Characterization Of Water Quality And Development Of Ancillary Techniques For Organic Pollutants Analyses

As the country economic increasing and the society advancing, the problem of water resource pollution attracts more and more attention. It is necessary to monitoring many kinds of pollutant indexes to estimate water quality. Chemical oxygen demand (COD), biological oxygen demand (BOD) and dissolved organic carbon (DOC) are employed to estimate organic pollutant level in waters. BTEX (benzene, toluene, ethylbenzene and xylene) is an important special organic pollutant.Recently, the standard methods for COD and BOD determination suffer from a series of drawbacks: complicated steps, long analysis time and high consumption of reagent. Especially the low dissolved oxygen concentration leads to much higher error for diluting a water sample during the BOD determination. An expensive instrument is employed to determine DOC, whose pitfalls include high background levels and memory effects. The CS₂-GC method for BTEX determination also has complicated steps. CS₂ is a kind of poisonous organic compound. For all such instances, it's necessary to develop methods with simple, fast, low cost, low reagent consumption, high precision and accuracy. Correlative relations among several indexes were discussed after simultaneous determination for them.Closed reflux was employed to digest water samples. COD were determined by spectrometric method. The produced carbon dioxide from organic carbon was purged by high purified nitrogen into 50 mL triethanolamine (TEA) solution. The pH of TEA solution was analyzed by a pH meter, which was proportional to DOC values indirect. This method only use 5 mL reagent to digest 2 mL sample. The RSD is less than 5%, and the analytical recoveries are 95% -110%. The method was used to determine and relate COD and DOC values for dyestuff wastewater, medical sewage and river water.A new activated sludge aeration device was prepared by adding activated sludge into filter cartridge. The organic matters were degraded by active aeration. Biodegradable chemical oxygen demand (bCOD) was obtained by measuring the chemical oxygen demand values during the digestion time, which was determined byclosed reflux spectrometric method. The method developed shortens the analytical time from 5 days to 8 hours. During the best range of 50 - 1600 mg/L COD, the RSD is less than 10%. The rates of BOD to COD for brewhouse effluent, saponification wastewater and phenol solution after electrochemical degradation were established, which showed the biodegradability of wastewater.The headspace solid phase microextraction (SPME) was used for detecting BTEX in water matrix with a constant temperature. The extraction fiber was made by new active carbon fiber (ACF). Optimized conditions such as extraction time, extraction temperature and thermal desorption temperature were discussed. It had good precision with relative standard deviations less than 4% for all values. The recoveries are 94 - 104%. Compared with the traditional fore treatment methods, it is typically simple, timesaving and solventless.The article indicated that these methods all had high accuracy and reliability, which satisfied with the organic pollutants' monitoring requirement. It can used to be a conventional approach to determine organic pollutants. The article established correlative relations among multiple indexes, which has practical significance to realize the water organic pollution in the round.