Light attenuation parameters for waste stabilisation ponds

• Main Authors: Heaven, S. (Author), Banks, C.J (Author), Zotova, E.A (Author)
• Format: Article
• Language: English
• Published: 2005-06-01.
• Subjects: Article
• Online Access: Get fulltext; Get fulltext

 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 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 1(-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.