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Subject: Microbiology × Author: Diksha × End date: 2019 × Start date: 2019 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Bioremediation of phenolic compounds in sewage water using bacterial consortia
    (CCSHAU, 2019) Diksha; Rakesh Kumar
    Sewage water is a rich source of organic waste and nutrients in the form of nitrates and phosphates, due to which it can be used in agriculture after proper treatment. Sewage water contains various harmful compounds like phenolics which need to be treated before discharge. The direct discharge of sewage water into natural water sources leads to the obstructive impacts on the water sources and aquatic life, sewage water becomes an open source of harmful microbes and pollutants. To demolish these problems the treatment of domestic waste water is must and its reuse for the domestic as well as agriculture purpose can become an eco-friendly solution for the conservation of water. A total of 29 bacterial isolates were retrieved from seven sewage water samples collected from Sewage Treatment Plant, CCS HAU, Hisar. All bacterial isolates were screened for phenol degradation in mineral salt medium supplemented with 250, 500 and 750 ppm concentration of phenol. Out of 29, only 8 bacterial isolates were able to grow in mineral salt medium having 750 ppm concentration of phenol. These eight bacterial isolates were further observed for growth upto 1500 ppm concentration of phenol, out of eight, only four bacterial isolates (NI6, NI5, NR1 and JC1) were able to grow upto 1250 ppm concentration of phenol. Cultural conditions, inoculum size and aeration were optimised in culture medium as well as sewage sludge. Fifteen percent inoculum and 2 LPM aeration rate were found to be optimum for efficient phenol degradation. Least residual phenol in culture medium and sewage sludge at 15% inoculum was left with bacterial isolate NI6 (265.2 ppm and 607.30 ppm respectively). Same was observed in culture medium and sewage sludge at 15% inoculum and 2 LPM aeration in lab scale fermenter for bacterial isolate NI6 (352.3 ppm and 761.27 ppm respectively). A consortium of four bacterial isolates (25% each of NI6, NI5, NR1 and JC1) was found to leave least 276.93 ppm residual phenol in sewage sludge as compared to individual isolates. Consortium was further tested for removal of phenolic compounds, COD, BOD and Heavy metal at STP, CCS HAU, Hisar. At 9th day of application, highest phenolic compounds degradation was observed in sewage sludge (120 ppm) and outlet of clarifier (172.9 ppm), thereafter phenolic compounds concentration started to increase. At 9th day COD reduced from 460 mg/L to 60 mg/L and 100 mg/L to 40 mg/L while BOD decreased from 153 mg/L to 18 mg/L and 28 mg/L to 17 mg/L in sewage sludge and outlet of clarifier respectively. Removal of Zinc and Chromium was observed in outlet of clarifier and sewage sludge.