Latornell Conservation SymposiumNovember 15th, 2018

Phosphorus Reduction Strategies for Greenhouse OperationsNathan Warkentin – Energy & Environment Analyst – OGVG

Agenda

• Sector Overview

• Greenhouse 101

• Nutrient Management Approaches

• OGVG’s Role

• Recent Initiatives

Sector Overview

• ~200 greenhouse vegetable farmers across Ontario; ~3000 acres of production

41% Tomatoes, 33% Peppers, 26% Cucumber

• $850M farmgate sales, $1.5B economy contribution

• 6% compounded growth rate over the past 20 years*

• ~85% of Ontario production occurs in Essex and Chatham-Kent

• 70% of Ontario produce is exported out of the Province

Greenhouse 101

• Plants are grown in inert media slabs

• Slabs sit on top of graded troughs

• Plants are fertigated using drip irrigation• Fertigation = irrigation + fertilizer

• Excess solution is captured by trough, treated, balanced and recirculated

Dirty Recirc

Clean Recirc Fresh water

Water inlet

Fertilizer stock tanks

Disinfection system

Fertilizer Injector

Blending point of water and recircsolution

100%

25% 75%

Nutrient Management Approaches

• Minimize inputs

• Maximize reuse

• Manage excess

• Goal: Effective and economical recirculation of nutrients in greenhouse operations

Input Management• Precision fertigation

• Minimize presence of counter ions (Na, Cl, SO4) by using high quality fertilizers and high purity water

• Plan for end of crop management (dial back fertilizer and water)

• Consider time of day and light intensity

Maximize Reuse

• Use clean substrates

• Recirculate as much as possible

• Invest in reliable and effective treatment systems

• Provide sufficient storage to enable treatment and reuse

• Develop contingency plan in case of equipment failure

• Conduct routine ‘leak checking’

UV/Ozone

Reverse Osmosis

Pasteurization

Advanced Membranes

Manage Excess

• Discharge to municipal sewers (geographic limitation)

• Discharge to septic system (volume limitation)

• Licensed hauler removal (volume limitation)

• Fertilize a secondary crop• In the greenhouse

• Land application under NMA

OGVG’s Role

• Grower education and outreach:• Technology• Planning• Regulatory requirements and compliance

• Work with government to ensure support is available to meet commitments under DAP

• Collaborate with stakeholders for regional approach

Recent Initiatives

• Data Collection

• Dye Test Protocol and Implementation

• GLIER Research Project

• Municipal Consultations

• Water Group Participation

Data Collection

• Annual Producer License Forms

• Track grower recirculation over time

• Estimate reduction in Phosphorus

• 79% reduction per acre since 2010

Data Collection

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2010 2017 2018

Greenhouse Waste Water Management

Not reported Sanitary Sewer Recirculation None

Dye Test Protocol

• OGVG worked with an engineering firm to develop a water systems test

• Visual test to determine if water handling systems are operating as intended (no cracked pipes, no missed connections)

• Identify where fix is required

GLIER Research Project• Analysis of stormwater

retention pond source-sink relationship

• Focus on Phosphorus

• Develop realistic management recommendations to improve pond environmental performance

• 2 year project – funded by OGVG and AAC

Municipal Consultations

• Regional Sanitary Sewer Expansion Project• Kingsville

• Leamington

• Example of Sanitary Sewer GNF limitations from Kingsville:• Discharge between 2am-6am

• Max 457 L/acre/day

• Charged at 130% incoming water rate

• Water must meet specific discharge limits

Water Group Participation

• CFFO Water Stewardship

• Agriculture Sector Working Group

• ERCA SWP Committee

Questions

Nathan Warkentin

Energy & Environment Analyst

n.warkentin@ogvg.com