Investigation of the Effect of Treated Wastewater on River Temperature and pH

Authors

  • Simran Dhaliwal
  • Harsajjan Dhillon
  • Parmvir Shergill
  • Simran Shergill

Abstract

The Squamish Wastewater Treatment Plant (WWTP) utilizes bacteria to biodegrade organic matter and sulphur dioxide for the process of dechlorination, which increase the temperature and reduce the pH of the treated water, respectively. This process can modify the temperature and pH levels of effluent water flowing back into rivers, resulting in detrimental consequences for keystone species in B.C., particularly salmon. This study aims to compare temperature and pH both upstream and downstream of Squamish’s WWTP to identify the impact of the treatment process on river properties. We hypothesized that the treated wastewater released from the outflow site would (1) lower river pH and (2) increase river temperature. Using a pH probe and a thermometer, pH levels and temperature were measured 100 feet upstream (n=5) and 100 feet downstream of the WWTP outflow site (n=5). Collecting data from two separate trials, a two-sample t-test indicated that pH levels upstream and downstream were significantly different in both trial 1 (p = 0.0363) and trial 2 (p = 0.0000343). Furthermore, the two-sample t-test conducted on the temperature data indicated that the mean temperature difference between the upstream and downstream sites was statistically insignificant in both trial 1 (p = 0.2826) and trial 2 (p = 0.2844). In conclusion, our findings supported our pH hypothesis and failed to support our temperature hypothesis. This observed alteration of river pH can have adverse implications on salmon survival at all stages of life.

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Published

2021-09-16

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Section

Articles