Los retos en la gestión de residuos urbanos en una economía globalizada

Els reptes en la gestió de residus urbans en una economia globalitzada

Challenges in waste management in a globalized economy

ORGANIZADO POR: CON LA COLABORACIÓN DE:

VOC emissions from organics management: Measurement, speciation and mitigation

Robert HorowitzCalifornia Dept. of Resources, Recycling & Recovery

(CalRecycle)robert.horowitz@CalRecycle.ca.gov

This Presentation1. Composting in California today2. Do compost emissions lead to harmful air

pollution?3. Composting emissions research4. Odor issues and research5. Climate change research

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California LawCities and counties must divert >50% of their

solid waste away from landfills or CalRecycle can issue fines

Composting IS recyclingNEW: CA recycling goal: 75% by 2020NEW: Businesses with >3 cubic meters of

garbage per week must recycleNEW: Apartment buildings with 5 or more units

must offer recycling to residents

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Open-windrow composting

20 hectare green waste facility near Modesto, CA

Composting in California

Most facilities compost source separated green waste in open windrows

115 facilities / 4 million tonnes processedMost compost sold to agriculture, but farmers do not

want to pay too muchNew air- and water-quality regulations will require

facility upgrades better windrow management and engineered systems to capture volatile organic compounds and ammonia

Economics do not support engineered facilities

$35 millionBiosolids and bulking agentsIndoor tipping and mixing areasNegative aeration; biofilterSynagro-Southern Kern County

Outdoor ASP85% VOC/ 99% NH3 Capture455 tonnes/day

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Indoor ASP95% VOC capture99% NH3 capture 380 tonnes/day

$80 millionBiosolids and bulking agentsConverted IKEA warehouse8-12 air changes per hour Negative aeration; 1.2 ha biofilterInland Empire Utilities District - Rancho Cucamonga

Tarped, aerated systems

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Micro-pore covers80%-plus VOC & NH3 captureScalable size and costNegative air/Biofilter or positive aeration

Do composting emissions lead to harmful air

pollution?Compost piles emit Volatile Organic

Compounds (VOCs)When reactive VOCs mix with oxides of

nitrogen (NOx), in the presence of sunlight, photochemical “smog” results

Smog includes ground-level ozoneOzone is very harmful to human health, as

well as plants and agricultural cropsUS Clean Air Act regulates ozone levels,

mandates action to cut precursors like VOCs9

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Ozone non-attainment areas in the USA

Source: USEPA

8-hour ozone (1997 standard) As of April, 2011

1996-2002 Emissions Studies

Southern California—AQMD & CalRecycleFirst attempts in CA to quantify emissions

factors for composting facilitiesCalRecycle helped with concurrent testing

using lasers, and studied process controlsEmissions factors in mg of pollutant per kg

of feedstock

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VOC CH4 NH3

Biosolids 1205 8930 1525

Greenwaste 1880 435 410

AQMD data, average of two studies

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2005-6 CalRecycle StudyModesto - Northern California

70-80% of total VOCs emitted during 1st two weeks 70-85% of total VOC emissions vent through top of windrow “Pseudo-biofilter” compost cap reduced VOC emissions up to

75% for first two weeks. Additives reduced VOC emissions 42% for first week; 14% for

first two weeks 15% food waste roughly doubled VOC emissions compared to

“straight” green waste Lifecycle VOC emissions from pure greenwaste windrow

@450 mg/kg of feedstock

Pseudo-biofilter compost cap

15 cm layer of unscreened finished compost or overs on top of actively composting pile

Takes advantage of natural pile convectionCap layer

Active compost pile

AirflowAirflowWarm

pile core

2009 San Joaquin APCD study

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Study: Irrigation system used for 3 hours before turning reduced emissions by 24% over first 3 weeks

New Rule 4566: Facilities between 10,000-200,000 tons/year must achieve 24% reduction

Study: Pseudo-biofilter compost cap reduced emissions by 53% over first three weeks.

New Rule 4566: Facilities over 200,000 tpy must achieve 53% emissions reduction

2009-2011 Compost Emissions Reactivity Studies

Not all VOCs are equal; focus on ozone formation potential (OFP)

Compare modeled ozone formation to ozone measured in portable chamber

Tested OFP of windrows, tip piles, oversTested impact on OFP of a pseudo-biofilter

cap made of composting oversProven method used at many agricultural

sites in San Joaquin Valley15

Mobile Ozone Chamber

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Holds 1000-liter teflon bag3-hour experimentsUsed at many ag sites

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Inside the MOChA chamber:UV light similar to summer day

Phase 1 study resultsCompost VOC emissions 80-95% light

alcohols: ethanol, methanol, isopropyl alcohol (2 butanol)

Light alcohols have low OFPMore than 80 other compounds1-3% highly reactive terpenes, aldehydes

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TOP COMPOUNDS IN COMPOSTING EMISSIONS•Isopropyl alcohol•Ethanol•Methanol•Acetic Acid•Limonene

•Camphor•Alpha Pinene•3 hydroxy 2 butanone•Butanoic acid

•Eucalyptol•Methylthymyl ether•Bornyl acetate•Pinene isomer

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More 2010-2011 results

Alcohols more than 90% of emissionsMIR of greenwaste composting

emissions mix:.9 - 1.5 - LOWMIR of biosolids co-composting

emissions mix @1 - LOWOvers cap effective in reducing

observed ozone formation by 27-36%

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Maximum Incremental Reactivity scale (MIR)*

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*Similar to POCP

VOCs and Odors

Not all VOCs are odorous and not all composting odors are VOCs

A lot of research but still subjective when it comes to what is offensive

Odors issues are the single biggest threat to any composting operation

California currently looking at its regulations to see whether there is a more objective way to handle odor complaints

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Emissions & their odorsCompounds OdorsAldehydes Sweet, pungent, greenAmines Fishy, putrid, dead

animals, ammonia, fertilizer

Sulfur compounds Rotten eggs, cabbage, skunk, garlic

Terpenes Fruity, pine, citrus, eucalyptus, menthol

Volatile Fatty Acids Fecal, vomit, sweat, vinegar

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Comprehensive Compost Odor Response Project,

2007CalRecycle study, available on lineLiterature review on odor impacts of

temperature, C:N, moisture, aerationLaboratory test of mitigation strategiesMisting, odor neutralizers, oxygenators,

hydrogen peroxide, compost capPseudo-biofilter compost cap out-

performed all commercial preparations

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Too hot?DMDS

Too much woody material (carbon)?Terpenes

Too much grass or food (nitrogen)?Amines

Too dense?Mercaptans

Not enough oxygen?More odors of all kinds

Composting GHG study

Funded by CalRecycleResearch conducted by Univ. Calif.Focus on N20 and CH4

Field work 2010-2013Final report May, 2014Concurrent with and complementary

to other ongoing ag GHG studies26

Dual approach

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1. Measure CH4 and N20 from composting windrows of green waste and food waste

2. Measure N20 and CH4 emissions from compost amended and conventionally fertilized croplands

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Increasing compost use…

…may decrease use of less sustainable methods.

Related Web Pages My CalRecycle web page:

http://www.calrecycle.ca.gov/Organics/Air/default.htm CalRecycle Greenwaste Compost Reactivity Study:

http://www.calrecycle.ca.gov/Publications/Organics/2011006.pdf CASA Biosolids Co-compost Reactivity Study

http://casaweb.org/documents/2011/werf2c10_web.pdf CalRecycle/Modesto Compost Study

http://www.calrecycle.ca.gov/publications/Organics/44207009.pdf Composting: Feedstock control vs. Aeration study

http://www.calrecycle.ca.gov/Publications/Organics/2008016.pdf Comprehensive Composting Odor Response Project

http://www.calrecycle.ca.gov/Publications/Organics/44207001.pdf

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Summary• Composting gives off VOCs• Emissions rates are highly variable• MIR / POCP for emissions is LOW• Composting VOCs around 1/3 as potent as

average urban air for ozone formation• Pseudo-biofilter compost cap effective in reducing

emissions and odors• Greenhouse gas impacts of compost production

and use need further research

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Thank You

Bob Horowitz(916) 341-6523

Robert.Horowitz@CalRecycle.ca.govhttp://www.calrecycle.ca.gov/Organics/Air/default.htm