Biological nutrient removal activated sludge (BNRAS) systems remove carbon, nitrogen and phosphorus by biological means with low costs and less waste sludge production (Metcalf and Eddy, 2003). One of the most commonly applied BNRAS methods for ur- ban wastewater treatment relies on the University of Cape Town (UCT) concept. The UCT process was designed to minimize the ef- fect of nitrate to the anaerobic contact zone, which is crucial for maintaining truly anaerobic conditions and thus, allowing biologi- cal phosphorus release (Ekama and Wentzel, 1999; Metcalf and Eddy, 2003; Vaiopoulou et al., 2007a). In fact, the higher the phos- phorus concentration released in the anaerobic tank, the higher is the phosphorus concentration taken up under aerobic conditions. From a biological aspect, the anaerobic selector not only contrib- utes to phosphorus removal, but also forms heavy large ﬂocs that enhance settleability (Metcalf and Eddy, 2003).
Denitrifying polyphosphate accumulating bacteria (DPB) under anaerobic/anoxic alternate environment used oxygen, nitrite and nitrate as terminal electron acceptor to replace the traditional phosphorus accumulation organisms, through their metabolism to complete phosphorus uptake and denitrification, it was considered as a sustainable wastewater treatment process because it can solve the problem of carbon source competition, reduce sludge production and the reaction time.Typical denitrifying phosphorus removal processes is divided into single and dual sludge system. In single sludge system, DPB, nitrifying bacteria and other heterotrophic bacteria are stay in same reactors. In dual sludge system, DPB and nitrifying bacteria exist alone in immobilized membrane bioreactor or aerobic nitrification sequencing batch reactor.
Summary and place of the MUCT system
The drive to intensify the activated sludge (AS) system so that it requires less space and consumes less energy without com- promising delivery of a high-quality treated effluent has led to some remarkable inventions and developments in biological nutrient removal over the past 2 decades. To reduce the sludge age required for nitrification, static or moving fixed media (e.g. solid AccuFAS or Bio-Blok), sus- pended rope (e.g. Ringlace) or moving bed (e.g. Kaldness) carriers are added to the aerobic reactor (Wanner et al., 1988; Sen et al., 1994; Thomas et al., 2008). Such systems are called integrated fixed-film activated sludge (IFAS).
Удаление биогенных веществ из сточных вод г. Челябинска. Челябинск: ЮУрГУ, АС-227, 2018. Варианты процесса биологического удаления азота и фосфора, применяемые в России: - процесс АА/О, - процесс Кейптаунского университета (UCT), - модифицированный процесс UCT (МUCT) В качестве проработки рассматривались две схемы: UCT процесс и модифицированный UCT процесс, как наиболее оптимальные схемы для очистных сооружений города Челябинска