Molecular and culture-based assessment of the microbiome in a zebrafish (Danio rerio) housing system during set-up and equilibration

Background Zebrafish used in research settings are often housed in recirculating aquaculture systems (RAS) which rely on the system microbiome, typically enriched in a biofiltration substrate, to remove the harmful ammonia generated by fish via oxidation. Commercial RAS must be allowed to equilibrate following installation, before fish can be introduced. There is little information available regarding the bacterial community structure in commercial zebrafish housing systems, or the time-point at which the system or biofilter reaches a microbiological equilibrium in RAS in general. Methods A zebrafish housing system was monitored at multiple different system sites including tank water in six different tanks, pre- and post-particulate filter water, the fluidized bed biofilter substrate, post-carbon filter water, and water leaving the ultra-violet (UV) disinfection unit and entering the tanks. All of these samples were collected in quadruplicate, from prior to population of the system with zebrafish through 18 weeks post-population, and analyzed using both 16S rRNA amplicon sequencing and culture using multiple agars and annotation of isolates via matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry. Sequencing data were analyzed using traditional methods, network analyses of longitudinal data, and integration of culture and sequence data. Results The water microbiome, dominated by Cutibacterium and Staphylococcus spp., reached a relatively stable richness and composition by approximately three to four weeks post-population, but continued to evolve in composition throughout the study duration. The microbiomes of the fluidized bed biofilter and water leaving the UV disinfection unit were distinct from water at all other sites. Core taxa detected using molecular methods comprised 36 amplicon sequence variants, 15 of which represented Proteobacteria including multiple members of the families Burkholderiaceae and Sphingomonadaceae. Culture-based screening yielded 36 distinct isolates, and showed moderate agreement with sequencing data. Conclusions The microbiome of commercial RAS used for research zebrafish reaches a relatively stable state by four weeks post-population and would be expected to be suitable for experimental use following that time-point.

Fabrication of potable and eco-friendly solar disinfection (sodis) unit and its performance analysis

Solar disinfection (SODIS) is a technique, which involves utilization of solar energy to make safe drinking water from biologically contaminated water. In the conventional SODIS method, the PET bottles are filled with polluted water and exposed to the sunlight for a certain period depending upon the local weather conditions. However much more effective disinfection system is needed to overcome the problems of inefficient utilization of available solar energy and the health risk posed by treating the water using chemicals during the purification process. Hence, the present work aims in designing a portable solar disinfection unit that can efficiently use solar energy by manually adjusting the unit according to sunlight availability. Along with it, incorporation of the additional eco-friendly unit with water purifying plants Vetiveria zizanioides (Vetiver) and Hemidesmus indicus (Nannari) is done to achieve high efficiency in producing potable water from biologically contaminated water. The contaminated water samples treated in the solar disinfection unit and eco-friendly water purifying unit are analyzed for the presence of total coliforms and E-coli by using the Most probable Number method and P/A analysis, respectively. A reduction in 99.74% of total coliform count and absence of E-coli was observed in the treated water samples. The physicochemical analysis was carried out to ensure the suitability of treated water for consumption and the results revealed a notable reduction in the parameters, and all the parameters came under the permissible range of IS drinking water characteristics. The designed system can be used to disinfect the contaminated water sample most efficiently, thereby making the water suitable for consumption.

Evaluation of the efficiency of a gray water treatment system based on aeration and filtration

Gray water is a great resource for replacing fresh water to be used in standardized usages. The use of treated gray water reduces water consumption and the entry of pollutants into the environment. However, if left untreated, it can be dangerous. The present study examines the efficiency of a gray water treatment system consisting of primary filter, aeration, secondary filter and ultraviolet disinfection unit. After examining the characteristics of gray water, the efficiency of this system was analyzed to remove the pH, TSS, BOD, COD, ABS and total coliform parameters. Then, the gray water treated through this system was compared with the environmental standard of Iran. The pH of the treated gray water was 7.5–7.6. The efficiency of this system for removing the BOD and COD parameters was 98–100 and 76–100%, respectively. This system had an efficiency of 96–97% to eliminate the ABS parameter. Also, this system was able to eliminate total coliform with 100% efficiency. Results showed that in the three series of experiments performed on this system, according to the Iranian standard, the treated wastewater is suitable for irrigation and agricultural uses. However, this system could not be licensed for the COD parameter regarding the discharge to surface water and absorbent wells.

Sewer Mining as A Basis for Technological, Business and Governance Solutions for Water in the Circular Economy: The NextGen Athens Demo

The Athens Water in the Circular Economy demo case examines all three of the following as associated with Circular Economy (CE) in wastewater streams: water, energy and materials. The application area is the Athens Urban Tree Nursery, which is located in the center of Athens, in order to address real world problems in water-scarce cities. The Athens demo application includes sewer mining, a technology first pioneered in Australia related to mobile wastewater treatment units in containers that are able to treat and provide reused water at the point of demand in dense urban environments. The installed pilot unit consists of a membrane bioreactor unit (MBR) and a UV disinfection unit. The sewer mining is achieved with a prefabricated pumping statiοn that will be demonstrated in the main sewer network for feeding the sewer mining unit with wastewater. The unit will produce fresh water that will be used for irrigation needs, and also during the winter for aquifer discharge. The Athens Tree nursery also has significant amounts of pruning materials that, until now, have remained untapped resources. The excess sludge produced from the unit along with the green and wood waste will go through a rapid composting process in order to produce fertilizer. The first stage will be a pre-treatment unit that includes the shredding, homogenizing and sorting of the pruning materials. The second stage is rapid composting that will last approximately 2 weeks. The last stage is the compost that will be used again on-site as a fertilizer full of nutrients as part of a renewable energy solution for the area to support more complete autonomy.

Standalone Solar-Powered Ultraviolet Mobile Disinfectant: Bringing Solar Energy in the Global Fight against COVID-19

As the first initiative of its kind in Algeria, here is presented a solar-powered mobile “Ultraviolet Germicidal Irradiation” disinfection unit (UVGI) based on a special germicidal ultraviolet-C (UVC) radiator. The system was designed to disinfect several objects such as: medical tools, reusable masks, face-shields, gloves, phones, laptops, keys, money and many other portable devices that need to be disinfected/sterilized. It offers the advantage of complete autonomy through the built-in photovoltaic (PV) system that includes a solar panel, a gel battery, a charge controller and a power inverter. The system provides an extra 220V-50Hz outlet with 375VA maximum power to be used when energy is needed. The system is easily scalable to generate higher ultraviolet dosages by adding more UVC lamps. The chemical-free germicidal UVC sanitizing method employed by this device effectively disactivates a very wide range of microorganisms (microbes, bacteria and fungi and viruses including the actual SARS-CoV-2 that causes COVID-19 respiratory disease) and it has several advantages in comparison to chemical-based sanitizing methods. The total cost to make this open source device is below 1000 € and is easily customizable and scalable. This device is an open source, secure and fast equipment for objects and surface disinfection. The device will be fully automated by adding PIR sensors or remote control after further funding will be received.

EU Horizon 2020 Research for A Sustainable Future: INNOQUA—A Nature-Based Sanitation Solution

This paper explores the experiences of partners in the multi-national, EU-funded INNOQUA project, who have developed and are currently demonstrating the potential for novel nature-based, decentralised wastewater treatment solutions in ten different countries. Four solutions are under investigation, each at different Technology Readiness Levels (TRLs): Lumbrifilter; Daphniafilter; Bio-Solar Purification unit; UV disinfection unit. An overview of the solutions is provided, along within data from pilot sites. The project is currently entering an intensive demonstration phase, during which sites will be open for visits and act as the focus for training and dissemination activities on sustainable wastewater treatment. Barriers to market for nature-based solutions are also explored.

Value Flow Map: application and results in the disinfection center

ABSTRACT Objective: To identify and eliminate steps that do not add value for customers in the disinfection center. Method: We applied the Lean tool: Value Flow Map, using the concepts of gemba and kaizen in the work process of the disinfection unit for ventilatory care materials, aiming at improving such process. After performing a training with the team on the Lean concepts described above, applying the Value Flow Map in the gemba, analyzing the opportunities for improvement, and approving the changes, the Value Flow Map of the future state was devised and changes were implemented. Result: The time of the disinfection process was reduced in 2h37 and the financial resources required also decreased, in R$ 809.08/month. Conclusion: The application of Lean concepts presented positive results for the elimination of wastages in the disinfection center.

Constructed wetlands and solar-driven disinfection technologies for sustainable wastewater treatment and reclamation in rural India: SWINGS project

SWINGS was a cooperation project between the European Union and India, aiming at implementing state of the art low-cost technologies for the treatment and reuse of domestic wastewater in rural areas of India. The largest wastewater treatment plant consists of a high-rate anaerobic system, followed by vertical and horizontal subsurface flow constructed wetlands with a treatment area of around 1,900 m2 and a final step consisting of solar-driven anodic oxidation (AO) and ultraviolet (UV) disinfection units allowing direct reuse of the treated water. The implementation and operation of two pilot plants in north (Aligarh Muslim University, AMU) and central India (Indira Gandhi National Tribal University, IGNTU) are shown in this study. The overall performance of AMU pilot plant during the first 7 months of operation showed organic matter removal efficiencies of 87% total suspended solids, 95% 5-day biological oxygen demand (BOD5) and 90% chemical oxygen demand, while Kjeldahl nitrogen removal reached 89%. The UV disinfection unit produces water for irrigation and toilet flushing with pathogenic indicator bacteria well below WHO guidelines. On the other hand, the AO disinfection unit implemented at IGNTU and operated for almost a year has been shown to produce an effluent of sufficient quality to be reused by the local population for agriculture and irrigation.