Halton Region is concerned…

Halton Region is concerned with the term “putrescible” in its definition and use in describing Tier 3 odorous waste transfer and/or processing stations that are categorized in Table F. The following definitions were provided in the draft odour guidelines:

“Waste transfer and/or processing (putrescible) means a waste transfer and/or processing station accepting or storing putrescible waste such as SSO, fats, oils, biosolids, leachate, agricultural, etc.”

“Putrescible Waste means waste of vegetable or animal origin of a similar nature and characteristics, that is liable to become putrid, rotten or decayed, but does not include leaf and yard waste.”

 As biosolids management practitioners, we feel that the use of the term “putrescible” and “putrescible waste” does not accurately describe biosolids that are captured under the definition of Waste transfer and/or processing (putrescible). By adopting the draft odour guideline’s definitions and classification as written, it will undermine the positive work that the Ontario Government and its industry organizations (such as WEAO and WEF) have done to implement the Nutrient Management Act and its regulations including all efforts to gain a positive public acceptance with the land application of biosolids or other end uses.

 Biosolids are included in the Ontario Regulation 347 under the definition of processed organic waste whereas:
- “processed organic waste” means waste that is predominantly organic in composition and has been treated by aerobic or anaerobic digestion, or other means of stabilization, and includes sewage residue from sewage works that are subject to the provisions of the Ontario Water Resources Act;
- The definition implies that biosolids are stabilized in the digestion process at the WWTP, this is further supported by the definition of “wastewater sludge” that is provided in the draft odour guidelines which states:
- Wastewater sludge means a mixture of non-stabilized solids separated from the liquid train of various types of wastewater treatment”

 Only upon completion of a stabilization process at the wastewater treatment plant, we can use the term “biosolids” which is not defined in the Draft Odour Guidelines.

 Similarly, the federal government has provided the following biosolids definition from the CFIA Schedule II:
- “Solid, semi-solid or liquid material made from septage and/or municipal sewage or sludge, that are freed from grit and coarse solids, that have been subjected to physical, chemical or biological treatment including composting, or a combination thereof, sufficient to mitigate against the presence and/or effect of generally detrimental or serious injurious substances that may be associated with untreated forms of this material”.

 In the definitions and the messaging utilized by the biosolids industry and our regulators to communicate biosolids issues in a proactive manner, all imply that biosolids are stable materials that won’t further degrade. This directly contravenes and conflicts with the draft odour guideline definition of putrescible waste which means “waste of vegetable or animal origin of a similar nature and characteristics that is liable to become putrid, rotten or decayed, but does not include leaf and yard waste.”

 In Halton’s 35 year experience of managing a biosolids storage and transfer facility, there has been no material received that has become “putrid, rotten or decayed” while in storage. In fact stored biosolids over time, become less odorous and only when handled are odours observed. In any biosolids storage and/ or transfer facility there is no off gassing, gas collection or creation of odours beyond the initial WWTP digestion process and to describe biosolids through definition as “putrescible wastes” in the process categorization does a disservice to the all stakeholders involved from the generating municipalities, to research academia, to the end users, to the regulators and only opens the door for anti-biosolids activist to gather momentum and have their voices heard. The federal and provincial governments have gone through great strides to create and promote science based regulations through the EPA, NMA and the federal fertilizer act and where conflicting legislative definitions, meanings and terminology occur, we open the door to greater scrutiny.