Development of water treatment best management practices for the greenhouse and nursery industries on Ontario; hybrid treatment systems

This project was intended to provide guidance on innovative water treatment technologies for the horticulture sector in Ontario. The scope of the project included: installation of 2 portable hybrid treatment systems (HTS) to test the operational parameters needed to treat (i.e. clean) floriculture greenhouse and nursery wastewater so that it can be either safely discharged to the environment, or rendered suitable for re-use within the operation, installation of 2 permanent hybrid treatment systems (HTS), one at a container nursery and one at a flower greenhouse, using information obtained from the pilot systems as well as previous studies, and development of a Guidance Document for growers to help them make informed decisions regarding water management and treatment options. The Hybrid Treatment System represents a flexible tool for water treatment, particularly in situations where there is a desire to recirculate or discharge very clean water. Removal rates in each of the selected media are dependent on temperature, flow rate (hydraulic retention time), and nutrient concentration. Temperature is particularly important for the woodchip cells, since these are primarily a biological treatment. For optimum performance these systems need to be designed on the basis of projected daily water volumes, concentrations for treatment, and expected temperatures over the entire production period. While these systems do require a significant footprint outdoors, they can be tailored to match the volumes and fluctuations of a particular operation. And in many cases, the surface of the treatment can be used as a production area, but machine traffic should be avoided. It is highly recommended that growers conduct a self-assessment of the farm prior to choosing a water management solution.

Links: https://www.flowerscanadagrowers.com/uploads/2018/04/guidance%20document.pdf; https://www.flowerscanadagrowers.com/uploads/2018/04/factsheet%205%20final%20hts%20jan%2030.pdf
Keywords: hybrid treatment systems, pilot plants, woodchip denitrification bioreactor, nutrient removal, nitrogen, phosphorus, slag, gravel, wollastonite, filter sand, guidance document