Particle filtration, marine

An attempt has been made to use Millipore cellulose ester membranes to size sewage and sludge particles (see Chen et al. (15)). However, previous work on marine particle filtration (see Sheldon (16), Sheldon and Sutcliff (17), and Cranston and Buckley (18)) clearly shows that cellulose ester membranes are unsuited for such separation. Sheldon and Sutcliffe (17) point out that one manufacturer of such membranes, Millipore, actually recommends that their product not be used in such applications. 

Effective inlet air filtration is required to ensure satisfactory operation of the engine. The location of the unit determines the most appropriate filter system to use. Desert environments where a large amount of sand particles could be expected in the ambient air may use an automatic roll type of filter that allows new filter material to be rolled in front of the inlet without frequent shut-downs to change filters. Arctic or extremely cold locations may use pad type filters, snow hoods to prevent blockage, and exhaust recirculation to prevent icing. Filter assemblies for offshore marine environments may include weather louvers, demister pads, and barrier elements for salt and dirt removal. Screens may be u.sed for insect removal prior to filtration in areas with bug problems. 

As far as the environment is concerned the main factor is to remove solid particles by settling and filtration and to remove marine Crustacea by screening. 

Buesseler KO, Bauer JE, Chen RF, Eglinton TI, Gustafsson O, Landing W, Mopper K, Moran SB, Santschi PH, Vernon Clark R, Wells ML (1996) An intercomparison of cross-flow filtration techniques used for sampling marine colloids overview and organic carbon results. Marine Chem 55 1-31 Buffle J, Perret D, Newman M (1992) The use of filtration and ultrafiltration for size fractionation of aquatic particles, colloids, and macromolecules. In Enviroiunental particles. Buffle J, van Leeuwen HP (eds) Lewis Publishers, Boca Raton FL, pl71-230... 

Two simulations of the effects of solid-liquid separation are considered here. From, algae to aquifers, these are, first, a consideration of the effects of coagulation on algal populations and sedimenting algal fluxes in marine waters taken from Jackson and Lochmann (28) and, second, evaluation of the effects of deposition or filtration on the transport of particles in groundwater systems taken from Tobiason (29). 

Seawater is pretreated before reaching the reactor and generally involves screening and filtration to remove suspended particles such as silts, sand, and marine creatures followed by decarbonation. Decarbonation is achieved by adding concentrated sulfuric acid to the seawater to lower the pH to 4 see reaction (3.9). The seawater is then passed over a wooden (creosote- and tar-treated) desorption tower where it is aerated to remove carbon dioxide. 

Petrick G, Schulz-Bull DE, Martens V, Scholz K, and Duinker JC (1996) An in-situ filtration/extraction system for the recovery of trace organics in solution and on particles tested in deep ocean water. Marine Chemistry 54 97-103. 

Filtration is used either to separate particulate matter in sea water fof analysis or to obtain a particle-free sample of water for the analysis of soluble material. Several types of filter have been recommended for marine work and continuous centrifugation at high speed can be surprisingly effective although it is generally inconvenient to manipulate. To replace paper filters, organic membrane filters and glass-fiber or silver-fiber filter papers are commonly employed. Vacuum may be controlled by one of the devices mentioned on p. 182. 

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