Solid waste filter solids

A summary of any liquid or solid waste (filter cakes, washes, mother liquors or distillates) which will be produced in the process. The composition of each particular waste stream is given as well as an indication of any associated disposal problems of which the chemist may be aware. 

Semidry Scrubbers The advantage of semidry scrubbers is in that they remove contaminants by way of a solid waste that is easier to dispose of (less expensive). Initially, the scrubbing medium is wet (such as a lime or soda ash slurry). Then a spray dryer is used to atomize the slurry into the gas which evaporates the water in the droplets. As this takes place, the acid in the gas neutralizes the alkali material and forms a fine white solid. Most of the white solids are removed at the bottom of the scrubber while some are carried into the gas stream and have to be removed by a filter or electrostatic precipitator (discussed later). Although semidry systems cost 5-15% more than wet systems, when combined with a fabric filter, they can achieve 90-95% efficiencies. Dry scrubbers are sometimes used in a very similar fashion, but without the help of gas-liquid-solid mass transfer, these systems use much higher amounts of the solid alkali materials. 

A number of things are not shown on these process flow sheets. One is the storage facilities for the feed, product, and by-products. The second is the waste treatment facilities. All water leaving the process must be sent through treatment facilities before it can be discharged into lakes or rivers, and some means must be devised to get rid of the solid wastes from the filters and the centrifuge (see Chapter 16). 

A primary and secondary treatment plant to handle all process water. Any solid waste that cannot be sold will be used for landfill. All air laden with polystyrene dust will be sent through bag filters before it is discharged to the atmosphere. 

The environmental impact of the proposed GATS process appears to be minimal. All handling and processing of agent will be conducted indoors in sealed rooms that are vented through HEPA and carbon filters. Liquid and solid waste streams will be relatively small and manageable and will be subjected to hold-test-release procedures. 

Disposal of solid wastes is a significant problem for the petrochemical industry. Waste solids include water treatment sludge, ashes, fly ash and incinerator residue, plastics, ferrous and nonferrous metals, catalysts, organic chemicals, inorganic chemicals, filter cakes, and viscous solids. 

Waste material snch as tank bottoms from crude oil storage tanks constitute a large percentage of refinery solid waste and pose a particularly difficult disposal problem due to the presence of heavy metals. Tank bottoms are comprised of heavy hydrocarbons, solids, water, rust, and scale. Minimization of tank bottoms is carried ont most cost-effectively through careful separation of the oil and water remaining in the tank bottom. Filters and centrifuges can also be used to recover the oil for recycling. 

The SpinTek technology involves membranes that are bonded to two sides of a disk. Multiple disks are mounted on a hollow shaft that rotates the membranes, and stationary turbulent promoters are mounted near the rotary membranes to create high shear and turbulence. Liquid waste is pumped into the system that hits the spinning disk and spreads across the membrane. Centrifugal force pulls the solid waste outward to the perimeter of the filter disks, where it is removed from the system. By pulling the solids outward, the centrifugal force keeps the filter clear so that the system can run continuously. 

Solid wastes from the commercial production of technical OBDE, such as filter cakes, are disposed of in hazardous waste landfills (EPA 1994). These wastes may contain toluene from the production process. 

Amounts of consumables (resins, membranes, filters, disposable bags, and tubings/connectors) that end up as solid wastes could be large. 

The top of the bench should always be kept clean and dry this can easily be done if a wet and a dry rag are kept at hand. Apparatus not immediately required should be kept as far as possible in a cupboard beneath the bench if it must be placed on the bench, it should be arranged in a neat and orderly manner. All apparatus should be washed immediately after use and placed in a position to drain at the first opportunity, the apparatus should be dried. It must be emphasised that as a general rule a deposit of dirt or tar is more easily removed when it is freshly formed a suitable cleaning agent can usually be found while one still remembers the nature of the material or the circumstances attending its formation. It is hardly necessary to add that solid waste and filter papers must not be thrown into the sink, and that all operations requiring the handling of unpleasant and noxious materials should be carried out in the fume cupboard ( hood ). 

Control Filtration Analytical chemistry Activated carbon Diatomaceous earth Filter media--paper, polypropylene, cotton Low or high pH Organic compounds Dissolved metals Compl exed metals Solid metals SIudge Waste chemicals Waste filter media... 

Was this your answer Primary treatment uses settling basins to remove the bulk of solid waste and sludge from sewage effluent. Secondary treatment uses aeration to decrease effluent BOD.Tertiary treatment removes pathogens and wastes not removed by eariieT treatments by filtering effluent through powdered carbon or other fine particles. 

Figure 11.6. Thickeners for preconcentration of feed to filters or for disposal of solid wastes [see also the rake classifier of Fig. 12.2(e)]. (a) A thickener for concentrating slurries on a large scale. The rakes rotate slowly and move settled solids towards the discharge port at the center. Performance data are in Table 11.11 Brown, Unit Operations, Wiley, New York, 1950). (b) Deep cone thickener developed for the National Coal Board (UK), in a unit about lOftdia the impellers rotate at about 2rpm and a flow rate of 70 m3/scc with a solids content of 6wt%, concentrates to 25-35 wt % (Svarovsky, 1981).

Decontaminated ton containers are sent to the Rock Island Arsenal for smelting and reclamation. The 6,260 lbs/day of biosolids filter cake is sent to an off-site disposal facility. Spent activated carbon from the various filters, estimated to be generated at a rate of 600 lbs/day, will be tested for 3X surety and sent to the same contractor that takes other carbon filter material from facilities at Aberdeen Proving Ground. Demilitarization protective ensembles, which are at the 3X level after normal decontamination procedures, will be placed in 55 gallon drums, stored in a solid waste storage area, and then shipped off site. 

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