Alkaline Stabilization & Screening of Septage in Ontario

Lead Researcher: Doug Joy –
Prepared for: Ontario Ministry of Environment
Partners: Ontario Association of Sewage Industry Services, XCG Consultants Ltd.

Land application of untreated septage (domestic wastewater from septic tanks, holding tanks, and portable toilets) in Ontario is being phased-out by the Ontario Government over a period of five years. This move was prompted by concern over pathogens in untreated septage and their potential to impact source waters. Additional concerns with septage include odour, vector attraction and the presence of debris. One method to reduce pathogens is through the alkaline stabilization process. Debris can be removed through effective screening of septage prior to land application.

Alkaline stabilization is currently not carried out within Ontario and, therefore, a study was required to demonstrate this process. The MOE retained the Ontario Rural Wastewater Centre and XCG Consultants Ltd, with input from the Ontario Association for Sewage Industry Services (O.A.S.I.S), to demonstrate and train Ontario septage haulers on cost effective approaches to alkaline stabilize and screen septage prior to land application.

The study comprised three phases. Phase 1 dealt with collecting information on screening and lime stabilization of septage from U.S. haulers and regulators. Phase 2 consisted of field trials of screening and lime stabilization of septage in Ontario. In Phase 3, a course was developed to provide training to Ontario haulers on screening and lime stabilization. The reports for Phase 1 and 2 can be downloaded from the following links.

Phase 1 report – XCG Consultants Ltd.
Phase 2 report – ORWC & OASIS