Showing 25 results for Wastewater
A. Erfani, G.h. Haghnia, A. Alizadeh,
Volume 6, Issue 1 (4-2002)
Abstract
A field study was conducted at the College of Agriculture, Ferdowsi University of Mashhad, to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of lettuce and some soil characteristics. Five irrigation treatments were applied to a clay loam soil, classified as fine loamy mixed mesic Calcixerollic Xerochrepts, in a randomized block design with 5 replications. The treatments consisted of T1 (Irrigation with treated wastewater over all growing season), T2 (Alternate irrigation with treated wastewater and well water), T3 (Irrigation with well water and application of cattle manure), T4 (Irrigation with well water plus fertilizer N and P), and T5 (Irrigation with well water only as control). Chemical analysis of well water proved to be a suitable source for agriculture.
The results showed that the yield was higher in T1, T2, T3 and T4 as compared to the control treatment. Maximum fresh and dry yields were obtained from T3 & T1 and T1 & T3, respectively. Plant tissue analysis showed an increase in macronutrients (N, P, K) and heavy metal concentrations in shoots and roots of lettuce in the first four treatments as compared to the control. In T1, iron concentration was maximum while that of cadmium was minimum. Furthermore, microbial contamination was considerably higher in T1 and T2. Soil analysis indicated that in plots treated with wastewater, electrical conductivity, total nitrogen, available phosphorus, soluble boron and heavy metal concentration increased. However, their values were all below international standards. More experiments seem to be necessary in this regard.
J. Abedi Koupai, A. Bakhtiarifar,
Volume 8, Issue 3 (10-2004)
Abstract
Water crisis is an important issue in arid and semi-arid regions like Iran. The situation has been getting more worse over recent years drought. Hence, there is a growing need to utilize low quality water where freshwater is scarce. In this regard, urban wastewater is a promising source but there are concerns about the environmental and health aspects of using such water. The main problem regarding the performance of trickle irrigation system utilizing wastewater effluents is clogging of the emitters. In this study, field trials at pilot scale were carried out to investigate the hydraulic properties of emitters using two types of water including treated wastewater and groundwater. The trickle irrigation system consisted of three 16 mm lateral tubes placed at 300 mm spacing in the main tube and each lateral tube had 16 emitters at 300-mm spacing. The designed discharge of the emitters was 4 L/h. The hydraulic properties of the different commercial emitters (micro flapper, long path, turbo plus and Eurokey) were assessed at different time periods.
The results indicated that the Eurokey and long path emitters had the maximum and minimum emission uniformity, respectively, when applying wastewater. using groundwater, the Eurokey and turbo plus emitters had the maximum and minimum emission uniformity, respectively, during the initial phase of the study. However, the Eurokey and long path emitters had the maximum and minimum uniformity values, respectively, at the end of the study. The turbo plus emitters are regulated and, as a result, showed no evidence of sensitivity to pressure variations hence, they can be used on uneven lands and where the trickle irrigation system has long lateral tubes.
A. Hassanoghli, A. Liaghat, M. Mirabzadeh,
Volume 10, Issue 4 (1-2007)
Abstract
Increased chemical compounds in soil are the most important results of irrigation with domestic wastewater and treated effluents which contain some nutrients such as phosphorous (P). This process could increase the soil fertility, leading to the decrease of chemical nutrient consumption and consequently the cost of agricultural production. A research project was carried out in Tehran region for two years in order to investigate the capabilities of soil and plant in absorption and storage of wastewater contaminants, namely, phosphorous, and also the transmission of them to drain depth as a result of irrigation practice. To do the research, a series of lysimeters based on a statistical factorial experiment in the form of randomized complete design (3x3x3) were used. Raw and treated domestic wastewater, obtained from Ekbatan Housing Complex, and well water (control) were used to irrigate raw edible vegetables including parsley, carrot and tomato. The results showed that the amount of phosphorous leaching through soil to drain depth was between 0.90% and 3.56%, and between 1.03% and 4.15% of the phosphorous concentration in raw wastewater and treated one entered into the soil, respectively. Also, mass balance analyses showed the average phosphorous reduction ranged from 97.2% to 99.9% of the phosphorous entered with wastewater. During two years of study, the maximum concentration of PO4 measured in drained water was about 0.21 mg/L obtained from lysimeters irrigated with raw wastewater. This was much lower than the permissible PO4 amount for discharging the effluents to the surface water resources (6 mg/L PO4 is permitted by Iranian Environmental Protection Organization).
A. Ghanbari, J. Abedi Koupai, J. Taie Semiromi,
Volume 10, Issue 4 (1-2007)
Abstract
A field study was conducted at the Zabol Agricultural Research Center during the years (2003-2004) to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of wheat and some soil properties. Irrigation treatments were: T1: Irrigation of wheat with well water during entire period of growing season T2: Irrigation of wheat with well water until the begging of flowering stage, and irrigation with wastewater in every other turns of irrigation T3: Irrigation of wheat with well water until the beginning of booting stage, and irrigation with wastewater in every other turns of irrigation T4: Irrigation of wheat with well water until the begging of tilling stage, and irrigation with wastewater in every other turns of irrigation and T5: Irrigation of wheat with wastewater during entire period of growing season. A complete randomized block design with four replications was adopted for this experiment. The soil was sandy loam with no limitation for internal drainage. Chemical and physical aspects of soil were measured during the experiment. Grain yield, yield components and chemical composition of wheat grain were also measured. The results showed that yield of wheat and total biomass production were statistically significant in T3, T4 and T5 compared with the control treatment. Plant height, width and length of flag leaf, numbers of fertile tillers, length of panicle, numbers of grains per panicle and weight of 1000 grains were also statistically significant with the control treatment. Percentages of protein were statistically different among various irrigation treatments. No significant changes in accumulation of heavy metals in soil and plant grains were observed. The increase of SAR, ECe, O.C% and total nitrogen in the T4 and T5 were statistical significant compared with the control treatment. In summary, for sustainable use of Zabol municipal wastewater, the growth stages of wheat should be irrigated with municipal wastewater and other growth stages should be irrigated with nonsalinty water, so that the maximum yield is obtained and soil salinitisation and sodication is prevented.
A Jalali, M Galavi, A Ghanbari, M Ramroudi, M Yousef Elahi,
Volume 14, Issue 52 (7-2010)
Abstract
Using treated wastewater led to increasing crop yield, but it may causes heavy metals accumulations and also their toxicity in soil and plant. In order to investigate the effects of wastewater on yield, forage yield components, and heavy metals concentrations in stem and leaf of sorghum, an experiment was conducted in the agricultural Research Institute of Zabol University in 2006-2007, using a randomized complete block design with four replication. The irrigation treatments were: 1) well water for whole growing season as control (T1), 2) well water for all growing season along with NPK application (T2), 3) wastewater during the first half of growing season (T3), 4) wastewater during the second half of growing season (T4), 5) wastewater and tapwater alternately (T5) and 6) wastewater for whole growing season (T6). The results showed that irrigations with wastewater and well water alternately and wastewater for whole growing season produced the maximum forage yield and the maximum heavy metal accumulation in plant organs observed by irrigation with wastewater for hole growing season, and wastewater and well water alternately. There was significant increase between T5 and T6 relative to control and other treatments. The elements concentration such as Cu, Pb and Fe in leaf was more than stem, but Zn and Ni concentration in stem were more than leaves. There were no significant differences for Mo and Cr concentration between stem and leaf. Forage yield in T6 and T5 relative to T2 were increased 38.96 and 51.95 percent respectively. In all irrigation treatments the amount of elements and heavy metals in sorghum were lower than standard limits. Based on the results, alternative irrigation method (T5) is recommended for forage sorghum production.
H. Alinezhad Jahromi, A. Mohammadkhani, M. H. Salehi,
Volume 16, Issue 60 (7-2012)
Abstract
Nowadays, due to drought and water shortage, use of unconventional waters, particularly sewage, has become usual in agriculture whereas they often contain heavy metals. The present study was employed to evaluate the effect of urban wastewater of Shahrekord on growth, yield and accumulation of heavy metals (lead and cadmium) in balm (Melissa officinalis) as a medicinal plant with five treatments (0, 25, 50, 75 and 100 percent wastewater) and three replications in a completely randomized experimental design. The results showed that the highest shoot length, stem diameter and stem number, number of leaves and tillers are achieved in the treatment of 100 percent. The wet and dry weight of shoots and roots was highest in 100 % of wastewater. Oil percentage of the leaves was also the highest amount (1.23 %) in 100 % of wastewater. Accumulation of lead in roots and aerial parts and its transmission factor was not significant for the treatments. However, the highest concentration of lead in root (0.057 mg/kg) and shoots (0.013 mg/kg) was observed in 100 % of wastewater and the lowest one was related to zero percent of wastewater treatment. The lead concentration was less than the critical limit for all the treatments. The amount of cadmium was undetectable in all the plant samples. The results of this study demonstrated that urban wastewater of Shahrekord, in addition to providing water, increases plant growth and essential oil.
S. Marofi, N. Parsafar, Gh. Rahimi, F. Dashti,
Volume 16, Issue 61 (10-2012)
Abstract
In this study, a completely randomized experiment was designed with four irrigation treatments and three replicates. The irrigation programs were raw wastewater, treated wastewater, a combination of 50% raw wastewater and 50% potable water and a combination of 50% treated wastewater and 50% potable water. The experiments were run within a greenhouse. The lysimeters were built up on September 2009 and they were filled with two layers of soil. The upper (0-30 cm in depth) and lower (30-70 cm in depth) layers were sandy loam and sandy clay loam, respectively. A total of eight watering programs with an interval of elevens-day were applied. After each irrigation program, intake wastewater and drainage water of each Lysimeter was sampled in order to analyse the transport of heavy metals (Cu, Zn, Fe and Mn, Ni, Cd and Pb). Results showed that the effect of water quality was significant on percentage of transport of heavy metals. The lowest transport percentage of heavy metals belonged to raw wastewater treatment. Also, the highest percentage of transport of Cu, Zn, Fe, Ni and Pb belonged to the combination of 50% raw wastewater and 50% potable water. In most cases, we observed that the transport percentage of these elements increased by continuing the irrigation
S. A. Ghasemi , Sh. Danesh,
Volume 16, Issue 61 (10-2012)
Abstract
In this research, the quality of the effluent from the City of Mashhad wastewater treatment plants was evaluated based on Ayers and Westcot irrigation water quality guideline, and the potential impacts of these effluents on soil and plants were assessed. For this purpose, the effluent from each of the three existing wastewater treatment plants was sampled on a regular basis, for a period of one year, and their parameters of importance in regard to the agricultural use such as pH, electrical conductivity (EC), concentrations of Sodium, Calcium, Magnesium, Chloride, Boron, Nitrate (NO3-N), bicarbonate and heavy metals were measured. Based on the obtained results, the agricultural use of the effluents from the wastewater treatment plants has severe restriction in regard to the bicarbonate concentrations (8-12.1 meq/L). Also, in view points of parameters such as EC (1250-1874 µS/cm), Sodium (5.8-8.7 as SAR), Chloride (3.2-6.5 meq/L) and adj RNa (7.8-11.7), the effluents were categorized in the class of waters with low to moderate restrictions. However, the measured values of pH (7.3-8), Boron (0.2-0.8 mg/L), Nitrate Nitrogen (0.5-4.2 mg/L) and heavy metals did not indicate any restrictions for agricultural use. From the results of this research, it can be concluded that the use of effluent as irrigation water requires careful planning, monitoring and management strategies.
J. Abedi Koupai, S. S. Eslamian, M. Khaleghi,
Volume 16, Issue 62 (3-2013)
Abstract
Crisis of quality and quantity of water resources is one of the most important problems in arid and semi-arid areas such as Iran. Wastewater treatment and reuse as a potential source of water can not only compensate for the water scarcity but also can prevent the hazardous pollutants from entering the groundwater and surface water resources. There are various methods to improve water quality, among which method of filtration is an effective and efficient method to remove elements. The most important issue for filter system is the selection of adsorbent materials. In this work, the tire chips were used as adsorbent. Column adsorption tests in a pilot system were conducted in two distinct steps using two types of water, including salt water and industrial effluents. Each test was conducted as a factorial experiment with three factors based on a completely randomized design with three replications. Three factors were studied including particle size (2-5 mm and 3-5 cm), filter thickness (10, 30 and 50 cm) and sorbent contact time with solution. The results showed that adsorption rate increased by increasing the thickness of the filter and sorbent contact time with solution. The best performance of reducing the salinity was observed in the treatment with 50 centimeter thickness and 24 contact hours. The salinity of this treatment was reduced by 20.3 percent (in the test with salt water) and 11.2 percent (in the test with industrial effluents). This filter reduced the heavy metals of lead, zinc and manganese up to 99, 72.1 and 41.4 percent, respectively. Also, the performance of millimeter and centimeter particles did not show a significant difference. Generally, the tire chips showed a proper performance to improve the water quality especially for industrial wastewater.
N. Parsafar, S. Marofi ,
Volume 17, Issue 66 (2-2014)
Abstract
In this study, a completely randomized experiment was designed with five irrigation treatments and three replicates. The irrigation programs were raw wastewater (T1), treated wastewater (T2), a combination of 50% raw wastewater and 50% fresh water (T3), a combination of 50% treated wastewater and 50% fresh water (T4), and fresh water (T5). The experiments were run within a greenhouse. The lysimeters were built up in September 2009 and they were filled with a two layer soil. The upper (30 cm) and lower (40 cm) layers were sandy loam and sandy clay loam, respectively. The results showed that the effects of watering treatments on transfer coefficients of heavy metals from soil to shoots (except Cd) and tubers of potato (except Zn and Cu) were significant (p <0.01). Maximum and minimum transfer coefficients of heavy metals were observed in the (T1) and (T5) treatments, respectively. Also, the transfer coefficients of Cd from soil to shoots were lower than tubers. In the case of Zn, Cu and Pb, transfer coefficients from soil to tubers were lower than shoots. In this study, the maximum transfer coefficients to shoots were Cd (0.331-0.463), Zn (0.383-0.230), Cu (0.173-0.386) and Pb (0.003-0.057), respectively. Maximum transfer coefficients toward tubers (except T5) were Cd (0.439-0.572), Cu (0.081-0.138), Zn (0.170-0.217) and Pb (0-0.017), respectively. The combination of wastewater and fresh water use in short-term irrigation might be feasible, but a heavy metal monitoring program is necessary.
A. Parnian, M. Chorom, N. Jafarzadeh Haghighi Fard, M. Dinarvand,
Volume 18, Issue 70 (3-2015)
Abstract
Cadmium is a trace element which is harmful to life and is considered as a dangerous pollutant. This element leads to pollution and reduction of water quality and sometimes even to toxicity through contaminated sources such as wastewater (municipal and industrial). Due to the growing population's need for more water resources and increased water resource pollution, a need for new and inexpensive methods for remediation and improving water quality is felt. Phytoremediation with aquatic macrophytes is an effective and inexpensive method for improving water quality and wastewater. In this study, biological removal of cadmium from simulated wastewater was reviewed within 11 days of cultivation of Lemna gibba in Hoagland nutrient solution, at four different concentrations of cadmium (0, 1, 2, 4, and 6 mg L-1). Maximum Bioconcentration Factor and maximum Uptake Index were calculated from 6 mg L-1 metal concentration. Maximum (4.71 g/day) and minimum (2 g/day) Biomass production measurement was obtained from 0 mg L-1 and 6 mg L-1 of pollutant concentration. The plant used in this study was able to accumulated cadmium with the efficiency of up to 91%. However, the pollutant remediation was not completed in a short time. Thus, pollutants' bioremediation from wastewater solutions by Lemna gibba, a native hydrophyte of southern Iran’s pounds, is efficient and appropriate.
S. M. Mousavi, S. M. Mirlatifi, S. H. Tabatabaei,
Volume 19, Issue 71 (6-2015)
Abstract
The effects of water quality, installation depth and space of subsurface drip irrigation (SDI) laterals on yield and visual quality of turfgrass were investigated. A field experiment was conducted at the experimental farm of Shahrekord University. The experimental design was a Split-Split Plot with experimental arrangement of completely randomized block design with 16 treatments and three replications. Treatments included two types of water quality: well water (W) and treated wastewater (WW), two installation spaces of SDI laterals (45 and 60 cm) and four depths of placement of SDI laterals (15, 20, 25 and 30 cm). Turfgrass indices recorded during the experiment included height, dry mass, color, visual density and growth uniformity. The ANOVA results showed that interaction of irrigation water quality × lateral spacing × installation depth of SDI laterals is significant on the height, dry mass and growth uniformity of turfgrass. Irrigation with wastewater as compared to well water produced grass with significantly higher height and more dry weight. Treatments irrigated with well water had a better growth uniformity than those treatments irrigated with wastewater. Results indicated that there was no significant effect of experimental factors on turfgrass color. The interactional effect of lateral spacing and installation depth on the turfgrass density was significant. Increasing installation depth and laterals spacing caused a decrease in turf’s yield and visual quality.
N. Jafarzadeh Haghighi Fard, M. Abbasi, R. Alivar Babadi, H. Bahrani, A. Mirzaie, M. Ravanbakhsh,
Volume 19, Issue 71 (6-2015)
Abstract
As there are some health and environmental concerns about wastewater, dewatered sludge, increase in green waste, and restricted legislation about burning them outdoors, environmental health engineers are investigating to find a simple, cost effective and efficient method. This is aimed to have healthy, safe and sustainable disposal of such materials. Co-composting of sludge and green waste is a newly developed process which can help us to achieve this goal. This study was to investigate the most suitable ratio of dewatered sludge to green waste from Chonibieh wastewater treatment plant in Ahvaz, Iran, and assess the feasibility of co-composting of this waste. So, dewatered sludge was composted with green waste as a bulking agent in three different ratios (1:1 ,2:1 ,3:1 : green waste: dewatered sludge W:W). Then composting proceeded in pilot vessels (M1, M2, M3) for 23 days. The C/N ratio, the percentage of total nitrogen, phosphorus, total organic carbon, humidity and pH were tested in certain periods and compared with the national standards. This study showed that in M1, M2, M3 pilots, all parameters (except for total phosphorus) including C/N ratio, percentage of total nitrogen and total organic carbon, humidity, pH could meet class 1 national standard in Iran. Moreover, this compost product could meet the EPA microbial standards, class A. So, the product of this compost process is completely stabilized and could be used in agricultural lands.
E. Ahmadpoor Dehkordi, M. R. Tadayon, A. Tadayon,
Volume 19, Issue 73 (11-2015)
Abstract
In order to evaluate the effect of urban wastewater and different fertilizer sources on macro and micro nutrients' concentration and shoot dry weight of sugar beet, a field experiment was arranged as a split plot in RCBD design with three replications at Research Station of Shahrekord University in 2013. The main factors included irrigation with urban wastewater at 2-4 leaf stage and 8-12 leaf stage, and irrigation with normal water (control). The four types of fertilizer included sheep manure, spent mushroom compost, chemical fertilizer and no fertilizer (control) in the sub-plot. The results showed that the plot irrigated with urban wastewater at 8-12 leaf stage significantly increased leaf number and shoot dry weight of sugar beet compared to the plot irrigated with tap water. Besides, the plot irrigated with urban wastewater at 8-12 leaf stage had a significant effect on the elements of N, P and K concentration in shoot dry weight of sugar beet, but the plot irrigated with urban wastewater did not significantly affect the elements of Fe and Zn concentration. From among the fertilizer treatments, the maximum shoot dry weight and leaf number per plant belonged to the application of sheep manure and also the highest elements of Fe and Zn concentrations belonged to the treatment of spent mushroom compost.
V. Moradinasab, M. Shirvani, M. Shamsaee, M. R. Babaee,
Volume 19, Issue 74 (1-2016)
Abstract
Mobarakeh Steel Complex has been using treated industrial wastewater for irrigation of green space to combat water shortage and prevent environmental pollution. This study was performed to assess the impact of short-, middle-, and long-term wastewater irrigation on soil quality attributes in green space of this complex. Soils were sampled from the wet bulb produced by under-tree trickles in three depths of forested lands irrigated with treated wastewater (for 2, 6 and 18 years) or groundwater. Several chemical, physical and biological characteristics of the soil samples were determined in the laboratory and compared to those of the native unirrigated soils as the controls. The results showed that pH was significantly reduced in the wastewater-irrigated soils as compared to the control. Organic matter content and cation exchange capacity significantly increased in the irrigated soils due to the incorporation of tree leaves into soil. Soil salinity also increased as the irrigation period increased because of the relatively high salinity of water and wastewater used for irrigation. Microbial basal respiration and arginine ammonification were greater in the irrigated soils in comparison to the control. In general, forestation and irrigation management have improved most of the soil quality indexes in the Mobarakeh Steel Complex green space, but some soil characteristics, such as salinity, need to be monitored and improved in future.
R. Mollaei, J. Abedi Koupai, S. S. Eslamian,
Volume 20, Issue 75 (5-2016)
Abstract
Water scarcity forced farmers to use wastewater as water source, without considering its effects on environment and resultant contamination of soils and plants especially with heavy metals. The objectives of this study are to evaluate the application effects of zeolite as soil amendments on the uptake of Cd by spinach (Spinach Oleares L.) irrigated with wastewater (containing 10 ppm Cd). Different levels amounts of zeoilte (0, 1% and 5% w/w) were added to the soil and the experiment was conducted as a completely randomized design in a green house with 3 replications. The results indicated that, the addition of zeolite 1% (w/w) in soil treated with wastewater reduced cadmium concentration in plant, and consequently the percentage of extractable Cd using DTPA was decreased. However, application of zeolite 5% (w/w) increased the soil salinity, and as a result increased Cd concentration in the plant but this increase was not statistically significant, comparing with control. Spinach biomass did not differ significantly under irrigation with wastewater, but the Cd available in wastewater caused a decrease in Spinach biomass yield.
A. Haghshenas-Adarmanabadi, M. Heidarpour, S. Tarkesh-Esfahani,
Volume 20, Issue 77 (11-2016)
Abstract
In this paper, the efficiency of four hybrid horizontal-vertical subsurface constructed wetlands which have been built for the tertiary treatment of Isfahan North Wastewater Treatment Facility and removal of organic matters was evaluated. In these constructed wetlands three plants including Phragmites australis, Typha latifolia and Arundo donax were planted and one unit left unplanted. The results of 12 months of sampling showed that the type of vegetation has no significant influence on the organic matter removal in the subsurface constructed wetlands, although the removal efficiencies in the planted constructed wetlands were more than unplanted control one. The COD and BOD5 removal efficiency in the constructed wetlands changes between 77% to 83% and 84% to 86%, respectively, during the operation period. The results of this research also showed that the organic matter removal was dependent on the influent organics nature and biodegradability. The first order model constants were calibrated in different wetlands for designing main projects. The organic concentration in the wetland effluents met the Iranian regulation limits for different reuse applications that shows the constructed wetland is a suitable technology for wastewater treatment in Iran.
Y. Choopan, A. Khashei Siuki, A. Shahidi,
Volume 21, Issue 4 (2-2018)
Abstract
Limited water resource in arid and semi-arid areas is one of the most important problems in the agricultural sector. Therefore, the use of non-conventional water resources becomes more important. For this reason, a study was conducted on barley to evaluate the effect of irrigation with sugar plant wastewater as a factorial randomized complete block design field experiment. Treatments include water well I1, wastewater I2, combined water and wastewater I3 (the ratio of seven to one, according to local practice) in two levels of without water stress S1 and %75 water stress S2 and treatment I1S1 was considered as control. The results showed changes in surface tension of %1 had a statistically significant effect on plant height, grain yield and root length. As well changes of irrigation water in the level of %1 had a statistically significant effect on plant height, grain protein yield and root length. Maximum grain yield was obtained in treatment I1S1 with the weight of 4034 kg per hectare and lowest grain yield was obtained in treatment I2S2 with the weight of 1564 kg per hectare. The lowest and highest percentages of protein content were observed in treatment I1S1 for 12.37% and treatment I2S2 for 13.47%, respectively. The plant height showed the highest amount in control treatment, i.e. 82.87 Cm.
R. Soltani, M. R. Mosaddeghi, M. Ayuni, Sh. Ayoubi, M. Shirvani,
Volume 23, Issue 1 (6-2019)
Abstract
Long-term use of treated wastewaters for irrigation adds compounds and/or ions to soils which might alter the soil physical, hydraulic and mechanical properties. Soil mechanical properties are closely linked with the plant growth. This study was conducted to investigate the effect of short-, mid- and long-term applications of the treated wastewater of Mobarake Steel Company in Isfahan on the soil penetration resistance and shear strength in the company green space. Soil penetration resistance and shear strength were measured using a pocket penetrometer and in situ shear box, respectively. The results showed that soil penetration resistance (i.e. soil hardness) at both dry and wet conditions significantly was increased upon short-, mid- and long-term applications of wastewater; 19 years of the application of wastewater resulted in the highest soil penetration resistance at wet condition, but the well water did not significantly affect it. Surface crust in the non-irrigated locations increased the soil penetration resistance, but the irrigated sealed soils were not significantly different from the virgin soil in terms of dry and wet penetration resistances. For the soil shear strength parameters, wastewater, well water and surface crust did not significantly affect soil cohesion (c), they but significantly affected the angle of internal friction (φ). Overall, soil shear strength parameters were not greatly affected by the irrigation water treatments because of the dominant effect of the soil fractions (texture and gravel content) and the microstructure.
A. Sheykhan, M. Shayannejad, V. Arab-Nasrabadi,
Volume 23, Issue 2 (9-2019)
Abstract
Today, the use of refined urban wastewater for agriculture is growing considerably. One of the methods for the natural treatment of wastewater is the constructed wetland. In this study, the effects of three and six days retention time on the vertical, horizontal and hybrid constructed wetland (first vertical and then horizontal) with perlite beds and Cyperus plants on the urban wastewater were investigated. In this study, horizontal wetlands were designed with 0.75 m width, 0.5 m depth and 6 m length; the vertical wetlands were designed as cylinders with a diameter of 0.7 m and the height of 1.2 m. On average, for the three days retention time, in the wetland with the vertical flow, 5the horizontal flow and the hybrid wetland, nitrate was 31.0, 36.7 and 56.3 percent, ammonium was 7.6, 32.7 and 37.8 percent, and the fecal coliform was decreased by 53.3, 93.4 and 96.9 percent, respectively. Also, during the six days retention time in the wetland with the vertical flow, the horizontal flow and the hybrid wetland, nitrate was 45.7, 58.5 and 77.5 percent, ammonium was 16.8, 75.2 and 79.4 percent, and fecal coliform was decreased by 58.0, 97.5 and 99.0 percent, respectively. Overall, the results showed that constructed wetland with perlite beds and Cyperus plants had a good function in removing pollutants, especially fecal coliform.
