Volatile suspended solids removal

Figure 15. Volatile suspended solids removal efficiencies for various media 6 fxm 0,1 fim A, 21 p.m and following 21 p.m.

MLVSS Mixed Liquor Volatile Suspended Solids - the volume of organic solids that can evaporate at relatively low temperatures (550 C) from the mixed liquor of an aeration tank. This volatile portion is used as a measure or indication of microorganisms present. Volatile substances can also be partially removed by air stripping. 

Hydrogen Oxidation Kinetics. Shea et al. (22) studied the kinetics of methane fermentation by an enrichment culture of lithotrophic (autotrophic) hydrogen oxidizing methanogenic bacteria at 37 °C. Reported values of the kinetic coeflScients are as follows (1) Y = 0.043 mg volatile suspended solids per mg of hydrogen COD removed, (2) b = —0.009 day"S (3) k = 24.8 mg hydrogen COD removed per mg volatile suspended solids per day and (4) Ks = 569 mm of mercury, hydrogen pressure. 

As shown in Figure 10, all of the organics removed in the process are either oxidized to CO and H O or synthesized to biomass generally expressed as volatile suspended solids. As previously noted, a small portion of the organics removed results in SMP products. 

Assay of polymer was by precipitation with Isopropyl alcohol. Procedures varied in detail from time to time, but in general, biomass was removed by centrifugation before precipitation. Biomass was taken to be "volatile suspended solids," the weight loss of the washed centrifugate between 102°C and 550°C. 

Cory Neth, an analyst for the City of Lincoln, Nebraska, Wastewater Treatment Plant Laboratory, removes a tray of crucibles from a muffle furnace. The crucibles are filtering crucibles used in the determination of suspended solids. The muffle furnace is used in the total suspended volatile solid test. 

Polybrominated Biphenyls. PBBs existed predominantly in the particulate phase in the atmosphere. Particulate phase PBBs are removed from the atmosphere by wet and dry deposition and should not travel long distances in the environment. In water, PBBs are expected to absorb strongly to suspended solids and sediment, and may bioconcentrate in aquatic organisms. The volatilization of PBBs from water to air is not expected to be important due to attenuation by adsorption in the water column. In soil, PBBs are adsorbed strongly and will be immobile. Volatilization of PBBs from soil to air is not important due to the low volatility of PBBs and strong adsorption of PBBs to soil. 

A. B. Gerber s process, cone, phosphoric acid is partially freed from arsenic, lead, lime, and fluorine by chemical methods, and is then subjected to a current of air at a temperature of 50° to remove volatile impurities. The suspended solids are then separated and the acid cooled, when crystalline phosphoric acid separates. 

Many processes are operative in the environment that contribute to the regional elimination of a contaminant by altering its distribution. Contaminants with sufficiently high vapor pressure can evaporate from contaminated terrestrial or aquatic compartments and be transferred through the atmosphere to new locations. Such processes of global distillation are considered largely responsible for the worldwide distribution of relatively volatile organochlorine pesticides such as lindane and hexachlorobenzene. Entrainment by wind and upper atmospheric currents of contaminant particles or dust onto which the contaminants are sorbed also contribute to contaminant redistribution. Sorption of contaminant to suspended solids in an aquatic environment with commensurate sedimentation can result with the removal of contaminants from the water... 

Narkis and Henfield-Furie [578] have described a direct method for the identification and determination of volatile water-soluble Ci C5 acids in municipal waste water and raw sewage. The method involves direct injection of the sewage into a gas chromatograph equipped with a Carbowax 20m on acid-washed Chromosorb W column and a flame ionisation detector. Preliminary preparation of the sample is limited to the addition of solid metaphosphoric acid to the sewage and removal of precipitated proteins and suspended solids by centrifuging. 

Evaporation is the major route by which chlordane is removed from soil. Photochemical breakdown by exposure to sunlight plays a very minor role in eliminating chlordane from soil. In water, the major mechanism by which chlordane exits is by volatilization or by adsorption to sediments. Therefore, surface water almost always has very little chlordane while the higher concentrations are found in suspended solids and sediments. 

In aquatic environments, the heavier and less vola-tile/soluble compounds in crude oil will adsorb to suspended solids and subsequently settle in the sediments. Some heavy fractions with high density may sink into the sediment. This happens after the initial removal of the smaller and more volatile chemicals by either dissolution or volatilization. This is followed by biodegradation of those crude oil constituents that can serve as a food source for bacteria. Biodegradation is a significant mechanism for removal of hydrocarbons released into the environment. However, this generally occurs on the order of months and years. It is not believed that there is significant bioaccumulation of petroleum hydrocarbons in aquatic organisms. 

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