title: Light attenuation parameters for waste stabilisation ponds.
abstract: Effective modelling of shallow water ecosystems, including waste stabilisation ponds, is strongly dependent on the availability of good estimates of the light attenuation coefficient k (m(-1)). Experimental data is presented on its determination using purpose-built laboratory apparatus with a near-parallel halogen light source and an array of photodiodes allowing measurements of irradiance at different depths. The equipment was used to compare k values from 4 different pure cultures, and mixed cultures of algae taken from a pilot-scale WSP. Laboratory values were compared with in situ measurements in the pond. At concentrations above 50 mg l(-1) the relationship between k and suspended solids is non-linear; k also varied with depth. This could be modelled by a single equation, suggesting similarity of response in different cultures. At shallow depths and low suspended solids concentrations k values are variable and hard to measure reliably. The results highlight the need to standardise on a method for the measurement and reporting of k values if these are to be widely applicable in the development of pond models.
authors.affiliation: School of Civil Engineering and the Environment, University of Southampton, Southampton S017 1 BJ, UK. sh7@soton.ac.uk
authors.forename: S
authors.initials: S
authors.lastname: Heaven
authors.forename: C J
authors.initials: CJ
authors.lastname: Banks
authors.forename: E A
authors.initials: EA
authors.lastname: Zotova
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D002734:Chlorophyll / Q000032:analysis; D017753:Ecosystem; D006219:Halogens; D008027:Light; D008954:Models, Biological; D014865:Waste Disposal, Fluid / Q000379:methods*; D014881:Water Supply
chemical_list: D006219:Halogens; D002734:Chlorophyll