Scholarly article on topic 'The Investigation and Designing of an Onsite Grey Water Treatment Systems at Hazrat-e-Masoumeh University, Qom, IRAN'

The Investigation and Designing of an Onsite Grey Water Treatment Systems at Hazrat-e-Masoumeh University, Qom, IRAN Academic research paper on "Agriculture, forestry, and fisheries"

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Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — Narges Shamabadi, Hasan Bakhtiari, Nafise Kochakian, Mahmood Farahani

Abstract Limited water supplies remind the environmental ethics of recovery and reuse of limited resources. One of the interesting options in this context is Grey water. Grey water is wastewater originating from showers, baths, bathroom sinks, kitchen sinks and laundries. It does not include toilet or garbage wastes, or wastewater contaminated by soiled diapers. Despite the fact that it may include a complex mixture of organic matter, suspended solids, bacteria and common household chemicals, when used wisely and in a manner that is protective of public health and the environment, it can help preserve limited water supplies. Qom Province is located in the central part of Iran, at the Latitude and the Longitude of 34° 38’ 24N and 50° 52’ 35 E respectively. The city of Qom is the 7th most populated city of Iran. With an altitude of 933 meters above the sea level and a location adjacent to two great deserts Qom has a very hot and dry weather. The salt lake (Daryacheh-ye Namak) in the east of the city has caused the ground to be usually arid and parched. Due to proximity to desert region, the climatic changes and the low value of precipitation, water resources are under pressure, and under such harsh conditions, water is very precious. The onsite wastewater treatment systems can reduce the water crisis. To this end the Hazrat-e-Masoumeh University was selected as a pilot to investigate the feasibility of reusing the produced grey water. Based on studies undertaken to propose a grey water treatment system, the Hazrat-e-Masoumeh University has recommended the application of trickling filters with suspended plastic media. In this method, waste particles (if existing) are first removed from the system by a 1cm mesh screen. Then the grey water is conducted to a buried septic tank and the resulting water is pumped to a trickling filter containing suspended plastic media and the sludge, amounting to thrice the discharge of the pumped water is returned to the septic tank. After passing through the trickling filter, water is led to the settling tank, where the produced sludge is settled. Finally a chlorination system is used to disinfect the treated effluent. It should be noted that the kitchen effluent needs to be pre-treated to remove fat and 4. Furthermore, this project is the first report of designing an onsite grey water treatment system in a university in Iran.

Academic research paper on topic "The Investigation and Designing of an Onsite Grey Water Treatment Systems at Hazrat-e-Masoumeh University, Qom, IRAN"

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Energy Procedia 74 (2015) 1337 - 1346

International Conference on Technologies and Materials for Renewable Energy, Environment and

Sustainability, TMREES15

The investigation and designing of an onsite grey water treatment systems at Hazrat-e-Masoumeh University, Qom, IRAN

Narges Shamabadia, Hasan Bakhtiari b*, Nafise Kochakianc, Mahmood Farahanib

aGreen Research Center, al-Ghadir BLVD, Qom, University of Qom, Qom,3716146611, Iran bWater & Wastewater Co. al-Ghadir BLVD, Qom, Qom,3716146835, Iran cGene Fanavaran Co,Tehran, IRAN

Abstract

Limited water supplies remind the environmental ethics of recovery and reuse of limited resources. One of the interesting options in this context is Grey water. Grey water is wastewater originating from showers, baths, bathroom sinks, kitchen sinks and laundries. It does not include toilet or garbage wastes, or wastewater contaminated by soiled diapers. Despite the fact that it may include a complex mixture of organic matter, suspended solids, bacteria and common household chemicals, when used wisely and in a manner that is protective of public health and the environment, it can help preserve limited water supplies. Qom Province is located in the central part of Iran, at the Latitude and the Longitude of 34° 38' 24 N and 50° 52' 35 E respectively. The city of Qom is the 7th most populated city of Iran. With an altitude of 933 meters above the sea level and a location adjacent to two great deserts Qom has a very hot and dry weather. The salt lake (Daryacheh-ye Namak) in the east of the city has caused the ground to be usually arid and parched. Due to proximity to desert region, the climatic changes and the low value of precipitation, water resources are under pressure, and under such harsh conditions, water is very precious. The onsite wastewater treatment systems can reduce the water crisis. To this end the Hazrat-e-Masoumeh University was selected as a pilot to investigate the feasibility of reusing the produced grey water.

Based on studies undertaken to propose a grey water treatment system, the Hazrat-e-Masoumeh University has recommended the application of trickling filters with suspended plastic media. In this method, waste particles (if existing) are first removed from the system by a 1cm mesh screen. Then the grey water is conducted to a buried septic tank and the resulting water is pumped to a trickling filter containing suspended plastic media and the sludge, amounting to thrice the discharge of the pumped water is returned to the septic tank. After passing through the trickling filter, water is led to the settling tank, where the produced sludge is settled. Finally a chlorination system is used to disinfect the treated effluent. It should be noted that the kitchen effluent needs to be pre-treated to remove fat and 4. Furthermore, this project is the first report of designing an onsite grey water treatment system in a university in Iran.

© 2015PublishedbyElsevierLtd. Thisisanopenaccess article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the Euro-Mediterranean Institute for Sustainable Development (EUMISD)

1876-6102 © 2015 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4 .0/).

Peer-review under responsibility of the Euro-Mediterranean Institute for Sustainable Development (EUMISD) doi: 10.1016/j.egypro.2015.07.780

Keywords: Grey water; Hazrat-e-Masoumeh University; Treatment; Reuse

1. Introduction

In past centuries, given the low number of world population, the small size of communities and the prevailing culture of consumption, the water problem as we know it today did not exist [1]. However, after industrialization, the phenomenon of urbanization and the easier exploitation of the God given natural resources, the trend of erratic consumption increased more and more and led to the appearance of numerous difficulties [2]. Consequently with the increase of global population and the global warming, the search for new resources to reduce the use of natural resources has become an inevitable necessity [3]. One efficient method of using water resources is their re-treatment and reuse in sectors such as agriculture and landscaping [4]. This research studies the reuse of grey water as a recyclable water resource. The per capita grey water production in different countries is shown in table 1.

According to Merriam Webster Encyclopedia, grey water includes household wastewater (as from a sink or bath) that does not contain serious contaminants (as from toilets or diapers) [5]. This word was applied for the first time, in 1977 [1, 6]. Nowadays, Grey water defines as a wastewater originating from showers, baths, bathroom sinks, kitchen sinks and laundries. In fact, it is a subset of sewage having the capability of being purified for reuse by sewage treatment and disposal systems [1].

Although the use of grey water is not that welcomed in some countries, others have embraced the technology, for instance [6-9]:

• Many grey water systems are installed each year in Germany.

• Australia offers grants for the installation of grey water systems.

• In Tokyo, grey water recycling is mandatory for buildings with an area >30,000 m2 or with a potential non-potable water demand of more than 100 m3/day (CBSE 2003).

• Cyprus subsidizes the use of grey water for toilet flushing and garden irrigation by offering subsidies of €1700. The subsidy is valid up to 1 December 2008.

Table 1. Per capita grey water production in various countries

73 percent of the domestic wastewater Moderate climate, industrialized country (Hansen and Kjellerup, 1994) (Ledin et al., 2001a) (Eriksson et al., 2002)

30 percent of the domestic water consumption - (Jefferson et al., 2001)

65 l/c/d Housing area in Stockholm (Ottoson and Stenstrom, 2003)

5% of the water used in the kitchen, 26% of the water

used for washing and bathrooms, 15% of laundry water Melbourne, Australia Christova Boal et al.,1996)

and 20% of the toilet water

123 l/c/d/ Tucson, Arizona (Casanova et al., 2001)

Less than 50% of domestic wastewater Arid regions (WHO, 1989b)

75.7 - 132.5 l/c/d Arizona, USA -

58 l/c/d in a 3-bedroom building Brisbane (Queensland, 2002)

50 - 80% of the domestic wastewater - (Del Porto and Steinfeld, 2000)

125 l/c/d Massachusetts (Del Porto and Steinfeld, 2000)

68% of the domestic wastewater Industrial (NSW Health, 2000)

Qom Province is located in the central part of Iran, at the Latitude and the Longitude of 34° 38' 24 N and 50° 52' 35 E respectively. The Qom city is the 7th most populated city of Iran. With an altitude of 933 meters above the sea level and a location adjacent to two great deserts Qom has a very hot and dry weather. The salt lake (Daryacheh-ye Namak) in the east of the city has caused the ground to be usually arid and parched. Due to proximity to desert

region, the climatic changes and the low value of precipitation, water resources are under pressure, and under such harsh conditions, water is very precious.

1.1. The application of grey water

In addition to potable water, which must be from a treatment plant, a transmission line and urban water distribution network, there are other uses in the Hazrat-e-Masoumeh University, which do not require potable water quality and lower quality waters with an adequate level of treatment according to the relevant environmental standards can easily be used. Samples of consumptions that can be supplied from the University's treated grey water

1.2. Reuse of treated grey water to irrigate the University's green space

The effluent to be reused for irrigation of green spaces must be treated to environmental standards for the relevant purpose. The standards for reuse of effluents and recycled waters are as follows:

a) The effluent meant for irrigation of inedible products and crops consumed raw as well as the green spaces, golf courses must be treated to a minimum of secondary level, filtered and disinfected. The quality of the treated effluent must be as follows:

• pH = 9-6

• BOD5 < 10mg/l

• Turbidity < 2NTU

• Residual Chlorine < 1 mg/l

• Fecal coliforms should be zero

b) The effluent meant for irrigation of inedible products and crops consumed after cooking as well as the fodder and fibrous plants, forests and grazing pastures must be treated to a minimum of secondary level and disinfected.

The quality of the treated effluent must be as follows:

• pH = 9-6

• BOD5 < 30mg/l

• SS < 30mg/l

• Residual Chlorine < 1 mg/l

• Fecal coliforms less than 200/100ml

Table 2. The proposed quality standards for application of treated effluents and recycled water in irrigation of green spaces Parameter Unit Max. permissible amount

pH - 6.5-8.4

EC ^s/cm 700

Sodium absorption ratio mg/l 3

Sodium mg/l 70

Chloride mg/l 100

Boron mg/l 0.7

Carbonates mg/l 3

Bicarbonates mg/l 90

Phosphate mg/l 50

Nitrogen nitrate mg/l -

Nitrogen ammoniac mg/l 5

TSS mg/l 40

TDS mg/l 450

BOD mg/l 30

Fecal coliforms MPN/100 ml 1000

Nematode eggs number/ l 1

1.3. Reuse of treated grey water firefighting and flushing The quality of the treated effluent must be as follows:

• pH = 9-6

• BOD5 < 10mg/l

• Turbidity < 2NTU

• Residual Chlorine < 1 mg/l

• Fecal coliforms should be zero

1.4. Reuse of effluent for fountains, decorative water structures and ponds

Effluent to be reused for building fountains, decorative water structures and ponds to beautify urban environment needs a minimum of secondary treatment and disinfection. The quality of the treated effluent must be as follows:

• pH = 9-6

• BOD5 < 30mg/l

• TSS < 30mg/l

• Residual Chlorine < 1 mg/l

• Fecal coliforms less than 200/100ml

1.4.1. Reuse of effluent for building construction and uses

The treated effluent can be used in buildings for applications such as soil compaction, controlling dust and preparing concrete. For these purposes the effluent must undergo a minimum of secondary treatment and be disinfected.

The quality of the treated effluent must be as follows:

• pH = 9-6

• BOD5 < 30mg/l

• TSS < 30mg/l

• Residual Chlorine < 1 mg/l

• Fecal coliforms less than 200/100ml

1.4.2. Reuse of treated grey water for the University's covered swimming pool

The treated grey water that is to be reused in the swimming pool is recommended to have the following specifications. It must have a pH of 7.2 - 8. The recommended alkalinity for swimming pool water must be a minimum of 50 and maximum of 150 mg/l of CaCo3. The recommended hardness for swimming pools is 200 to 300 mg/l CaCo3, with an ideal water temperature of 27o Celsius. Moreover, the quality of water used must be higher than the rage of environmental standards for discharge to surface waters.

The quality of the treated effluent must be as follows:

• BOD5 < 10mg/l

• COD < 20 mg/l

• TSS < 30mg/l

• Residual Chlorine = 0.5 - 1 mg/l

• No fecal coliforms

The other uses of treated grey water could be:

1. Washing the University's premises

2. Chillers

3. Use in the toilet flushes in the offices and dormitories

4. Irrigation of greenhouses

1.5. Determining the treatment degree required

An important criterion in designing treatment systems related to selection of the required degree of treatment. The quality parameters requirements of the treated grey water are shown in table 3. Since there is a higher probability of allocating the treated grey water to irrigation of green spaces in the Hazrat-e-Masoumeh University, it will have to comply fully with the standards for discharge of treated effluents to surface water and those for reuse to irrigate green spaces and in agriculture.

Table3. Quality parameters for treated grey water

Parameter_Amount

COD ( mg/l ) 30

BOD5 ( mg/l ) 10

TSS (mg/l ) 10

Turbidity ( NTU ) 30

N-NH3 ( mg/l ) 2.5

N-NO3 ( mg/l ) 50

TP ( mg/l ) 6

Surfactants ( mg/l ) 1.5

Fecal Coliforms ( cfu/100ml ) 400

pH 6.5-8.5

The grey water treatment system (GTS) collects, stores, treats, and may disinfect grey water to the standards. There are some issues to be considered during the design and operation of these systems. Some of these issues are mentioned here and must be considered during the design stage.

The wastewater samples were collected from baths, kitchens and bath sinks, department buildings, kitchens and restaurant, pools, gyms, dormitories and other buildings and carried to the laboratory. The quality of samples were measured and mentioned in table 4.

Table 4. The quality assay of samples

Parameter Kitchen Bath Laundry's machines Bath/shower Kitchen

COD (mg/l) 300 278 305 291 365

BOD ( mg/l) 130 109 115 129 170

TSS ( mg/l) 89 75 122 70 155

Turbidity (NTU) 63 54 114 55 138

TN (mg/l) 29 25 31 22 42

TP (mg/l) 4.8 4.1 7.6 4.1 8

Surfactants (mg/l) 56 31 83 20 15

Coliforms (cfu/100ml) - - 1.5x10 - 1.2x103 2.1x10 - 3.4x103 -

pH 8.3 8.4 9.2 6.3 6.5

2. Design of the treatment system

Based on studies undertaken to propose a grey water treatment system, the Hazrat-e-Masoumeh University has recommended the application of trickling filters with suspended plastic media. In this method, waste particles (if existing) are first removed from the system by a 1cm mesh screen. Then the grey water is conducted to a buried septic tank and the resulting water is pumped to a trickling filter containing suspended plastic media and the sludge, amounting to thrice the discharge of the pumped water is returned to the septic tank. After passing through the trickling filter, water is led to the settling tank, where the produced sludge is settled. Finally a chlorination system is used to disinfect the treated effluent. It should be noted that the kitchen effluent needs to be pre-treated to remove fat and grease.

grey water

screening

system 1-

septic tank

trickling filter with plastic media

settling tank

chlorination

system

return sludge: 3Q

2.1. The technical issues of the proposed screen

Since the design discharge rate of the system in modules 1 and 2 is low, a coarse screen can initially be considered for each of the three modules at peak flow, and another screen as reserve for occasions when the operating screens require repair or cleaning.

• Average flow: 1054 m3/day = 0.012 m3/s

• Peak flow (with application of the coefficient of 2.5) = 2635 m3/day

Screen 1 (coarse) should have an angle of 45 degrees, a height of 0.7 m, bar intervals of 50 mm, belt thickness of 10 mm and a canal width of 0.5 m, while screen 2 (fine) should have an angle of 45 degrees, a height of 0.7 m, bar intervals of 20 mm, belt thickness of 10 mm and a canal width of 0.5 m. As far as possible they should be made of stainless steel 316 or otherwise from carbon steel with special covers.

2.2. Design of the septic tank:

It should be noted that the volume of the inlet should be twice the outlet. Therefore, if the total volume is 300 m3, the volume on inlet section should be 200 m3 and the outlet section 200m3. By supposing a septic tank depth of 2.5 m, the length to breadth ratio of the septic tank can be obtained as follows: L/B=2 H-2.5 m B=7.75m L=15.5m

2.3. Design of trickling filter

2.3.1. Design of trickling filter with plastic media

By supposing that 60% of the TSS and 305 of BOD will be removed in the septic tank these parameters at the inlet of the trickling filter would be 52 mg/l and 98 mg/l respectively. This filter has been designed with this assumption that thrice the inlet flow would be returned to the trickling filter, while the inlet flow to the filter would be 4 times the treatment plant's inlet flow and its return flow would be three times the initial flow.

Consequently the outlet BOD would be 40mg/l. Moreover by removing about 30% of TSS, the effluents TSS would reach to 37 mg/l.

BIOLOGICAL TOWER

D 4.2 m

H media 3.5 m

BOD 5 98 mg/lit

Temp 20 °C

N media 0.5

K20 media 0.002 (lit/m2.s)(

As media 135 m2/m3

Q influent 1816 m3/d

Q recycle 1362 m3/d

2.3.2. Design of trickling filter with mineral Lika

Lika is a substance that obtained by heating 2 micron clay particles at temperatures of above 1000o C in kilns. The gases inside them expand resulting in hard and porous aggregates and after cooling. Lightness, non-decomposition and fire resistance are among the properties of Lika. In the proposed method, Lika aggregates of 4-7 mm in diameter will be used.

grey water

screening system

trickling filter

with mineral Lika

chlorination system

2.4. Design of the settling tank The rate of surface loading at average and peak flows would be in order 16 to 32 and 40 to 64 m3/m2/d, while the rate of solids loading at average and peak flows would be 90 to 148 and less than 244 kg/m2/d. Since the design was undertaken on the basis of surface loading assumption, a retention time of 5 hours has been considered for settlement in the secondary settling tank. Therefore the effluent's BOD and TSS will be 20 mg/l and 18.5 g/l demonstrating the proper functioning of the system.

As (m2/m3) 85 140

BOD loading (g/m3.d) 80 or greater

Surface loading 0.68 or greater

60 or greater

n 0.5 vertical flow media

0.5 cors flow media

044 random pack media

k20 (lit/m2.sec) 0.001 0.002 vertical flow media

0.00325 random pack media

0.0012 0.0023 cors flow media

2.4. Design of the chlorination system

chlorine gas cylinders are used for the purpose. For the purpose of designing the chlorination system and determining the capacity of chlorinators, residual chlorine of 5mg/l and 8mg/l respectively for the average and the peak flows is acceptable.

3. Problems of equipment, process and operation related to the reuse of grey water

3.1. Equipment issues:

The most common problems are sedimentation and clogging. In general the phenomena of clogging and sedimentation are the main problems during the operation of water systems, and their control is quite important due to reasons such as protection of public health, increasing the quality of water, increasing the volume and discharge, increasing the service life of the pipes and connections and proper execution of the water supply projects.

Pipe cogging and sedimentation can be due to the accumulation of solid particles, which obstruct the hydraulic flow and reduce the flow velocity in transmission lines and water supply networks. Physically they can be the result of mud and silicate sand accumulation, biologically by ferns, algae and animal corpse, chemically by lime sediments and biochemically by bitumen shale or be in the form removable objects. In the grey water system available in the Hazrat-e-Masoumeh University, if the TSS standard in the effluent meets the requirements of the intended treatment degree, a major cause of sedimentation would be removed.

In addition to TSS, control of other parameters such as TDS, calcium, alkalinity and pH, and the calculation of the Index of Saturation (IS) throughout the operation to learn of the corrosive or sedimentary qualities of the water produced from the treated grey water will be another solution to control corrosion and sedimentation.

3.2. Process issues:

If the grey water treatment system is not operated appropriately and according to principles, the quality of the effluent will be reduced leading to problems in places where it is reused. If the treated grey water is applied for irrigation of green spaces, the followings negative consequences can be expected:

1. The effects of trace elements available in the effluent on the irrigation of green spaces

2. The effects of organic matters available in the effluent on the irrigation of green spaces in the long run

3. The effects of nutrients on the irrigation of green spaces

In general taking into account the following five points can effectively increase the benefits of applying the treated effluents for irrigation of green spaces:

• The public health, and in particular the health of labor working in the green spaces;

• Protecting the soil as one of the most essential environmental resource and preventing its pollution

• Application of efficient technologies related to reuse of effluents for irrigation and protecting the irrigation systems to resolve a part of the related problems.

Issues related to the application of effluents for irrigation include:

• Effective use of nutrients available in the effluents and preventing their loss

• The impacts on cooling the installations

• Propagation of odors

• Probable problems of repair and maintenance

4. 4. Results and conclusion

In this research the quality of wastewater generated in different units of Hazrat-e-Masoumeh University, including the administration and training units, the dormitories and the kitchen was determined first. Then the system to treat the grey water collected from these units was designed based on the studies of demands that can be met in different sections of the University, including the green spaces and the flush tanks of the administration buildings and the dormitories. Two options were proposed for treatment of the grey water from Hazrat-e-Masoumeh University.

1- Application of trickling filter using suspended plastic media

2- Application of trickling filter using Lika aggregates

The client, which is the management of Hazrat-e-Masoumeh University, in collaboration with the Water and Wastewater Company sought the trickling filter using Lika aggregate in the first stage due to easier execution, lower space requirement, upgradability, and higher efficiency in removing pollutants and pathogens and then applying the trickling filter with suspended plastic media in the next stage.

The reuse of treated effluents has long been practiced in different countries of the world [10]. In advanced countries, the treated wastewater is reused according to the environmental regulations, which focus on protection of human health and environment, and on prevention of soil and water pollution, and which are revised and updated at specific time intervals [1]. Whereas in developing countries, in addition to treated effluents, raw wastewater is also applied in agricultural production [6, 9].

The latter lack proper strategies and plans as well as specific guidelines on the reuse of effluents and recycled waters, and for this reason, the exploitation of these resources is often accompanied with negative health and environmental consequences and the pollution of water and soil resources [1]. As a Middle Eastern country, Iran faces the reduction of renewable water resources, and currently throughout the country at in particularly in the margins of large cities and provincial centers, large areas are irrigated with effluents and recycled water. In most cases this reuse is inappropriate and is undertaken to produce herbs and vegetables, and has led to the pollution of the environment, accumulation of pollutants in the soil and their transfer to the crops [11].

Given the interest and the need to use effluents and recycled waters in the agriculture, most wastewater treatment plants in the country are designed and built with the objective of applying the resulting effluent for agriculture [4]. In this context, the relevant officials have focused their attention treatment and reuse of urban and industrial wastewaters as well as recycled waters as new resources that can compensate for part of the shortages [12].

The study of the global practice of reusing treated effluents and recycled waters underlines the importance of their reuse as a valuable water resource in view of the shortages, and this importance will only increase as time goes by [13]. For the proper and sustainable use of these resources it will be necessary to compile appropriate standards and regulations, and an attention to this principle will guarantee beneficial impacts such and protecting the quality and quantity of water resources and reducing the environmental pollution [14]. Irrigation of green spaces and gardens is the primary application for reuse of treated grey water [15]. Most studies conducted to date have concentrated on the physical specifications of grey water that could leave a long term impact on the quality of the soil and the crops [16]. Parameters considered for irrigation of crops using grey water include metals, salinity, pH and pathogens, which can accumulate in soil. In particular, due to their direct impact on human health, pathogens are the most important factors in this group [17].

Research has demonstrated that irrigation with grey water that has not been adequately treated and has a high level of surfactants, will lead to the hydrophobic (non-absorption) condition to the soil. The report published by Water Environment Research Foundation (WERF) in the year 2006 underlines the dangers of irrigating green spaces with grey water and stresses that the impacts of the grey water are greatly related to the composition of water, rate of chemicals decomposition, absorption, type of soil, soil permeability and water absorption by the plants [18]. WERF report explains that grey water can cause direct effects such as increased pH, excessive increase of salinity and creation of organic compounds, which cause the indirect impacts of altering the bioactivity of the soil resulting from the contact of soil bacteria with the organic matters in the grey water composition [17].

Household cleaning products usually contain high levels of sodium, chloride and salinity [11, 19]. In subsurface irrigation, the sodium and chloride contents are in order 110 and 140 mg/l, which may be toxic for trees sensitive to salinity [11]. The average content of sodium accumulated in grey water in Los Angeles is 118 mg/l [6]. It is further reported that the amount of boron in water during domestic consumptions increases up to 0.1 - 0.4 mg/l, while in grey water it can reach to 1.0 to 4 mg/l [6]. If this amount in grey water used for irrigation is 0.5 - 1.0 mg/l, it can have toxic effects on sensitive trees and bushes [11]. Therefore, only trees that are not sensitive to irrigation with grey water should be selected for the purpose [11]. The design of such systems can result in the management of grey waters and finding a solution to the water crisis, particularly in critical regions.

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