Solubility of 1:1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water:1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water

To increase the available data oil systems containing supercritical water and inorganic compounds, all experimental setup was designed to investigate the solubilities of inorganic compounds Ill supercritical water, In this work, three alkali chloride salts (LiCl, NaCl, KCl) and three alkali nitrate salts (LiNO(3), NaNO(3), KNO(3)) were investigated in the range from (653 to 693) K and from (18 to 23.5) MPa. The experimental results were correlated with a model based on the phase equilibrium between the inorganic compound and supercritical water. When available, the experimental data were extended with data available ill the open literature. The experimental results and parameters obtained by this model were compared with each other and evaluated under consideration of the physical aspects of the inorganic compounds. In addition to the Main purpose of the experiments, side reactions like decomposition of nitrate and changes in pH were observed and discussed in this work. The presented data are the first coherent Study of the Solubility of six common inorganic compounds in one setup and with one method

Removal of inorganic compounds via supercritical water : fundamentals and applications

Desalination is seen as one of the key technologies to satisfy the growing global water demand due to urbanization, population growth and depletion of natural water resources. One of the major drawbacks of current desalination technologies is the production of a liquid brine stream as a waste stream. This thesis introduces supercritical fluids - a highly regarded technology in process engineering and chemical industry - in a new field: the treatment and purification of aqueous streams. The resulting technology - a new approach to remove inorganic compounds from these streams and to offer a way for desalination without the production of a liquid waste stream -, its basics, its options and potential are the tenor of this thesis. The separation principle of this approach is based on the changed solvation behavior of supercritical water. While water represents an excellent solvent at ambient conditions, it changes to a poor one at supercritical conditions (T > 647 K; p > 22.1 MPa). The decreased solubility of inorganic compounds leads to precipitation and formation of an additional solid phase. This behavior allows for treatment of saline streams without production of a waste stream; an option that current technologies like Reverse Osmosis and Multi-Stage-Flash do not offer. New and unique experimental data on behavior and solubility of inorganic compounds in supercritical water are presented. Relations between solubility, system parameters and properties of the inorganic compounds are shown. Process options and concepts are discussed regarding their potential, their sustainability and their synergy with other technologies.

A new approach to nationwide sanitation planning for developing countries : Case study of Indonesia

Many developing countries struggle to provide wastewater and solid waste services. The backlog in access has been partly attributed to the absence of a functional sanitation planning framework. Various planning tools are available; however a comprehensive framework that directly links a government policy to nationwide planning is missing. Therefore, we propose a framework to facilitate the nationwide planning process for the implementation of wastewater and solid waste services. The framework requires inputs from government planners and experts in the formulation of starting points and targets. Based on a limited number of indicators (population density, urban functions) three outputs are generated. The first output is a visualization of the spatial distribution of wastewater and solid waste systems to support regional priority setting in planning and create awareness. Secondly, the total number of people served, budget requirements and distribution of systems is determined. Thirdly, the required budget is allocated to the responsible institution to assure effective implementation. The determined budgets are specified by their beneficiaries, distinguishing urban, rural, poor and non-poor households. The framework was applied for Indonesia and outputs were adopted in the National Development Plan. The required budget to reach the Indonesian government's 2019 target was determined to be 25 billion US$over 5 years. The contribution from the national budget required a more than fivefold increase compared to the current budget allocation in Indonesia, corresponding to an increase from 0.5 to 2.7 billion US$ per year. The budget for campaigning, advocacy and institutional strengthening to enable implementation was determined to be 10% of the total budget. The proposed framework is not only suitable for Indonesia, but could also be applied to any developing country that aims to increase access to wastewater and solid waste facilities

Feasibility analysis of wastewater and solid waste systems for application in Indonesia

Indonesia is one of many developing countries with a backlog in achieving targets for the implementation of wastewater and solid waste collection, treatment and recovery systems. Therefore a technical and financial feasibility analysis of these systems was performed using Indonesia as an example. COD, BOD, nitrogen, phosphorus and pathogen removal efficiencies, energy requirements, sludge production, land use and resource recovery potential (phosphorus, energy, duckweed, compost, water) for on-site, community based and off-site wastewater systems were determined. Solid waste systems (conventional, centralized and decentralized resource recovery) were analyzed according to land requirement, compost and energy production and recovery of plastic and paper. In the financial analysis, investments, operational costs & benefits and Total Lifecycle Costs (TLC) of all investigated options were compared. Technical performance and TLC were used to guide system selection for implementation in different residential settings. An analysis was undertaken to determine the effect of price variations of recoverable resources and land prices on TLC. A 10-fold increase in land prices for land intensivewastewater systems resulted in a 5 times higher TLC,whereas a 4-fold increase in the recovered resource selling price resulted in maximum 1.3 times higher TLC. For solid waste, these impacts were reversed — land price and resource selling price variations resulted in a maximumdifference in TLC of 1.8 and 4 respectively. Technical and financial performance analysis can support decision makers in system selection and anticipate the impact of price variations on long-termoperation. The technical analysiswas based on published results of international research and the approach can be applied for other tropical, developing countries. All costs were converted to per capita unit costs and can be updated to assess other countries' estimated costs and benefits. Consequently, the approach can be used to guide wastewater and solid waste system planning in developing countries

Flexible design in water and wastewater engineering - Definitions literature and decision guide

Urban water and wastewater systems face uncertain developments including technological progress, climate change and urban development. To ensure the sustainability of these systems under dynamic conditions it has been proposed that technologies and infrastructure should be flexible, adaptive and robust. However, in literature it is often unclear what these technologies and infrastructure are. Furthermore, the terms flexible, adaptive and robust are often used interchangeably, despite important differences. In this paper we will i) define the terminology, ii) provide an overview of the status of flexible infrastructure design alternatives for water and wastewater networks and treatment, and iii) develop guidelines for the selection of flexible design alternatives. Results indicate that, with the exception of Net Present Valuation methods, there is little research available on the design and evaluation of technologies that can enable flexibility. Flexible design alternatives reviewed include robust design, phased design, modular design, modular/component platform design and design for remanufacturing. As developments in the water sector are driven by slow variables (climate change, urban development), rather than market forces, it is suggested that phased design or component platform designs are suitable for responding to change, while robust design is an option when operations face highly dynamic variability