مدل شبیه سازی از انتقال نیتروژن در نی تالاب های ساخته شده

Nitrogen has been considered as one of important elements in domestic wastewater and resulted in frequent algal blooms over a wide range of water body. In this study, a dynamic system was constructed to simulate nitrogen transformation in reed constructed wetlands. The various nitrogen forms in the system were considered as the parameters. The effects of mineralization, nitrification, denitrification, plant uptake and plant decay were investigated. The overall performance of the model was validated with different data sets of parameters from the case study spanning 3 years. The results indicated a good fit between the simulated and observed data. It appears that the model can give a reliable prediction for nitrogen removal performance in reed constructed wetland.

Untreated or insufficiently treated wastewaters containing high concentrations of nitrogen effluents into receiving rivers are undesirable, for enrichment of nitrogen is one of the worst polluting agents for aquatic life resulting in serious eutrophication of lakes and rivers [1]. For developing countries, some conventional treatment techniques of wastewater have several disadvantages, such as expensive cost, continuous addition of toxic chemicals, extensive space and side effects of secondary pollution. In the 21th century, the new technologies have focused on natudoiral systems, especially constructed wetlands (CWs). The CWs are engineered systems by applying various technological designs to treat domestic wastewater, using natural wetland processes, associated with wetland hydrology, soils, microbes and macrophytes. Due to low cost of construction and operation, CWs have generally been regarded as an effective method of removing nitrogen from domestic wastewater, especially sub-surface flow CWs, which have gained increased attention for on-site treatment of domestic wastewater

In this paper we consider a mass balance model where only non-negative equilibrium points are meaningful. So we only pay attention to the nonnegative fixed points of system. Validation of the model for prediction of total nutrient removal rate in CWs requires data from the same systems that have been in operation for an extended period. In this paper, the best values of unknown coefficients were found by calibration according to the data collected from a different time period. For the verification data set, the calibrated model predicted effluent total N concentrations well in both cells.