Lagoons process

Kjerfve, B J. (ed.) (1994) Coastal lagoons. In Coastal lagoon Processes, pp. 1-7, Elsevier Oceanography Series, New York. 

Although the sludge evaporation lagoon process is also called a sludge drying process, there is a difference between evaporation and drying. 

Residue Disposal. The major environmental problem in the Bayer process is disposal of bauxite residue which is effected by marine disposal, lagooning, use of underdrain lakes, or semidry disposal. Marine disposal in oceans or rivers, diluting the alkaline residue by large quantities of water, is environmentally unacceptable. Lagooning behind retaining dikes built around clay-sealed ground is commonly used, but there have been isolated leaks into aquifers. This has motivated installation of underdrains between the residue and clay-sealed, plastic-lined, lake bottom. This design removes the hydraulic head from the lake bottom and improves consoHdation of the residue. 

Aerated lagoons are employed for the treatment of nontoxic or nonha2ardous wastewaters such as food processing and pulp and paper. Retention time varies from 3 to 12 d, so a large land area is usually required. 

The BPT is defined as the level of treatment that has been proven to be successful for a specific industrial category and that is currendy in fuU-scale operation. Sufficient data exist for this level of treatment so that it can be designed and operated to achieve a level of treatment consistendy and with rehabUity. For example, in the pulp and paper industry, BPT has been defined as biological treatment using the aerated lagoon or the activated sludge process with appropriate pretreatment. 

The goethite process precipitates crystalline aFeO-OH (goethite) as well as PFeO-OH, aFe202, and amorphous phases. The reaction is carried out at 90°C and pH 3.0, for 4—6 h in either batch or continuous fashion, and the iron(III) ion must be kept <1 g/L. Both jarosite and goethite soHds are usually lagooned. 

The four most common aerobic biological treatment processes are stabilization ponds, aerated lagoons, trickling filters, and activated sludge (see... 

USATHAMA) completed a trial burn of explosive, contaminated soil in a rotary kiln (Noland, 1984). Soil contaminated from red and pink water lagoons was successfully burned. A transportable rotary kiln yrstem was set up. The technology by Therm-All, Inc., had been used in industry for destruction of solid wastes. The normal screw feed system was not used, due to fear of a soil explosion during the extruded plug feed process. Therefore, the soil was placed in combustible buckets and individually fed by a ram into the incinerator. The feed rate was 300 to 400 Ib/hr and the operational temperature was 1200° to 1600°F in the kiln and 1600° to 2000°F in the secondary chamber. 

In the profiles of the core from the industrial area, mercury displays the highest accumulation. Mercury in this area, close to the industrial district, has probably derived from a large chloralkali plant which has employed mercury cathodes since the fifties. Whereas, at present, very severe measures are taken to prevent mercury spills into the Lagoon, in the past, polluted waters and solid materials were discharged almost untreated. In the most superficial strata a marked decrease in the accumulations is, in fact, recorded. Lead and Cd accumulations are lower here by a factor of 5-10. The presence of cadmium in the sediments of the Lagoon has been referred to sphalerite (ZnS) processing on the basis of a strict concomitant... 

The milk production stage is the largest source of GHG emissions over the entire life cycle of fluid milk production. CH4 is generafed primarily through enteric fermentation of dairy cows and also through the microbial, anaerobic decomposition of manure. Manure deposifed on soil or handled as a solid, an aerobic process, emits little CH4. However, manure generates CH4 when stored under the aerobic conditions of a lagoon. 

It is worth noting that there are preparation stages of the plant biomass before they can be used for pollutants removal, in the case of rhizofiltration and bioadsorbents-based systems (Figure 10.2), which may increase the investment and operational costs. On the contrary, the lagoons and CWs are designed to process the influents in one single stage. 

Bioremediation is defined as the use of microorganisms or microbial processes to degrade environmental contaminants. Bioremediation has numerous applications, including cleanup of groundwater, soils, lagoons, sludge, and process waste streams. 

The aerobic biofilter used in the study had a capacity of 10 L. The reactor was packed to 60% of the empty bed volume with Cosmo ball media. The biofilter was seeded with active innoculum taken from an active aerated lagoon of a nearby landfill leachate treatment. Fresh raw leachate was used as feed to the reactor at a rate of 5 L/d over 24h. The loading rates applied to the bioreactor were between 1.6 and 22.2 kg COD/m3d. Initial studies were conducted as a batch process lasting for a period of 24 d. Thereafter, the biofilter was fed continuously for a total period of 240 d. 

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