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04/17/1995 15:49 303-782-0~ CDH WWCD WOCC PAGE 03 <br />• <br />r ~. <br />Urad Wt,i•tewater Tr~atmaat Procse• <br />Wastewater comes from four general sources at the Urad <br />reclamation site. The first source ie the collection of seeps and <br />subdraina along the toe of the dam of the upper tailing impoundment <br />(Urad 002). This water is piped by gravity to the treatment ponds. <br />The second source is the collection of seeps, aubdraine, and the <br />original decant line along the toe of the dam of the lower tailing <br />impoundment (Urad 003). This water is contained in the lower pump <br />pond and is pumped to the treatment ponds. The third source is the <br />aurficial drainage and seasonal runoff that ie collected between <br />the Urad portal and the plug. This water is piped by gravity to <br />the inlet of #1 Treatment Pond. The fourth source ie etormwater <br />collected on top of the lower tailing impoundment. The quality of <br />this source ie monitored and pumped to treatment as necessary. <br />The treatment system is composed of a aeries of unlined ponds <br />that reside on the lower tailing impoundment. A etxong base <br />(sodium hydroxide or equivalent) is used to adjust the pH to <br />precipitate dissolved metals, and a flocculant (Nalco 9710 or <br />equivalent) is used to assist in settling. #1 and #2 treatment <br />ponds comprise the basis for this chemical precipitation, and they <br />can be used in series (either direction) or in parallel. If <br />required, emergency treatment can be performed at the lower pump <br />house pond. After treatment the water flows into the c:learwell <br />system which is physically divided into two ponds. The first of <br />these ponds is called the j-well; it allows for clarification <br />(final polishing). At the end of this pond concentrated sulfuric <br />acid (or equivalent) is added to adjust the pH to meet permit <br />limitations. The final pond is called the clearwell; it aJ.lows for <br />complete mixing of the acid to maintain a stable pH prior to <br />discharge into Woods Creek (Urad 004). The purpose of the unlined <br />ponds is to allow leakage of high pH water through the tailing <br />impoundment and provide some in-situ treatment of metals within the <br />tailing area itself. <br />There are two main buildings used for the addition of <br />chemicals at the Urad site. The largest of these buildings is <br />known ae the reagent building and is located within the "~~ld Mill <br />Building". Ten thousand gallons of sodium hydroxide soltation ie <br />stored in this facility. Injection pumps deliver caustic: to the <br />ponds in buried, contained lines (pipe within a pipe). A carrier <br />stream of clean (woods Creek) water or treated process water ie <br />used to convey chemicals to their respective deatination~e. The <br />flocculant polymer ie stored in a 200 gallon tote and i.s flash <br />mixed and carried to the ponds in buried, contained piping. The <br />second building, which ie located near the j-well/clearwe:L1 dike, <br />presently has a large tote of acid that supplies small dosing pumps <br />for acid injection into a carrier system similar to that of the <br />caustic and flocculent. Installation of a four thousand gallon <br />bulk acid storage tank in the "Old Mill Building" is nearly <br />complete. The acid will then flow in a contained line from bulk <br />storage to the acid building. other satellite building6 serve <br />ancillary functions like housing pumps for supplying Carrier water <br />or vaults for accessing buried piping. <br />