Full Scale Biological Filters: assessing backwash performance on microbial and organic carbon outcomes

The City of Ottawa operates two water treatment plants, Britannia and Lemieux Island Water Purification Plants. Their treatment consists of coagulation with alum, filtration and post-filter disinfection. The City operates its filters within a “biofiltration” framework intended to allow for the beneficial growth of friendly bacteria on the filter media surface. Biofiltration enhances removal of organics in the water system that may otherwise contribute to disinfection by-product formation. To allow filters to operate properly, filters are cleaned via a backwash step at regular time periods to clean and maintain the proper function of filters. This research aims to assess various methodologies to evaluate the health of filtration systems coupled with backwash operation. Due to plant maintenance, the Lemieux filter backwashing was supplemented with a chlorine wash. This project aims to evaluate whether a chlorinated backwash affects the organic removal performance at Lemieux WTP, investigate the presence and changes in the microbial population within the biofilter systems, and assess recovery times after transitioning from a chlorinated backwash to a standard water wash. This full-scale research study aims to provide valuable insights for the optimization of filtration systems and map out changes to microbial populations with chlorinated and un-chlorinated backwashes.

Faculty Supervisor:

Onita Basu

Student:

Partner:

City of Ottawa

Discipline:

Engineering

Sector:

Public administration

University:

Carleton University

Program: