environmental impact statement kilmainhamwood compost facility ...

5361- Kilmainhamwood Compost Facility Extension- EIS
Table 2.1 Water Management Plan
Facility Area Water Use m 3 per Day Water Source
Composting Building
Facility Administration
Building
Washing
Requirements
Washing
Requirements and
Potable Water
27
0.6
0.3
Rainwater
Storage Tank
On Site
Borehole (BH3)
The capacity of the rainwater storage tank is 36m 3 . Given that:
� The rainwater storage tank can provide wash water requirements for a dry weather period of 60
days; and
� 4.5mm of rainfall will replenish the tank on the basis of a total roofed area of 7961m 2 ;
It is reasonable to assume that all water usage for washing requirements within the composting building
can be provided by collection of rainfall.
An onsite water treatment plant is proposed at the point of entry to the facility administration building to
treat the borehole (BH3) supply to drinking water standards. It is proposed to provide a package plant in
the Tea Station providing chlorination and filtration.
Surplus roof rainwater will overflow from the rainwater storage tank to the roof water sewer and will
combine with the yard water sewer (downstream of the oil interceptor). The green field runoff rate to the
existing drainage ditch will be controlled by a hydrobrake. An overflow, downstream of the oil
interceptor, will discharge into a proposed attenuation area as shown on Drawing No. 5361-2402.
2.5.7 Odour Abatement System
The odour abatement system currently in operation at the Kilmainhamwood Compost facility involves
biofiltration.
Biofilter Principle
For inspection purposes only.
Consent of copyright owner required for any other use.
It is widely accepted that the wide range of micro-organisms found in soils can oxidise many
compounds, including both volatile organic compounds and other odourous compounds. Prepared beds
have therefore been used for odour control for about 40 years. With adequate construction and
maintenance of biofilter beds, they can be very effective for odour abatement. Mixtures of porous, well
structured material with some compost are typically used and the bed is kept open by turning the top
layer two or three times per year. Adequate bottom drainage is essential, as is the facility to keep the
bed moist in dry weather.
The residence time in a biofilter depends largely on the substrate. For most odorous air or gases, a
residence time of approximately 28 seconds is required. The typical height of biofilter beds is 1 to 2
metres, so that a linear flow rate of approximately 130 m3 (h) (m2) is provided. Greater bed heights will
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