Under Scrutiny: Aquifer Pollution in Wastewater Irrigation Systems

News
Projects
  • 2018/06/20     Dresden, Germany

    On the field: Wastewater-fed paddy rice plantation in the peri-urban Hyderabad, India (Image: Mahesh Jampani/UNU-FLORES)

    By Mahesh Jampani, Systems and Flux Analysis Considering Global Change Assessment

    Around 20 million hectares of agricultural area globally are believed to be irrigated with wastewater. Many people around the world depend on wastewater for irrigation, as it has become a common livelihood practice – especially among poor urban and peri-urban dwellers. While this may be a reasonable solution for food security in times of depleting water resources, the questionable quality of wastewater poses health and environmental risks.

    At the Musi River in the peri-urban Hyderabad of South India, our research revealed that water used for irrigation consists of a mixture of untreated and secondary treated wastewater from Hyderabad city. In the peri-urban Hyderabad – where wastewater irrigation has been practised for the last 40 years – the current quality of (untreated) wastewater used for irrigation is expected to have adverse impacts on the local aquifers, which makes the local groundwater unsuitable for domestic, drinking, and irrigation purposes.

    This example is just one of many cases in the developing world. Especially in South Asia, the water used for irrigation is mostly withdrawn from rivers and lakes, which consists to a large extent of wastewater that has been either partially treated or remained untreated. Moreover, the lack of alternative or cost-effective water resources pushes farmers to depend on wastewater for irrigation completely.

    With the continuous irrigation, groundwater systems in these regions are perceived to have adverse impacts due to inadequate infrastructure to treat the wastewater.

     

    In the recent publication “Spatio-temporal Distribution and Chemical Characterization of Groundwater Quality of a Wastewater Irrigated System” published in the journal Science of The Total Environment (Elsevier), our research analysed the dynamics of groundwater quality and the impacts of seasonality of the wastewater irrigation on the peri-urban agricultural system. Particular to the case of Musi River, the areas irrigated by wastewater and groundwater coexist next to each other. In our research, in a bid to comprehensively analyse the situation, emphasis is placed on the detailed evaluation of the groundwater processes and spatio-temporal variability in the watershed system using various statistical techniques.

    The concentrations of the major ionic substances are found to increase after the monsoon season, especially in wastewater irrigated areas. The major polluted groundwaters come from the wastewater irrigated parts of the watershed, and groundwater pollution is highly impacted by the mineral interactions and long-term wastewater irrigation. This means the quality of groundwater in the local aquifers deteriorates year by year, with especially salinity values on the rise.

    To ensure that nutrient enrichment – which can be a risk for groundwater pollution – will not become problematic in the future, one needs to evaluate the optimum requirement of wastewater to irrigate crops, where farmers practise flood irrigation. Regular monitoring of water resources and the development of sustainable management strategies, for instance, can help mitigate aquifer pollution in wastewater irrigation systems.


    Further Reading

    Jampani, Mahesh, Stephan Huelsmann, Rudolf Liedl, Priyanie Amerasinghe, Sahebrao Sonkamble, Shakeel Ahmed. 2018. “Spatio-temporal Distribution and Chemical Characterization of Groundwater Quality of a Wastewater Irrigated System”. Science of the Total Environment (Elsevier) 636:1089–1098. (Available for free until 22 June 2018)

    Hettiarachchi, Hiroshan and Reza Ardakanian, eds. 2016. Environmental Resource Management and the Nexus Approach: Managing Water, Soil, and Waste in the Context of Global Change. First edition. Cham: Springer International Publishing.

    Sonkamble, Sahebrao, Md. Wajihuddin, Mahesh Jampani, S. Sarah, VK. Somvanshi, S. Ahmed, P. Amerasinghe, A. Boisson. 2018. “Natural treatment system models for wastewater management: A study from Hyderabad, India”. Water Science and Technology (IWA) 77(2):479–492.

    Wintgens, Thomas, Anders Nattorp, Elango Lakshmanan, Shyam R. Asolekar, eds. 2016. Natural Water Treatment Systems for Safe and Sustainable Water Supply in the Indian Context: Saph Pani. First edition. International Water Association (IWA) Publishing. ISBN: 9781780407104. (Open access book)

    Mahesh Jampani is a PhD Researcher in the Systems and Flux Analysis Considering Global Change Assessment Unit at UNU-FLORES. A hydrologist specialised in Groundwater and Environmental Modelling, his thesis is on the integrated evaluation of wastewater irrigation for sustainable agriculture and groundwater development. Read More >>