No abstract

Managing urban water systems in which stormwater, wastewater, and drinking water sectors affect each other is a difficult task that requires the right modeling tools for decision making. Integrated urban water management models (IUWMs) are tools that allow decision makers to demonstrate the effectiveness of various management, operational and design strategies. Although models are useful tools, the wide range of available models with many different capabilities make it challenging for the users to select an appropriate model for their specific objectives. In this review we investigated the capabilities of popular models in IUWM. We developed a comprehensive list of indicators to compare the capabilities of the models. We also analyzed the application of these models in a comparative way and evaluated their input requirements. Finally, we provided a procedure to select the appropriate model in the management environment based on the user’s needs. In summary, the results show that most of the models’ applications are focused on supply and demand, wastewater management, and stormwater management. Very few models consider social factors and policy aspects in IUWM. While each model has its own advantages, we found some of them, such as MIKE Urban, Hydro Planner, and Aqua Cycle, to be more comprehensive. Nevertheless, there are still gaps in the models in areas such as water-energy nexus, evaluating ecosystem services, including socioeconomic factors and sustainability analysis.

Effective management of cities using ecosystem services from green infrastructure (GI) requires explicit consideration of the linkages between provision of services and ecosystem service demands (i.e., governance priorities). Identi cation of stakeholder knowledge and objectives in GI decision-making contexts with respect to ecosystem services may improve urban planning; yet this information is rarely explicit in local contexts and cases. We address this gap by surveying environmental stakeholders and practitioners to investigate how perceptions of ecosystem services in uence GI practice in Tucson, AZ.Results indicate that the semi-arid environment and urban design led to prioritizations that focus on water sustainability and urban heat mitigation. We found strong agreement in environmental perceptions between different management sectors. We observed matches (as well as mismatches) between the ecosystem service priorities and important environmental issues. Ecosystem services prioritization revealed a unique classi cation of ecosystem services that re ects stakeholder priorities. Our ndings suggest the study of ecosystem services supply and demand can inform local urban management. These ndings from a semi-arid city further suggest that understanding stakeholder knowledge, perceptions, and priorities should be important for cities in other regions where GI is being implemented as an environmental solution to provide ecosystem services.

Background: The most important process in water treatment plant is coagulation and flocculation. Regular chemical coagulant which used in Iran are aluminum sulfate (Alum) and ferric chloride. Chemical coagulants have hazardous effect on human health and their cost is high for developing country. The purpose of this study was to evaluate the comparison of chemical coagulants accompany with corn starch as a coagulant aid, for the turbidity removal from water. Methods: This study was accomplished in pilot-scale with synthetic turbid water using clay. In this research, initial turbidity of 250 and 500 NTU was experimented. Chemical coagulant dose during the experiment was 1, 2 and 5 ppm and natural coagulant dose was 0, 0.1, 0.3, 0.5 and 0.7 ppm. Results: The results showed that maximum removal efficiency of turbidity in initial turbidity of 250 NTU belonged to poly aluminum chloride with 5 ppm dosage and corn starch with 0.7 ppm dosage which removed and reduced the initial turbidity to 98.48% and 3.73 NTU, respectively. Moreover, in initial turbidity of 500 NTU the maximum removal efficiency was 98.52% which belonged to ferric chloride and corn starch (5 and 0.7 ppm respectively) and reduced the initial turbidity to 7.4 NTU. Conclusions: The results of this study showed that using natural coagulant aid reduce the chemical coagulant consumption, and also does not have significant effect on pH range and reduce the health risks. While huge amount of required polyelectrolytes for water treatment plant imported to the country and the production of corn starch in our country is high, it is hope that the results of this project can be used in industrial scale.