| Total suspended solids (TSS) in discharge water can have significant impacts on fish health. A polishing pond system is a common control often installed to mitigate TSS. The objective of this work was to examine the design of a polishing pond and use field data to determine if the design settles out TSS without exceeding the regulatory limit of 25 mg/L. Averages of these data were used to examine trends and then compared to the criteria for the design basis. The results of the field study indicated that the operating system exceeded all the design inputs, in particular soil type, velocities and TSS water quality data. This showed the need for collection of field parameters to confirm the design basis prior to construction. It also demonstrated the benefits of assessing an operating system against the design parameters in an effort to continuously improve the mitigation measures for TSS. |
