................................................... 8
Table 5: Estimated potential of wet sludge in local wastewater treatment sites ..................................................... 9
Table 6: estimation of waste generation in Maragheh ................................................................................................ 9
Table 7: estimated product from supplementary local resources .............................................................................. 9
Table 8. The limit for pathogens for compost ............................................................................................................10
Table 9. Limit of Heavy Metals for Compost or Organic Fertilizer .......................................................................11

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An introduction to Maragheh
The city of Maragheh is located in north-west part of Iran in East Azerbaijan Province. This
city is located in the south part of Sahand mountain and near Soufichai Rive. It is 135 km
away from south part of Tabriz. Figure 1 shows the geographical location of Maragheh.
Maragheh is the second largest city in East Azarbaijan after Tabriz and its area is 65.22
square kilometers. This city has more than 177,000 inhabitants, including the population of
nearby villages, the total population increase to 262,000 [1].
Figure 1: geographical location of Maragheh
Average daily water consumption in are in Iran is 190 liters per day per capita [2] and in rural
area average water consumption is 155 lit per day per capita [3].
Currently sewage water of Maragheh enters to the wastewater treatment plant with the
capacity of 500 l/s. It has two modules. Each one receives 250 l/s of sewage. The technology
of older module is surface aeration and sludge separation and the technology of the new one
is SBR 1and sludge separation, similarly. Separated sludge from both units enters to an
Aerobic digestion and after dewatering, the remained solid compost is sold to the local
farmers. Due to population growth, the wastewater treatment plant is working overload by
100 l/s and 150 - 200 l/s of execs sewage cannot enter to the wastewater treatment plant and it
directly discharges to Soufichai River.
Comparing average water consumption per capita and wastewater load, it is apparent that
generated wastewater is about 2 times greater than average water consumption by the
population in this city. If we assume 85% of consumed water changes into the wastewater,
wastewater flow is greater than expected flow. Discharging industrial wastewater to the
municipal wastewater network may be one reason of excess wastewater. Expanding the
wastewater network to the countryside could be the other reason.
1sequence batch reactor

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Maragheh wastewater treatment plant
Wastewater treatment plant is located in south west side of the city of Maragheh. Designed
capacity of this plant is 500 l/s, consisting of two 250 l/s modules. Inlet wastewater pass
through head riser pump, bulky solid separation units, surface of deep aeration, two levels of
sludge separation, Sludge aeration and finally sludge dewatering. Figure 2 to
Figure 5 represents location and processes of wastewater treatment in Maragheh.

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Figure 2:location of Maragheh waste water treatment plant
Figure 3: Maragheh wastewater treatment plant and its vicinity
Figure 4: top view of Maragheh wastewater treatment plant

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Figure 5: schematic reference flow of wastewater
Development programs
Major challenges facing this wastewater treatment plant are mentioned below:
1- Capacity Shortage
Even though the designed capacity of wastewater treatment plant is 500 l/s, it is working
overload by accepting 600 liters of wastewater per second and about 200 l/s of untreated
wastewater is discharging to Soufichai River, directly.
2- Fluctuation in the pH of Inlet Stream
Lack of supervision on wastewater discharge, has provided an opportunity for nearby
industries (mainly food and fruit juice industries) to discharge their wastewater to municipal
sewage system, illegally. This unexpected flow decrease the pH of inlet stream and it makes
the system unstable to meet the required standards of the outlet. According to the site visit,
the newer system (SBR technology) can tolerate higher level of fluctuation in comparison to
the conventional surface aerator system. It is also noted that rain water and flooding in
autumn and winter do mix with the sewage water and it leads to increased inlet stream.
3- Population Growth

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According to the last census report, population of Maragheh has an increasing trend. The last
five years average of the annual growth rate in the city of Maragheh is 1.54% while the
annual growth rate of the city and the county is 1.17% and it is estimated that the population
will increase to 278,500 in 2021[1]. Immigration from nearby villages will increase the
population with a higher rate.
4- City Development Programs
The history of this city goes back to about 7000 years ago and there are remarkable historical
and geological attractions. Tourism development programs of the city of Tabriz provide a
unique opportunity to follow similar programs in Maragheh, in parallel.
5- Meeting Water Quality Standards for Agriculture Application
Treated wastewater will pass downstream agriculture lands and it is clear that expansion of
treatment facilities is essential for the health of environment and product cultivation.
6- Certified Compost Quality for Agriculture Applications
Local farmers use generated compost in wastewater treatment without any consideration of
pathogen activities or the amount of heavy metals remained in the compost. The development
programs should consider the activity of pathogens and heavy metals content.
Products of wastewater treatment units and their applications
Final products in an anaerobic digestion could be:
 electricity
 heat
 sludge
Ministry of Energy guarantees purchase of generated electricity from biomass/biogas for 20
year. Table 1 presents the feed-in-tariff of generated electricity from biomass.
Table 1: Feed-in-Tariff of electricity from biomass [4]
Feed-in-Tariff for anaerobic digester of wastewater, municipal solid waste and agriculture waste
treatment plants
Feed-in-Tariff (Rials/kWh) 350
Purchase Period (year) 20
Increase in Feed-in-Tariff for Made in Iran tech. up to 30%
Maximum Construction Period (months) 30
Maximum Delay in Operation (months) 9
Potential Added Feed-in-Tariff cost of connection to distribution grid
Generated excess heat can be used in the nearby area, building complex or probable industrial
zones which some of them are illustrated in Figure 6.

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Figure 6: probable heat application sites
While there are intensive agriculture and horticulture activities in the region of Maragheh,
there is high demand for compost made out of sludge. The conventional price for trading the
compost is 4000 Rials/kg.
The other applications for the generated sludge would be:
 burning for heat recovery or electricity generation
 extraction of phosphorous material
 extraction of nitrous
Efficiency increase solutions -anaerobic digester technology
Using solid-state anaerobic digestion and increasing organic loading in digester are strategies
for increasing the efficiency of anaerobic digestion technology. Therefor increasing the
degradable content of inlet stream makes the plant attractive from economic point of view
2-1-1- Solid state anaerobic digestion
Solid-state anaerobic digestion is used to increase the percentage of solid content in the feed
of anaerobic digester. In this digester, the percentage of solids can be higher than 15%, while
the percentage of solid in conventional liquid-state anaerobic digesters is less than 15%.[5].
2-1-2- Increased amount of organic material in digester
Carbon to nitrogen (C / N) is an important factor in the process of anaerobic. Sewage sludge
has a higher carbon content in comparison to nitrogen. Adding food waste or agricultural
waste to sewage sludge can improve this factor and accelerates the hydrolysis process and
increases efficiency [6]

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Estimation of Local biomass sources to use in anaerobic
digester
The wastewater treatment plant of Maragheh has a potential production of 20 tons per day2of
sludge. There is also potential for using sludge from wastewater treatment plants in nearby
cities, agricultural waste and food waste.
Sewage sludge potential in nearby cities
Excluding the city of Tabriz, the only wastewater treatment site near Maraghrh belongs to
Bonab. The population of Bonab is approximately 85,000 people. The wastewater treatment
plant of Bonab is located 19 kilometers far from Maragheh and its potential to produce dry
sludge is 10 tons per day.
Agricultural wastes potential
The city of Maragheh with a cultivated area of 100,000 hectares and approximately 18,000
hectares is allocated to garden products. A brief list of agriculture products is represented in
Table 2.
Table 2: summery of main agricultural products in Maragheh
Product apple Grapes Almond walnut greengage wheat
Amount of production tons 175000 16000 3180 2044 4484 40000
Factor of waste production % 28 34 67 48 3 15
Amount of waste tons 49000 5440 2130 981 134.5 6000
Challenges and uncertainties of agricultural wastes
There will be a lot of uncertainty about the amount of agricultural waste produced in
Maragheh, because agricultural waste is produced in different stages consisting of harvest,
storage, transport and consumption. It should be noted that products of Maragheh are usually
exported to other locations and even other countries.
Other resources available for increasing the organic material of digester
Organic part of municipal waste, restaurant waste, fruit and vegetable wastes, and wastes
from factories of food industry are other options to increase degradable content of inlet to
anaerobic digester. Markets for fruits and vegetable and waste part of industrial and large-
scale refrigerators are the other probable resources. No further data is available now.
2based on unwritten statistics

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Products from anaerobic digestion
According to descriptions in 1-1-. The inlet flow of water stream is between 600 to 800
l/s. When inlet steam exceed wastewater treatment capacity, the untreated wastewater
goes to the nearby river. Considering city development programs, it is required to
increase wastewater treatment capacity at least by 250 l/s. generated sludge in primary
and secondary sludge separation units would be used in anaerobic digestion unit. Table
3 shows a brief estimation of products.
Table 3: estimated products form anaerobic digester
Inlet
flow
(l/s)
Ave TSS
in (mg/l)
Ave BOD
in (mg/l)
Generated
sludge inlet to
AD (m3/day)
Estimated
compost
(ton/day)
Estimated potential
of electric power
generation (kW)
Estimated
heat in CHP
(kW)
800 368 364 840 15 450 830
600 368 364 630 11 390 716
integrated production plants and value maximization
Extraction of valuable materials from waste resources is investigated to increase profitability
of the unit. This method is based on the concept of developing an industrial park. In this case,
extraction of pectin is an alternative to use waste or remained apple fruit in the region of
Maragheh.
Pectin has a vast broad of application in food industry. According to Table 4 the import
statistics in 2016 shows that about 70 tons of Pectin was imported.
Table 4: statistics of Pectin import in April – August 2016[7]
country import weight (kg)
Italy 17,000
India 10,000
United Arab Emirate 17,500
Germany 18,175
Turkey 6,180
Belgium 1,125
total weight 69,980
total monetary value ($) 1,151,330
total monetary value (1000 Rials) 34,877,654
pectin content in apple peel is about 1.2% [8], but in another study pectin extraction yield
from fresh pomace reported 13.3% on dry weight basis [9]. Considering that 20 to 30 percent
of the weight of original fresh fruit remains as pomace [10].
Remain solid residues from Pectin extraction processes can increase organic content of the
anaerobic digresser, theoretically. pectin extraction usually need dissolving in acids in very
low pH. for example pH solid waste is about 1- 1.5 and the remaining residues have sodium

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hydroxide and ethanol [10]. Therefor application of the remaining solid needs primary
treatment.
Estimated potential for wastewater treatment sludge
Local potential to increase organic content of the anaerobic digester could be municipal
solid waste, agriculture solid waste and sludge from nearby centralized or decentralized
wastewater treatment sites. Table 5 shows a brief review of probable potential of sludge
from wastewater treatment sites.
Table 5: Estimated potential of wet sludge in local wastewater treatment sites
Location Population Estimated water consumption
(m3/day)
Estimated sludge to AD
(kg/day)
The city of Bonab 85,274 13217 136.53
Tazeh Kand
village
1112 172 1.78
Gheshlagh village 353 55 0.57
Ezbak village 140 22 0.22
Eshan village 1279 198 2.05
Haris village 233 36 0.37
Someah village 442 69 0.71
Bay Shahr village 475 74 0.76
Sonkesh village 711 110 1.14
Esfestanaj village 391 61 0.63
Kahagh 1489 231 2.38
Estimated potential for organic solid waste
Generally, food waste is used for animal feeding in rural area and organic waste
potential is considered for the city of Maragheh in this study. Daily waste generation per
capita is 560 g per capita and 70% of this amount is considered as the organic and
digestible content [11].
Table 6: estimation of waste generation in Maragheh
Population of the city of
Maragheh in 2016
Estimated waste generation
(tpd)
Estimated organic material in
waste (tpd)
177,100 100 70
It is further assumed that degradation yield of organic MSW is 50% and generated gas
per kg of volatile solid (VS) is 246 liters for the retention time of 20 -25 days and the VS
content of MSW 2.5 kg/m3 [12] and the density of solid waste to 205 kg/m3[13]. A brief
estimation of heat, power and sludge generation by using local MSW and wastewater
sludge is presented in Table 7.
It should be noted that household waste is not completely separated and more training
and activation of the local NGOs will be helpful to promote waste separation culture.

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Table 7: Estimated product from supplementary local resources
Component Inlet material
(tpd)
electricity
(kW)
Thermal
(kW)
compost
(tpd)
Sludge from other wastewater
treatment plants
153 91 167 3
Organic material of solid waste 70 11 20 35
Compost quality improvement
In 1-2- it was noted that local farmers use generated compost without appropriate treatments.
Two applicable methods to remove heavy metals are source separation and avoid the country
to use environmentally pollutant material and the other option is end of pipe treatment. While
heavy metal separation at source is challenging, heavy metal separation by other conventional
methods is suggested.
Reduce heavy metals by using vermicomposting
Produced compost from Vermicompost process has less heavy metal than animal fertilizers
and compost fertilizers, due to the absorption of heavy metals by the body of the composting
worm. For the production of vermicompost farm anaerobic digester sludge is required to
purchase a worm and worm bed. To convert one ton of sludge to Vermicompost the required
investment cost is about 30,000,000 Rials.
Product standards
The objectives of the existing standards for compost are to determine the physical-chemical
characteristics, determine the limit values for heavy metals and pathogens in compost manure.
Table 8 and Table 9 show the limit values for pathogens and heavy metals, respectively. In
these tables RWANDA standards, the Iranian national standard (compost-physical and
chemical features), European eco label and the national standard of the Philippines have been
compared.
Table 8. The limit for pathogens for compost
S/N Properties Allowable levels
RWANDA
STANDARD
ISIRI3 European Eco-
Label
PHILIPPINE
NATIONAL
STANDARD
1 Faecal Streptococci,
CFU/g, max
5 x 102
_ _ 5 x 102
2 Total coliforms
CFU/g, max
5 x 102
_ _ 5 x 102
3The Institute of Standards & Industrial Research of Iran

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3 Salmonella 0 _ 0 0
4 E. coli _ _ < 1000 MPN/g _
5 Infective parasites _ _ _ 0
The Potential of Maragheh University in analyzes of standards
The University of Maragheh has the potential to analyze the pathogens and heavy metals
found in compost and sludge from the digestion and treatment plant.
Table 9. Limit of Heavy Metals for Compost or Organic Fertilizer
S/N Properties Allowable maximum level (mg/kg, dry weight) Test method
RWANDA
STANDARD
ISIRI European Eco-
Label
PHILIPPINE
NATIONAL
STANDARD
1 Arsenic (As) 5 10 10 5
2 Zinc (Zn) 5 1300 300 5
3 Lead (Pb) 250 200 100 250
4 Copper (Cu) 300 650 100 300
5 Chromium (Cr) 150 150 100 150
6 Nickel (Ni) 50 120 50 50
7 Mercury (Hg) 2 5 1 2
8 Cadmium (Cd) 5 10 1 5
9 Cobalt (Co) _ 25 _ _
10 Molybdenum (Mo) _ 5 2 _

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Economic Analysis
The required expansion capacity of sewage treatment plant is assumed to be 250 l/s of
sewage water inlet. In addition to the expansion of sewage treatment plant a production
line of pectin from the apple waste in the region shall be envisaged. Therefore, economic
analysis shall include expansion of sewage treatment plant together with the production
line of pectin from apple wastes.
Cost Items
No Cost Item Million €
1 Sewage treatment Plant Expansion (250 l/s Inlet) 9
2 Pectin production Line from Apple (250 tons/Year) 1
3 Total Capital Costs 10
4 Apple Waste Purchase (30000 tone/Year) 2
5 Maintenance Cost per Year 0.3
6 Other Operation Costs 0.3
7 Total Annual Costs 2.6
Revenue Items
No Revenue Items Million €
1 Water Sell to Industry (7.2 Million m3
) 1.1
2 Sludge & Compost from Sewage (9000 t/Year) 0.8
3 Compost from Apple Waste (10000 t/Year) 0.9
4 Pectin from Apple Pomace (300 t/Year) 2.4
5 Total Annual Revenue 5.2
Cash Flow
It is assumed that the project could be in the form of a BOT and 20% of investment
for sewage water treatment shall be paid by Sewage Water Treatment Company
(SWTC) of Maragheh. The shareholders shall be SWTC with 25%, SE3T with 10%,
University of Maragheh with 5% and private investor 60%. SWTC shall not get any
income from net revenue in the period of 10 years.
If it is assumed that the revenue from sale of water to industry to be 1.6 Million € and
the share of Sewage Water Treatment Company (SWTC) of Maragheh in new Sewage
Water Treatment plant to be 35%, the cash flow shall be as follows. The shareholders
shall be SWTC with 35%, SE3T with 10%, University of Maragheh with 5% and
private investor 50%. SWTC shall not get any income from net revenue in the period
of 10 years.
Time 0 1 2 3 4 5 6 7 8 9 10
Income Mio. € 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1
Cash Flow -7.75 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1 2.1
IRR % 24%
NPV Mio. € 8.0

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It can be concluded from both tables that private investment would be in the range of
6.9 to 7.8 Million €. IRR and NPV of the project would be in the range of 24% - 33%
and 8.0 to 10.9 Million €.
In both cases it has been assumed that 15% total net revenue shall belong to SE3T and
University of Maragheh.
Time 0 1 2 3 4 5 6 7 8 9 10
Income Mio. € 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4
Cash Flow -6.85 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4
IRR % 33%
NPV Mio. € 10.9

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Conclusion
Expansion of sewage water treatment is required in the city of Maragheh. The treated
water can be delivered to the neighboring industry. In addition to that the by-product shall
be compost that can be sold to the farmers. It will be possible to generate electric power
with a capacity of 400 kW and district heating. If the extension of sewage water treatment
is associated with utilization of agricultural waste in the region, it shall be possible to
increase the value-added of the whole complex. Therefore, utilizing apple waste to
produce pectin has been considered as a part of the project.
If the expansion of sewage water treatment is associated with utilization of apple waste in
the region, it shall be possible to enhance the value-added of the whole project.
A discussion with sewage water treatment company of Margheh confirms that it is
possible that up to 35% of investment on expansion of sewage water treatment can be
covered by the local Sewage Water Treatment Company. Such an undertaking by the
local Sewage Water Treatment Company can contribute to increased value-added of the
complex and it could increase IRR of the project to more 33% over 10 years. In this case
the total NPV of the project with a discount rate of 5% over 10 years period shall be 10.9
Million €. In both cases it was assumed that 15% of net revenue would belong to SE3T
and university of Maragheh.

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References
[1] East Azerbaijan Planning and Budget Organization, “A Brief Review Of Population
And Housing Census, in persian,” 2017.
[2] “average water consumption,” Online, 2017.
[3] “rural water consumption,” IRNA, 2014.
[4] SATBA, “Guaranteed Electricity Purchase Price From Renewable And Clean Power
Plants.” Available: http://www.satba.gov.ir/fa/guidance/guidance/guidance1/tariff
[5] Y. Li, S. Y. Park, and J. Zhu, “Solid-State Anaerobic Digestion For Methane
Production From Organic Waste,” Renew. Sustain. Energy Rev., vol. 15, no. 1, pp.
821–826, 2011.
[6] E. Iacovidou, D. G. Ohandja, and N. Voulvoulis, “Food Waste Co-Digestion With
Sewage Sludge - Realising Its Potential In The UK,” J. Environ. Manage., vol. 112, pp.
267–274, 2012.
[7] Customs Administration, “Pectin Import Statistics,” 2017. http://www.foodyar.com.
[8] B. S. Virk and D. S. Sogi, “Extraction and Characterization of Pectin from Apple
( Malus Pumila . Cv Amri) Peel Waste,” Int. J. Food Prop., vol. 7, no. 3, pp. 693–703,
Dec. 2004.
[9] P. C. Sharma, A. Gupta, and P. Kaushal, “Optimization of method for extraction of
pectin from apple pomace,” indian J. Nat. Prod. Resour., vol. 5, no. 2, 2014.
[10] L. Miceli-Garcia, “Pectin From Apple Pomace:Extraction, Characterization, And
Utilization In Encapsulating Alpha-Tocopherol Acetate,” University of Nebraska-
Lincoln, 2014.
[11] N. Salehi and M. Kolagar, “Varamin Green region development,” 2017.
[12] C. Eliyan, “Anaerobic Digestion Of Municipal Solid Waste In Thermophilic
Continuous Operation,” Asian Institute of Technology, 2007.
[13] M. T. Samadi and M. . Seif, “The Investigation Of Physical Composition And Amount
Of Waste Generation In The City Of Hamedan From 1999 To 2000,” J. Hamadan
Univ. Med. Sci. Heal. Serv., no. in persian, 2003.

IRAN - WASTEWATER TREATMENT CITY OF MARAGHEH

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IRAN - WASTEWATER TREATMENT CITY OF MARAGHEH