Combined photochemical and biological processes for the treatment of industrial wastewater

本研究计划涉及建模、优化和开发结合高级氧化技术和生物工艺处理选定的工业废水，如柴油、石化、纸浆和造纸废水。由于个别化学、物理或生物过程在其有效性或经济可行性方面的限制，几乎没有一个是单独充分适用的。该提案涉及如何最好地将先进氧化技术（AOTs）的新应用（如光催化，光解和UV/过氧化氢）与生物工艺结合起来用于工业废水处理的问题。在光化学氧化步骤中，不可生物降解的、生物难降解的和抑制性污染物被转化为生物可降解的中间体，这些中间体又在随后的生物步骤中被降解。为了杀死生物废水中的有毒微生物和使可能的病毒失活，并降解其他低分子副产品，将在生物过程之后使用进一步的光化学过程。该研究计划的主要目标是开发、优化、工程模型，研究系统的动力学，并最终设计组合过程。在该项目的第一阶段，将对光催化、光解和UV/过氧化氢的组合进行经济、接触次数、整体效率和工艺顺序方面的研究和优化。已经设计和建造的两个中试工厂光反应器用于检查光解和光催化过程。在该项目的下一阶段，优化的光化学工艺将与生物工艺相结合，作为预处理、后处理或两者兼而有之。废水的生物处理是在顺序间歇式反应器和搅拌槽反应器中进行的，使用活性污泥作为微生物的来源。为了优化这些过程，分析了这些过程的总成本、降解率、在每个反应器中的停留时间、总体效率以及母体和中间副产物的浓度。

This research proposal deals with modeling, optimization, and the development of combined advanced oxidation technologies and biological processes for the treatment of selected industrial wastewater such as diesel, petrochemical, and pulp and paper wastewater. Due to the limitations of individual chemical, physical, or biological processes in their effectiveness or economical feasibility, almost none is sufficiently applicable on its own. This proposal deals with the question of how best to combine the new applications of Advanced Oxidation Technologies (AOTs) such as photocatalysis, photolysis, and UV/hydrogen peroxide together with biological processes for the purpose of industrial wastewater treatment. In the photochemical oxidation step, the non-biodegradable, bio-refractory, and inhibitory contaminants are converted to biodegradable intermediates, which, in turn, are degraded in the subsequent biological step. To kill toxic microorganisms and deactivate possible viruses from biological effluents, and degrade other low molecular by-products, a further photochemical process will be used after the biological process. The development, optimization, engineering models, studying the dynamics of the systems, and eventually the design of the combined processes are the main objectives of this research proposal. In the first phase of this project, the combination of photocatalysis, photolysis, and UV/hydrogen peroxide will be studied and optimized in terms of economics, contact times, overall efficiency, and the sequence of the processes. Two pilot-plant photoreactors, already designed and constructed, are used to examine the photolytic and photocatalytic processes. In the next phase of this project, the optimized photochemical processes are integrated with the biological process as either pretreatment, post-treatment, or both. The biological treatment of the wastewater is examined in a sequential batch reactor as well as a stirred tank reactor using activated sludge as the source of microorganisms. To optimize these processes, the total cost of the processes, degradation rates, residence time in each reactor, overall efficiency, and the concentrations of the parent and intermediate by-products are analyzed.