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Assessment of the impacts of sewerage network on groundwater quantity and nitrate contamination: case study of tehran

Khorasani, H ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. Publisher: American Society of Civil Engineers (ASCE) , 2020
  3. Abstract:
  4. Many communities in arid and semi-Arid areas rely on groundwater for drinking water. However, anthropogenic activities such as the use of fertilizers and human waste disposal impose the risk of nitrate pollution to the aquifers. With over 8.5 million population, Tehran, the capital of Iran, has experienced rapid population growth during the past decades while the majority of the city did not have a sewerage network and the main way of wastewater disposal was individual cesspits inside houses. The long-Term discharge of raw wastewater in cesspits has increased nitrate concentration in the Tehran aquifer which serves as a source of one-Third of drinking water for the city. Although the construction of a sewerage network seems vital for improving the groundwater quality, one of the main concerns of this network is the drawdown of the water table in aquifer due to reduced recharge. A dynamic mass-balance model is developed for simulating water quantity and nitrate concentration in Tehran aquifer in order to study the impacts of sewerage network on the quantity and quality of groundwater. Considering that the sewage disposal in cesspits is one of the main sources of recharge, the results show the construction of sewerage network does not necessarily result in a reduction of nitrate concentration in long-Term. This seems to be mainly because the reduced aquifer recharge results in groundwater depletion and the depleted aquifer is more prone to pollution even with smaller amounts of pollutants. Based on this modeling approach, we suggest that the reduced recharge due to construction of sewerage network should be compensated by either reduction of groundwater withdrawal or managed artificial recharge. The results of this study can provide a step toward application of sustainable water resources management in arid and semi-Arid areas where the cesspits and septic tanks are common for wastewater disposal. © 2020 American Society of Civil Engineers
  5. Keywords:
  6. Groundwater ; Mass Balance Modeling ; Nitrate ; Sewerage Network ; Tehran ; Aquifers ; Arid regions ; Climate change ; Groundwater resources ; Hydrogeology ; Nitrates ; Population statistics ; Potable water ; Recharging (underground waters) ; Sewage ; Sewers ; Sustainable development ; Wastewater disposal ; Water conservation ; Water levels ; Water quality ; Anthropogenic activity ; Arid and semi-arid areas ; Groundwater depletion ; Groundwater withdrawal ; Managed artificial recharges ; Nitrate concentration ; Rapid population growth ; Sustainable water resources ; Groundwater pollution
  7. Source: World Environmental and Water Resources Congress 2020: Groundwater, Sustainability, Hydro-Climate/Climate Change, and Environmental Engineering, 17 May 2020 through 21 May 2020 ; 2020 , Pages 53-66
  8. URL: https://ascelibrary.org/doi/abs/10.1061/9780784482964.006