Subsurface flow wetlands are one of the natural treatment methods used for municipal and industrial wastewater treatment that are economical in terms of energy consumption and cost-effectiveness. Much research has been conducted on wetland operation with continuous flow but not enough information is available on batch flow. This study investigates wetland efficiency in batch flow. For the purposes ofthis research, two pretreatment units of the anaerobic pond type with digestion pits and two subsurface flow wetlands with a 2-day detention time were built on the pilot scale. The cells were charged with sand of 5 mm effective size, uniformity coefficient of 1.5, and a porosity of 35%. One wetland cell and one pretreatment unit were used as control. The municipal wastewater selected to be monitored for the one-year study period had a flow rate of 26 m3/day and average BOD5 of 250mg/l, TSS of 320mg/l, TKN of 35mg/l, TP of 12mg/l and TC of 2x108 MPN/100ml from Sabzevar Wastewater Treatment Plant. The average removal efficiencies of BOD5,TSS,TKN,TP,and TC in the continuous flow for the combined control pretreatment and wetland cell were 77.2%, 92%, 91%, 89%, 96.5% while the same values for the batch flow for the combined experimental pretreatment and wetland cell were 92%, 97%, 97.5%, 97%, and 99.75%, respectively. The removal efficiency in the subsurface flow wetlands in the batch flow was higher than that of the continuous flow. Thus, for wastewaters with a high pollution level, the batch flow can be used in cell operation in cases where there is not enough land for spreading the wetland cell.

Antibiotics are potential pollutants that represent an important environmental problem because of their toxic effects on the food chain and aqueous streams. The goal of this study was determining the efficiency of a horizontal subsurface flow constructed wetland for a pharmaceutical pollutants antibiotic penicillin G. This study used constructed wetland pilot system for removal of penicillin G in artificial wastewater. in this study, the effects of initial concentration of wastewater, hydraulic retention time and reed on the pollutant removal efficiency were investigated. The data was analyzed using the central composite design which is the most commonly used response surface methodology design. 30 Samples of wastewater were taken from the output of constructed wetlands subsurface and tested in laboratory based on the standard reference method for experiments in water and wastewater. The results showed that reed, and retention time, has a direct relationship, and enhance them to increase efficiency. The initial concentration of wastewater is inversely related to removal efficiency. In the constructed wetland, the removal efficiency for 72 hours and different input concentrations was between 94. 17% and 73. 61%. Based on the study results, it can be stated that subsurface constructed wetland can remove the maximum concentration of hospital wastewater and even double this concentration with efficiency up to 90 percent, and it can be used as a proper treatment system for removal of penicillin G.

The type of rivers are dry or seasonal in arid or semiarid zone and current flowing through them is short or if there is no flow. One of the best methods to divert the flow in the river basin system is implementation with subsurface drainage network in the river bed A laboratory model for study the effects of hydraulic and geometric characteristics of the intake flow rate diversion was designed, Which the possibility measuring the inflow and outflow of diversion was considered.in this study were evaluated the effect of bed slope intake and diameter size of particle on diversion flow in two condition, water level constant and without control input discharge. The results showed that the slope of the porous medium tangible impact on current of deviation is in a state of constant water level. But the steep increase in input mode increases the deviation is negligible in Dubai. The 20% increase in diameter drains, in case the input of 9% and 20% in fixed alignment surface water drainage flow improves.The SPSS were using to obtain an equations that by them can estimate the diversion flow base of head flow hydraulic conductivity in porous media.

Introduction: Subsurface flow estimation (SUF) is important in many catchments with suitable vegetation and high soil permeability and plays an essential role in the production of direct runoff in the basin. The concept of SUF in soil is even more complex compared to surface flow, so the presentation of SUF prediction models of basins with simple and practical methods is important. Methods: In this study, SCS and Nash surface runoff precipitation models were used to estimate the subsurface flow of the catchment hillslopes. From the unit hydrograph equations of the two models, which are a function of the subsurface travel time and the amount of penetration, equations were presented to calculate the actual subsurface travel time of the hillslopes for the use of the models. Findings: For verification of the results, the laboratory rain model with the ability to measure the flow rate of surface and subsurface hillslopes was used. The average error of SCS model compared to the laboratory model in estimating surface runoff peak is 7. 8% and in estimating subsurface flow is 6. 7% and the average error of Nash model in estimating runoff peak is equal to 11. 21% and in estimating subsurface flow is 11. 32%. The effect of slope and hydraulic conductivity of hillslopes on SUF hydrograph was also evaluated by two models.

Landfill leachate usually contains high concentrations of pollutions that are seriously harmful to the environment and human health. The main purpose of this study was removing organic pollution, ammonia, nitrate and total nitrogen in Isfahan composting facility leachate by horizontal constructed wetland systems. A pilot-scale study was conducted on subsurface flow constructed wetland systems operated in horizontal mode (HFCWs). Two horizontal systems with different plants were constructed, one planted with Vetiver and the other one without plant as a control. They were operated identically at a flow rate of 27 L/day with a 5 day hydraulic retention time. The average removal efficiencies for control and experiment were BOD5, 9% and 30%; COD, 19 and 34%; TN, 37 and 50%; Ammonium, 8 and 26%; nitrate 33 and 40% respectively. Due to high concentration of pollutants (the mean leachate concentrations of COD, BOD5, TSS, NH4+ -N, NO3- -N, TN were 104514.9, 69200.0, 8478.3, 317.5, 4633.2 and 1500 mg/L, respectively) the subsurface flow constructed wetland systems with Vetiver plant is a suitable solution for leachate treatment.

Background: Natural methods of wastewater treatment, such as wetlands, are simple, cheap and acceptable for developing countries, especially small and remote cities. The aim of this study was to evaluate the efficiency of Typha Latifolica in subsurface flow constructed wetland for wastewater treatment in Yazd city, Iran.Methods: In this experimental research, the efficiency of Typha Latifolica in subsurface flow wetland for removing chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), nitrate-N (NO3-N), ammonia-N (NH3-N), orthophosphate (PO4-P), total coliform and fecal coliform was evaluated. Two reactors (without and with the plant) were made, as a pilot study, by subsurface flow constructed wetland with the dimensions of 2 × 1.5 × 0.6 m and with a retention time of 4 days. In two months, samples were taken from the incoming and outgoing flow of the reactors and were analyzed according to standard methods.Results: The efficiency of Typha Latifolica wetland for removing COD, BOD5, TSS, NO3-N, NH3-N, PO4-P, total coliform and fecal coliform was 72, 72, 85, 31, 25, 40, 94 and 59 percent, respectively, and 44, 34, 77, 15, 0.3, 1, 17 and 29 percent for the control wetland; all the differences were statistically significant, except for NH3-N and fecal coliform.Conclusion: According to the result of this study, Typha Latifolica has a high efficiency in removing organic material and suspended solids; and the treated wastewater by Typha Latifolica can achieve the national environmental standards for agriculture and irrigation use.

Constructed wetlands are natural systems that have the ability to purify the chemical, physical and biological and can remove variety pollutants from wastewater. The purpose of this study was investigation of the performance of horizontal subsurface flow constructed wetland for lead removal in wastewater treatment. This research was conducted in 2014 at Birjand University and evaluated efficiency of Carex for heavy metal removal. A total of, 12 rectangular concrete reactor in parallel was built at the desired location. The overall dimensions of 12 reactor is sized length 220, width 75 and height 50 cm. in 6 reactor of coarse gravel and was used in six other reactor of fine-grained sand that 4 ponds as control and other ponds were working with Carex plant. Horizontal flow pattern done through a split pipe and valve controls. The data from this study indicates that the maximum lead removal of reactor No. 8 was 51 percent and the minimum the removal of related to wetland No. 9 by 35 percent. The most remove done by increasing the hydraulic detention time. As a result, we can say that the removal efficiency when the lead initial concentration was Equal in all cells, detention time high, with plant cells and as well as fine bed material used, Removal rate is the highest value, It is obvious that such high efficiency without the high cost and adverse environmental effects is highly desirable.

In order to determine and analyze the head losses caused by the combined effect of entrance resistance and approach flow convergence to drains, some known models were studied. The field data of an existing Sub-surface drainage system were applied for evaluating the models and selecting the best one. The hodograph solution was employed to compute the water head, directly above the drain, while the Oosterbaan model was used to validate the hodograph results. Total head loss between two drains, was determined using Ernst equation. The results showed that increasing total head loss caused reduction of hydraulic head in approach flow region in a non-linear manner. Application of Youngs and Hoffman equations as well as EnDrain program based on energy and Darcy equations could simulate drain discharge to some extent. Hoffman equation gave some promising results among the others in term of R (0.928), RMSE (0.0007) and SI (1.09).