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Effect of Flow Velocity on Chlorine Decay in Water Distribution Network:A Pilot Loop Study


Affiliations
1 Centre for Environment and Development, Ashoka Trust for Research in Ecology and the Environment, Jakkur, Bengaluru 560 064, India
2 Department of Civil Engineering, Indian Institute of Science, Bengaluru 560 012, India
 

Experiments were run in the pipe loop setup to estimate bulk and wall chlorine decay rates under varying flow and chlorine levels for groundwater. A recirculating loop of 50 mm inner diameter polyvinyl chloride pipe and a variable flow pump with feed and recirculation tank were used to design a pipe loop. Sodium hypochlorite was introduced as free chlorine into the test water. The study came up with three important findings: (a) bulk chlorine decay rate in test water decreased with increase in chlorine levels, which is attributed to the type and level of organic matter present in test water. (b) Chlorine decay rate in pilot loop setup increased with increase in flow velocity. The result showed that under turbulent conditions, in addition to chlorine, mass flux transfer from bulk to wall and biofilm removal from pipe surface contributed to chlorine decay. We also noted that with increase in flow velocity the contribution of bulk reaction to total chlorine decay in pipe loop decreased. (c) ANOVA test on experimental dataset showed that as compared to initial chlorine levels, flow velocity has statistically significant effect on chlorine dissipation in a pipe loop. We also found that after turbulent flow is achieved, the effect of flow velocity on the wall decay is negligible.

Keywords

Chlorine Decay, Pipe Loop Setup, Reynolds Number, Water Distribution Systems.
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  • Effect of Flow Velocity on Chlorine Decay in Water Distribution Network:A Pilot Loop Study

Abstract Views: 228  |  PDF Views: 91

Authors

Priyanka Jamwal
Centre for Environment and Development, Ashoka Trust for Research in Ecology and the Environment, Jakkur, Bengaluru 560 064, India
M. S. Mohan Kumar
Department of Civil Engineering, Indian Institute of Science, Bengaluru 560 012, India

Abstract


Experiments were run in the pipe loop setup to estimate bulk and wall chlorine decay rates under varying flow and chlorine levels for groundwater. A recirculating loop of 50 mm inner diameter polyvinyl chloride pipe and a variable flow pump with feed and recirculation tank were used to design a pipe loop. Sodium hypochlorite was introduced as free chlorine into the test water. The study came up with three important findings: (a) bulk chlorine decay rate in test water decreased with increase in chlorine levels, which is attributed to the type and level of organic matter present in test water. (b) Chlorine decay rate in pilot loop setup increased with increase in flow velocity. The result showed that under turbulent conditions, in addition to chlorine, mass flux transfer from bulk to wall and biofilm removal from pipe surface contributed to chlorine decay. We also noted that with increase in flow velocity the contribution of bulk reaction to total chlorine decay in pipe loop decreased. (c) ANOVA test on experimental dataset showed that as compared to initial chlorine levels, flow velocity has statistically significant effect on chlorine dissipation in a pipe loop. We also found that after turbulent flow is achieved, the effect of flow velocity on the wall decay is negligible.

Keywords


Chlorine Decay, Pipe Loop Setup, Reynolds Number, Water Distribution Systems.

References





DOI: https://doi.org/10.18520/cs%2Fv111%2Fi8%2F1349-1354