Session Presenter: Dr. Sara Heger, University of Minnesota
Title: How Even are Gravity Distribution Devices
Content: Gravity-fed septic systems rely on distribution devices such as header pipes, splitter tees, or distribution boxes to divide effluent between multiple soil treatment trenches or beds. The University of Minnesota conducted experiments testing the ability of various devices to provide even lateral distribution between multiple drain pipes and longitudinal distribution along the length of each pipe. The devices tested included header pipes, splitter tee, and distribution box, as well as a surge box that accumulates and releases effluent in higher-volume doses. Each device was tested in multiple configurations including level and tilted, with gravity inflow rates of two gallons per minute (GPM) and 5 GPM and pumping to gravity, with two or four outlets, and with and without drain holes at the 6 o’clock (bottom) position of each drain pipe. It was observed that the surge box provided the most even lateral and longitudinal distribution in almost all test cases. All devices performed well when level with an inflow of 5 GPM, two outlets, and no 6 o'clock drain holes, but when these parameters were varied the performance of the header pipes, splitter tee, and distribution box deteriorated.
Title: Lessons Learned from Commercial Sampling
Content: Taking wastewater samples from septic systems is an important task regularly performed by service providers, operators, and maintainers along with designers/engineers to collect data as far as organic loadings and constituent levels. This data is sometimes used for regulatory purposes or to help us understand what we are working with. This data can be used to compare systems, rate performance, and calculate loading rates. This presentation will include the equipment needed and provide instruction on how to take a good sample and the related timing. It will show case studies of commercial system sampled and range in data and related performance.
Title: Flows: Design to Maintenance
Content: This presentation will begin with the options for determining flows for homes and commercial establishments The methods to collect flow data from commercial properties will be discussed. It will review examples of challenging flow determination with mixed-used commercial and residential applications. The presentation will then discuss during management how to determine the flows the structure is generating and relate that to the design flow. Implications for management, including adjustment of time dosing, will be discussed.
Title: Inspecting and Troubleshooting Soil Treatment Systems
Content: This session will cover the process of evaluating and inspecting soil treatment systems including trenches, low-pressure pipe systems and mounds. As part of troubleshooting, we must evaluate the vegetation and depth of ponding. It will include a discussion on various distribution methods and the related development of a biomat. Problems associated with hydraulic and organic overload will be highlighted. Common device and product issues from within homes and businesses will be discussed.