Process Operation

Lagoon operation is quite straightforward. It generally involves placing the required number of units in service to achieve the desired VOL or AOL and performing necessary maintenance so that facilities are available for service.

One of the principal difficulties experienced with lagoon processes other than CMALs is odors. The potential for odor production is an inherent part of anaerobic and facultative lagoons because the anaerobic metabolism occurring in them forms odoriferous organic and inorganic end products. Emission of these products can be controlled by minimizing transport to a receptor. For some wastewaters, scum and other materials accumulate on the surface of the lagoon, sealing it and restricting odor emissions. In other cases an overlying layer of relatively clean, oxygenated water is provided by encouraging the growth of algae in the overlying clear water (facultative lagoons), by providing devices that transfer oxygen into the overlying clear water (benthal stabilization basins), or by recirculating oxygenated water from a downstream aerobic unit. This latter approach is typically used when an anaerobic-lagoon is followed by a facultative lagoon. Covers can also be added to anaerobic-lagoons to contain odoriferous materials and collect the methane gas.

Organic overloads can cause odor problems when oxygen demands exceed oxygen supplies in any lagoon. Such upsets require that additional electron acceptor

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