Wastewater (including complete blow-down) from boiler systems should only be discharged to the sanitary sewer system if pollutants are within Drainage Bylaw 18100 restricted limits. Other sources of wastewater produced in maintaining or cleaning boiler systems must also meet the Bylaw's restricted limits. The main parameters of concern are:
- Nitrite/ Nitrates
- BOD (Biochemical Oxygen Demand)
- COD (Chemical Oxygen Demand)
- Total Suspended Solids
- Oil and Grease
To establish if parameters are within the restricted limits, a sample can be collected from the flow monitoring point for the property such as a manhole. If no manhole is available, an alternative sampling location should be established, such as a clean-out for the building.
In the case of ensuring compliance with restricted metals and hazardous waste limits (nitrite/nitrates, phosphate, pH, molybdenum, zinc, boron, and copper), samples should be collected directly from the point of discharge from the boiler. Since these parameters have the potential to cause adverse impacts on the wastewater treatment process, there needs to be efforts to remove these at the source.
Outdated additives and test reagents shall be recycled as per manufacture specifications to ensure compliance with Drainage Bylaw 18100 and the Municipal Solid Waste Regulations.