Details of Rivenhall Plume Plotter

This page should be read in conjunction with How Plume Plotter Works. It provides more details specific to the Rivenhall version of Plume Plotter.

Important: the plume plotter only models the CHP emissions. As [1] states, "the exhaust air from the pulp plant, and the AD biofilter will vent to atmosphere via within (sic) the same wind shield as the CHP and gas engines exhaust. Although there will be no combustion gases within the exhaust from the pulp plant or the biofilter, the temperature of the release is much lower than the CHP and will impact upon the buoyancy of the plume". For this reason, the plume plotter tends to underestimate the ground-level pollution: predicted concentrations seem to average about 40% of those predicted in [1].

This version of the plume plotter assumes a stack height of 55m instead of the original 35m. All other details are the same as before.

Stack measurements

All of these are taken from [1]:

The following values are used for albedo, Bowen ratio, and roughness length. Roughness length is as specified in [1]:

Emissions

The emission rates of pollutants are taken from [1]. These are:

PollutantEmission rate
per second
Oxides of nitrogen10.27 g
Sulphur dioxide2.568 g
Carbon monoxide2.568 g
Particulates514 mg
Hydrogen chloride514 mg
VOCs514 mg
Hydrogen flouride51 mg
Ammonia514 mg
Cadmium and thallium2.568 mg
Mercury2.568 mg
Other metals25.68 mg
Benzo(a)pyrene5.393 μg
Dioxins and furans5.136 ng
PCBs256.8 μg

Background levels

The background levels of pollutants are taken from [1]. These are:

PollutantBackground
concentration per m3
Oxides of nitrogen14.89 μg
Sulphur dioxide3.65 μg
Carbon monoxide267 μg
Particulates19.58 μg
Hydrogen chloride720 ng
VOCs490 ng
Hydrogen flouride2.35 μg
Ammonia1.48 μg
Cadmium and thallium200 pg
Mercury1.38 ng
Other metals21.62 ng
Benzo(a)pyrene2 ng
Dioxins and furans22.82 fg
PCBs141.5 pg

Weather data

Wind speed, wind direction, temperature, pressure, and solar radiation are the latest values reported by one of two weather stations. If a value is not available from the primary weather station it is obtained from the secondary weather station. (Some weather stations do not measure solar radiation at all.) The primary weather station is IWITHAM3 and the secondary weather station is IKELVEDO5.

Upper air data is the latest reported by the Herstmonceux upper air station.

References

1. GENT FAIRHEAD & CO: RIVENHALL DISPERSION MODELLING ASSESSMENT, Fichtner, July 2015.