Environmental Impacts

Dr. Bruce T. Bowman

Chair, CARC Expert Committee on Manure Management

April 30, 2002

Waterloo, Ontario

ManureNethttp://www.agr.gc.ca/science/initiatives/manurenet/

Livestock Manure Treatment Technologies:

IF managed properly… Valuable recycled nutrient source Excellent soil conditioner (biological)

IF managed poorly… Nuisance waste Environmental liability

What is the Value of Manure?

Some History

Manure issues have challenged farmers for well over a century

What has changed?

Technology has advanced a lot … however …

Same old issues … Odour Impacts on Water quality

Odour intensity

Pathogen levels

Nutrient excesses

Large water volumes

Greenhouse gas emissions

What are the Major Issues?

Manure has not been actively treated

Exception – composting

Solid manure piles Accidental curing – less odour, pathogens

Traditionally

Liquid systems - more popular since 1970’s labour-saving – OK for moderate-size operations

Recent trends in livestock operations Great increase in herd size Geographic concentration

Problem issues Increased odour Excess water volumes – land application Nutrient accumulations – P & N

The Current Situation

Constructed wetlands / filter strips Solid-liquid separation Composting Digestion (anaerobic, aerobic)

Nutrient recovery/recycling Value-added processing Other Treatments

Manure Treatment Technologies

Benefits Polishing run-off waste water from barn/milkhouse Reducing water volumes (evaporation)

Drawbacks Possible ghg emissions Sediment buildup Nutrient accumulations (P) Significant area at farm site Can’t handle high solids content

Constructed Wetlands / Filter Strips

Variety of screens, filters, presses, settling beds

Benefits Reducing water volumes – reduced storage Opportunities for nutrient partitioning Flexibility of use - transportation

Drawbacks Possible problems if low solids content Cost – both liquid & solid handling equipment

Solid-Liquid Separation

Solid-Liquid Separation

Benefits Reduce water volumes Eliminate odour & pathogens, kill weed seeds Mature compost - low risk for water contamination Soil conditioner

Drawbacks More Labour-intensive Considerable ammonia losses (open composting) Possible GHG emissions (open composting)

Composting

Composting

Odour Closed vessel - greatly reduce odours Ammonia emissions minimized Surface application of digested manure?

Suitable for No-till operations?

Pathogens Greatly reduced or eliminated

GHGs Minimal GHG losses during treatment Methane captured and utilized

Anaerobic Digestion

Anaerobic Digestion

Nutrients Closed vessel, nutrients conserved Increased N content; better N:P ratio Neutral pH to reduce ammonia losses Nutrients more available for plant use

50% of carbon methane

Eco-

Efficiency

Methane captured - heat or electricity Recycled energy

“Green power”; distributed generation Energy independence, revenue source

(power generation being privatized)

Anaerobic Digestion

Lagoon Additives (odour control) Generally not (cost)-effective at claimed rates

Ozonation Reduce odours in air & in manure slurries Reduce pathogens in manure slurries

Other Treatments

Phosphorus – “non-renewal” resource Re-cycle nutrients – sustainability issue 150 M t/yr P extracted & processed (85% Ag)

Flexibility for nutrient utilization On-farm – limited by land base, NMP (P, N) Diverting off-farm, amendments/fertilizer

Nutrient Recovery / Recycling

Nutrient Recovery / Recycling

Integrated Waste Management System

Integrated Farm Energy System (IFES)

Blending manure-based amendments Supplementing with mineral fertilizers Fertilizer vs amendment (guaranteed analysis)

Pasteurizing Adding back specific microbes (disease control)

Pelletizing Easier storage, transportation, application

Value-Added Processing

Need to manage manure for: Soil conditioning value Nutrient value Energy content Value-added products Minimize negative environmental impacts

Innovative partnerships for waste management Other Ag (food processors, rendering, deadstock) Municipal (residential wastes, sewage) Industrial (energy producers, commercial alcohol)

Looking Ahead

Conference Announcement

A National Conference and Exhibition on

Integrated Solutions to Manure Management: Working Together on Challenges and Opportunities

Location: Convention Centre London, Ontario

September 11-13, 2002

http://res2.agr.ca/initiatives/manurenet/ismm/