Constructed wetland for improved wastewater management and increased water use efficiency in resource scarce SAT villages: a case study from Kothapally village, in India

Abstract

Evaluation a field-scale of constructed wetland (CW) for the treatment of rural wastewater (WW), in resource-scarce semi-arid tropic (SAT) villages, to provide improved wastewater management and increased water use efficiency, was the main objective of this study. A CW was commissioned in Kothapally village of Telangana to treat the wastewater generated from 100 households. The CW was vegetated with Typha latifolia and Canna indica. Average COD, sulfate and inorganic nitrogen removal efficiencies observed were 65%, 60% and 67% respectively, for the study period (one year). Removal efficiency for total coliform was consistently above 80%. The treated wastewater was stored in a farm pond and was utilized for irrigation in the nearby agricultural fields (0.6 ha). This perennial source of water, helped the nearby farmers to cultivate two additional crops, chickpea during rabi and sweetcorn during summer. The assured availability of water reduced their vulnerability to dry spells during the kharif by providing means for lifesaving irrigation. The biomass harvested from the constructed wetland was used as fodder for the livestock. A net additional income of Rs.70,000 (∼US$1,000) was realized by the farmers using the treated wastewater for cultivation. Similar constructed wetland-based wastewater management system can be scaled up across water scarce semi-arid tropics.

Novelty statement

Field-scale performance evaluation of constructed wetland based wastewater treatment in a semi-arid tropic village is scarce in the literature. The work presented gives a feasibility assessment for this technology critical for its wide-scale application to augment rural wastewater management in resource poor villages.

Keywords:

• Constructed wetland
• decentralized wastewater treatment
• phytoremediation
• subsurface flow

Acknowledgments

We acknowledge the Department of Bio-Technology, Government of India for the resources provided through a mirror project between EU and – Water4Crops ‘Integrating bio-treated wastewater reuse and valorization with enhanced water use efficiency to support the Green Economy in Europe and India’. The authors acknowledge the contribution of Mrs. Chetana Nimje and Dr. AVR Kesava Rao for the plant tissue analysis and for providing the Kothapally weather data, respectively. The authors are thankful to the farmer Mr. P. Narasimha Reddy for providing access to his agricultural field as well as co-operation in gathering data for the study.