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05/25/2009 13:27 9518273349 DOUGLAS KUNEY PAGE 05/14 <br /> Mechanical aerators may reduce the surface requirement <br /> considerably, but at the expense of signifiLant operating w <br /> costs. Aerators are normally applied to soave actor problems <br /> with existing lagoons. So, aerobic processes are usually <br /> ill suited for lagooning poultry waster. :rI <br /> Anaerobic systems are generally the iagoan stems of choice <br /> for treating poultry wastes. These systemsare designed ori <br /> the basis of volume for a specified unit wa to load, and can <br /> decamspoze %oxe organic material per unit of volume thAn <br /> aerobic processes. Thr balance of this dinzussion will deal <br /> with anaerobic lagoon systems. <br /> Sdeolly, lagoon temperature should be c t at 95 F to : <br /> maintain a balance between acid-forming and met�eana--forming <br /> ana�arobic bacteria,. The lagoon will produe�e minim%= odors <br /> when these bacteria groups are balanced. iovever, as• a <br /> kalamctical matter, the operator has little c�ontral aver <br /> lagoon temperatures. Rapid fluctuations int vexature may <br /> bo avoided by making the lagoon as deep as ,`possible. <br /> However, there are practical limits to depth; deep lagoons <br /> warm more slowly than shallow lagoons in spring and suamrer, <br /> and cool more slowly in the fail. The net effect is that <br /> more days of higher summer temperature are likely to be more <br /> biologically productive than a few degrees of higher winter <br /> temperature; when temperature of the lagoon falls into a <br /> range of 59 to 39 F, bacterial activity isiminimal. <br /> Therefore# a moderate depth Dr a to 12 feel+ is generally a , <br /> good compr=ize. <br /> The vide range of temperatures given for mLimal bacterial <br /> activity is due, in part, to the fact that I the lagoon <br /> process is two-staged, composed of two v different type <br /> of bacteria. The first, an acid-forming stage, is quite <br /> robust and is active down to about 39 F. the second stage, <br /> =thane formation,, is more sensitive to chdnge, and .has vexy <br /> limited activity below 59 F. So, acid levils typically <br /> inareass during winter Vithout significantutilisation of <br /> acids by methane bacteria. Consequently, cess acidity <br /> preduced during winter is similar in effectl to lagoon <br /> overloading, and contributes to an increamok in spring odor <br /> levels from the lagoon. Lik doe, aUddea -+- eraturs <br /> mages upowt the baste ria balance and resiLlt in an i n *"* <br /> in acid-foxxs= and disag eabIs odors. Vise usually occurs k <br /> in early spring, and sometimes its the fallL After a winter <br /> of little bacterial action, but with contifiucuse loading or <br /> wastes er <br /> matials, higher spring water t -, I--tures increase <br /> microbial action, and foul odors are soat,et� mes generated as <br /> bacteria populations are re-established. <br /> Desirable combinations of bacteria groups ars obtained when, <br /> among other conditions, lagoon pa is betwebn 7.0 and 7.5. <br /> Imbalances In pH are most often S molt o sudden <br /> temperature changes, overloading, or slug loading of waste*, <br /> M <br />