Waste material production

Waste materials Production (million metric tons) % Recycled Highway applications ... 

For biotechnological purposes, the production of lactic acid from different waste streams in a first fermentation process by lactobadUi appears very reasonable. This is due to the fact that, caused by the low-pH conditions, lactic acid can easily be stored without major conservation requirements. Hence, this compound features an excellent stable intermediate for a versatile range of follow-up products. In contrast to the transportation of lignocellulosic waste or whey, the transportation of lactic add in a concentrated form to production facilities where it will be converted might be economically reasonable in many cases. Whereas the production of lactic acid itself is dependent on the seasonal availability of the waste materials, production facilities for the subsequent conversion of lactic acid to final products such as PHAs can be supplied from lactic acid stocks independent of the season. 

Reducing waste from feed impurities which undergo reaction. If feed impurities undergo reaction, this causes waste of feed material, products, or both. Avoiding such waste is most readily achieved by purifying the feed. Thus increased feed purification costs are traded off against reduced raw materials, product separation, and waste disposal costs (Fig. 10.2). 

The oil and gas industry produces much waste material, such as scrap metal, human waste, unspent chemicals, oily sludges and radiation. All of the incoming streams to a facility such as a production platform end up somewhere, and only few of the outgoing streams are useful product. It is one of the responsibilities of the engineer to try to limit the amount of incoming material which will finally become waste material. 

Miscellaneous. Hydrochloric acid is used for the recovery of semiprecious metals from used catalysts, as a catalyst in synthesis, for catalyst regeneration (see Catalysts, regeneration), and for pH control (see Hydrogen-ION activity), regeneration of ion-exchange (qv) resins used in wastewater treatment, electric utiUties, and for neutralization of alkaline products or waste materials. In addition, hydrochloric acid is also utilized in many production processes for organic and inorganic chemicals. 

Includes other graded coarse aggregate, dam constmction, drain fields, building products, pipe bedding, and waste material. 

Weapons materials from production reactors were accumulated during the Cold War period as a part of the U.S. defense program. Prominent were tritium, ie, hydrogen-3, having a of 12.3 yr, and plutonium-239, 1/2 = 2.4 X lO" yr. The latter constitutes a waste both as a by-product of weapons fabrication in a waste material called transuranic waste (TRU), and as an excess fissionable material if not used for power production in a reactor. 

A considerable quantity of oil can be extracted from waste material from shelling and processing plants, eg, the inedible kernels rejected during shelling and fragments of kernels recovered from shells. About 300 t of pecan oil and 300—600 t of English walnut oil are produced aimuaHy from such sources. The oil is refined and used for edible purposes or for the production of soap the cake is used in animal feeds (see Feeds and feed additives). Fmit-pit oils, which closely resemble and are often substituted for almond oil, are produced on a large scale for cosmetic and pharmaceutical purposes (143). For instance, leaves, bark, and pericarp of walnut may be used to manufacture vitamin C, medicines, dyes and tannin materials (144). 

Reverse Osmosis. In reverse osmosis (qv), a solution or suspension flows under pressure through a membrane the product is withdrawn on the other side. This process can treat dissolved soHds concentrations ranging from 1 mg/L to 35 g/L (14). The principal constraint is the requirement that the waste material be relatively nonfouling. Recent advances have been mosdy in membrane development, and pilot studies are required (15). Energy costs can be significant, and it is frequently necessary to pretreat influent in order to minimize fouhng. Reverse osmosis can deal with particles < 1 to 600 nm in size. 

Clinker production requires large quantities of fuel. In the United States, coal (qv) and natural gas are the most widely used kiln fuels but fuels derived from waste materials, eg, tires, solvents, etc, are increasing in importance (53) (see Fuels fromwaste Gas,natural). In addition to the kiln fuel, electrical energy is required to power the equipment. This energy, however, amounts to only about one-ninth that of the kiln fuel. The cement industry carefully considers all measures that can reduce fuel demand. 

The economic balance must be considered between recovery, reuse, and modification of a waste material or by-product and its disposal. The future is expected to bring iacreases ia the practice of recycle, recovery, modification, and upgrading of wastes of all sorts, and a reduction ia disposal by iaciaeration (qv), biochemical oxidation, or discharge to the environment (see Recycling). 

Processing and Recovery The functional element of processing and recoveiy includes all the techniques, equipment, and facilities used both to improve the efficiency of the other functional elements and to recover usable materials, conversion products, or energy from solid wastes. Materials that can be recycled are exported to facilities equipped to do so. Residues go to disposal. 

Dietary additives can affect the microbiota that are associated with the faeces of animals and degradation of the faeces may be impaired because of the influence of the excretory products on insects, microbes and fungi. The microbiota in the soil and waste material may be affected, thus altering the fertility of the pasture and sustainability of other wildlife. These microbiota can be used as dietary ingredients for animals, so inhibition of their production would be an unsatisfactory consequence of dietary additives. ... 

The toller needs to be familiar with all raw materials, intermediate materials, products and wastes, used, produced or generated, respectively, while operating the process. Tollers in the U.S. should comply with the Federal OSHA Hazard Communication Standard, codified as 29 CFR. 1910.1200 and any similar state right-to-know laws that are currently in force or may be enacted during the term of the contract. This is often stated in the contract. The contract may require the toller to inform its employees of the chemical hazards associated with products or chemicals and may also be responsible for training its employees in the proper handling methods. The toller has an obligation when in doubt about a product or chemical, to seek further information from the product s manufacturer. 

Clean up includes identifying, gathering, storing (when appropriate), and classifying materials associated with a specific toll. Decisions can then be made as to which raw materials, intermediates, and product will be shipped back to the client or kept by the toller. Some off-spec product, retained samples, or unused intermediates may be considered waste materials at this point. Equipment clean up can be extremely important to preserving quality and process safety integrity prior to the next production run of a new product. 

Wood-fired power boilers are generally found at the mills where wood products are manufactured. They are fired with waste materials from the process, such as "hogged wood," sander dust, sawdust, bark, or process trim. Little information is available on gaseous emissions from wood-fired boilers, but extensive tests of particulate matter emissions are reported (19). These emissions range from 0.057 to 1.626 gm per dry standard cubic meter, with an average of 0.343 reported for 135 tests. Collection devices for particulate matter from wood-fired boilers are shown in Table 30-21. 

It is possible to produce adipic acid by a variety of methods from such diverse starting points as benzene, acetylene and waste agricultural products. In practice, however, benzene is the favoured starting point and some of the more important routes for this material are illustrated in Figure 18.4... 

Quality control on raw materials, materials in process, products and wastes Materials control to enable losses, over-use, under-use or accumulations to be detected control of quantities in storage... 

Chemicals in ores, wastes, etc., that undergo beneficia-tion tor purposes of production of that chemical. For example, a company recovers silver by processing waste material containing silver at less than 1% total weight of the material. Although silver is received at less than the de minimis concenlration, the de minimis would not apply because the process concentrates and produces silver as an end product. 

Often, the immobilized product has a structural strength sufficient to prevent fracturing over time. Solidification accomplishes the objective by changing a non-solid waste material into a solid, monolithic structure that ideally will not permit liquids to percolate into or leach materials out of the mass. Stabilization, on the other hand, binds the hazardous constituents into an insoluble matrix or changes the hazardous constituent to an insoluble form. Other objectives of solidiflcation/stabilization processes are to improve handling of the waste and pri uce a stable solid (no free liquid) for subsequent use as a construction material or for landfilling. 

Using high purity raw materials and products can reduce the amount the waste material that must be handled. 

Abfallerzeugnis, n. waste product. Abf everWertung,/. utilization of waste. Abfall-fett, n. waste fat or grease, -gummi, n. waste rubber, scrap rubber, -gut, n. waste material (to be treated for recovery), -hefe, /. waste yeast, -holz, n. waste wood, abfallig, a. falling off, sloping, etc. (see abfallen) deciduous adverse. 

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