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Ammonia oxidation is the rate-limiting step in nitrification process and dominated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). In the present study, a highly enriched culture of AOA was obtained from urban polluted water in Shahe River, Shenzhen, China. The optimum growth conditions were identified by orthogonal analysis as 37 °C, with pH 7.0 and initial ammonia concentration of 1.0 mM. Under these conditions, the highest abundance of AOA was obtained as 4.6 × 107 copies/ng DNA. Growth of AOA in polluted river water showed significant reduction in ammonia concentration in AOA-enriched cultures without antibiotics after 10 days of incubation, while synchronous increase in nitrate concentration was up to 12.7 mg/L. However, AOA-enriched by antibiotic showed insignificant changes in ammonia or nitrite concentration. This study showed that AOB play an important role in ammonia oxidation of polluted river water, and AOA alone showed insignificant changes in ammonia or nitrite concentrations. Therefore, the ammonia oxidation performance of natural water could not be improved by adding high concentration AOA bacterial liquid. Image 1 • Optimum growth conditions of AOA were identified by orthogonal analysis. • Highest abundance of AOA was obtained by 4.6 × 107 copies/ng DNA. • AOB play an important role in ammonia oxidation of polluted river water. • AOA-enriched by antibiotic showed insignificant changes in NH 4 + and NO 2 −. In this study, the optimum growth conditions of AOA in a polluted river were investigated. AOB also play an important role in ammonia oxidation in the river water. [ABSTRACT FROM AUTHOR]

• An intelligent planning model for UUS development and utilization was established. • An improved AIGA with an additional correlation operator was developed. • A three-dimensional UUS planning scheme of Luohu District in Shenzhen was derived. Development and utilization of Urban underground space (UUS) is one of the key ways for developing sustainable cities. However, the development and utilization of UUS is currently occurring in a passive manner, lacking proactive and quantitative planning. In this paper, an intelligent planning model was established to guide the future development and utilization of UUS. The proposed model, in which more than twenty factors were considered, is capable of analysing the suitability of UUS development in different regions and at different depths. In addition, an improved artificial intervention genetic algorithm (AIGA) with an additional correlation operator was integrated into the proposed model to achieve the optimal two-dimensional (2D) planning scheme by quantitively analysing the matching of the ground surface and underground space, and the compactness and suitability of underground space. A three-dimensional (3D) planning scheme was obtained by analysing the stratification of the underground space and hierarchical development. The proposed intelligent planning model was, subsequently, applied to the development and utilization of UUS in Luohu District in Shenzhen. An analysis of the geological conditions and the current construction status of the ground surface showed that 69.4% of the underground space is suitable for shallow layer developments, and this proportion further increases to 76% for the sub-shallow, sub-deep and deep layers, indicating that the Luohu District is highly suitable for developing underground space. Furthermore, the derived optimal 2D planning scheme indicated that the suitability component plays a greater important role in the objective values than the matching and compactness components, and more attentions should be paid to the development of municipal facilities in the shallow layer in Luohu District. The derived 3D planning scheme of Luohu District showed the characteristics of an "inverted cone", where the utilization rate significantly decreases with increasing depth. The findings in this paper provide new insights for the future development and utilization of UUS. [ABSTRACT FROM AUTHOR]