Kurdistan University of Medical Sciences Journal of Advances in Environmental Health Research 2676-3478 6 4 2018 10 01 Effects of nanobubble aeration in oxygen transfer efficiency and sludge production in wastewater biological treatment 225 233 75560 10.22102/jaehr.2018.135459.1086 EN Mehrdad Ahmadi PhD Scholar, Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran Gholamreza Nabi Bidhendi Professor, Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran Ali Torabian Professor, Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran Nasser Mehrdadi Professor, Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran Journal Article 2018 06 11 Low efficiency of conventional aeration techniques and the excessive production and disposal of sludge are great concerns in biological wastewater treatment systems. The present study aimed to evaluate the active sludge method using batch reactors under continuous operation to determine the efficiency of aeration and sludge production through microbubble and nanobubble aeration. The results indicated that compared to microbubble aeration, nanobubble aeration increased the concentration of dissolved oxygen in the mixed liqueur of the reactor (from 2 to 4.5 mg/l), while reducing the production of excess sludge from 100 to 40 ml/g (SRT: 15-40 d). With the same SRT duration, these values were within the range of 160-70 ml/g using fine-bubble aeration. According to the results, nanobubble aeration could increase the efficiency of aeration, thereby increasing the capacity of the treatment plant and reducing the costs of biological wastewater treatment. https://jaehr.muk.ac.ir/article_75560_9fd9120176ef4c6e15191f212a18d306.pdf