BARLEY STRAW TO IMPROVE PERFORMANCE OF SMALL WASTEWATER TREATMENT LAGOON SYSTEM

Algae blooms occur in many wastewater treatment lagoons during summer months, resulting in increased concentrations of total suspended solids (TSS) in these lagoons' effluents. The 0.4 Mgd wastewater treatment lagoon in New Baden, IL often exceeds its TSS discharge criteria in summer due to algae overgrowth. New Baden used copper sulfate to control algae in the past, but discontinued its use because of the expense of the chemical, and the concerns of copper build-up in lagoon's sediments, as well as possible toxic effects to the receiving water of the lagoon's effluent. Several field and lab studies, conducted in U.K. during the 1990s, reported that decomposing barley straw in ponds, canals, or reservoirs showed inhibitory effect on algae growth in the tested water bodies. There appears to be the potential to use barley straw as a cost-effective means for algae control in wastewater lagoons. This report documents the findings of a field study investigating the impact of decomposing barley straw on algae growth and water quality in New Baden's wastewater treatment lagoon. The field work was conducted from March to November 2004. Three batches of barley straw were deployed in two of the lagoon cells at a loading rate of 200 pounds/acre. The deployed barley straw remained in the lagoon for 3-4 months. Monitored parameters included chlorophyll a (indicating the amount of algae), TSS, pH, BOD5, phosphate, dissolved oxygen (DO), and temperature. Results showed that, when the lagoon effluent quality in the application year of 2004 was compared to that in the non-application year of 2003, TSS was consistently lower in the application year, BOD5, pH, DO, and ammonia-N were comparable. The application of barley straw did not result in much change in the concentrations of orthophosphate. In the lagoon cells where barley straw was applied, the concentrations of chlorophyll a remained unchanged from the inlet to the outlet, indicating the inhibitory effect on the further growth of algae in these lagoon cells. The results of this field study demonstrated that barley straw is a promising means by which wastewater treatment lagoons could improve performance and meet discharge permit requirements.