Treatment Technologies

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0 height="100%"><tr> <td valign="top" width=200 BGCOLOR="#003333" TEXT="#F7F7FF" background="040d4c00dduajq.gif"> <div> <TABLE BORDER="0" CELLPADDING="2" CELLSPACING="0" WIDTH="95" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="ALL" ALIGN="BOTTOM" HSPACE="0" VSPACE="0" > <tR> <tD VALIGN=TOP HEIGHT= 46 WIDTH="91"><IMG BORDER="0" SRC="1x1.gif" HEIGHT="46" ALIGN="bottom" WIDTH="91" HSPACE="0" VSPACE="0"></tD> </tR> </TABLE></div> <bR> <div> <IMG SRC="099a5e90.gif" border=0 width="165" height="233" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> </td> <td valign="top" BGCOLOR="#FFFFFF" TEXT="#080000"> <div> <FONT SIZE="5" COLOR="#003333" FACE="Arial" ><B>Tradable Pollution Discharge Permitting for Industrial Users</B></FONT>     |     <A HREF="index.htm" TARGET="_top" TITLE="Tradable Pollution Discharge Permitting "><U>home</U></A></div> <div> <A HREF="id17.htm" TARGET="_top" TITLE="About Me"><U>About Me</U></A>   |   <A HREF="id23.htm" TARGET="_top" TITLE="Tradable Discharge Permits For Industria"><U>Tradable Discharge Permits For Industrial Users</U></A>   |   <A HREF="id18.htm" TARGET="_top" TITLE="Equimarginal Principal (a simplified app"><U>Equimarginal Principal (a simplified application using two firms)</U></A>   |   <B>Treatment Technologies</B>   |   <A HREF="id19.htm" TARGET="_top" TITLE="Segregation of Wastestreams"><U>Segregation of Wastestreams</U></A>   |   <A HREF="id24.htm" TARGET="_top" TITLE="News Items"><U>News Items</U></A>   |   <A HREF="id22.htm" TARGET="_top" TITLE="Favorite Links"><U>Favorite Links</U></A>   |   <A HREF="id20.htm" TARGET="_top" TITLE="Contact Me"><U>Contact Me</U></A></div> <div> Treatment Technologies</div> <bR> <div> Treatment Technologies for General Wastewater Applications</div> <div> Some of the processes used in the POTW are similar to those used by the IUs such as coagulation/precipitation; however, the WWTP by the nature of its function must use technology such as <I>aeration</I> processing that is simply not needed by the firms. Another example is preliminary treatment using the <I>barscreen </I>process to remove hard objects before entering the POTW. Firms have no need for this technology because they have total control over what goes into the wastestream and generally speaking, hard objects are not a consideration for IUs with metal wastewaters. First we will describe the POTW treatment technologies, then we will look at the IUs technologies.</div> <bR> <div> <B><U>Review of Basic </U></B><B><U>WWTP</U></B><B><U> Technologies</U></B></div> <div> <B>Barscreen</B>; for removal of solids such as rocks, rags, wood, and other "hard" objects from the wastestream as it leaves the <FONT SIZE="4" COLOR="#FF0000" FACE="Arial" ><I>collection system</I></FONT> and enters the plant treatment system.</div> <div> <B>Aeration;</B> in this process (used primarily for BOD and suspended solids removal) raw wastewater influent is agitated and fed waste activated sludge or "WAS" from the clarifier system. The WAS acts to feed the microorganisms in the aeration "mixed liquor", where they remove organic and other molecules trapped in the sludge.</div> <div> <B>Clarification</B>; the metal ions in solution react with the hydroxide ions to form solid particles that sink and separate from the liquid wastewater into the residual sludge or solids portion of the separation process. This technology has proven to be quite reliable and inexpensive, especially in cases where acceptable discharge levels separation can be achieved without the use of chemical additives.</div> <div> <B>Dissolved Air Flotation</B>; basically, the DAF system is the clarification process in reverse; the sludge is floated to the surface using forced air, becomes thickened WAS or “TWAS” then is skimmed off and pumped to the digesting system. This particular sort of separation is necessary in order to condition the sludge for processing in the digester unit.</div> <div> <B>Digester</B>; the digester<B> </B>process involves anaerobic sedimentation and digestion of organics; the by-product of this anaerobic process is the release of digester gas (a form of CH4) where low levels of metals are removed in the volatile exchange, from the sludge/wastewater train.</div> <div> <B>Dewatering</B>; from the digesters, the sludge is pumped to the <B>belt-press system</B> where the sludge is dewatered and loaded onto trucks for either landfill (about 20%) or land spreading disposal. </div> <bR> <bR> <div> <B>     </B><B><U>Review of IU'S Technology</U></B><B> </B></div> <div> <B>Precipitation/coagulation</B>; this is basically the same clarification process being employed by the POTW, but on a much smaller scale.</div> <div> <B>Ion Exchange</B>; This method involves a complex chemical reaction; as the wastewater passes over a process resin, undesirable metal ions dissolved in the wastewater are exchanged for desirable ions of similar electrostatic charge. Cation particles (such as H+) attached to the resin particles, exchange adsorption sites with the metal ions; the resin now has the metal ions attached to it and the wastewater contains the H+ ions.</div> <div> <B>Membrane processes</B>; There are a number of membrane processes used for pretreatment of industrial wastewater; electrodialysis, ultra filtration, and reverse osmosis are commonly used control technologies for metals removal. Each of these technologies utilizes membrane separation processes to control metals in their wastewater discharge.</div> <div> <B>Evaporation</B>; During evaporation, a solution is concentrated when a portion of the solvent (in most cases water) is vaporized, leaving behind a concentrated saline liquor that contains virtually all of the dissolved solids from the original wastestream.</div> <div> <B>Adsorption</B>; the adhesion of dissolved substances to the        </div> <div>       surface of solid particles. One familiar example is the</div> <div>       use of <I>activated carbon</I> that is capable of removing           </div> <div>       impurities from drinking water.</div> <bR> <div> A basic method for achieving effective pollution control   by IU's is through <FONT SIZE="4" COLOR="#0000FF" FACE="Arial" >segregation of wastestreams...</FONT><FONT SIZE="2" COLOR="#000000" FACE="Arial" >(click this title/page next)</FONT> By separating wastreams of different constituents, firms can apply specific technologies that are suited to particular pollutants, thereby achieving the highest possible level of total control. </div> <bR> <bR> <div> <A HREF="id17.htm" TARGET="_top" TITLE="About Me"><U>About Me</U></A>   |   <A HREF="id23.htm" TARGET="_top" TITLE="Tradable Discharge Permits For Industria"><U>Tradable Discharge Permits For Industrial Users</U></A>   |   <A HREF="id18.htm" TARGET="_top" TITLE="Equimarginal Principal (a simplified app"><U>Equimarginal Principal (a simplified application using two firms)</U></A>   |   <B>Treatment Technologies</B>   |   <A HREF="id19.htm" TARGET="_top" TITLE="Segregation of Wastestreams"><U>Segregation of Wastestreams</U></A>   |   <A HREF="id24.htm" TARGET="_top" TITLE="News Items"><U>News Items</U></A>   |   <A HREF="id22.htm" TARGET="_top" TITLE="Favorite Links"><U>Favorite Links</U></A>   |   <A HREF="id20.htm" TARGET="_top" TITLE="Contact Me"><U>Contact Me</U></A></div> <bR> </td> </tr></table></body>