Biological


Combustion in an incinerator is the only practical way to deal with many waste streams.This is particularly true of solid and concentrated wastes and toxic wastes such as those containing halogenated hydrocarbons, pesticides, herbicides, etc. Many of the toxic substances encountered resist biological degradation and persist in the natural environment for a long period of time. Unless they are in dilute aqueous solution, the most effective treatment is usually incineration.  [c.299]

Primary or pretreatment of wastewater prior to biological treatment involves both physical and chemical treatment depending on the nature of the emission.  [c.310]

Prepare the aqueous waste for biological treatment by removing excessive load or components that will inhibit the biological processes.  [c.310]

The pretreatment processes may be most effective when applied to individual waste streams from particular processes or process steps before effluent streams are combined for biological treatment.  [c.310]

The capital cost of most aqueous waste treatment operations is proportional to the total flow of wastewater, and the operating cost increases with decreasing concentration for a given mass of contaminant to be removed. Thus, if two streams require different treatment operations, it makes no sense to mix them and treat both streams in both treatment operations. This will increase both capital and operating costs. Rather, the streams should be segregated and treated separately in a distributed effluent treatment system. Indeed, effective primary treatment might mean that some streams do not need biological treatment at all.  [c.310]

Z. Evaporation. If the wastewater is in low volume and the waste material involatile, then evaporation can be used to concentrate the waste. The relatively pure evaporated water might still require biological treatment after condensation. The concentrated waste can then be recycled or sent for further treatment or disposal. The cost of such operations can be prohibitively expensive unless the heat available in the evaporated water can be recovered.  [c.313]

Biological treatment. In secondary, nr biological treatment, a concentrated mass of microorganisms is used to break down organic matter into stabilized wastes. Large chemical factories might require their own biological treatment processes. Smaller sites might rely on local municipal treatment processes which treat a mixture of industrial and domestic effluent.,  [c.313]

There are two main types of biological reaction, aerobic and anaerobic  [c.313]

In all types of biological processes, excess sludge is produced which must be disposed of. The treatment and disposal of sludge are major problems which can be costly to deal with. Anaerobic processes have the advantage here, since they produce considerably less sludge than aerobic processes (on the order of 5 percent of aerobic processes for the same throughput).  [c.317]

Sludge disposal typically can be responsible for 25 to 40 percent of the operating costs of a biological treatment system. Treatment of sludge is aimed primarily at reducing its volume. This is so because the sludge is usually 95 to 99 percent water and the cost of disposal  [c.317]

Adsorption. Some organics are not removed in biological systems operating under normal conditions. Removal of residual organics can be achieved by adsorption. Both activated carbon and synthetic resins are used. As described earlier under pretreatment methods, regeneration of the activated carbon in a furnace can cause carbon losses of perhaps 5 to 10 percent.  [c.319]

Nitrogen and phosphorus removal. Since nitrogen and phosphorus are essential for growth of the microorganisms, the effluent from secondary treatment will contain some nitrogen and phosphorus. The amount discharged to receiving waters can have a considerable effect on the growth of algae. If discharge is to a high-quality receiving water with low dilution rates, then removal may be necessary. Nitrogen principally occurs as ammonium (NH4), nitrate (NO3), and nitrite (NO2). Phosphorus principally occurs as orthophosphate (PO4 ). A number of biological and chemical processes are available for the removal of nitrogen and phosphorous. These processes produce extra biological and inorganic sludge that requires disposal.  [c.319]

Foams are used industrially and are important in rubber preparations (foamed-latex) and in fire fighting. The foam floats as a continuous layer across the burning surface, so preventing the evolution of inflammable vapours. Foams are also used in gas absorption and in the separation of proteins from biological fluids. See anti-foaming agents.  [c.180]

M.p. 83-5 - C. Does not occur naturally, but has been obtained synthetically. It is the basic hydrocarbon skeleton of biologically and clinically important steroids.  [c.326]

A fully updated edition of a classic work - far and away the best one-volume survey of all the physical and biological sciences.  [c.441]

Biology Physical Geography  [c.448]

The purge stream is sent to the biological treatment plant.  [c.405]

The objective of an EIA Is to document the potential physical, biological, social and health effects of a planned activity. This will enable decision makers to determine whether an activity is acceptable and if not, identify possible alternatives. Typically, ElA s will be carried out for  [c.70]

Another application areas of microtomography are biology and agriculture. Fig.4a shows an X-ray transmission image through the tulip bulb in wet conditions. Damaged area can be found in the surface of this bulb. Fig.4b shows the reconstructed cross section with information about depth of damaged volume.  [c.581]

Basic principles of URT are now well established for weakly varying media as biological structures [1].  [c.743]

On Russia territory there are about 100 thousands of dangerous enterprises and objects, comprising about 1500 nuclear facilities and 3000 chemical and biological extremely hazardous objects. The average period of emergency situations is 10 — 15 years for accidents and disasters with the material loss up to 2 billion USDs, and 15 — 45 days, when the material loss is up to 100 million USDs.  [c.910]

Wet oxidation is particularly effective in treating aqueous wastes containing organics with a COD up to 2 percent prior to biological treatment. COD can be reduced by up to 95 percent and organic halogen compounds by up to 95 percent also. Organic halogen compounds are p2irticularly resistant to biological degradation.  [c.312]

The degradable organic matter in the wastewater is used as food by the microorganisms. However, biological growth requires ample supplies of carbon, nitrogen, phosphorus, and inorganic ions such as calcium, magnesium, potassium, etc. Domestic sewage satisfies the requirements, but industrial wastewaters may lack nutrients, and this can inhibit biological growth. In such circumstances, nutrients may need to be added. As the waste treatment progresses, the microorganisms multiply, producing an excess of this sludge which cannot be recycled.  [c.314]

In attached growth film) methods, the wastewater is trickled over a packed bed through which air is allowed to percolate. A biological film or slime builds up on the packing under aerobic conditions. Oxygen from the air and biological matter from the wastewater diffuse into the slime. As the biological film grows, it eventually breaks its contact with the packing and is carried away with the water. Packing material varies from pieces of stone to preformed plastic packing.  [c.316]

CtHjCIjNS, PhC(S)NH2, a herbicide with a high level of biological activity.  [c.96]

Morphine and its salts are very valuable analgesic drugs but are highly addictive. In addition to suppression of pain, morphine causes constipation, decreases pupillary size and depresses respiration. Only the (-l-)-stereoisoraer is biologically active. They appear to produce their effects on the brain by activating neuronal mechanisms normally activated by  [c.266]

In the early stages of an EIA a baseline studyls carried out, usually following the scoping stage (see below). The baseline study consists of the a description of those aspects of the physical, biological and social environment which could be affected by a proposed development. It is an before project audit. However, baseline studies may be required again later on in the project, for instance to help refine impact predictions. Baseline studies can account for a significant part of the overall EIA cost since they require extensive field studies.  [c.72]

Weathering and transportation is followed by the sedimentation of material. The depositional environment can be defined as an area with a typical set of physical, chemical and biological processes which result in a specific type of rock. The characteristics of the resulting sediment package are dependent on the intensity and duration of these processes. The physical, chemical, biological and geomorphic variables  [c.78]


See pages that mention the term Biological : [c.310]    [c.311]    [c.313]    [c.313]    [c.315]    [c.477]    [c.40]    [c.59]    [c.75]    [c.96]    [c.105]    [c.130]    [c.141]    [c.146]    [c.161]    [c.177]    [c.182]    [c.292]    [c.307]    [c.331]    [c.369]    [c.402]   
Agricultural Chemicals and the Environment (1996) -- [ c.0 ]