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This study is carried out within the framework of the requirements of ensuring reliable operation of the Central Wastewater Treatment Plant of Ulaanbaatar to increase the treatment performance and mitigate the adverse impacts of the current poor performance on nature and ecology. The dynamic of the current influent was studied in order to find the best-suited solution as a means of improvement for the WWTP. As an immediate and fast-to-build solution, an equalization tank and pre-aeration facilities were proposed. The positive effect of the facilities on the biological treatment stage and the overall treatment performance was estimated both theoretically and empirically. The results showed that the overall performance of the treatment for BOD5 and TSS will be increased by up to 30% and 10%, respectively. Furthermore, the high fluctuation problems the central WWTP in terms of hydraulic and pollution load will be positively affected by the intervention, eliminating the main cause of the current poor treatment performance. [ABSTRACT FROM AUTHOR]

This paper reports on the progress of the liquid-solid phase transition modeling of water in open channel flow by using the lattice Boltzmann method with the immersed boundary modification. The phase transition in a fluid flow has a moving interface between the liquid and solid state, which leads complicated treatments in existing numerical models. By applying the immersed boundary modification in the lattice Boltzmann method and the non-iterative enthalpy approach for the separation of the states, the moving boundary of the melting or solidification front is solved without any difficulty. The ice bed and the submerged ice cover under dynamic flow conditions is exercised to demonstrate the model performance. The model is extremely suitable in the formulation in terms of its simple and compact framework extendable to any dimensions. [ABSTRACT FROM AUTHOR]

The South Gobi region (including Umnugovi, Dundgovi and Dornogovi aimags - provinces) of Mongolia is becoming a leading region of the nation's economic and social development. Water resources play an important role in ensuring sustainable economic development of the South Gobi region. In the South Gobi region, lack of proven groundwater resources, data on water extraction and consumption makes it difficult to accurately identify risks and to manage limited resources for sustainable development. Based on the available historical data between 2015 and 2019 on water resources and water use, the water demand in this region has been projected up to the year 2050 on the basis of dynamic modelling of water management, including major stakeholders, country's sustainable economic development vision up to the year 2050, and the impact of climate change. The model predicts continued increasing demand for mining, agricultural, industrial and social services and rural water demands, while gradual decline for the livestock water demand was projected after the gradual increase in the first half of the period. Basing on the system dynamic modelling of water management, it can be said that the groundwater resources of the South Gobi region may not be able to meet the above needs after 2037. Economically feasible measures and managements to prevent the risk of water scarcity before water shortage happens are proposed based on the results of the model. [ABSTRACT FROM AUTHOR]