The Open Agriculture Journal




ISSN: 1874-3315 ― Volume 13, 2019
RESEARCH ARTICLE

Reclaimed Wastewater Quality Assessment for Irrigation and Its Mid-Time Reuse Effects on Paddy Growth and Yield under Farmer Management



Kami Kaboosi*, Reza Esmailnezhad
Department of Water and Agriculture, Gorgan branch, Islamic Azad University, Gorgan, Iran

Abstract

Introduction:

Many studies have been conducted on irrigation of upland crops with reclaimed wastewater while there have been a few reports about wastewater reuse for paddies. The majority of irrigation water requirement of paddy field in Bandargaz region (Iran) during the dry season within the last 12 years is dependent on effluent of treatment plant. Accordingly, different water parameters and 12 irrigation water quality indexes and economical- environmental filed management factor (fertilizer application rate) and crop growth and yield were studied in freshwater (FW) and wastewater (WW) filelds.

Explanation:

Unexpectedly, wastewater and freshwater salinity was less and more than the threshold salinity of paddy (2.0 dS.m-1), respectively and due to the high concentration of chlorine, FW is not suitable for irrigation. Based on almost all of indices and standards for assessing irrigation water quality, WW was significantly better than FW.

Conclusion:

The average concentration of heavy metals in both FW and WW samples were in the order of Cr˂Cd˂Pb˂Ni. However, results showed that concentration of heavy metals in WW was significantly more than FW. Nevertheless, these were below maximum allowable based on international standards and guidelines. The average nitrogen concentration in the reclaimed wastewater was 11.2 mg.lit-1 that was more than the required nitrogen concentration (7 mg.lit-1). So, a dilution strategy could be adopted when reclaimed water is used. No significant difference was observed in two type farms based on plant height, spike length, and 1000-seed weight, but this factor was significantly effective on seed per spike and seed yield so that they were higher in WW irrigated farms by 12.4 and 10 percent, respectively.

Keywords: Golestan, Heavy metal, Nutrients, Rice, Paddy, Waste water.


Article Information


Identifiers and Pagination:

Year: 2018
Volume: 12
First Page: 64
Last Page: 73
Publisher Id: TOASJ-12-64
DOI: 10.2174/1874331501812010064

Article History:

Received Date: 02/01/2018
Revision Received Date: 03/03/2018
Acceptance Date: 08/04/2018
Electronic publication date: 26/4/2018
Collection year: 2018

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 871
Abstract HTML Views: 913
PDF Downloads: 494
ePub Downloads: 627
Total Views/Downloads: 2905

Unique Statistics:

Full-Text HTML Views: 583
Abstract HTML Views: 341
PDF Downloads: 350
ePub Downloads: 196
Total Views/Downloads: 1470
Geographical View

© 2018 Kaboosi and Esmailnezhad.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Department of Water and Agriculture, Gorgan branch, Islamic Azad University, Kami Kaboosi, Gorgan, Iran; Tel: 00989113738102; E-mail: kkaboosi@yahoo.com




1. INTRODUCTION

Rice is one of the most important crops in the world, including Iran. Worldwide, about 162.7 million ha of rice is cultivated that seed production is 741.5 million ton. In Iran, rice harvested area and production were 529 thousand ha and 2.3 million ton, respectively [1 FAO, (2017) FAOSTAT. Available from: http://www.fao.org/faostat/en/#home [Accessed on April 24,2017]]. Irrigation water for paddy rice production accounts for more than 70% of the total irrigation water in Asia and paddy rice is the largest consumer of freshwater resources in South and Southeast Asia [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.].

Domestic wastewater reuse and land application are not new, and knowledge on this topic has evolved and advanced throughout human history (since the Bronze Age ca. 3200-1100 BC) which has gone through different stages of development [3Angelakis AN, Snyder SA. Wastewater treatment and reuse: past, present, and future. Water 2015; 7: 4887-95.[http://dx.doi.org/10.3390/w7094887] ]. Due to the availability constraint of the freshwater for irrigation, a vast majority of the reclaimed water is used for landscape and agricultural irrigation, especially in arid and semi- arid region [4Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003] -6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.]. There is no complete global data on the extent of wastewater usage for land irrigating mostly due to a lack of heterogeneous data. Nonetheless, the global figure commonly cited is at least 20 million hectares in 50 countries (around 10 percent of irrigated land) are irrigated with raw or partially treated wastewater [7Jang T, Jung M, Lee E, Park S, Lee J, Jeong H. Assessing environmental impacts of reclaimed wastewater irrigation in paddy fields using bioindicator. Irrig Sci 2013; 31: 1225-36.[http://dx.doi.org/10.1007/s00271-013-0401-5] -9Water for people, water for life 2003.] and it has been applied in nearly 120 countries [10Guidelines for water reuse 1992; 262.]. It is also estimated that more than 10% of the world’s population consumes crops irrigated with wastewater [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.].

As an irrigation water resource, reclaimed wastewater can promote soil quality by nutrients and organic matter, biodegradable organic matter, beneficial microorganisms and soil biological activities. However, the most prevalent risks for irrigation use of wastewater are those associated with increasing pH, salinity, sodicity, and boron in water, as well as the potential accumulation of pathogens, nonessential toxic metals, and organic chemicals in the receiving soils [4Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003] , 11Albalawneh A, Chang TK, Chou CS. Impacts on soil quality from long-term irrigation with treated greywater. Paddy Water Environ 2016; 14: 289-97.[http://dx.doi.org/10.1007/s10333-015-0499-6] -14Lyu S, Chen W. Soil quality assessment of urban green space under long-term reclaimed water irrigation. Environ Sci Pollut Res Int 2016; 23(5): 4639-49.[http://dx.doi.org/10.1007/s11356-015-5693-y] [PMID: 26527339] ]. Water quality criteria, guidelines, and standards for irrigation are the result of scientific examinations on the suitability of water and wastewater based on its effects on soil, crop and health. Many organizations and countries such as the FAO in 1992 [6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.], WHO in 1989 and 2006 [15WHO. Guidelines for the safe use of waste water and excreta in agriculture and aquaculture: measures for public health protection 1989; 187., 16WHO. Guidelines for the safe use of wastewater, excreta and greywater 2006; 114.], EPA in 1980, 1992, 2004 and 2012 [10Guidelines for water reuse 1992; 262., 17EPA. Protocol development: criteria and standards for potable reuse and feasible alternatives 1980.-19EPA. Guidelines for water reuse 2012; 643.], Israel in 1952, 1999 and 2010 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.], Italy in 1977 and 2006 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.], France in 1991 and 2010 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.], Iran in 2000 [20DOE. Iranian standard for wastewater discharge and reuse 2000; 55.], Jordan in 2002 [21WHO. A compendium of standards for wastewater reuse in the Eastern Mediterranean region World Health Organization Press 2006; 242.], Cyprus in 2005 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18., 22Brissaud F. Criteria for water recycling and reuse in the Mediterranean countries. Desalination 2008; 218: 24-33.[http://dx.doi.org/10.1016/j.desal.2006.07.016] ], Portugal in 2006 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.], Spain in 2007 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.], Greece in 2011 [23Agrafioti E, Diamadopoulos E. A strategic plan for reuse of treated municipal wastewater for crop irrigation on the Island of Crete. Agric Water Manage 2012; 105: 57-64.[http://dx.doi.org/10.1016/j.agwat.2012.01.002] ] and South Korea in 2011 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.] have suggested and modified water quality guidelines or standards for safe wastewater reuse. Existing water quality criteria for irrigation and wastewater reuse were examined and water quality standards of many countries were analyzed to set agricultural water quality standard for indirect wastewater reuse considering for both paddy and upland crops [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.].

Wastewater is a valuable source of plant nutrients needed for maintaining fertility and productivity levels of the soil. Irrigation with wastewater has been shown to increase which results in growth and yield of different plants such as paddy [5Singh PK, Deshbhratar PB, Ramteke DS. Effects of sewage wastewater irrigation on soil properties, crop yield and environment. Agric Water Manage 2012; 103: 100-4.[http://dx.doi.org/10.1016/j.agwat.2011.10.022] , 24Carlos FS, Santos BL, Andreazza R, Tedesco MJ, Morris L, Camargo FAO. Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity, plant nutrition, and chemical characteristics of soil. Paddy Water Environ 2017; 15: 133-44.[http://dx.doi.org/10.1007/s10333-016-0535-1] ].

Assessments of wastewater reused for agriculture has been performed in many countries, but the findings are not directly applicable to paddy fields because of paddy rice production require large volumes of water. Paddy fields are flooded before plowing, and the water level is kept as high as up to 10 cm during the growing season [25Rhee HP, Yoon CG, Son YK, Jang JH. Quantitative risk assessment for reclaimed wastewater irrigation on paddy rice field in Korea. Paddy Water Environ 2011; 9: 183-91.[http://dx.doi.org/10.1007/s10333-010-0212-8] ]. While there are many studies providing assessments of wastewater reuse for upland crop, few of the findings are applicable to paddy irrigation with wastewater [26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ] in respect of water quality assessment [27Kaboosi K. The assessment of treated wastewater quality and the effects of mid-term irrigation on soil physical and chemical properties (case study: Bandargaz treated wastewater). Appl Water Sci 2017; 7(5): 2385-96.[http://dx.doi.org/10.1007/s13201-016-0420-5] ], changing physical or chemical properties of soil [24Carlos FS, Santos BL, Andreazza R, Tedesco MJ, Morris L, Camargo FAO. Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity, plant nutrition, and chemical characteristics of soil. Paddy Water Environ 2017; 15: 133-44.[http://dx.doi.org/10.1007/s10333-016-0535-1] , 27Kaboosi K. The assessment of treated wastewater quality and the effects of mid-term irrigation on soil physical and chemical properties (case study: Bandargaz treated wastewater). Appl Water Sci 2017; 7(5): 2385-96.[http://dx.doi.org/10.1007/s13201-016-0420-5] ] and crop growing [24Carlos FS, Santos BL, Andreazza R, Tedesco MJ, Morris L, Camargo FAO. Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity, plant nutrition, and chemical characteristics of soil. Paddy Water Environ 2017; 15: 133-44.[http://dx.doi.org/10.1007/s10333-016-0535-1] , 28Jang T, Lee SB, Sung CH, Lee HP, Park SW. Safe application of reclaimed water reuse for agriculture in Korea. Paddy Water Environ 2010; 8: 227-33.[http://dx.doi.org/10.1007/s10333-010-0203-9] ]. Specially, the effects of reclaimed wastewater on plant growth and crop production are rarely studied in field conditions and thus, this kind of study is scarce [26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ]. Therefore, the present study was undertaken to evaluate the effect of wastewater irrigation on growth and yield of rice crop in fields under farmer management and the safety of irrigation water containing toxic heavy metals based on different water quality standards. It was hypothesized that huge use of wastewater for paddy irrigation will not only reduce the paddy growth but also enhance the soil fertility and crop yield.

2. MATERIALS & METHODS

2.1. Study Area

Bandargaz city is located in the of Golestan province, Iran. The direct distance of Bandargaz municipal wastewater treatment plant from the Caspian sea (Gorgan Gulf) is about 1.7 Km. Also, the distance where the wastewater discharged into the Caspian sea to the Miankaleh protected zone is 35 Km (Fig. 1). Plant was launched in 2005 with a capacity of 3100 m3.day-1. Wastewater using concrete pipe reached to the earth channels and then emptied to the sea (Fig. 1). In Bandargaz region, irrigation water scarcity in the summer season, which coincides with the peak crop water requirement period, has caused the farmers interested to usage of treated wastewater as an unconventional water resource for supplying a large portion of water requirement in more than 700 ha of paddy field in around of plant [27Kaboosi K. The assessment of treated wastewater quality and the effects of mid-term irrigation on soil physical and chemical properties (case study: Bandargaz treated wastewater). Appl Water Sci 2017; 7(5): 2385-96.[http://dx.doi.org/10.1007/s13201-016-0420-5] ]. Rice cultivation is dominant in this area and irrigation season is approximately 3-month (late-May to late-August) along with the peak of irrigation water requirement within July. There are more than 700 ha paddy farm that are located near Bandargaz wastewater treatment plant. The majority of the flow in these farmlands is dependent on effluent of treatment plant during the dry season. Within the last 12 years, farmers remove of manhole doors and directly pumping the treated wastewater for irrigation. Most farmers ignore the hazards of the indiscreet reuse of wastewater for irrigation. During the dry season, which is the most intensive agricultural irrigation period in the region, a large portion of paddy irrigation water supply in these areas depends on discharge from the plant.

Fig. (1)
Location of Bandargaz wastewater plant and fields irrigated by freshwater (blue) and wastewater (red).


2.2. Treatments

To study the effect of reclaimed wastewater (WW) on growth traits and yield of paddy crop and its comparison with the tube well freshwater (FW) farms in Bandargaz, 40 paddy farms were randomly selected (Fig. 1). Half of these farms have been irrigated by freshwater and the rested half by the reclaimed wastewater in recent 12 years. A similar study method was used by Jang et al. [7Jang T, Jung M, Lee E, Park S, Lee J, Jeong H. Assessing environmental impacts of reclaimed wastewater irrigation in paddy fields using bioindicator. Irrig Sci 2013; 31: 1225-36.[http://dx.doi.org/10.1007/s00271-013-0401-5] ]. All the farming operations, conducted under farmers’ management during growth season, were recorded precisely including farm area, the value of used seed for planting, dates of planting and harvesting, growth season length and application amount of nitrogen, phosphate, and potassium fertilizers. During growth season, 7 samples from each water resource (totally 14 samples) were taken coincident with different phonological stages.

2.3. Water Quality Assessment

Water samples were taken from June to August 2016 with an approximate interval of two weeks according to phonological stage of rice crop. 14 water quality parameters including pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), calcium, magnesium, sodium, potassium, chloride, sulphate, carbonate, bicarbonate, nitrate (NO3-), phosphate (PO4-) and Total Hardness (TH) and four target heavy metals (Pb, Ni, Cd, and Cr) were measured. Total water properties were measured based on APHA [29APHA. Standard methods for examination of water and wastewater 2017; 541.]. Some irrigation water index such as Potential soil Salinity: PS [30Ramakrishna A, Nagaraju D, Balasubramanian A, Siddalingamurthy S. Assessment of groundwater quality for irrigation in the Tattekere watershed, Periyapatna and Hunsur Taluks in Mysore district, Karnataka, India. Int J Curr Eng Tech 2015; 5(2): 942-8.], Sodium Adsorption Ratio: SAR [31Wilcox LV. Classification and use of irrigation waters 1955; 28.], Kelley’s Ratio equal to Exchangeable Sodium Ratio: ESR [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ], sodium percentage 1: Na%1 [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ], sodium percentage 2: Na%2 [31Wilcox LV. Classification and use of irrigation waters 1955; 28., 33Zouahri A, Dakak H, Douaik A, El Khadir M, Moussadek R. Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco. Environ Monit Assess 2015; 187(1): 4184.[http://dx.doi.org/10.1007/s10661-014-4184-9] [PMID: 25467415] ], Magnesium Ratio [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ], Ca:Mg ratio [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.], Calcium Ratio [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.], Residual Sodium Carbonate: RSC [31Wilcox LV. Classification and use of irrigation waters 1955; 28., 32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ], Residual Sodium Bicarbonate: RSBC [33Zouahri A, Dakak H, Douaik A, El Khadir M, Moussadek R. Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco. Environ Monit Assess 2015; 187(1): 4184.[http://dx.doi.org/10.1007/s10661-014-4184-9] [PMID: 25467415] ] and Permeability Index: PI [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ] were calculated. Values obtained from each water resource were treated as replicates. The concentration of heavy metals in samples was estimated by using atomic absorption spectrophotometer (Model AA-10, Varian Inc., Australia) fitted with a specific lamp of particular metal using appropriate drift blank. For minimizing time changes in water quality, samples were collected at 10:00. In order to assess the water resources for irrigation, different irrigation water quality standards including United State Salinity Laboratory: USSL [31Wilcox LV. Classification and use of irrigation waters 1955; 28.], FAO 29 [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.], FAO 47 [6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.], Shainberg and Oster [35Shainberg I, Oster JD. Quality of irrigation water 1978; 65.], Indian irrigation water quality [36Jangir RP, Yadav BS. Management of saline irrigation water for enhancing crop productivity. J Sci Indus Res 2011; 70: 622-7.], Oster and Schroer -after [37Phocaides A. Handbook on Pressurized Irrigation Techniques 2nd ed. 2nd ed.2007; 282.]- and Indian Council of Agricultural Research [38Minhas PS, Gupta RK. Quality of irrigation water: assessment and management 1992; 123.] and different organizations and countries guideline for reclaimed wastewater reuse were considered.

The heavy metal pollution index (HMPI) was calculated by the following formula to show the level of contamination in water [39Singh A, Agrawal M. Effects of Waste water irrigation on physical and biochemical characteristics of soil and metal partitioning in Beta vulgaris L. Agric Res 2012; 1(4): 379-91.[http://dx.doi.org/10.1007/s40003-012-0044-4] ].

HMPI = Ci/Si

Where Ci and Si are heavy metal content in a water sample and permitted standard of the same metal (μg.Lit-1), respectively. When the HMPI values exceed than 1.0, water is said to be contaminated by anthropogenic inputs and requires continuous environmental monitoring of the area [39Singh A, Agrawal M. Effects of Waste water irrigation on physical and biochemical characteristics of soil and metal partitioning in Beta vulgaris L. Agric Res 2012; 1(4): 379-91.[http://dx.doi.org/10.1007/s40003-012-0044-4] ].

2.4. Plant Sampling and Studied Traits

At the time of maturity, three plots (1*1 m2) were randomly selected in each farm. Then, 10 samples were collected from each plot. Identical amounts of each field were obtained by average of samples. Values obtained from different farms were treated as replicates. Samples were oven-dried separately at 80ºC until a constant weight was achieved [39Singh A, Agrawal M. Effects of Waste water irrigation on physical and biochemical characteristics of soil and metal partitioning in Beta vulgaris L. Agric Res 2012; 1(4): 379-91.[http://dx.doi.org/10.1007/s40003-012-0044-4] ]. Yield and growing traits including plant height, spike length, number of seed per spike, thousand seed weight, seed yield, biological yield and harvest index (ratio of seed yield to biological yield) were measured.

2.5. Statistical Analysis

Data normality was evaluated and proved by one-sample Kolmogorov-Smirnov test at 5% probability level [40Smirnov N. Table for estimating the goodness of fit of empirical distributions. Ann Math Stat 1948; 19(2): 279-81.[http://dx.doi.org/10.1214/aoms/1177730256] ]. The data of water quality and crop traits were subjected to t- student test for assessing the significance of differences. Statistical test and calculating of some descriptive statistics were performed using SPSS software (SPSS Inc., version 21).

3. RESULTS AND DISCUSSION

3.1. Assessment of Water Quality for Irrigation

The results of t-test at 5% probability level on water quality parameters are presented in Fig. (2) and Table 1. Carbonate was not found in any sample of FW and WW, and no significant difference was observed between FW and WW based on pH and bicarbonate concentration. Calcium, magnesium, sodium, chlorine and sulfate concentration in FW are significantly more than WW which can be resulted by the adjacency of this region wells with Caspian sea and seepage of brackish seawater into groundwater resources. This matter is discernable particularly from chlorine and sodium concentrations than the other ions in FW.

Fig. (2)
Mean comparison of different water ions and metals in FW and WW.


Table 1
Different water quality index of FW and WW.


The standard of FAO [6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113., 34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.], Australia [41Myers BJ, Bond WJ, Benyon RG, et al. Sustainable effluent- irrigated plantations: an Australian guideline. An Australian Guideline CSIRO Forestry and Forest Products, Melbourne,1999; 286.], EPA, Jordan and South Korea recommend the appropriate pH range for irrigation to be 6.5-8.4, 6.5-8.5, 6.0-9.0, 6.0-9.0 and 5.8-8.5, respectively [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.]. Outside of the normal range, water might be suitable for irrigating, but has the potential to cause an imbalance of nutrients, corrosion or sedimentation of irrigation facilities, mobility of heavy metals in the soil and poisonous ions [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18., 34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.]. In this research, the pH values of FW and WW are in the permitted range for irrigation based on different standards.

Salinity is the most important factor of irrigation water quality that can create a hostile environment. The salinity of FW samples was significantly greater than WW because of more concentration of cations and anions in freshwater. The allowed irrigation water EC for paddy crop was reported to be 2.0 dS.m-1 [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.]. In this regard, wastewater and freshwater salinity were less and more than the threshold salinity of paddy, respectively.

Nitrogen (N), phosphorus (P) and potassium (K) are major nutrients for the crop. It was reported that reclaimed water has more essential nutrients (N, P, K) and some micronutrients for plant growth than freshwater [4Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003] , 42Pirsaheb M, Sharafi K, Dogaohar K. Comparison of Mashhad Aolang wastewater treatment plant effluent with wells water quality for irrigation. J Water Wastewater 2013; 4: 116-21.]. However, those Nutrients can give negative effects such as nutrient imbalances, groundwater contamination, over-growing and lodging, excessive vegetative growth, failure to ripen, increased susceptibility to pests and disease, reduced fruit set for crops, delays in maturation and decreases in food nutrient quality especially for paddy rice [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18., 4Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003] , 6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.]. In consideration of the above negative effects of nitrogen on paddy rice growth, Taiwan, Japan and Jordan have set standards for allowable N in reclaimed water for paddy rice [2Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18., 4Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003] , 43Chiou RJ. Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation. Environ Monit Assess 2008; 142(1-3): 255-62.[http://dx.doi.org/10.1007/s10661-007-9922-9] [PMID: 17929185] ]. The amount of potassium, nitrate, and phosphate in the reclaimed wastewater is significantly more than freshwater that can lead to soil fertility (Fig. 2). Mass loads of N, P and K can be calculated by multiplying irrigation water volume and the corresponding concentration. Considering the irrigation water requirement of paddy crop in the studied area (13000 m3.ha-1), 193, 145.6, and 22.8 Kg of potassium, nitrogen, and phosphorus are added to per hectare of rice during total growth season that is 3.3, 15.3 and 8.5 times more than irrigation by freshwater, respectively. Therefore, it seems that the main part of paddy nutrition needs to potassium and nitrogen, and some phosphorus requirement is supplied through reclaimed wastewater.

The significant difference of FW with WW treatment in various irrigation water quality indexes is related to the difference of the dominant ions concentration (Table 1). The value of PS index is dependent on chlorine and sulfate concentration. The less amount of this index means the better quality for irrigation water; so that water with PS index greater than 5 is harmful for irrigation [44Tripathy DP, Bhushan Dhar B. Environmental Pollution Research 2002.]. According to this, although using wastewater for irrigation doesn’t have the potential risk of salinity, freshwater quality has this hazard.

It has suggested that the sodium problem in irrigation water could be very conveniently worked out on the basis of the values of ESR or Kelley’s ratio. Generally, water is considered as unfavorable for irrigation if ESR be more than one [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ]. Therefore, FW and WW are unfavorable and favorable water for irrigation, respectively.

The amount of Na%1 and Na%2 were very close to each other because of low concentration of potassium. As per the Bureau of Indian Standards the sodium percentage of 60 is the maximum recommended limit for irrigation water [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ]. Thus, FW is at the border of unsuitable irrigation water. However, WW has good quality because the water with sodium percentage between 20 to 40 percent is described as good water [44Tripathy DP, Bhushan Dhar B. Environmental Pollution Research 2002.].

Excess of magnesium (high Magnesium Ratio) in water affects the quality of soils, which causes poor yield of crops [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ]. In magnesium dominated water (Ca:Mg ratio less than 1), the potential effect of sodium may be slightly increased. In other words, a given SAR value will show slightly more damage if the Ca:Mg is less than 1 [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.]. Also, if irrigation water has calcium to total cation ratio less than 0.15, a further evaluation is needed. Such water may pose a potential problem related to plant nutrition [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.]. The result showed that both water resources have good quality in the aspect of Magnesium Ratio, Ca:Mg ratio and Ca Ratio, although the WW is significantly better than FW.

High concentration of CO32− and HCO3 represents alkaline nature of water. Use of such water promotes the precipitation of calcium and magnesium present in the soil solution which causes an increase in exchangeable sodium. For this reason, waters with high level of RSC or RSBC are unfavorable for irrigation uses. When RSC and RSBC are less than 2.5 and 5.0 meq.lit-1 respectively, irrigation water is safe in the aspect of alkaline hazard [31Wilcox LV. Classification and use of irrigation waters 1955; 28.-33Zouahri A, Dakak H, Douaik A, El Khadir M, Moussadek R. Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco. Environ Monit Assess 2015; 187(1): 4184.[http://dx.doi.org/10.1007/s10661-014-4184-9] [PMID: 25467415] ].

Regarding the relative equity of bicarbonate concentration in wastewater and freshwater, the value of these two indicators in freshwater is less affected by the more concentration of calcium and magnesium in the tube well water and this difference is statistically significant. Nonetheless, for both water resources, these two indexes are within safe limits for irrigation and there is no limitation in using them.

Irrigation water is divided into 3 classes by amount PI [32Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597] ]. In this study, both FW and WW belong to the first class (PI >75%) considered as good for irrigation.

Total hardness (TH) of the FW is significantly more than WW because of more concentration of calcium and magnesium. When the concentration of chloride in irrigation water is more than 4 meq.lit-1, toxicity problems can occur, especially for sensitive crops [33Zouahri A, Dakak H, Douaik A, El Khadir M, Moussadek R. Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco. Environ Monit Assess 2015; 187(1): 4184.[http://dx.doi.org/10.1007/s10661-014-4184-9] [PMID: 25467415] ]. In terms of chlorine concentration, FW and WW are brackish and fresh, respectively, indicating that FW is not desirable for irrigation due to the high concentration of chlorine.

Classification of Bandargaz FW and WW based on USSL [31Wilcox LV. Classification and use of irrigation waters 1955; 28.] were C4S2 and C3S1, that represent FW has very high salinity and medium- sodium hazard while WW has high salinity and low- sodium hazard, respectively. Irrigation water was classified by Shainberg and Oster [35Shainberg I, Oster JD. Quality of irrigation water 1978; 65.] based on EC and SAR to good, moderate and bad. In this study, FW and WW have good quality. Criteria of FAO 29 [34Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.] and FAO 47 [6Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.] guides showed that FW has severe limitation in the aspect of EC and Chloride. Nevertheless, WW is suitable for crop irrigation (Table 2). Comparing water quality with Manual of Indian Council of Agricultural Research [38Minhas PS, Gupta RK. Quality of irrigation water: assessment and management 1992; 123.] indicated that FW cannot be used for irrigation of sensitive crops. However, Bandargaz WW has not any limits for irrigation of all crops. Indian assessment of irrigation water quality by EC, SAR, RSC [36Jangir RP, Yadav BS. Management of saline irrigation water for enhancing crop productivity. J Sci Indus Res 2011; 70: 622-7.] showed that FW and WW have marginally salinity (suitable for coarse textured soils) and good quality (suitable for all soils and crops), respectively. Oster and Schroer [37Phocaides A. Handbook on Pressurized Irrigation Techniques 2nd ed. 2nd ed.2007; 282.] considered EC and SAR for determination of potential of infiltration problem due to sodium in irrigation water. Both FW and WW have no negative effect on infiltration.

Table 2
Water assessment based on FAO 29 and FAO 47 Guides.


Table 3 lists the levels of studied heavy metals detected in FW and WW and compare them with different national and world standards. The results showed that the average of heavy metal concentrations in both FW and WW samples were in the order of Cr˂Cd˂Pb˂Ni. This finding was very close to order of Cd˂Cr˂Pb˂Ni that reported by Chopra and Pathak [45Chopra AK, Pathak C. Accumulation of heavy metals in the vegetables grown in wastewater irrigated areas of Dehradun, India with reference to human health risk. Environ Monit Assess 2015; 187(7): 445.[http://dx.doi.org/10.1007/s10661-015-4648-6] [PMID: 26092239] ] for wastewater and tubewell water. However, the study of Huong et al. [46Huong NTL, Ohtsubo M, Li L, Higashi T, Kanayama M. Assessment of the water quality of two rivers in Hanoi City and its suitability for irrigation water. Paddy Water Environ 2008; 6: 257-62.[http://dx.doi.org/10.1007/s10333-008-0125-y] ] on surface water and Rhee and et al. [25Rhee HP, Yoon CG, Son YK, Jang JH. Quantitative risk assessment for reclaimed wastewater irrigation on paddy rice field in Korea. Paddy Water Environ 2011; 9: 183-91.[http://dx.doi.org/10.1007/s10333-010-0212-8] ] on FW and WW showed this order as Cd˂Ni˂Pb˂Cr. Also, the paired two-sample t test showed that there was a significant level of Cd, Cr, Pb and Ni (P<0.01) concentrations in WW as compared to FW.

Table 3
Levels of detected and allowed heavy metals in irrigation water (μg.lit-1).


The concentration of the Cr, Pb and Ni were found to be within safe limit in both FW and WW used for irrigation so that the maximum HMPI index for these metals in freshwater was 0.01, 0.14, and 0.12, respectively and in wastewater was 0.05, 0.28, and 0.16, respectively. However, in both water resources particularly in wastewater, Cd concentration was near to the maximum permission limits of different standards and even it was more than the maximum permission level based on Italian standard (Table 3) so that the maximum value of HMPI index for this metal was 0.67 and 1.01 in freshwater and wastewater, respectively.

Comparison of the permitted concentration of these four metals in different standards shows that FAO 47, EPA and WHO standards are exactly equal, and within surveyed national standards, Iranian and Italian standards are the easiest and the most rigorous national standards. For this reason, the concentration of studied heavy metals satisfied the Iranian wastewater quality standards for agriculture [20DOE. Iranian standard for wastewater discharge and reuse 2000; 55.] and those were within the recommended maximum concentrations. The values of the heavy metal concentration of FW and WW of this research were far less than the values observed by Chopra and Pathak [45Chopra AK, Pathak C. Accumulation of heavy metals in the vegetables grown in wastewater irrigated areas of Dehradun, India with reference to human health risk. Environ Monit Assess 2015; 187(7): 445.[http://dx.doi.org/10.1007/s10661-015-4648-6] [PMID: 26092239] ].

3.2. Field Management and Rice Growth and Yield

When wastewater is used, farmers make changes to farm management due to the awareness of wastewater benefits, especially the presence of nutrition elements that are required by crop. The effect of irrigation water resource on farm management and crop growth and yield is shown in Table 4. There wasn’t any significant difference between freshwater and wastewater irrigated farms in terms of farms area and amount of seeding per hectare. On average, date of planting was two days earlier in wastewater irrigated farms than freshwater ones while date of harvest was two days later. Consequently, the difference between two farms type, because of increasing about 4 days (equal to 3.8%) growth season length affected by wastewater, was significant at 10% probability level.

Table 4
The effects of reclaimed wastewater on rice paddy filed management and crop growth.


Farmers in the Bandargaz region have found that wastewater leads to fertile soil due to the presence of nutrients. Therefore, they reduced application of chemical fertilizers in paddy farms as this reduction of nitrogen and phosphorus fertilizers was significant at 5% probability level (Table 4). Application of nitrogen, phosphorus and potassium fertilizers in WW irrigated farms was 23, 22 and 20 percent less than FW irrigated farms, respectively which is a kind of economic and environmental management. However, if the amount of nitrogen, phosphorus and potassium in wastewater added to the amount of direct consumed fertilizers, it is found out that total imported nutrition materials to the WW irrigated farms are more than the ones under FW irrigation. This point was also emphasized by Jung et al. [26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ]. For example, considering the ratio of 46% for net nitrogen to nitrogen fertilizer, N added to fields by both fertilizing and irrigating ways was 52.1 and 178.4 Kg.ha-1 in FW and WW farms, respectively. One of the effects of high nitrogen consumption in paddy field is a significant prolonged growth period by 6% [50Ramazani A, Jalali AH. Effect of nitrogen fertilizer and transplanting date on yield, yield components and stem lodging of rice in Isfahan region. J Crop Prod Process 2013; 3(9): 45-54.] which is consistent with the results of this research.

The appropriate nitrogen fertilizer demand depends on characteristics of soil, farming pattern and cultivated variety. So, the total amount of nitrogen required during the growth and maturity period needs to be reviewed [43Chiou RJ. Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation. Environ Monit Assess 2008; 142(1-3): 255-62.[http://dx.doi.org/10.1007/s10661-007-9922-9] [PMID: 17929185] ]. In general, paddy rice requires 90 Kg.ha-1 of net nitrogen in a complete cycle [43Chiou RJ. Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation. Environ Monit Assess 2008; 142(1-3): 255-62.[http://dx.doi.org/10.1007/s10661-007-9922-9] [PMID: 17929185] ]. With respect to irrigation water requirement of 13000 m3.ha-1 in Bandargaz region, the average required nitrogen concentration is about 7 mgN.lit-1. Meanwhile, the average nitrogen concentration in the reclaimed wastewater was 11.2 mg.lit-1. So, original nitrogen fertilizer can be replaced by nitrogen in the reclaimed wastewater. The “nitrogen excess” phenomenon in reclaimed wastewater is concerned and a dilution strategy could be adopted when reclaimed water from traditional secondary treatment is used [43Chiou RJ. Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation. Environ Monit Assess 2008; 142(1-3): 255-62.[http://dx.doi.org/10.1007/s10661-007-9922-9] [PMID: 17929185] ].

No significant difference was observed in two type farms based on plant height, spike length, and 1000-seed weight, but this factor was effective significantly at 5% probability level on seed per spike such that it was in farms with WW irrigation about 12.4% higher than FW irrigated farms. Insignificant effect of reclaimed wastewater on paddy crop height [51Alghobar MA, Suresha S. Effect of wastewater irrigation on growth and yield of rice crop and uptake and accumulation of nutrient and heavy metals in soil. Appl Ecol Environ Sci 2016; 4(3): 53-60.] and 1000-seed weight [26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ] was reported.

According to the dependency of seed yield to yield component including 1000-seed weight and seed per spike [26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ], the effect of water type on seed yield was significant at 10% probability level so that this trait was 10% more in WW irrigated farms than ones with FW irrigation. This conclusion is closely in line with findings of other researches which reported increasing seed yield of paddy by 15-19% under reclaimed wastewater irrigation [7Jang T, Jung M, Lee E, Park S, Lee J, Jeong H. Assessing environmental impacts of reclaimed wastewater irrigation in paddy fields using bioindicator. Irrig Sci 2013; 31: 1225-36.[http://dx.doi.org/10.1007/s00271-013-0401-5] , 26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] , 28Jang T, Lee SB, Sung CH, Lee HP, Park SW. Safe application of reclaimed water reuse for agriculture in Korea. Paddy Water Environ 2010; 8: 227-33.[http://dx.doi.org/10.1007/s10333-010-0203-9] ]. It seems that this difference was resulted from lower water salinity, chlorine and sodium concentration, and more nutritional materials in wastewater than freshwater. N fertilizer had a significant effect on paddy yield [50Ramazani A, Jalali AH. Effect of nitrogen fertilizer and transplanting date on yield, yield components and stem lodging of rice in Isfahan region. J Crop Prod Process 2013; 3(9): 45-54., 52Asadi R, Alizadeh A, Ansari H, Kavoosi M, Amiri E. Effect of the amount of water and nitrogen on water productivity, yield, and yield components in two different rice cultivation methods. J Water Res Agr 2016; 30(2): 145-57.]. Hereof, it was reported that significant correlation between nutrient input in irrigation water (N and P) and paddy seed yield which led to an increasing productivity in reclaimed wastewater irrigated fields [7Jang T, Jung M, Lee E, Park S, Lee J, Jeong H. Assessing environmental impacts of reclaimed wastewater irrigation in paddy fields using bioindicator. Irrig Sci 2013; 31: 1225-36.[http://dx.doi.org/10.1007/s00271-013-0401-5] , 26Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017] ]. However, insignificant decrease of seed per spike and seed yield and significant decrease of 1000-seed weight were reported because of the adverse effect of excessive salts and high concentration of trace metals in wastewater [51Alghobar MA, Suresha S. Effect of wastewater irrigation on growth and yield of rice crop and uptake and accumulation of nutrient and heavy metals in soil. Appl Ecol Environ Sci 2016; 4(3): 53-60.]. There wasn’t any significant difference between irrigated farms with WW and FW in respect of biological yield and harvest index; although, harvest index was 14% more in farms with wastewater irrigation.

CONCLUSION

There was a significant difference between freshwater and wastewater in almost all parameters and indices which can be resulted by the adjacency of this region wells with Caspian sea and seepage of brackish sea water into groundwater resources and wastes in WW. According to different guidelines, the potential hazard associated with Bandargaz reclaimed wastewater reuse for irrigation was low. The results showed that the average of heavy metal concentrations in both FW and WW samples were in the order of Cr˂Cd˂Pb˂Ni and there was a significant level of Cd, Cr, Pb and Ni concentrations in WW as compared to FW. However, the concentrations of the Cr, Pb and Ni in both FW and WW used for irrigation were found to be within safe limit based on different national and world standards. There was no observed adverse effects on the use of reclaimed wastewater for paddy rice cultivation but also there was a statistically significant indication that rice growth and yield from reclaimed wastewater reuse was even greater than that from control plots irrigated with groundwater. These results imply that reclaimed wastewater reuse can be a practical alternative to conventional irrigation. However, long-term monitoring of soil chemical characteristics and related health concerns are recommended.

ETHICS APPROVAL AND CONSENT TO PARTICIPATE

Not applicable.

HUMAN AND ANIMAL RIGHTS

No animals/humans were used for studies that are the basis of this research.

CONSENT FOR PUBLICATION

Not applicable.

CONFLICT OF INTEREST

The authors declare no conflict of interest, financial or otherwise.

ACKNOWLEDGMENTS

Authors would like to thanks from contribution of Islamic Azad University- Gorgan branch.

REFERENCES

[1] FAO, (2017) FAOSTAT. Available from: http://www.fao.org/faostat/en/#home [Accessed on April 24,2017]
[2] Jeong H, Kim H, Jang T. Irrigation water quality standards for indirect wastewater reuse in agriculture: a contribution toward sustainable wastewater reuse in South Korea. Water 2016; 8(169): 1-18.
[3] Angelakis AN, Snyder SA. Wastewater treatment and reuse: past, present, and future. Water 2015; 7: 4887-95.[http://dx.doi.org/10.3390/w7094887]
[4] Chen W, Lu S, Jiao W, Wang M, Chang AC. Reclaimed water: a safe irrigation water source. Environ Dev 2013; 8: 74-83.[http://dx.doi.org/10.1016/j.envdev.2013.04.003]
[5] Singh PK, Deshbhratar PB, Ramteke DS. Effects of sewage wastewater irrigation on soil properties, crop yield and environment. Agric Water Manage 2012; 103: 100-4.[http://dx.doi.org/10.1016/j.agwat.2011.10.022]
[6] Pescod MB. Wastewater treatment and use in agriculture (FAO 47). Rome, 1992; pp. 113.
[7] Jang T, Jung M, Lee E, Park S, Lee J, Jeong H. Assessing environmental impacts of reclaimed wastewater irrigation in paddy fields using bioindicator. Irrig Sci 2013; 31: 1225-36.[http://dx.doi.org/10.1007/s00271-013-0401-5]
[8] Chen W, Lu S, Peng C, Jiao W, Wang M. Accumulation of Cd in agricultural soil under long-term reclaimed water irrigation. Environ Pollut 2013; 178: 294-9.[http://dx.doi.org/10.1016/j.envpol.2013.03.036] [PMID: 23590877]
[9] Water for people, water for life 2003.
[10] Guidelines for water reuse 1992; 262.
[11] Albalawneh A, Chang TK, Chou CS. Impacts on soil quality from long-term irrigation with treated greywater. Paddy Water Environ 2016; 14: 289-97.[http://dx.doi.org/10.1007/s10333-015-0499-6]
[12] Chen W, Lu S, Pan N, Jiao W. Impacts of long-term reclaimed water irrigation on soil salinity accumulation in urban green land in Beijing. Water Resour Res 2013; 49: 1-10.[http://dx.doi.org/10.1002/wrcr.20550]
[13] Chen W, Lu S, Pan N, Wang Y, Wu L. Impact of reclaimed water irrigation on soil health in urban green areas. Chemosphere 2015; 119: 654-61.[http://dx.doi.org/10.1016/j.chemosphere.2014.07.035] [PMID: 25150469]
[14] Lyu S, Chen W. Soil quality assessment of urban green space under long-term reclaimed water irrigation. Environ Sci Pollut Res Int 2016; 23(5): 4639-49.[http://dx.doi.org/10.1007/s11356-015-5693-y] [PMID: 26527339]
[15] WHO. Guidelines for the safe use of waste water and excreta in agriculture and aquaculture: measures for public health protection 1989; 187.
[16] WHO. Guidelines for the safe use of wastewater, excreta and greywater 2006; 114.
[17] EPA. Protocol development: criteria and standards for potable reuse and feasible alternatives 1980.
[18] EPA. Guidelines for water reuse 2004; 480.
[19] EPA. Guidelines for water reuse 2012; 643.
[20] DOE. Iranian standard for wastewater discharge and reuse 2000; 55.
[21] WHO. A compendium of standards for wastewater reuse in the Eastern Mediterranean region World Health Organization Press 2006; 242.
[22] Brissaud F. Criteria for water recycling and reuse in the Mediterranean countries. Desalination 2008; 218: 24-33.[http://dx.doi.org/10.1016/j.desal.2006.07.016]
[23] Agrafioti E, Diamadopoulos E. A strategic plan for reuse of treated municipal wastewater for crop irrigation on the Island of Crete. Agric Water Manage 2012; 105: 57-64.[http://dx.doi.org/10.1016/j.agwat.2012.01.002]
[24] Carlos FS, Santos BL, Andreazza R, Tedesco MJ, Morris L, Camargo FAO. Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity, plant nutrition, and chemical characteristics of soil. Paddy Water Environ 2017; 15: 133-44.[http://dx.doi.org/10.1007/s10333-016-0535-1]
[25] Rhee HP, Yoon CG, Son YK, Jang JH. Quantitative risk assessment for reclaimed wastewater irrigation on paddy rice field in Korea. Paddy Water Environ 2011; 9: 183-91.[http://dx.doi.org/10.1007/s10333-010-0212-8]
[26] Jung K, Jang T, Jeong H, Park S. Assessment of growth and yield components of rice irrigated with reclaimed wastewater. Agric Water Manage 2014; 138: 17-25.[http://dx.doi.org/10.1016/j.agwat.2014.02.017]
[27] Kaboosi K. The assessment of treated wastewater quality and the effects of mid-term irrigation on soil physical and chemical properties (case study: Bandargaz treated wastewater). Appl Water Sci 2017; 7(5): 2385-96.[http://dx.doi.org/10.1007/s13201-016-0420-5]
[28] Jang T, Lee SB, Sung CH, Lee HP, Park SW. Safe application of reclaimed water reuse for agriculture in Korea. Paddy Water Environ 2010; 8: 227-33.[http://dx.doi.org/10.1007/s10333-010-0203-9]
[29] APHA. Standard methods for examination of water and wastewater 2017; 541.
[30] Ramakrishna A, Nagaraju D, Balasubramanian A, Siddalingamurthy S. Assessment of groundwater quality for irrigation in the Tattekere watershed, Periyapatna and Hunsur Taluks in Mysore district, Karnataka, India. Int J Curr Eng Tech 2015; 5(2): 942-8.
[31] Wilcox LV. Classification and use of irrigation waters 1955; 28.
[32] Karunanidhi D, Vennila G, Suresh M, Subramanian SK. Evaluation of the groundwater quality feasibility zones for irrigational purposes through GIS in Omalur Taluk, Salem District, South India. Environ Sci Pollut Res Int 2013; 20(10): 7320-33.[http://dx.doi.org/10.1007/s11356-013-1746-2] [PMID: 23636597]
[33] Zouahri A, Dakak H, Douaik A, El Khadir M, Moussadek R. Evaluation of groundwater suitability for irrigation in the Skhirat region, Northwest of Morocco. Environ Monit Assess 2015; 187(1): 4184.[http://dx.doi.org/10.1007/s10661-014-4184-9] [PMID: 25467415]
[34] Ayers S, Westcot DW. Water quality for agriculture (FAO 29). Rome,1985; 174.
[35] Shainberg I, Oster JD. Quality of irrigation water 1978; 65.
[36] Jangir RP, Yadav BS. Management of saline irrigation water for enhancing crop productivity. J Sci Indus Res 2011; 70: 622-7.
[37] Phocaides A. Handbook on Pressurized Irrigation Techniques 2nd ed. 2nd ed.2007; 282.
[38] Minhas PS, Gupta RK. Quality of irrigation water: assessment and management 1992; 123.
[39] Singh A, Agrawal M. Effects of Waste water irrigation on physical and biochemical characteristics of soil and metal partitioning in Beta vulgaris L. Agric Res 2012; 1(4): 379-91.[http://dx.doi.org/10.1007/s40003-012-0044-4]
[40] Smirnov N. Table for estimating the goodness of fit of empirical distributions. Ann Math Stat 1948; 19(2): 279-81.[http://dx.doi.org/10.1214/aoms/1177730256]
[41] Myers BJ, Bond WJ, Benyon RG, et al. Sustainable effluent- irrigated plantations: an Australian guideline. An Australian Guideline CSIRO Forestry and Forest Products, Melbourne,1999; 286.
[42] Pirsaheb M, Sharafi K, Dogaohar K. Comparison of Mashhad Aolang wastewater treatment plant effluent with wells water quality for irrigation. J Water Wastewater 2013; 4: 116-21.
[43] Chiou RJ. Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation. Environ Monit Assess 2008; 142(1-3): 255-62.[http://dx.doi.org/10.1007/s10661-007-9922-9] [PMID: 17929185]
[44] Tripathy DP, Bhushan Dhar B. Environmental Pollution Research 2002.
[45] Chopra AK, Pathak C. Accumulation of heavy metals in the vegetables grown in wastewater irrigated areas of Dehradun, India with reference to human health risk. Environ Monit Assess 2015; 187(7): 445.[http://dx.doi.org/10.1007/s10661-015-4648-6] [PMID: 26092239]
[46] Huong NTL, Ohtsubo M, Li L, Higashi T, Kanayama M. Assessment of the water quality of two rivers in Hanoi City and its suitability for irrigation water. Paddy Water Environ 2008; 6: 257-62.[http://dx.doi.org/10.1007/s10333-008-0125-y]
[47] Choi J, Yoon CG, Rhee HP, Son Y, Cho M, Ryu J. National risk assessment of irrigation on farmland near wastewater treatment plants in Korea. Paddy Water Environ 2016; 14: 281-8.[http://dx.doi.org/10.1007/s10333-015-0498-7]
[48] Angelakis AN, Durham B, Marecos Do Monte MHF, Salgot M, Witgens T, Thoeye C, et al. Wastewater recycling and reuse in EUREAU countries: trends and challenges. Desalination 2008; 218: 3-12.[http://dx.doi.org/10.1016/j.desal.2006.07.015]
[49] Son YK, Yoon CG, Rhee HP, Lee SJ. A review on microbial and toxic risk analysis procedure for reclaimed wastewater irrigation on paddy rice field proposed for South Korea. Paddy Water Environ 2013; 11: 543-50.[http://dx.doi.org/10.1007/s10333-012-0347-x]
[50] Ramazani A, Jalali AH. Effect of nitrogen fertilizer and transplanting date on yield, yield components and stem lodging of rice in Isfahan region. J Crop Prod Process 2013; 3(9): 45-54.
[51] Alghobar MA, Suresha S. Effect of wastewater irrigation on growth and yield of rice crop and uptake and accumulation of nutrient and heavy metals in soil. Appl Ecol Environ Sci 2016; 4(3): 53-60.
[52] Asadi R, Alizadeh A, Ansari H, Kavoosi M, Amiri E. Effect of the amount of water and nitrogen on water productivity, yield, and yield components in two different rice cultivation methods. J Water Res Agr 2016; 30(2): 145-57.

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


Browse Contents



Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open