Pesticide concentrations activated carbon wastewater

The supernatant from flocculation was then passed through activated carbon columns. The exact concentration of dlnoseb, alachlor and 2,4-D used In the study Is shown In Table IV. Two carbon column exhaustion studies were conducted. In both cases 300 L of wastewater were pumped through the columns. The carbon adsorbed slightly over 300 mg of pesticide per gram of carbon In both tests. 2,4-D and Dlnoseb broke through simultaneously after 1500 L of supernatant with a concentratfon of about 600 mg/L Dlnoseb and 90 mg/L 2,4-D had passed through the carbon. The columns were not totally exhausted until 3000 L had passed through. 

Activated carbon studies on widely used herbicides and pesticides have shown that it is successful in reducing the concentration of these toxic compounds to very low levels in wastewater [16]. Some examples of these include BHG, DDT, 2,4-D, toxaphene, dieldrin, aldrin, chlordane, malathion, and parathion. Adsorption is affected by many factors, including... 

Figure 8.3 shows the molecular structure of six pesticides that were tested and their solubility levels in supercritical CO2 at one set of test conditions, 275 bar (4,000 psia) and 100°C. Also included in this figure is the solubility of phenol, which was studied because it is a raw material in the production of some of the pesticides and thus might be found in pesticide plant wastewaters. The solubility of these compounds varies over a one hundredfold concentration range, but the regenerability of activated carbon is not necessarily related solely to the solubility level. Specifically, a high solubility in supercritical CO2... 

For the purpose of evaluating the efficacy of using supercritical CO2 to regenerate spent activated carbon, a series of adsorption and desorption experiments is performed and the capacity and capacity recovery of the activated carbon are measured. A fixed bed of activated carbon is exposed to a synthetic wastewater stream containing a single pesticide. The wastewater in most cases is synthesized at a concentration level of about 80% saturation. The... 

---