Improved Water Quality of Lake Ranisagar using Bioaugmentation Technology
Abstract
Bioaugmentation technology achieved rapid bioremediation to significantly improve the water quality of Ranisagar Chaupati Lake over the course of our 8-week study. At the beginning of our study, Ranisagar Chaupati Lake was graded on the Water Quality Index (WQI) as bad water quality and on the Trophic State Index (TSI) as highly eutrophic. Bioaugmentation technology was added to the lake as an all-natural, environmentally safe protocol to improve water quality. This resulted in overall improvement in the WQI from 36.6 (Bad quality) to 57.5 (Moderate quality) and the trophic status of the lake improved from hypereutrophic to eutrophic state.
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Introduction
The state of Chhattisgarh in central India was created in the year 2000 as a result of the Madhya Pradesh Reorganization Act. It is the 10th largest state in India (by surface) and with a population of over 25 million people it is one of the fastest developing states in India. The state is dotted with numerous lakes, ponds and other water bodies that serve as a major tourist attraction.[1] Most of the pilgrimage sites in Chhattisgarh are located in the vicinity of a lake or a pond. Human activities in the vicinity of the water bodies have caused deterioration of water quality. The Ranisagar Chaupati – a highly eutrophic lake, located in Rajnandgaon district of the state Chhattisgarh – was suggested by the local municipal corporation as a location to demonstrate Bioaugmentation technology capacity to improve water quality through an all-natural bioremediation protocol. The Ranisagar Chaupati Lake situated at 21°5’28”N 81°1’22”E in Rajnandgaon district is surrounded by garden which is used for public recreation and is likely to receive a higher nutrient load than any other lake situated in its vicinity. The lake has a surface area of 20100 m2 (2.01 ha) and an average initial water depth of 1.3 m. Stagnant bodies of water such as lakes or ponds are typically more affected by surrounding human activities than flowing surface water (like streams or rivers).
Ranisagar Chaupati is used for public recreation, but the pond has been receiving discharges of domestic sewage and gray waters from an open canal which collects from surrounding settlements (nallah) for over a decade. The main objective behind the project was to improve the overall water quality of Ranisagar Chaupati Lake through the implementation of an all-natural, environmentally safe protocol using Bioaugmentation Technology.
Conclusion
Bioaugmentation in Ranisagar Chaupati Lake helped to remarkably improve the water quality. We saw an overall improvement in the water quality index (WQI) from 36.6 (Bad quality) to 57.5 (Moderate quality) and the trophic status of the lake improved from hypereutrophic to eutrophic state. The concentration of chlorophyll a, an algal pigment that imparts green color to the water[7], decreased by 40%. Decrease in concentration of Chlorophyll a was due to significant change in the population density (size) and dynamics of phytoplankton (algal) species. 21% reduction was observed in the phytoplankton population after Bioaugmentation. The reduction in population of phytoplankton was reflected in reduction in pH of the lake water from an average value of 9.3 to 8.8. Very high pH in lake bodies results due to high photosynthetic activity[8]. Bioaugmentation also caused significant reduction in the concentrations of organic ammonia (represented as TKN), inorganic ammonia and nitrate by 65%, 40% and 79%, respectively. The organic carbon concentration of lake water, as represented in terms of BOD concentrations also showed an average reduction of 29% within two months of Bioaugmentation. Similarly, the lake sediment also showed a 72% reduction inorganic fraction during this period. Improvement in the water quality is also reflected by an overall decrease in the amount of pollution indicating algal species in lake water as represented by Palmer’s Pollution Index (PPI). The PPI of the lake decreased by 47% indicating improvement of lake water quality in terms of reduced nutrient concentration.
TABLE 6 EFFECT OF BIOAUGMENTATION ON SEVERAL PARAMETERS BEFORE AND AFTER DOSING Before Dosing (13th After Dosing (24th Parameters Observation Remarks Dec 2015) Feb 2016) pH 9.3 8.8 Decreased by 5% Improved Dissolved Oxygen 3.6 8.4 Increased by 133% Improved Chlorophyll a 0.30 0.18 Decreased by 40% Improved TKN (as N) 98.7 34.5 Decreased by 65% Improved Ammonia (as N) 9.8 5.9 Decreased by 40% Improved Nitrate (as NO ) 2.4 0.5 Decreased by 79% Improved 3 Phosphate (as P) 1.0 0.6 Decreased by 40% Improved BOD (3d, 27oC 35 25 Decreased by 29% Improved Sediment Organics (%) 8.7 2.4 Decreased by 72% Improved Phytoplankton (Density/L) 7.7 × 106 6.1×106 Decreased by 21 % Improved Palmer's Pollution Index (PPI) 19 10 Decreased by 47% Improved Zoopankton (Density/L) 81333 81 Decreased by 99.9% Improved
