The need of an adaptive sustainable solution for the increased land scarcity, growing urbanization, climate change and flood risks resulted in the concept of the floating urbanization. In The Netherlands this new type of housing attracted the interest of local authorities, municipalities and water boards. Moreover, plans to incorporate floating houses in the urban planning have already been developed. However, the knowledge gap regarding the potential effect on the water quality halts the further development of the floating houses. This paper shows the results of a water quality measurement campaign, as part of the national program “Knowledge for climate”, at a small floating houses project in Delft and serves as a case study for addressing the environmental-ecological knowledge gap on this topic.
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Urban delta areas require innovative and adaptive urban developments to face problems related with land scarcity and impacts of climate change and flooding. Floating structures offer the flexibility and multi-functionality required to efficiently face these challenges and demands. The impact of these structures on the environment, however, is currently unknown and research on this topic is often disregarded. This knowledge gap creates a difficulty for water authorities and municipalities to create a policy framework, and to regulate and facilitate the development of new projects.Monitoring the effects of floating structures on water quality and ecology has been difficult until now because of the poor accessibility of the water body underneath the structures. In this work, a remote controlled underwater drone equipped with water quality sensors and a video camera was used to monitor dissolved oxygen near and under floating structures. The collected data showed that most water quality parameters remain at acceptable levels, indicating that the current small scale floating structures do not have a significant influence on water quality. The underwater footage revealed the existence of a dynamic and diverse aquatic habitat in the vicinity of these structures, showing that floating structures can have a positive effect on the aquatic environment. Future floating structures projects therefore should be encouraged to proceed.
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Floating urbanization is a promising solution to reduce the vulnerability of cities against climate change, population growth or land scarcity. Although this type of construction introduces changes to aquatic systems, there is a lack of research studies addressing potential impacts. Water quality data collected under/near floating structures were compared with the corresponding parameters measured at the same depth at open water locations by (i) performing scans with underwater drones equipped with in situ sensors and video cameras and (ii) fixing two sets of continuous measuring in situ sensors for a period of several days/months at both positions. A total of 18 locations with different types of floating structures were considered in this study. Results show small differences in the measured parameters, such as lower dissolved oxygen concentrations or higher temperature measured underneath the floating structures. The magnitudes of these differences seem to be linked with the characteristics and type of water system. Given the wide variety and types of water bodies considered in this study, results suggest that water quality is not critically affected by the presence of the floating houses. Underwater images of biofouling and filter feeders illustrate the lively ecosystems that can emerge shortly after the construction of floating buildings.
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In recent years, the application of both hyperbolically constrained flow geometries and micro/nanobubbles have been gaining interests among industries and scientific fields due to their unique characteristics. Among other things, they can facilitate enhanced gas transfer through gas-liquid interfaces and promote particle interactions at bubble surfaces, subsequently resulting in improved water quality. Concomitantly, water is essential for crop production in agri- and horticulture and the main ingredient of many food and beverage products. Several studies have reported that micro/nanobubble enriched water has a beneficial impact for various agri- and food related processes. A concrete example is the experience of a recognized Dutch coffee brewer, ‘A Matter of Concrete’, which used a device fabricated to add micro-nano bubbles to their coffee brewing process water. Submitting the treated water and the coffee to a blind tasting test, many users and a (blind) jury reported noticeable improvements. This device is “Turritap”, a simple hyperbolical tap connector based on natural flow geometries. Turritap is elegantly simple, but its main principles and modus operandi are not (yet) completely understood. According to both manufacturer, academia[20] and several end-users, the lack of understanding hampers market diffusion and widespread use of Turritap. Turritest is structured to tackle this challenge. It is based on the hypothesis, backed up by recent published research[9], that the reported alterations in (chemical and aesthetic) water quality are linked to dissolved oxygen levels, which could be related to an observed change in the amount of micro/nanobubble in the water treated by Turritap. Turritest will thus focus on performing experiments which can substantiate the claim the capability of Turritap to form micro/nanobubble in water, while attempting to correlate these findings to changes in water quality. If effects are further confirmed, Turritest would substantiate an extremely simple but rather impressive enhancement of product water quality.
The EU Climate and Energy Policy Framework targets a 40% reduction in Greenhouse Gases (GHGs) emission by companies (when compared to 1990’s values) in 2030 [1]. Preparing for that future, many companies are working to reach climate neutrality in 2030. For water and wastewater treatment plants aeration processes could represent up to 70% of the whole energy consumption of the plant. Thus, a process which must be carefully evaluated if climate neutrality is a target. VortOx is an alternative to reduce power consumption in aeration processes. It is structured to test the applicability of geometrically constrained vortices in a hyperbolic funnel (aka “Schauberger”- funnel) as an innovative aeration technique for this industry. Recent investigations have shown that such systems allow an average of 12x more oxygen transfer coefficients (KLa) than that of comparable methods like air jets or impellers [10]. However, the system has a relatively small hydraulic retention time (HRT), which compromises its standard oxygen transfer ratio (SOTR). Additionally, so far, the system has only been tested in pilot (lab) scale. Vortox will tackle both challenges. Firstly, it will test geometry and flow adaptations to increase HRT keeping the same KLa levels. And secondly, all will be done using a real scale hyperbolic funnel and real effluent from Leeuwarden’s wastewater treatment plant demo-site. If proven feasible, Vortox can be a large step towards climate neutral water and wastewater treatment systems.
