Industrial, effluents

Industrial effluents tend to be complex and vary significantly from one industry to another consequently they must be treated on a case-by-case basis [40]. The potential impact of industrial effluents when discharged to sewer is assessed primarily by measurement of volume, COD (chemical oxygen demand) and suspended solids. Consents, or effluent standards, are normally issued by regulators for discharge to sewer [41 ], and these include limits on volume, COD, suspended solids and specific pollutant types, for example heavy metals, grease and oil, persistent and/or toxic organics and colour from waste dyes. 

To meet the consent limits and reduce the polluting load and hazardous substances to acceptable levels, most industrial facilities carry out some form of wastewater management and treatment. The simplest form of treatment entails settlement for removal of suspended solids. In such a case, addition of a high molecular weight polyelectrolyte based on polyacrylamide as sole fiocculant may be used to assist sedimentation of particles. The choice between anionic, non-ionic or cationic charge on the polyelectrolyte will depend to a large extent on the chemistry of the particles to be flocculated. Such treatment, however, will often remove only 10-30% of the COD. 

Industry Effluent characteristics Treatment process Chemical pre-treatment 

Tannery High COD and SS, Contains oils and fats, proteins, sulphide chrome, salts Screening, coagulation and flocculation, settlement or flotation prior to biological filter Aluminium or ferric sulphate followed by anionic polyacrylamide 

Slaughterhouse High dissolved and colloidal COD and SS. Contains fats and protein (blood), dirt and manure Grit chamber, screen, coagulation and flocculation, DAF Aluminium or ferric sulphate or PAC followed by cationic or anionic polyacrylamide 

A detailed analysis of the various effluent streams contributing to the final discharge from the South Teeside steelworks is presented in Table 3.2 (Fig. 3.1). The discrepancy between the summed source total and that measured in the final discharge probably reflects the inadequacy of performing a mass balance using data obtained as infrequent spot samples and showing a considerable range of concentrations (see Table 3.9 on p. 40). 

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Prada and colleagues recently described a new indirect method for determining sulfate in natural samples, such as sea water and industrial effluents. The method is based on... 

Treatment of Industrial Effluents. Solvent extraction appears to have great potential in the field of efduent treatment, both for the economic recovery of valuable materials and for the removal of toxic materials to comply with environmental requirements. 

Environmental Applications. Hydrogen peroxide is an ecologically desirable poUution-control agent because it yields only water or oxygen on decomposition. It has been used in increasingly greater amounts to convert domestic and industrial effluents to an environmentally compatible state... 

Wastewater Treatment Plants. Numerous studies have shown that phthalates in wastewater systems are removed to a significant extent by treatment plants. The concentration of phthalates in both domestic and industrial wastewater was measured before and after treatment (55). The total level of phthalates in domestic effluent was reduced by treatment from 32.7 to 0.92 )-lg/L and in industrial effluent from 93.6 to 1.06 )-lg/L. Thus between 97 and 99% of the phthalates are removed from wastewater by treatment plants. 

P. W. Lankford and W. W. Eckenfelder, eds.. Toxicity Reduction in Industrial Effluents, Van Nostrand Reiohold, New York, 1990. 

Biochemical Oxygen Demand. The biochemical oxygen demand (BOD) test is an empirical determination of the oxygen requirement of a sample. It is most often appHed to wastewaters, industrial effluents, and poHuted waters. The decrease in the dissolved oxygen concentration resulting primarily from biological action is measured after storage for 5 d at 20°C. 

Process industry Effluent guidelines and standards Reference Parameters regulated N eutralization Sedimentation and/or filtration Biological treatment... 

Industrial Wastes. Closely related to seawater concentration is the simultaneous concentration of industrial effluents and recycle of recovered water (see Wastes, industrial). These appHcations are expected to increase as environmental restrictions increase. Examples are the concentration of blowdown from cooling towers in power plants concentration of reverse osmosis blowdown and the processing of metal treatment wastes (11) (see... 

De-watering of coal, tin, copper or gold mines, coal washing and sludge pumping Pumping industrial effluents... 

The fluid being pumped is often not well defined. Terminology like well water, industrial effluent, raw water, boiler feed water, condensate water, etc., is usually the only definition we have of the fluid being pumped. Any of these fluids can contain several concentrations of. solids that cause erosion and wear inside the pump. 

The pH of rainwater is normally about 6 but can be reduced significantly by absorption of acidic exhaust gases from power stations, industrial combustion or other processes, and vehicles. Acids may also enter the waterways as a component of industrial effluent. In addition to the direct adverse effects on aquatic systems (Table 16.12) low pH can result in the leaching of toxic metals from land, etc. 

Table 16.16 Typical consent conditions for the discharge of industrial effluent to rivers and streams (UK)...

Like the analogous chrome alums they find use as mordants in dying processes. The sulfate is the cheapest salt of Fe and forms no less than 6 different hydrates (12, 10, 9, 7, 6 and 3 mols of H2O of which 9H2O is the most common) it is widely used as a coagulent in the treatment not only of potable water but also of sewage and industrial effluents. 

Most of water-soluble acrylamide polymers find practical applications as highly efficient flocculents for clarification and treatment of potable water and municipal and industrial effluents and in the mining, papermak-... 

Water treatment Clarification of potable water, industrial effluents, municipal waste water thickening and dewatering of sludge filtration of primary sludge, digested sludge food processing... 

Disposal of industrial effluents to controlled landfill sites is generally confined to slurries and sludge. The quantity and composition of the wastes acceptable for disposal is controlled by licenses issued by the waste disposal authority. 

Municipal sewage-treatment effluents discharge to surface waters and is subject to the same EPA control on quality and quantity as independent industrial surface-water discharges. Any tightening of EPA standards may therefore result in more stringent controls on industrial effluents discharged to sewers. All the water companies levy charges on industry for the reception, conveyance and treatment of the industrial effluents. 

The significance of these industrial effluent disposal options on the location of an industrial plant is essentially cost. As previously stated, the EPA does not, as yet, impose a cost on effluents complying with the Consent standards discharged to surface waters or to land. However, the cost of installing and operating treatment... 

The cost of industrial effluent disposal to the municipal sewers is based on a polluter pays policy, which takes account of the quantity and pollution loads in the discharge. All the water companies calculate their trade waste charges in accordance with ... 

Industrial effluents are a particularly difficult problem to discuss in general terms their nature is very diverse, possible methods of treatment vary correspondingly and their acceptability depends as much on the receiving body as on their flow and contents. There are, however, some common factors which are worth mentioning. 

Industrial plants also discharge domestic sewage. It is vital to keep this separate from any industrial effluent which may have to be treated, so that it can then be disposed of by conventional means (to the public sewer, septic tank, etc.). 

Typical applications in the inorganic field are the analysis of minerals, metals (including alloys), fertilisers, natural waters, industrial effluents and polluted atmospheres. The technique can also be used to establish the formulae of various complexes,... 

Industry Effluent Stream Major Contaminants Removed by Biodegradation... 

Currently available CRMs for Cr(lll)/(VI) species There exist a lyophilized water certified for Cr(III)/Cr(VI) and a binder-free glass fiber filter loaded with welding dust certified for Cr(VI) and total Cr (Vercoutere et al. 1998 Christensen et al. 1999) issued by the BCR. They consist of a set of specimens for single use. There is a need for more CRMs, such as a Cr(VI) in industrial effluents and in river water containing, e.g. humic substances. 

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