Organic pollutants, in waste water

Estevez, M.C., H. Font, M. Nichkova, et al. 2005. Immunochemical determination of pharmaceuticals and personal care products as emerging pollutants. In D. Barcelo (ed.), Emerging Organic Pollutants in Waste Waters and Sludge, pp. 181-244. Berlin Springer. 

NR/Ti02 nanocomposites can be used as antibacterial materials. Ti02-strewn rubber sheet can be used as a photocatalyst and is used to identify organic pollutants in waste water. 

The majority of systems studied have been aqueous solutions of either aromatic compounds or halogenated hydrocarbons. Such materials represent models for the major classes of organic pollutants in waste and ground water. The primary products resulting from the sonochemical treatment of phenol at 541 kHz (27 °C with bubbled air) are hydroquinone and catechol [22]. These compounds are easy to monitor and are clearly seen to be intermediates which disappear as the reaction progresses (Fig. 4.1). Similarly the sonolysis of aqueous 4-chlorophenol leads to products mainly characteristic of oxidation by OH radical e. g. 4-chlorocatechol but in both cases the final organic products are CO, CO2 and HCOOH (Scheme 4.2) [22-25]. 

BOD Sensor. The biochemical oxygen demand (BOD) test is one of the most widely used and important tests in the measurement of organic pollution. Since the BOD test measures biodegradable organic compounds in waste waters, it requires a long incubation period (5 days at 20C). Therefore a simple and reproducible method for estimation of 5-day BOD is required for pollution control(17). 

Geer, R.D. 1978. Predicting the anaerobic degradation of organic chemical pollutants in waste water treatment plants from their electrochemical reduction behavior. In Montana University Joint Water Resources Research Center, Bozeman, MT, Completion Report No. 96... 

Comninellis C. Electrocatalysis in the electrochemical conversion/combustion of organic pollutants for waste water treatment. Proceedings of the Symposium on Water Purification by Photocatalytic, Photoelectrochemical and Electrochemical Processes. Vol. 94-19. Pennington, NJ The Electrochemical Society, 1994 75-86. 

CO2 hydrogenation, ammonia synthesis, hydrogenation of unsaturated organics, methane reforming, hydrogenolysis of saturated hydrocarbons, and wet oxidation of pollutants in waste waters have been tested, the main reactions taking place in the auto-exhaust converters have received special attention. Such is the case of CO and hydrocarbon oxidations, NO reduction, steam reforming, and water-gas shift reaction. 

Comninellis CH. Electrocatalysis in the electrochemical conversion/combustion of organic pollutants for waste water treatment. 

Example 9.11. Retention of Hydrophobic Organic Pollutants in Ground-water Aquifer Because of a leak in a waste container, traces of tetrachlor-ethylene and 1,2,4,5-tetrachlorobenzene escape in a groundwater. Provide an estimate of how long it takes to find these pollutants at a distance (direction of flow) of 25 m. The flow velocity of the groundwater is 2 m day . The following characteristics of the aquifer are available ... 

In recent years, increasing attention has been paid to the detection, identification, and quantitation of trace organics and new emerging pollutants in waste-water samples. Analytical techniques for measuring organic compounds in industrial effluents require four general steps ... 

Biochemical oxygen demand (BOD) is one of the most widely determined parameters in managing organic pollution. The conventional BOD test includes a 5-day incubation period, so a more expeditious and reproducible method for assessment of this parameter is required. Trichosporon cutaneum, a microorganism formerly used in waste water treatment, has also been employed to construct a BOD biosensor. The dynamic system where the sensor was implemented consisted of a 0.1 M phosphate buffer at pH 7 saturated with dissolved oxygen which was transferred to a flow-cell at a rate of 1 mL/min. When the current reached a steady-state value, a sample was injected into the flow-cell at 0.2 mL/min. The steady-state current was found to be dependent on the BOD of the sample solution. After the sample was flushed from the flow-cell, the current of the microbial sensor gradually returned to its initial level. The response time of microbial sensors depends on the nature of the sample solution concerned. A linear relationship was foimd between the current difference (i.e. that between the initial and final steady-state currents) and the 5-day BOD assay of the standard solution up to 60 mg/L. The minimum measurable BOD was 3 mg/L. The current was reproducible within 6% of the relative error when a BOD of 40 mg/L was used over 10 experiments [128]. 

The Biochemical Oxygen Demand (BOD) is an important parameter for waste-water monitoring. It gives information about the biodegradable organic pollution in wastewater. The main disadvantage of the conventional BOD-method is the required extended investigation time, which for example takes five days for... 

---