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H1 Risk Assessment

When applying for a standard permit, the Environment Agency have done most of the risk assessment for you. When you apply for a bespoke permit their maybe some grey areas with regards to risk, as such a H1 Risk Assessment may be required.

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Aims of the H1 Risk Assessment

A H1 Risk Assessment is a method for gauging risks of certain aspects of your activities. Below we have jumped straight in to an example, as to why an H1 Risk Assessment is required:

https://upload.wikimedia.org/wikipedia/commons/thumb/6/67/Risk_Analysis_Chart.svg/512px-Risk_Analysis_Chart.svg.pngAn operator is recycling plastics, and there are several emissions points where vapors and particulates from the recycling process are escaping in to the air, of particular concern may be VOCs;

 - Bromodichloromethane

 - 1,1-Dichloroethane

 - Tetrachloromethane

The above three VOCs are being released and it unclear whether the levels are safe. Do they pose a risk to the environment? Do they pose a risk to nearby residents? This is where the H1 Risk Assessment comes in to play.

By assessing volumes, concentrations, dilution and sensitivity of receptors a risk level can be deduced. This information can be used to;

1 - Help Support an application for an Environmental Permit

2 - Lessen Monitoring Requirements for a Particular Substance

Wlofab [CC BY-SA 4.0], via Wikimedia Commons

There are four major steps in completing an H1 Risk Assessment, the first is to identify the risks associated with your permitted activity, the second is to assess those risks, the third to decide on appropriate measures (and to justify those measures, and finally to present your findings to the Regulator (Environment Agency).

If you have any question regarding H1 Risk Assessments in connection with Environmental Permits then please contact SWEL for a free initial consultation.

H1 Risk Assessment - Case Study - Typical Procedure & Data Requirements

SWEL have completed numerous H1 Assessments for various installations and discharge activities. The "meat" of the work is finding the data to put into the assessment, the rest is quite easy. The job can be very quick if the data is to hand but in most cases it is not, which may require monitoring or consultations with various bodies. For a H1 assessment for an Installation Permit we would require quite a lot of data.

Indirect Emissions

This covers thing like electricity use . . . . global warming potential and the likes.

Direct Emissions

This would deal with discharges to water, air and land. In each case you will need a wealth of data in order to populated the H1 software. The Environment Agency ordinarily insist on MCerts accredited monitoring. An example might be NOx, SOx or POx.

Environmental Data

River flow by volume, water quality and air quality, these are required to populate the H1 Assessment Software.

H1 Software Use

Once you have all of you data in place, this is put in to the H1 Software (which is freely available) and hopefully when you consider the volume of output, the concentration of output, the back ground level and the dilution and dispersion, then the substances such as lead, or copper will "screen out" if they do then this is good news. If they do not then you will either have to upgrade your abatement or treatment systems or undertake detailed modeling.

Detailed Monitoring

If the H1 tool does not screen out for a particular substance, then detailed modeling will have to be undertaken. This involves using a program such a aermod, to calculate concentration of certain substances at certain points. You may avoid abatement & treatment upgrades if it can be shown that concentrations are acceptable at nearby receptor locations.

H1 Risk Assessment - Air Impacts: Stage One Screening &  Stage Two Screening

There are two screening levels within the the Air Impacts section of the  H1 modeling software:

Stage 1 Screening

If you process contribution (emission) greater than 1% or 10% of the EAL (Environmental Assessment Level) then it will screen out at this stage. The EAL for different substances depends on the potential for harm that they have. For example PM10 particulates are thought to be less harmful than than PM2.5 Particulates and as such have a higher EAL. Some substances such a Chromium 6 have a very very low EAL. Because they are intensely carcinogenic.

Stage 2 Screening

In stage two screening various additional variables are added to the model. The main additional variable is Background Concentration. This can help of hinder you cuase in terms of screening out, but in our experience you are more likely to screen out at Stage 2 rather than Stage 1.

H1 Risk Assessment - Abatement

When you have received the monitoring data (as above) it is time to start experimenting within the H1 modeling software to see whether you will need abatement. The key here is to have conducted the right kind of monitoring. Each set of monitoring may take a month or so to arrange, it is best to get it all done in one hit. The way to do this is set up a test rig which includes an array of abatement technologies, say a scrubber, a centrifuge and a GAC filter. Monitoring is done at each stage of the test rig. This allows you to obtain data for a variety of abatement options simultaneously.

H1 Abbreviations

BAT - Best Available Technique
BATAEL - Best Available Technique Associated Emissions Level
EAL - Environmental Assessment Level
EQS - Environmental Quality Standard
H - Horizontal (Guidance)
NCCC - National Customer Contact Centre
OPRA - Operational Risk Appraisal
PC - Process Contribution
PEC - Predicted Environmental Concentration
PHS - Priority Hazardous Substance
PCOP - Photochemical ozone potential
Q95 - Freshwater flow equalled or exceeded for 95% of the year
TraC - Transitional and Coastal