نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری گروه مهندسی آب، دانشکده کشاورزی و منابع طبیعی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین.
2 دانشیار گروه مهندسی آب، دانشگاه بین المللی امام خمینی، قزوین
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Despite its significant importance, the Karun River is under serious threat from pollution caused by urban and industrial wastewater. Given the river's critical role in supplying drinking water, supporting agriculture, and facilitating industrial activities, maintaining its water quality is of vital importance. This study investigates the impact of the Ahvaz comprehensive sewage plan on the water quality of the Karun River using qualitative modeling. In this research, the QUAL2Kw model was employed to simulate water quality changes along a 28-kilometer stretch of the river. After validating the model, various wastewater management scenarios were examined, including the current situation, the operation of the eastern treatment plant, the expansion of the western treatment plant, full implementation of the Ahvaz comprehensive sewage plan, and drainage control measures. The results showed that the full implementation of the Ahvaz comprehensive sewage plan significantly improves water quality by reducing pollutants such as BOD, ammonium, organic and inorganic phosphorus. For instance, BOD concentration decreased from 6.1 to 2.6 mg/L, organic nitrogen concentration from 425 to 234 µg/L, organic phosphorus concentration from 135 to 35 µg/L, inorganic phosphorus concentration from 251 to 0.23 µg/L, and dissolved oxygen concentration increased from 5.55 to 6.79 mg/L. Additionally, controlling agricultural drainage also had a positive effect by reducing nitrate concentrations, EC, and enhancing overall water quality. This study demonstrates that proper and comprehensive wastewater management, especially in densely populated urban areas, can significantly improve river water quality.
کلیدواژه‌ها [English]
EXTENDED ABSTRACT
The Karun River, located in southwestern Iran, is susceptible to pollution from urban and industrial wastewater. Given the vital role of the Karun River in providing drinking water, agricultural use, and industrial activities, its water quality is of critical importance. The aim of this research is to investigate the water quality of the Karun River and the impact of the comprehensive urban wastewater project in Ahvaz on its water quality parameters. This study focuses on assessing spatial variations in water quality trends under different scenarios of wastewater management, including current conditions, operation of the East wastewater treatment plant, completion of the West wastewater treatment plant capacity, full implementation of the comprehensive urban wastewater project in Ahvaz, and controlling drainage inputs.
In this study, the QUAL2Kw model, a one-dimensional computer model for simulating water quality in rivers, was employed to investigate the water quality of the Karoun River. Data on flow, depth, velocity, temperature, electrical conductivity (EC), dissolved oxygen (DO), BOD, organic nitrogen, ammonia nitrogen, nitrate, organic phosphorus, inorganic phosphorus, alkalinity, and pH were collected at four stations along the Karoun River. August 2018 data were used for model calibration and September 2018 data were used for model validation. The accuracy of the model was evaluated using the RMSE, MAPE, and PBIAS error indices. After confirming the validity and accuracy of the model in the calibration and validation stages, the developed model was used to investigate different scenarios in the Karoun River. Considering the construction of wastewater treatment plants and the possibility of eliminating wastewater inputs into the river, the water quality in the downstream reach of the river was examined under different wastewater input scenarios.
The results indicated that the QUAL2Kw model satisfactorily simulated both hydraulic parameters (depth, velocity, flow rate) and quality parameters (EC, DO, BOD, organic nitrogen, ammonia nitrogen, nitrate, alkalinity, pH). The water quality of the Karun River deteriorates for all parameters as it moves from upstream to downstream. The main factors affecting water quality are the discharge of urban and industrial wastewater, agricultural drainage, and agricultural activities. Additionally, the impact of the comprehensive wastewater plan for Ahvaz was examined under various scenarios, with results showing a significant improvement in river water quality upon full implementation of the plan.
Based on the findings of this study, the QUAL2Kw model is an efficient tool for simulating the water quality of the Karun River. The results indicate that the water quality of the Karun River is in a poor state, necessitating effective measures to control and reduce pollutants entering the river. Implementing the comprehensive wastewater plan for Ahvaz and controlling drainage systems could significantly reduce the concentrations of pollutants such as BOD, nitrate, nitrite, ammonium, phosphorus, and heavy metals in the Karun River. Consequently, the implementation of this plan would improve water quality and mitigate environmental threats. Therefore, it is recommended that the implementation of this plan be pursued seriously and that necessary actions be taken to enhance the water quality of the Karun River.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
Data available on request from the authors.
The authors gratefully acknowledge the financial support of the Iran National Science Foundation (INSF), Grant No. 4024661, and Imam Khomeini International University (IKU) for conducting this research.
The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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