The performance of six separate percolation areas was intensively monitored to ascertain the attenuation effects of unsaturated subsoils with respect to on-site wastewater effluent: three sites receiving septic tank effluent, the other three sites receiving secondary treated effluent. The development of a biomat across the percolation areas receiving secondary treated effluent was restricted on these sites compared to those sites receiving septic tank effluent. This created significant differences in terms of the hydraulic loading on the percolation areas with implications for the transport and attenuation of indicator microorganisms and nitrogen down through the subsoils and into the groundwater. The results of this work have formed a large input into the production of a new Code of Practice Wastewater Treatment and Disposal Systems Serving Single Houses. This has led to changes in the design of on-site hydraulic loading from 180 L per capita per day (L/c.d) down to 150 L/c.d. The range of acceptable subsoils receiving septic tank effluent has narrowed for more highly permeable subsoils following a series of tracer studies using bacteriophages. However, the range has been extended for lower permeability subsoils (range 0.08 down to 0.06 m/d) receiving secondary treated effluent in order to encourage the effluent to spread further along the trenches. The maximum individual length of percolation trenches receiving secondary effluent has also been reduced to 10 m to encourage dispersion on a wider area. This paper thus highlights how research can directly feed into a Code of Practice.
Skip Nav Destination
Article navigation
Research Article|
August 01 2011
The development of a Code of Practice for single house on-site wastewater treatment in Ireland
L. W. Gill
1Department of Civil, Structural and Environmental Engineering, Trinity College, Dublin 2, Ireland
E-mail: [email protected]
Search for other works by this author on:
Water Sci Technol (2011) 64 (3): 677–683.
Article history
Received:
December 15 2010
Accepted:
May 16 2011
Citation
L. W. Gill; The development of a Code of Practice for single house on-site wastewater treatment in Ireland. Water Sci Technol 1 August 2011; 64 (3): 677–683. doi: https://doi.org/10.2166/wst.2011.685
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
eBook
Pay-Per-View Access
$38.00