Cano M L, Saterbak A, van Compernolle R, Williams M P, Huot M E, Rhodes I A, Allen C C
Shell Chemical LP Chemical Process Development Department, Shell Westhollow Technology Center, Houston, Texas 77251-1380, USA.
Water Environ Res. 2003 Jul-Aug;75(4):342-54. doi: 10.2175/106143003x141150.
The relative rates of biodegradation and stripping and volatilization of nonspeciated volatile organic compounds (VOCs) in wastewater treated with aerobic activated-sludge processes can be quantified using a newly developed procedure. This method was adapted from the original aerated draft tube reactor test that was developed to measure biodegradation rate constants for specific volatile pollutants of interest. The original batch test has been modified to include solid-phase microextraction (SPME) fibers for sampling in the gas phase. The experimental procedure using SPME fibers does not require specific identification and quantitation of individual pollutants and can be used to evaluate wastewater with multiple VOCs. To illustrate use of this procedure, laboratory experiments were conducted using biomass and wastewater or effluent from three activated-sludge treatment systems. Each experiment consisted of two trials: a stripping-only trial without biomass and a stripping plus biodegradation trial using biomass from the activated-sludge unit of interest. Data from the two trials were used to quantify the rates of biodegradation by difference. The activated-sludge systems tested were a laboratory diffused-air reactor treating refinery wastewater, a full-scale surface aerated reactor treating a petrochemical wastewater, and a full-scale diffused-air reactor treating a variety of industrial effluents. The biodegradation rate constant data from each laboratory batch experiment were used in model calculations to quantify the fraction emitted (fe) and the fraction biodegraded (fbio) for each system. The fe values ranged from a maximum of 0.01 to a maximum of 0.32, whereas fbio values ranged from a minimum of 0.40 to a minimum 0.95. Two of these systems had been previously tested using a more complicated experimental approach, and the current results were in good agreement with previous results. These results indicate that biodegradation rate constant data from this laboratory method can be successfully used to predict the fate of VOCs in field-scale treatment units, and thus could potentially be used for demonstration of compliance with wastewater VOC emission regulations.
采用一种新开发的程序，可以对采用好氧活性污泥法处理的废水中未分类挥发性有机化合物（VOCs）的生物降解、汽提和挥发的相对速率进行量化。该方法改编自最初开发的曝气导流管反应器试验，该试验用于测量特定目标挥发性污染物的生物降解速率常数。原来的批次试验已进行修改，纳入了用于气相采样的固相微萃取（SPME）纤维。使用SPME纤维的实验程序不需要对单个污染物进行具体鉴定和定量，可用于评估含有多种VOCs的废水。为说明该程序的用途，利用来自三个活性污泥处理系统的生物质以及废水或出水进行了实验室实验。每个实验包括两个试验：一个是不使用生物质的仅汽提试验，另一个是使用来自相关活性污泥单元的生物质的汽提加生物降解试验。通过两个试验的数据差值来量化生物降解速率。所测试的活性污泥系统包括一个处理炼油厂废水的实验室曝气式反应器、一个处理石化废水的全尺寸表面曝气反应器以及一个处理各种工业废水的全尺寸曝气式反应器。每个实验室批次实验的生物降解速率常数数据用于模型计算，以量化每个系统的排放分数（fe）和生物降解分数（fbio）。fe值范围为最大0.01至最大0.32，而fbio值范围为最小0.40至最小0.95。其中两个系统此前已采用更复杂的实验方法进行过测试，当前结果与先前结果吻合良好。这些结果表明，该实验室方法得出的生物降解速率常数数据能够成功用于预测VOCs在现场规模处理单元中的归宿，因此有可能用于证明符合废水VOC排放法规的情况。
