Water Recovery System Research Articles

Gray Water Recovery System Model by Solar Photocatalysis with TiO<sub>2</sub> Nanoparticles for Crop Irrigation

Gray Water Recovery System Model by Solar Photocatalysis with TiO<sub>2</sub> Nanoparticles for Crop Irrigation

Application of A Solar Desiccant/Collector System for Water Recovery from Atmospheric Air.(Dept.M)

An integrated desiccant/solar collector system for production of fresh water from atmospheric air has been described. The solar driven system provided about 1.5 liter of fresh water per square meter p er day. The system involves night absorption of water vapor from ambient air and simultaneous desiccant regeneration and water vapor condensation during the daytime. To enhance the mass transfer surface, a thick corrugated layer of cloth was used as a bed carrying the liquid absorbent in the nocturnal phase of operation, air is allowed to penetrate the desiccant bed. The forced airflow is driven by special fans supported on one side of the desiccant / solar collector unit In this study, the effect of different parameters on the absorption and regeneration p rocesses was discussed, and the operational conditions for the proposed equipment were found. Radiation intensity, ambient temperature, bed temperature and temperature of glass surface art recorded. Also, the productivity of the system has been plotted along the daytime, for given operating conditions. A mathematical model is prepared Where its output is compared with the analyzed experimental data. The experimental set-up, which has a square collection area of 2 m2 was op erated at the Solar Energy Application Laboratory, Mansoura University, Faculty of Engineering.

Analytical Investigation of a Novel System for Combined Dew Point Cooling and Water Recovery

This paper presents the analytical investigation of a novel system for combined Dew Point Cooling and Water Recovery (DPC-WR system). The operating principle of the presented system is to utilize the dew point cooling phenomenon implemented in two stages in order to obtain both air cooling and water recovery. The system performance is described by different indicators, including the coefficient of performance (COP), gained output ratio (GOR), energy utilization factor (EUF), specific energy consumption (SEC) and specific daily water production (SDWP). The performance indicators are calculated for various climatic zones using a validated analytical model based on the convective heat transfer coefficient. By utilizing the dew point cooling phenomenon, it is possible to minimize the heat and electric energy consumption from external sources, which results in the COP and GOR values being an order of magnitude higher than for other cooling and water recovery technologies. The EUF value of the DPC-WR system ranges from 0.76 to 0.96, with an average of 0.90. The SEC value ranges from 0.5 to 2.0 kWh/m3 and the SDWP value ranges from 100 to 600 L/day/(kg/s). In addition, the DPC-WR system is modular, i.e., it can be multiplied as needed to achieve the required cooling or water recovery capacity.

Projecting global water footprints diminution of a dew-point cooling system: Sustainability approach assisted with energetic and economic assessment

In the coming decades, a large portion of the world population is expected to embrace urbanization. The demand for thermal comfort in populous and congested urban centres, especially in developing countries across the globe, is expected to rise many folds. Alternates to conventional air-cooling systems are water-based evaporation cooling. Recently introduced efficient multi-stage indirect evaporative cooling using the Maisotsenko(M)-Cycle has shown success with improved performance by theoretically reaching the dew-point of the incoming air. However, the impact of large-scale use of such cooling devices shall inadvertently leave huge strains on the urban useable water resources. On the other hand, cooling, as usual, is not sustainable with the global demand for air cooling units shall grow many folds up to 5.0 billion units over the next decade compared to currently 1.3 billion in service units.Alternates of high electricity consuming air cooling, such as Maisotsenko cycle based devices are part of the solution only if the water impact can be brought to minimal in an efficient manner. A key development in this regard is the utilization of water recovery systems from waste air streams leaving air coolers. A few studies and models have shown their successful working and predictions. This paper initially analyzes the global impacts of air-cooling devices using the commercially available product designed to work on the Maisotsenko cycle. Moreover, the impact of these devices on the global scale in terms of utility as well as their water footprints are estimated. The results produce a grim picture since most favourable zones/regions in the globe for indirect evaporative cooling are also labelled as high on the water stress index. Secondly, global assessment of water recovery unit in terms of reduction in water footprint and combined cooling and recovery system Energy Efficiency Ratio (EER) are also assessed. Based on the assessments and predictions of global economic parameters, a wholesome Levelized Cost of Electricity of combined air cooling and water recovery system is estimated for each zone across the globe favourable for the Maisotsenko cycle based air cooler.The hypothesis postulate that the global projections of the energy-efficiency-ratio should be improved while diminishing its water footprints at a lower Levelized cost. The prime purpose of the research is to evaluate the technological advancement presented in the commercial M50 air cooler for energetic, economical, and water-related indicators with the consideration of global projections in similitude to the social contexts of the region. Our hypothesis is verified with our assessment and the principal results have suggested that recovering the water from M-50 cooler, a commercially available device working on M-Cycle, yields in the reduction of specific water usage per ton of air cooling by ~63% while the EER improved by ~26% as compared to the conventional air cooling and the Levelized Cost of energy is 0.014 USD/kWh which is much lower than the conventional air conditioning systems.The findings of this article have concluded that proposed technological advancement has better performance indicators, suiting the complicated local context, and it is suggested/recommended to the governments (especially the Middle East, South Asian, Central Asian, North African, and Australia) to include such natural air coolers (particularly M-Cycle machines) in the national energy efficiency plans to meet the global sustainability targets of United Nations.

The influence of water price and the number of residents on the economic efficiency of water recovery from grey water

This article presents the results of an analysis of the economic viability of using an installation for the treatment of grey water. Economic indicators in the form of simple payback time (SPBT) and net present value (NPV) were used in the analysis. The use of a dual water supply system should theoretically enable the reduction of the costs of both water supply and sewage disposal, ensuring investment profitability. The article presents the impact of the number of residents as well as the impact of water and sewage on the profitability of using example water-recovery systems. It was found that both factors have a huge impact on the result of the economic analysis. For a small number of residents and at a low price of water supply and sewage disposal, it is not profitable to invest in a water-recovery system. This is due to the high price of purification devices.

Industrial experience with Fukushima Daiichi Accident wastewater treatment: Part I

Based on existing information, this article focuses on the challenges of radionuclide removal and analysis of the performance of processes associated with the treatment of a large-scale volume of wastewater at the site of the Fukushima Daiichi nuclear disaster, which occurred ten years ago. The first instalment, which appears here, provides an introduction to the work and processes used. It discusses reverse osmosis and the role it has played in treating contaminated sea-water at the site. It also describes a laboratory-scale study and the first of two schemes – involving what is referred to as the Simplified Active Water Retrieve and Recovery (SARRY) system – that are used to purify reverse osmosis retentate.

Trajectory of sediment deposition at the bottom of water intake structures of pumping stations

The study of the causes and patterns of sediment deposition at the bottom of water intake structures of pumping stations, the negative impact of sediments on the efficiency of their operation is one of the important measures taken to improve the efficiency of the water recovery system. The issues of studying the determination of the deposition rate and the trajectory of solid particles at the bottom of structures were analyzed, and the main shortcomings and shortcomings in determining the parameters of particle deposition were identified. An equation is proposed that allows determining the trajectory of solid particles deposition taking into account their concentration in the flow, the main properties (density, geometric parameters) of particles and water flow, as well as the design dimensions of the pump station’s advance chamber. The obtained calculated results based on the proposed equation were verified by the results of the study of deposits at the bottom of the advance chamber of the operating pumping station, which showed that the spread of the obtained data does not exceed 7…12 %. At the same time, the smallest particles settle at the end of the prechamber in the water suction zone. The obtained data showed the possibility of using the proposed equation to determine the trajectory of sediment particles deposition at the bottom of water intake structures of pumping stations.

A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in an Indoor Vertical Farm. Part 2: Rainwater Harvesting

The aim of this study was to determine the suitability of a rainwater harvesting system to cover the water demand for indoor hydroponic lettuce cultivation located in Wrocław (Poland). The analysis was performed on the basis of the recorded rainfall in Wrocław in 2000–2019. The analyzed cultivation is located in a hall with an area of 300 m2, where the lettuce is grown vertically by the hydroponic method. The calculations of the rainwater harvesting (RWH) system were carried out considering the selection of the tank capacity for the collected water. The operation of the water storage is simulated using a yield after spillage (YAS) algorithm. It was evident that the proposed system might be an auxiliary system that relieves the water supply network or supports other water recovery systems (e.g., the water vapor condensation in a cross-flow heat exchanger operating as an element of the air conditioning system, proposed in Part 1 of this study). The harvesting system for the selected vertical farming indoor hall covers an average of 35.9% of water needs and allows a saving of 146,510 L of water annually for the cultivation. An average water demand coverage increases up to 90.4%, which allows a saving of 340,300 L per year when the RWH system is combined with water recovery from exhaust air from the hall.

A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air

This paper presents the characteristics of the operation of the system for recovery of water from exhaust air in moderate climates in the years 2012–2019. The proposed system for water recovery uses the phenomenon of condensation in a cross-flow heat exchanger operating as an element of the air conditioning system. The parameters of exhaust air behind the heat exchanger have been determined using a mathematical model of the so-called black box. The mathematical model considers the risk of the cross-freezing of the heat exchanger. The calculations carried out for variable parameters of external air during the analyzed period confirm that the system allows to cover the demand for water for lettuce irrigation during the cold and transitional period, which is a major part of the year. It has been noted that the effectiveness of the system is very high (av. 67.12% per year) due to the specific parameters of the internal air in which the lettuce must be grown and the need for continuous air exchange in such facilities. This means that air is a stable source of water recovery, where the recovery rate depends on the parameters of external air.

Thermal performance of heat and water recovery systems: Role of condensing heat exchanger material

A significant amount of sensible and latent heat can be recovered at low temperatures from the flue gas of process heating equipment. However, the condensation of acids and water vapor makes the flue gas a highly-corrosive environment, which is a challenge for condensing heat exchangers. Corrosion-resistant materials are usually expensive and/or have relatively low thermal conductivities. Hence, it is essential to characterize the role of thermal conductivity of heat exchanger material in the performance of condensing heat exchangers. In the present study, a new analytical model is proposed and validated against available experimental data to predict the thermal performance of a tube-bank heat and water recovery unit. Our study indicates a threshold for tube thermal conductivity (~0.75 ​W ​m −1 K −1 ), which is a point where further increase does not significantly improve the condensation efficiency. This relatively low value of thermal conductivity, compared to commonly-used materials, e.g., ~10–15 ​W ​m −1 K −1 for stainless steel, unlocks the potential of using materials such as natural graphite, plastics, polymers, and ceramics (with thermally conductive additives) for applications in condensing heat exchangers and heat/water recovery in industry.

Urine Treatment on the International Space Station: Current Practice and Novel Approaches.

A reliable, robust, and resilient water recovery system is of paramount importance on board the International Space Station (ISS). Such a system must be able to treat all sources of water, thereby reducing resupply costs and allowing for longer-term space missions. As such, technologies able to dewater urine in microgravity have been investigated by different space agencies. However, despite over 50 years of research and advancements on water extraction from human urine, the Urine Processing Assembly (UPA) and the Water Processor Assembly (WPA) now operating on the ISS still achieve suboptimal water recovery rates and require periodic consumables resupply. Additionally, urine brine from the treatment is collected for disposal and not yet reused. These factors, combined with the need for a life support system capable of tolerating even dormant periods of up to one year, make the research in this field ever more critical. As such, in the last decade, extensive research was conducted on the adaptation of existing or emerging technologies for the ISS context. In virtue of having a strong chemical resistance, small footprint, tuneable selectivity and versatility, novel membrane-based processes have been in focus for treating human urine. Their hybridisation with thermal and biological processes as well as the combination with new nanomaterials have been particularly investigated. This article critically reviews the UPA and WPA processes currently in operation on the ISS, summarising the research directions and needs, highlighted by major space agencies, necessary for allowing life support for missions outside the Low Earth Orbit (LEO). Additionally, it reviews the technologies recently proposed to improve the performance of the system as well as new concepts to allow for the valorisation of the nutrients in urine or the brine after urine dewatering.

A five-stage treatment train for water recovery from urine and shower water for long-term human Space missions

Long-term human Space missions will rely on regenerative life support as resupply of water, oxygen and food comes with constraints. The International Space Station (ISS) relies on an evaporation/condensation system to recover 74–85% of the water in urine, yet suffers from repetitive scaling and biofouling while employing hazardous chemicals. In this study, an alternative non-sanitary five-stage treatment train for one “astronaut” was integrated through a sophisticated monitoring and control system. This so-called Water Treatment Unit Breadboard (WTUB) successfully treated urine (1.2-L-d−1) with crystallisation, COD-removal, ammonification, nitrification and electrodialysis, before it was mixed with shower water (3.4-L-d−1). Subsequently, ceramic nanofiltration and single-pass flat-sheet RO were used. A four-months proof-of-concept period yielded: (i) chemical water quality meeting the hygienic standards of the European Space Agency, (ii) a 87-±-5% permeate recovery with an estimated theoretical primary energy requirement of 0.2-kWhp-L−1, (iii) reduced scaling potential without anti-scalant addition and (iv) and a significant biological reduction in biofouling potential resulted in stable but biofouling-limited RO permeability of 0.5 L-m−2-h−1-bar−1. Estimated mass breakeven dates and a comparison with the ISS Water Recovery System for a hypothetical Mars transit mission show that WTUB is a promising biological membrane-based alternative to heat-based systems for manned Space missions.

Physicians as Astronauts

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Pilot-scale study on flue gas moisture recovery in a coal-fired power plant

The exhaust gas from coal-fired power plants installed with desulfurization tower contains a large amount of water vapor, recovering water from flue gas for recycling is of great significance in water saving and sustainable development. In this work, a transport membrane condenser was assembled by using the 1 μm pore-sized ceramic membrane, and experimental research was performed on a coal-fired power plant. The influence of longitudinal tube spacing on the water recovery and total heat transfer coefficient of the membrane condenser under the condition of high cooling water temperature (greater than 30 °C) was analyzed. The results show that for three different longitudinal spacings of 8, 5, and 3 cm, the amount of reclaimed water first decreases slowly by increasing the cooling water temperature. When the temperature reaches about 36 °C, the amount of reclaimed water decreases significantly. Among the three longitudinal spacings, the membrane module with a spacing of 8 cm has the best water recovery performance. The maximum water flux and maximum total heat transfer coefficient can reach 22.23 kg/(m2•h) and 1068.2 W/(m2•K). The findings from the pilot-scale investigation provide important insights for optimizing large scale water and heat recovery systems.

Design and Optimisation of Water Recovery System for a Polylactide Production Process

Development of water recovery system improves sustainability of industrial water supplies and minimises water cost. This paper proposes an integrated simulation-optimisation approach for the design and optimisation of a water recovery system for a polylactide (PLA) production process. The latter is among the industrial processes that are known for consuming a high amount of water during its operation. In this work, an integrated simulation-optimisation approach is adopted to address water minimisation problem in a PLA production process. A steady-state process simulation software is first used to model the PLA production process, in order to obtain its mass and energy balances, as well as to identify the important process parameters that affect water recovery. The model simplifies the non-linearity of the reactor model, and also determines the relationship between reactor operating conditions with the water source flowrates. Mathematic programming technique is next used to synthesise its water recovery network which involves multiple impurities. Several water recovery scenarios with different optimisation objectives were used for the evaluation, i.e. minimising flowrate (scenario 1), minimising cost (scenario 2) and maximising profit (scenario 3). Both scenarios 2 and 3 that involve process optimisation at the reactor achieve the minimum freshwater and wastewater flowrates, with maximum profitability for the process. As compared with the base case process, the water reuse/recycle scheme for these scenarios leads to extra 34.3% and 17.5% reduction in freshwater demand and wastewater flowrates respectively.

Omni-Gravity Nanophotonic Heating and Leidenfrost-Driven Water Recovery System

Abstract Recycling systems aboard spacecraft are currently limited to approximately 80% water recovery from urine. To address challenges associated with odors, contamination, and microgravity fluid flow phenomena, current systems use toxic pretreatment chemicals, filters, and rotary separators. Herein, a semipassive and potentially contaminant- and biofouling-free approach to spacecraft urine processing is developed by combining passive liquid–gas separation, nanophotonic pasteurization, and noncontact Leidenfrost droplet distillation. The system aims to achieve >98% water recovery from wastewater streams in zero, Lunar, Martian, and terrestrial gravitational environments. The surfaces of the phase separator are coated with carbon black nanoparticles that are irradiated by infrared light-emitting diodes (LEDs) producing hyperlocal heating and pasteurization during urine collection, separation, and storage. For the prescribed flow rate and timeline, the urine is then introduced into a heated 8.5-m-long helical hemicircular aluminum track. The low pitch and the high temperature of the track combine to establish weakly gravity-driven noncontact Leidenfrost droplet distillation conditions. In our technology demonstrations, salt-free distillate and concentrated brine are successfully recovered from saltwater feed stocks. We estimate equivalent system mass metrics for the approach, which compare favorably to the current water recovery system aboard the International Space Station.

A novel technical route based on wet flue gas desulfurization process for flue gas dehumidification, water and heat recovery

To recover the water and heat in industrial flue gas before discharging, a novel dehumidification system was proposed by combining the liquid-desiccant-based dehumidification (LDD) method with the existing wet flue gas desulfurization (WFGD) process in a single spraying tower. Calcium chloride (CaCl2) solution was used as a liquid desiccant. A flow pattern controlling (FPC) device was designed to further enhance the mass transfer in the dehumidification process. The effects of liquid-to-gas ratio (L/G), desiccant solution temperature (Tde), desiccant concentration (ω), and superficial flue gas velocity (vg) on the dehumidification performance were investigated. The water and heat recovery process of the LDD-WFGD system were analyzed theoretically in detail. Furthermore, the application potential of the proposed LDD-WFGD system for water and heat recovery for coal-fired power plants was discussed by conducting case studies. The recovered water from flue gas could supply 47.2% and 44.8% of the water demand for the WFGD systems in 660 MW and 330 MW power plants, respectively.

Energy and exergy co-optimization of IGCC with lower emissions based on fuzzy supervisory predictive control

This paper presents an energy and exergy co-optimization method of integrated gasification combined cycle (IGCC) based on Fuzzy Supervisory Predictive Control (FSPC). Firstly, a green IGCC process is proposed which contains three principle couplings: air separation unit (ASU), heat recovery steam generator (HRSG) and CO2 capture/storage unit (CCS). From law of thermodynamics, using substance thermophysical parameters, the energy efficiency and exergy efficiency of IGCC are successively defined. The IGCC power station has features such as closed coupling, large time lag and non-linearity, however, faster response speed and lower overshoot are always the unremitting pursuits. Therefore, the Fuzzy Supervisory Predictive Control (FSPC) method is proposed to implement robust control under complex disturbances by pre-considering unmeasurable disturbance and measurable disturbance. The fuzzy rules extracted from historical bigdata are employed in supervisory layer to make the precise control decisions. Finally, the energy and exergy co-optimization model is built and solved for higher efficiency and economic effectiveness. Taking the large-scale (300MW) IGCC for example, after using FSPC, the efficiency of water recovery is increased from 40.7% to 62.1% with the ratio of 52.6% because of waste water recovery (WWR) system. The net efficiency of proposed IGCC system is increased from 37.6% to 41.7% with the ratio of 10.9%. The exergy efficiency of IGCC system is increased from 36.5% to 39.2% with the ratio of 7.4%. The proposed method has great significance for the energy-saving and Near-zero emissions (NZEC) IGCC with high safety and robust control under supercritical (SC) or ultra-super critical (USC) state.

Advanced heavy water reactor control with the aid of adaptive second-order sliding mode controller

PurposeAdvanced heavy water reactor (AHWR) is a pressure tube type of heavy water reactor. It eliminates high-pressure heavy water coolant resulting in a reduction of heavy water leakage losses and eliminating heavy water recovery system. It recovers the heat generated in the moderator for feed water heating. However, it requires a satisfactory technological response to develop an effective controller that attains the challenges of the very high-level safety system. Hence, they require application-specific improvement for better controlling performance.Design/methodology/approachThe purpose of this study intends to propose a system for controlling state vectors v1 and v2and in AHWR using Grey Wolf second-order sliding mode control (GW-SoSMC) technique. The main aim of the paper is to minimize the errors between the predicted and desired azimuthal angles of the system. With this proposed method, it is possible to mitigate both the chattering phenomenon and controlling performance of AHWR system. It implements a SoSMC controller based on GWO algorithm for the purpose of controlling the state vectors in the AHWR system. It aims to accomplish a controller for improving the performance of the AHWR system.FindingsThrough the performance analysis, the efficiency of the proposed GW-SoSMC technique was verified by comparing it with various conventional algorithms, such as GW-SMC, FF-SoSMC, ABC-SoSMC, GS-SoSMC and GA-SoSMC. From the analysis, it was obtained that the implemented GW-SoSMC technique was 65.3 per cent superior to GW-SMC, 65.32 per cent superior to both FF-SoSMC and 65 per cent superior to ABC-SoSMC, 65.8 per cent superior to the GS-SoSMC and 58 per cent superior to the GA-SoSMC methods. Thus, the effectiveness of the proposed method in controlling the state vectors in AHWR was obtained.Originality/valueThis paper presents a technique for controlling the state vectors in the AHWR system using GWO algorithm. This is the first work that uses GWO-based optimization for controlling state vectors in the AHWR system.

Utilization of innovative system for coke oven wastewater treatment as an element of stabilization technology for post-process waste from municipal incineration plants

The article discuss the possibility of using the system for coke oven wastewater treatment process that has been developed within the framework of the project: The innovative system for coke oven wastewater treatment and water recovery with the use of clean technologies — INNOWATREAT that has received funding from the Research Fund for Coal and Steel under Grant Agreement No. 710078 and from the Ministry of Science and Higher Education Poland from financial resources on science in 2016-2019, for the removing the hazardous elements and compounds from wastewater from leaching ashes from municipal waste incineration plants. The results achieved in the project are compared with analysis provided for two different sources of ash from Poland and one Lithuania. The article discuss predicted effectiveness of the method and possibility their use in wider method of post-process waste stabilization technology as well as potential risk connected with implementation this solution into practice.