Federal University of Rio de Janeiro - COPPE - Chemical Engineering Program, Rio de Janeiro, Brazil.
Federal University of Rio de Janeiro - COPPE - Chemical Engineering Program, Rio de Janeiro, Brazil.
J Environ Manage. 2019 Jan 15;230:168-182. doi: 10.1016/j.jenvman.2018.09.072. Epub 2018 Oct 3.
Aerobic granular sludge (AGS) is a promising technology for wastewater treatment. However, the success of the process depends on the formation of stable granular biomass, which is associated with the microbiological aspects of the sludge and reactor operating conditions. In this study, the development of AGS from a poor nitrifying flocculent sludge obtained in a sewage treatment plant designed only for organic matter removal was assessed in a sequencing batch reactor (SBR) under tropical climate conditions (temperatures of 28 ± 4 °C). The results showed that, despite the alternating anaerobic-aerobic conditions during the granules selection phase under high sludge washout rates (low settling time), readily biodegradable organic matter was mainly removed aerobically. The formed granules were unstable, exhibiting a substantial amount of filaments and pasty consistency. The biomass characteristics (e.g., sludge volume index, density, diameter and settling velocity) were negatively impacted as complete granulation was reached, while biomass loss and degranulation became inevitable. Poor nitrification and no enhanced biological phosphate removal (EBPR) were observed. Implementation of a new operational strategy incorporating an adaptation of the seed sludge under reduced washout conditions (high settling time) prior to the granules selection stage enabled most of the influent organics to be removed anaerobically. Besides allowing a feast-famine regime to be established in the reactor, the sludge acclimation phase favoured the development of slow-growing organisms and suppressed the appearance of filamentous-like structures. Fast-settling granules with regular shape remained stable in the long-term, while high ammonium (>95%) and total nitrogen removal (>90%) was obtained. However, EBPR activity was very unstable, most likely due to the high temperatures. The findings of this study are important for the spreading of the AGS technology worldwide, especially in developing countries where the conditions are different in all aspects.
好氧颗粒污泥（AGS）是一种很有前途的废水处理技术。然而，该工艺的成功取决于稳定的颗粒生物量的形成，而这与污泥的微生物方面和反应器的操作条件有关。在本研究中，在热带气候条件（温度为 28 ± 4°C）下，在序批式反应器（SBR）中评估了仅用于去除有机物的污水处理厂中获得的硝化絮状污泥在好氧颗粒污泥（AGS）的形成。结果表明，尽管在高污泥冲洗率（低沉降时间）下的颗粒选择阶段存在交替的厌氧-好氧条件，但主要通过好氧去除了易生物降解的有机物。形成的颗粒不稳定，表现出大量丝状和糊状稠度。当达到完全颗粒化时，生物量特性（例如污泥体积指数、密度、直径和沉降速度）受到负面影响，而生物量损失和颗粒解体则不可避免。观察到硝化不良和无增强生物除磷（EBPR）。在颗粒选择阶段之前，采用减少冲洗条件（高沉降时间）对种子污泥进行适应性调整的新操作策略的实施，使大部分进水有机物可以在厌氧条件下去除。除了允许在反应器中建立饱食-饥饿制度外，污泥驯化阶段还有利于缓慢生长的生物的发展，并抑制丝状结构的出现。快速沉降的规则形状的颗粒在长期内保持稳定，同时获得了高的氨（>95%）和总氮去除率（>90%）。然而，EBPR 活性非常不稳定，这很可能是由于高温造成的。本研究的结果对于AGS 技术在全世界的推广非常重要，特别是在发展中国家，这些国家的条件在各个方面都有所不同。
