Humic substances effluent water

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. 

Humic substances were concentrated more than 50-fold on the XAD-4 quaternary resin, but a saturated HCl/methanol solution was required for the desorption. This eluant was not concentrated further because the concentration of humic substances could be measured directly with a spectrophotometer. Total recovery of humic substances was higher in the bench-scale experiments than in the pilot plant studies. On the basis of the pilot plant results (see summary of experiment 3), it appears that the adsorption of humic substances was affected by the higher velocity or the loading capacity because 458 was recovered in the effluent water. The higher velocity in the pilot plant studies did not have a similar effect on other compounds such as quinaldic acid, for example, which was recovered at almost 100. It is believed that caffeine, which was concentrated during bench-scale studies, was also affected by the higher velocity in the pilot plant studies. 

Phenols of enviromnental interest are derived from a wide variety of industrial sources, or present as biodegradation products of humic substances, tannins, and lignins, and as degradation products of many chlorinated phenoxyacid herbicides and organophosphorous pesticides. Phenols, especially chlorophenols, are persistent, and toxic at a few pg/1. Therefore, phenols are hsted at the US-EPA hst of priority pollutants and the EU Directive 76/464/EEC as dangerous substances. The samples to be analysed can be surface waters or industrial effluents. 

Leenheer and Huffman (1976) have developed a fractionation procedure for aquatic organic solutes called dissolved organic carbon (DOC) fractionation. The procedure for the analytical DOC fractionation is shown in Figure 3. Hydrophobic solutes are first removed from water by adsorption on Am-berlite XAD-8 resin, hydrophilic bases in the effluent are removed by cation-exchange resins, and hydrophilic acids in the effluent are removed by anion-exchange resins. Aquatic humic substances occur primarily in the... 

For natural waters and/or effluent applications, some interference may occur with the presence of natural or anthropogenic chelating agents. For example, humic substances can compete with dithizone for metallic constituent complexation in natural waters [60]. In this case, the degradation of organometallic complexes must be effective before the analytical determination. A photodegradation step, with a simple device as the one already proposed in this chapter for N and P compounds determination, can be used... 

Natural organic matter from biosynthesis and biodegradation is ubiquitous in natural aqueous environments. Common examples of natural organic materials are extracellular polymeric matrices (biofilms) generated by bacteria, hydrocarbons from industrial effluents and fossil fuel products, and numerous humic substances. Because of their hydrophobicity, natural organic materials have low solubility in water and tend to accumulate at solid surfaces. As a result, in groundwater and soils, mineral surfaces are commonly coated with organic films. 

The concentration of orthophosphate used in the UK varies from 0.5 to 2.0 mg/1 (P), most typically between 1.0 and 1.5 mg/1 (P), and is generally two or even three times higher than that dosed in the US (IWA, 2010). Doses are water supply system specific, and are determined by both water quality and the extent of occurrence of houses with lead pipes. Higher doses have been used in supplies that have an elevated organic contenfi particularly where humic substances are involved (Cardew, 2009). No problems have been reported in relation to bacterial growths within distribution networks and the impact on sewage effluent is considered slight (IWA, 2010). 

Figure 10.5. Comparison of the mass balance (in % DOC) for different fractions obtained by the XAD-8 procedure (5a) (FA, fulvic acid HA, humic acid NHS, nonhumic substances) and by ultrafiltration (5b) (K, concentrate P, permeate cutoff, 4000g/mol). Abbreviations used HO, Lake Hohloh, brown water ABV, wastewater effluent numbers, sampling occasion.

Gel filtration chromatography using Sephadex G100 as column packing and ultraviolet detectors, have been used in studies carried out on the elution of humic acid [8] and in characterisation studies on secondary sewage effluents [9] and in organic substances in river waters [10],... 

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