ammonia waste water

8/11/2019 Ammonia Waste Water

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Management of Ammonia Wastewater

Eileen Woodbury, REHSSenior Hazardous Materials SpecialistMonterey County Health Department

Environmental Health Division


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What am I talking about?This is not a talk on the production of anhydrous ammonia

or aqueous ammonia, but rather a story of a CalARPinspectors journey into the DTSC world of hazardous waste

treatment and ammonia refrigeration systems.

Story begins with training!

Jan. 2007, Refrigeration Basics by ARTS Academy

First thing I learned as a CUPA inspector:

ASK QUESTIONS!


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Ammonia PropertiesQuick review Lighter than air

Gas at ambient, liquefied under pressure

Self alarming sight and smell with a pungent odor

Detectable by nose, from 5 to 25 ppm Highly irritating to eyes, skin, respiratory tract

Affinity to water, mixes readily

Service technicians take advantage of this propertyby bubbling vapor into water to work on a section or component


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GenerationGenerated during routine maintenance or

servicing of an ammonia refrigerationsystem. Technicians isolate a component orsection of pipe, and removes pressure from

a section of the system, i.e. vapor, bydirecting ammonia vapor into water. Also

generated as an emergency capture of

ammonia vapors from pressure reliefdevices to a diffusion tank.


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Venting to Atmosphere


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Bubbling Vapors into Water

Done safely, can reduce thelikelihood of employee

exposure and harm,

Reduce likelihood of offsiteconsequences, and

Reduce potential exposure tothe public.


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Diffuser

Capture and neutralize ammoniareleased from pressure relief valves.PRV discharges into common header

to water tank or diffuser. Consists of awater tank, with perforated pipe todistribute ammonia for mixing withwater.

Safety System: Diffuser Tank

Relief valves protect high and low sidesfrom overpressure. Factory set torelease to diffuser if pressures above150 (low), 250 psig (high side). Ifsystem pressure exceeds set points,release to tank, without releasing toatmosphere. Emergency Control Boxmay be used to manually transfer vaporto diffuser.


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Safe Operating Procedure: Neutralization

SOP from former River Ranch foods refrigeration technician.

Technician trained in ammonia safety,awareness, and SOP, including propertreatment and disposalConducted away from plant personnel,public, in secure area

Monitoring equipment: pH meter,ammonia detector Donn PPE, gloves, faceshield, apron


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Monitoring Equipment


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Treatment

Neutralization with muriaticacid, about 19% HCL, in

Ammonia/Water resultedin strong exothermicreaction


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Treatment

Stand-alone automaticneutralization system

Pump meters acid into ammonia/waterdrum at 30-second intervalsConcurrent agitation of drum contents to

promote even mixing of solutionTie-in pH meter to monitor changesOther designs have included ammoniavapor scrubber at vent


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TreatmentNeutralization to minimize pH

and

No Ammonia Vapors

pH must fall within 6-7 range Verify no ammonia vaporspresent with ammonia detector Notify POTW, CUPA prior to

discharge Discharge to sanitary sewersystem


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Disposal Some municipalities will not allow

discharges to the Industrial

Wastewater System (even if itsneutralized)

Contact POTWs for disposal tosanitary sewer.

Facilities in unincorporated areamust contact the Regional WaterQuality Control Board to determine

discharge requirements Haul ammonia wastewater by

contacting a licensed hazardouswaste transporter


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Regulatory World Anhydrous ammonia is deemed a hazardous wasteonce exits process equipment, or evacuated from pipe

or other component. Bubbling ammonia vapor intowater is considered hazardous waste treatment,changing the physical, chemical characteristics,thereby reducing the hazard to public health and theenvironment.

Bubbling not regulated by CUPAs under tieredpermitting structure.Initial review by DTSC: full standardized permitrequired, similar to TSDF, with implementation byDTSC


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DTSC regulates hazardous waste treatment, i.e. TSDfacilities requiring an expensive standardized permit.

In Monterey County, we have over 90 ammoniarefrigeration facilities, each servicing their equipmenteither by on site personnel or through a contractor.

Servicing equipment via zone isolation and purging ofvapors is a common industry practice.

Based on DTSC review, current practice of bubbling

constitutes illegal treatment of a hazardous waste.

Who regulates this treatment?


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Where do we go from here?Where do we go from here?

The Monterey Bay chapter of RETA and the ARTS Academy have come together to request a formaltechnical regulatory review by DTSC. A written

request has been submitted to the DTSC to make afinal determination of legal treatment methods. Theletter describes how ammonia vapors are drawn froma system component, the purpose of this practice,

the low hazard nature of the practice, and where thevapors go.


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In the meantime.Monterey County will continue industry outreach

efforts to promote safe treatment and disposalmethods.

Monterey County CUPA will not pursueenforcement action against those facilitiesconducting safe treatment of ammonia wastewater.

Facilities are required to properly dispose of orproperly discharge the ammonia wastewater andkeep records of disposal.

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