The internal recirculation plays an important role on the different biological processes of wastewater treatment plants because it has a great influence on the concentration of pollutants, especially nutrients. Usually, the internal recirculation flow rate is kept fixed or manipulated by control techniques to maintain a fixed nitrate set-point in the last anoxic tank. This work proposes a new control strategy to manipulate the internal recirculation flow rate by applying a fuzzy controller. The proposed controller takes into account the effects of the internal recirculation flow rate on the inlet of the biological treatment and on the denitrification and nitrification processes with the aim of reducing violations of legally established limits of nitrogen and ammonia and also reducing operational costs. The proposed fuzzy controller is tested by simulation with the internationally known benchmark simulation model no. 2. The objective is to apply the proposed fuzzy controller in any control strategy, only replacing the manipulation of the internal recirculation flow rate, to improve the plant operation.Therefore, it has been implemented in five operation strategies from the literature, replacing their original internal recirculation flow rate control, and simulation results are compared with those of the original strategies. Results show improvements with the application of the proposed fuzzy controller of between 2.25 and 57.94% in reduction of total nitrogen limit violations, between 55.22 and 79.69% in reduction of ammonia limit violations and between 0.84 and 38.06% in cost reduction of pumping energy.

内循环对污水处理厂的不同生物过程起着重要作用，因为它对污染物，尤其是营养物质的浓度有很大的影响。通常，内部再循环流量保持固定或通过控制技术控制，以在最后一个缺氧罐中保持固定的硝酸盐设定点。这项工作提出了一种新的控制策略，通过应用模糊控制器来控制内部再循环流量。建议的控制器考虑了内部再循环流量对生物处理入口以及反硝化和硝化过程的影响，目的是减少违反法律规定的氮和氨限制并降低运营成本。所提出的模糊控制器通过模拟测试与国际知名的基准模拟模型没有。2. 目标是将所提出的模糊控制器应用于任何控制策略，仅取代内部再循环流量的操纵，以改善工厂运行。因此，它已在文献中的五种运行策略中实施，取代了它们原来的内部再循环流量控制，并将模拟结果与原始策略进行比较。结果表明，应用所提出的模糊控制器后，总氮限制违规的减少量在 2.25% 到 57.94% 之间，氨限制违规的减少量在 55.22% 到 79.69% 之间，泵送能量的成本降低了 0.84% 到 38.06% 之间。