Madhavi Ganesan ¹

Affiliations
1 Centre for Water Resources, College of Engineering Guindy, Chennai, IN

Abstract

There are 39 temple tanks in the city of Madras, most of which have been dry for the past one decade due to rapid urbanization and continuous withdrawal of groundwater. Out 39 temple tanks one tank belongs to Mylapore Temple which is within Madras city and second one belongs to Thirupporur Temple which is out of city have been selected to compare the status of the temple tanks. Thirupporur Tank has been taken to find the reason for having water throughout the year. Then the Mylapore tank (within the city) has been taken and studied in detail. The study found the reason for the dryness of urban tanks. It also revealed the methods to rehabilitate and thus to re-establish the hydrological role and possible multiple use of the tanks. The study analysed both the quantity and quality aspects of the tanks.

Keywords

Temple Tanks, Rainwater Harvesting, Groundwater Recharge, SCS Method, Public Participation

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Selvakumar Thiagarajan ¹, Madhavi Ganesan ²

Affiliations
1 Centre for Water Resources, Anna University, Chennai - 600025, Tamil Nadu, IN
2 Centre for Water Resources, Anna University, Chennai - 600 025., IN

Abstract

Groundwater use is increasing all over India and Chennai is not an exception. A good possibility exists to recharge artificially the excess treated wastewater through Soil Aquifer Treatment (SAT) and use the recharged water for purposes other than drinking. Soil column experiments were performed, in order to study the ammonia, nitrite and nitrate reduction from Real Secondary Treated Wastewater (RWW). SAT was simulated in four 15 cm long soil columns packed with soils of Sandy Clay Loam (SCL) texture collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Soil Columns were ponded with wastewater to a depth of 2.5 cm above the soil surface and operated for a period of Ten cycles under 4 different alternating wet and dry cycles, 0.25 day wet/1.75 days dry (R1), 0.25 day wet/2.75 days dry (R2), 0.25 day wet/3.75 days dry (R3) and 0.25 day wet/7.75 days dry (R4). The effect of wetting and drying periods on SAT ammonia removal performance was assessed comparing ammonia, nitrite, nitrate nitrogen and TDS rates. The removal of ammonia was through nitrification process which is found to be a dominant removal mechanism of nitrogen. Nitrification differed according to the different drying cycle’s time with fixed flooding period. When the reduction performance achieved with different drying cycles were compared, it could be seen that longer drying periods with R3 column yielded with the least nitrate value of 0.58 mg/l. From this study, it was found that with the fixed wetting period, maximum drying period is required for nitrate reduction and minimum drying period is required for TDS reduction.

Keywords

Ammonia Transformation, Nitrate Removal, Nitrite, Real Secondary Treated Wastewater, Soil Aquifer Treatment

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T. Selvakumar ¹, Madhavi Ganesan ²

Affiliations
1 Department of Civil Engineering, KCG College of Technology, Chennai – 600097 , Tamil Nadu, IN
2 Centre for Water Resources, Anna University, Chennai – 600025 , Tamil Nadu, IN

Abstract

Artificial recharge of Aquifers with treated wastewater is one of the most promising techniques for its reuse. Usually laboratory and pilot scale field studies are conducted for investigating the feasibility of wastewater recharge for any aquifer. The addition of sand to the local soil can improve the performance of the Soil Aquifer Treatment (SAT) process. Thus, a laboratory study was conducted to investigate the effect of sand amendment with local Sandy Clay Loam (SCL) texture soil collected from Anna University Sewage Treatment Plant (STP), Chennai, India. Four 35 cm long PVC soil columns were fabricated and were filled with 5 % (R5), 10 % (R10), 15 % (R15) and 20 % (R20) sand amended soil. The experiments were run simultaneously for a period of ten cycles with 3 days wet/4 days dry cycles. Water samples were collected at the outlet of the columns and analysed for TDS, ammonia, nitrite and nitrates. The removal of ammonia was through nitrification process which was found to be a dominant removal mechanism of nitrogen. When reduction performance achieved with different sand amendment columns were compared, it could be seen that R10 column yielded with least nitrate value of 0.69 and 1.57 mg/l after 1st and 3rd wetting day.

Keywords

Artificial Recharge, Nitrate Reduction, Sand Amendment, Soil Aquifer Treatment, Wastewater Reuse

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