Inclusion of pond walls to enhance solar exposure and pathogen removal
A.L. Hawley1* and H. J. Fallowfield1
1 Health and Environment Group, School of the Environment, Flinders University, GPO Box 2100, Adelaide 5001, South Australia
(free)
Pathogen removal in wastewater treatment ponds is limited by poor light penetration in the water column. Solar exposure is increased in high rate algal ponds through paddlewheel mixing and shallow pond depths however; insufficiently exposed areas remain. To address this inclusion of an inclined plane to these treatment ponds was considered to increase the area available for disinfection and improve reduction rates. The application of inclined planes was investigated in a laboratory based model system and a pre-existing high rate algal pond in the field. Corresponding controls were assessed for comparison under normal pond conditions. Reduction of F-RNA bacteriophage; MS2 was significantly higher in model systems where an inclined plane was present (P>0.05), with an increase of 1.0 Log10 reduction difference observed after 49.5 h exposure. Systems operated at similar hydraulic loading rates presented identical reduction rates regardless of slope length. Preliminary results from the field based system were not as conclusive, with no observable difference identified. Despite initial results from the field proof of concept had been presented in this paper
