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Verma K, Manisha M, Santrupt RM, Anirudha TP, Goswami S, Sekhar M, Ramesh N, M S MK, Chanakya HN, Rao L. Assessing groundwater recharge rates, water quality changes, and agricultural impacts of large-scale water recycling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162869. [PMID: 36933723 DOI: 10.1016/j.scitotenv.2023.162869] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/05/2023] [Accepted: 03/10/2023] [Indexed: 05/06/2023]
Abstract
The over-exploitation and insufficient replenishment of groundwater (GW) have resulted in a pressing need to conserve freshwater and reuse of treated wastewater. To address this issue, the Government of Karnataka launched a large-scale recycling (440 million liters/day) scheme to indirectly recharge GW using secondary treated municipal wastewater (STW) in drought-prone areas of Kolar district in southern India. This recycling employs soil aquifer treatment (SAT) technology, which involves filling surface run-off tanks with STW that intentionally infiltrate and recharge aquifers. This study quantifies the impact of STW recycling on GW recharge rates, levels, and quality in the crystalline aquifers of peninsular India. The study area is characterized by hard rock aquifers with fractured gneiss, granites, schists, and highly fractured weathered rocks. The agricultural impacts of the improved GW table are also quantified by comparing areas receiving STW to those not receiving it, and changes before and after STW recycling were measured. The AMBHAS_1D model was used to estimate the recharge rates and showed a tenfold increase in daily recharge rates, resulting in a significant increase in the GW levels. The results indicate that the surface water in the rejuvenated tanks meets the country's stringent water discharge standards for STW. The GW levels of the studied boreholes increased by 58-73 %, and the GW quality improved significantly, turning hard water into soft water. Land use land cover studies confirmed an increase in the number of water bodies, trees, and cultivated land. The availability of GW significantly improved agricultural productivity (11-42 %), milk productivity (33 %), and fish productivity (341 %). The study's outcomes are expected to serve as a role model for the rest of Indian metro cities and demonstrate the potential of reusing STW to achieve a circular economy and a water-resilient system.
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Affiliation(s)
- Kavita Verma
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India.
| | - Manjari Manisha
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - R M Santrupt
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - T P Anirudha
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - Shubham Goswami
- Department of Civil Engineering, Indian Institute of Science, Bangalore, India
| | - M Sekhar
- Department of Civil Engineering, Indian Institute of Science, Bangalore, India
| | - N Ramesh
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - Mohan Kumar M S
- Department of Civil Engineering, Indian Institute of Science, Bangalore, India
| | - H N Chanakya
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India
| | - Lakshminarayana Rao
- Center for Sustainable Technologies, Indian Institute of Science, Bangalore, India; Interdisciplinary Centre for Water Research, Indian Institute of Science, Bangalore, India
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Manisha M, Verma K, Ramesh N, Anirudha TP, Santrupt RM, Das R, Mohan Kumar MS, Chanakya HN, Rao L. Socio-economic impact assessment of large-scale recycling of treated municipal wastewater for indirect groundwater recharge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160207. [PMID: 36402318 DOI: 10.1016/j.scitotenv.2022.160207] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/21/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
Reusing treated wastewater is an emerging solution to address freshwater scarcity, and surface water contamination faced worldwide. A unique large-scale wastewater recycling project was implemented to replenish groundwater by filling secondary treated wastewater (STW) into existing irrigation tanks in severely drought-hit areas of the Kolar districts of Southern India. This study quantifies the socio-economic impacts of this large-scale indirect groundwater recharge scheme. The changes in areas receiving STW i.e., impacted areas and those areas which did not receive STW i.e., non-impacted areas was studied. Also, pre and post recycling changes were quantified in the Kolar district. The results show that surface water quality meets India's most stringent treated wastewater discharge standards prescribed by the Hon'ble National Green Tribunal. Due to these recycling efforts, significant improvements in groundwater level and quality were found. It was observed that there was a noticeable difference in agricultural cropping areas, seasons, patterns, and production between impacted and non-impacted areas. Post-recycling, farmers tended to cultivate cash and water-intensive crops over less water-intensive crops. During the post-recycling period, livestock and milk production also increased, and in impacted areas, it was significantly higher. Post-recycling, fish production increased and land prices per hectare increased by 118 % in impacted areas. The farmer's net income under flowers and vegetable farming increased by 202 % and 150 % respectively in impacted areas compared to non-impacted areas. Furthermore, this project contributes to a circular economy transition in the water sector, which has economic, environmental, social, and cultural benefits. A key recommendation from the outcomes of the study is to draft and implement a policy that encourages the reuse of recycled water for groundwater recharge which in turn will improve the agro-economic system and food security.
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Affiliation(s)
- Manjari Manisha
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India.
| | - Kavita Verma
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - N Ramesh
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - T P Anirudha
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - R M Santrupt
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - Reshmi Das
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - M S Mohan Kumar
- Department of Civil Engineering, Indian Institute of Science, Bengaluru, India; Gitam University, India
| | - H N Chanakya
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
| | - Lakshminarayana Rao
- Center for Sustainable Technologies, Indian Institute of Science, Bengaluru, India
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Delgado-Gonzalez L, Forquet N, Choubert JM, Boutin C, Moreau M, Moreau S, Clement R. Flow path monitoring by discontinuous time-lapse ERT: An application to survey relationships between secondary effluent infiltration and roots distribution. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116839. [PMID: 36435132 DOI: 10.1016/j.jenvman.2022.116839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/02/2022] [Accepted: 11/18/2022] [Indexed: 06/16/2023]
Abstract
The infiltration of secondary treated effluent (STE) into the soil downstream of wastewater treatment plants is becoming increasingly common in a climate change context. In STE infiltration, STE is discharged onto the soil over a large surface allowing for a gradual infiltration of the water. This paper investigates a novel time-lapse electrical resistivity tomography strategy to evaluate the impact of STE infiltration on the water pathways of two planted loamy-soil trenches located in a Fluvisol region in southwestern France. The system has been monitored for 3 years using discontinuous monitoring of electrical resistivity tomography during four saline tracer tests. Results show that: 1) the new methodology has successfully highlighted the evolution of water pathways in the soil over time; 2) such evolution is in agreement with reeds root distribution in the trenches which seems to be affected by water quality i.e. sludge losses and TSS, for this study case. Indeed, for the infiltration trench receiving STE with lower pollution levels (2.2 mg TSS. L-1, 26 mg COD. L-1), the infiltration capacity is maintained over the years (4-6 mm h-1) and reed roots developed deeper in the soil. A sludge deposit present at the bottom of the second infiltration trench receiving higher pollution levels (7.2 mg TSS. L-1, 45 mg COD. L-1, plus episodic sludge release) could lead roots to develop close to the surface affecting the infiltration capacity which did not evolve over time. This work highlights the importance of long-term flow pathway monitoring in understanding the hydraulic behavior of infiltration surfaces submitted to STE.
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Affiliation(s)
| | - Nicolas Forquet
- INRAE, UR-REVERSAAL, 5 Rue de La Doua, CS 20244, 69625, Villeurbanne Cedex, France
| | - Jean-Marc Choubert
- INRAE, UR-REVERSAAL, 5 Rue de La Doua, CS 20244, 69625, Villeurbanne Cedex, France
| | - Catherine Boutin
- INRAE, UR-REVERSAAL, 5 Rue de La Doua, CS 20244, 69625, Villeurbanne Cedex, France
| | - Magali Moreau
- INRAE, UR-PROSE, 1 Rue Pierre Gilles de Gennes, 92160, Antony, France
| | - Sylvain Moreau
- INRAE, UR-PROSE, 1 Rue Pierre Gilles de Gennes, 92160, Antony, France
| | - Rémi Clement
- INRAE, UR-REVERSAAL, 5 Rue de La Doua, CS 20244, 69625, Villeurbanne Cedex, France
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Abstract
Groundwater models are powerful tools for purposes such as quantifying groundwater systems, examining various management scenarios, and for protection against contamination [...]
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