Auburn University Study: Investigation of covers for suppression of cyanobacteria in water treatment settling basins. By: Justin Box, Brendan T. Higgins, Xton Inc.
During the summer months, there is concern about algae and Cyanobacteria growth within water treatment facilities. Algae growth in settling basins can lead to toxins produced by certain Cyanobacteria as well as off-flavors due to geosmin and MIB production. Algal biomass also contributes to suspended solids which can lead to more rapid filter fouling. While water treatment plants have a variety of options for managing algae populations, we have investigated the use of Xton Inc. polypropylene covers to prevent algae and Cyanobacterial production within simulated settling basins. It was determined that the Xton Inc. covers prevented an algal bloom in mesocosms, likely due to a combination of blocking light and preventing insects from entering the mesocosms. It was found that insect populations led to increased levels of phosphate in the water, the key limiting nutrient for algae growth in freshwater systems.
Given that water treatment plants have a variety of options at their disposal for managing algae populations, the objective of this study was to conduct a comparison test among the options currently employed at the North Columbus Water Treatment Plant. As hypothesized, the Xton Inc. covers prevented algal growth in mesocosms. However, the effectiveness of the covers appeared to be derived largely from preventing insects from entering the mesocosms in addition to any light-blocking effects. An insect event coincided with a spike in phosphate levels in uncovered mesocosms which induced an algal bloom. There were no significant differences observed between single layer and double layer covers in terms of preventing algae growth. Cyanobacteria genes were detected in uncovered mesocosms but not in covered mesocosms, underscoring the effectiveness of the covers in preventing Cyanobacterial.