Case Study – OMND Plant in North Dakota

This presentation will discuss the operation of a 6 MGD pressurized two-stage Ultrafiltration (UF) plant over a 3 year period at the Oliver-Mercer-North Dunn (OMND) Drinking Water Treatment Facility. The OMND Treatment Facility utilizes Ultrafiltration followed by low pressure Reverse Osmosis Softening to produce a blended Finished Water capacity of 5.2 MGD. The 6 MGD capacity of the UF system supplies the feed water for the softening system and a softening bypass system for a blended Finished Water consisting of 60% softening system product water and 40% UF Product water. The plant is located approximately 12 miles (20 kilometers) northwest of Beulah, North Dakota, USA and uses Missouri River water from the Lake Sakakawea reservoir as a source of supply. At the OMND Plant calculated LRV values are consistently greater than 4.5 log using the Darcy-Pipe model. Other conservative parameters were also used in the LRV calculations in determining the minimum test pressure required for detection of a 3 Êm or smaller breach in the membrane surface. For the pore-shaped correction factor (?) the most conservative value of 1 was used. For the liquid – membrane contact angle (O) zero degrees was used as opposed to a measured contact angle.
Overall integrity performance of the plant will be discussed in detail, as well as Trans-Membrane Pressure (TMP), flux, temperature corrected permeability (specific flux) and cleaning efficiency for both the first and second UF stages will also be presented.