The Role of

Food Waste Disposers Joe Ferrara Dr Tim Evans

MD, InSinkErator Europe Tim Evans Environment

North East Recycling Forum20th September 2012

UK trade association for the manufacturers of small and large domestic appliances

 World’s largest manufacturer of FWDs

  In 2010 members who manufacture FWDs

formed AMDEA’s Food Waste Disposer Group

AIMPromote greater awareness of the benefits of food waste disposers

(FWDs) and contribute to efficient waste strategies.

About us

What is an FWD?

• Small device that fits under the kitchen sink

• Grinds practically all food waste into minute particles (there are no sharp blades)

• Carried away with the household waste water directly to wastewater treatment & anaerobic digestion (AD) plants where energy and fertiliser can be extracted

Why FWD?

• Easy and hygienic option for citizens/users

• Improve overall waste food diversion/capture

• Require minimal education and persuasion

• Lower collection and disposal costs

• Cut kerbside collection vehicles

• Reduce contamination of other recyclables

• Strong evidence base

• Good carbon footprint

• Improve value capture: energy & fertiliser

UK - untapped potential

Sustainable solution for

Areas where people unable/unwilling to

participate in separate kerbside collection or

home composting:

• High rise buildings

• Terraced houses

• Densely populated urban areas

• Elderly or infirm

High usage abroad

• 20% of Australian homes

• 34% of New Zealand homes

• 50% of US homes

- Around 80% of new homes have a FWD and more than 80 municipalities require

their installation as part of an overall environmental programme. 

BUTOnly used in about 6% of UK homes

Benefit - Efficiency

• Food waste is separated quickly at the source

• Capture more of this difficult waste stream than other solutions.

• Easy & hygienic – eliminate the “yuck factor”

- prevent contamination of other recyclables

• Eliminate the bins that lure urban foxes and other vermin to doorsteps

Benefit - Reduce landfill

• Can remove around 270 kilos of food waste per hshld per yr

• Significantly reduce waste sent to landfill

• Help authorities to meet zero waste targets

Each tonne of food waste diverted from landfill and sent via FWDs to AD can save the planet 1 tonne of CO2e

Benefit - Good CO2 footprint

• 2 – 3 kWh of electricity per hshld per yr = 37p yr

• 6Ls of water per day = 1 extra toilet flush

Each FWD creates 25 times more energy than it uses

• Reduce traffic emissions & use of additional fossil fuel

• At the end of life (approx 12 yrs) comprise primarily metal components & are 95% recyclable

Benefit - Energy capture

FWDs enhance the extraction of sustainable value from waste.  

• The food waste stream is rich in biogas

• Most sewage sludge is processed by anaerobic digestion and increasingly both biogas and fertiliser are extracted

• Food waste considerably increases the biogas/energy yield of sewage

Energy from waste

The Science

Large body of scientific research… 

• Environmental Impact for Herefordshire & Worcestershire County Council - Evans, T. D. (2007) - Global warming potential better than landfill, incineration or composting - Council saved £21 per household p.a. in 2005

• Life-Cycle Comparison of Five Engineered Systems, University of Wisconsin. January 1998-2002- FWD has the lowest cost to the municipality - Most environmentally friendly option for recycling biosolids

• Garbage Grinder Introduction - Sewage & Wastewater Dept, Hokkaido, Japan, 2003 - FWDs offer excellent cost benefits

- Quality of treated water and amount of system water usage is unchanged

• An Alternative to Separate Bio- Waste Collection? University of Karlsruhe, Germany, 2001- FWD output is transported through sewers easily- Density and settling of bio-waste particles are much less than the mineral particles

commonly found in sewer sediments

http://www.food-waste-disposer.org.uk/the-science

Tim Evans’ background

• Soil scientist [Newcastle upon Tyne and Madison, Wisconsin]

• Thames Water – included creating environmentally controlled biosolids recycling for 6.5 million people

• Independent consultant - mainly helping clients to sustainable solutions for organic residuals

• Other activities:– EU Soil Strategy, Sludge Directive, Biowaste Directive, EoW criteria– British and European Standards, – Foundation for Water Research– Chartered Institution for Water & Environmental Management– European Water Association

TIM EVANS ENVIRONMENT, Stonecroft, Park Lane, Ashtead, KT21 1EU, UK

tim@timevansenvironment.com T IM EVANSE N V I R O N M E N T

Fundamentals

• Legal obligation in EU to divert biodegradable municipal waste from landfill

• Climate change

• Phosphate crisis – essential for all life, – too precious to squander

• People are individuals: one size won’t fit all whatever we might think is good for them

Kitchen food waste• Is the most difficult fraction of municipal waste to manage

– 70% moisture content– Biodegrades rapidly with high oxygen demand – Prone to become putrid, smell and ooze leachate– Flies maggots and vermin

• Home composting done well is great– Many are unwilling or unable

• Source segregation and kerbside collection is good for those who are prepared to do it– Participation rates are low in ”flatted” properties– Physical contaminants in kerbside collected, source segregated biowaste [Germany, North

America, UK found 12-20% w/w]

• FWD is also source segregation

Total household waste (from Parfitt, 2002)

Quested and Johnson (2009) • Local authorities in UK

collect 5.8 Mt food waste • most of it is in the residual

waste bins

• equates to268 kg/hhd.yr

Inconvenient truth

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Flatted properties recycle lessLondon Boroughs - correlation -0.529

Kerbside to landfill (with landfill gas collection and use) +743

Kerbside to incineration (with energy recovery) +13

Kerbside to centralised composting -14

Kerbside to centralised AD -205

Food waste disposers to WwTP + AD -199

Environmental Impact Assessment

Environmental Impact Assessment

Food waste collection + disposal = £18.63/hhd.yearFood waste collection + disposal = £18.63/hhd.year

Food waste management GWP kgCO2e/t food waste

Herefordshire & Worcestershire (2005/06 data)

Cost transfer to waste water treatment

• Herefore & Worcestershire audited data showed financial saving and good carbon footprint but what was the cost transfer to Severn Trent Water which is– 100% AD – target for 30% self-generated electricity by 2012 – welcomes extra substrate (biosolids to farmland)

• Surahammar (SE) provided the answer– Influent monitored 4 weekly– FWD installation increased from 0% to 50% of households– Flow, ammoniacal-N, BOD7, COD did not increase

– Biogas increased 46% (P=0.01)

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Surahammar influent flow 1995-2008