Minimum Water Consumption Research Articles

A case study on the treatment and recycling of the effluent generated from a thermo-mechanical pulp mill in Brazil after the installation of a new bleaching process

A Brazilian thermo-mechanical pulp mill (TMP) was evaluating the installation of a proposed bleaching process, with changes in the qualitative and quantitative characteristics of the wastewaters and the Effluent Treatment Plant (ETP). The objectives of this research were to evaluate the treatment plant configuration for the future industrial effluent, consisting of a flotation unit followed by an upflow anaerobic sludge blanket reactor (UASB), an activated sludge process and nanofiltration (NF) using polymeric membranes, and to study the technical feasibility of recycling the treated effluents in the industrial process. The possible options for recycling the treated effluent were determined through a water balance of the mill. The pulp quality was evaluated in laboratory bleaching assays, based on brightness and brightness reversion tests after the recycling of 50%, 75% and 100% of the treated effluent. The buildup of the non-process elements (NPE) in the industrial water cycle after each effluent recycling proportion was evaluated through computer simulation, using the Aspen Plus® simulator software. The future mill effluent, considering the implementation of a proposed bleaching stage with hydrogen peroxide, was generated in the laboratory and treated in a bench-scale effluent plant, simulating the future configuration. The treatment plant removed 99.8%, 99.2% and 61.6% of soluble COD, BOD5 and color, respectively. The water consumption was highest in the bleaching plant and, therefore, the recycling of 50%, 75% and 100% of the treated effluent for washing the pulp was simulated. The brightness and brightness reversion of the pulp, with 100% of the treated effluent used in the bleaching process, were similar to those provided by fresh water. The recycling of 100% of the treated effluent in the proposed treatment plant was possible in the TMP pulp mill without decreasing the pulp quality.

Concentration and purification by crossflow microfiltration with diafiltration of carotenoids from a by-product of cashew apple juice processing

This work aimed to further investigate microfiltration with diafiltration to obtain a rich carotenoid extract from the solid by-product of cashew apple (Anacardium occidentale L.) juice processing. This solid residue called cashew fibers is rich in bioactive compounds, especially carotenoids. After mixing with water and pressing, an aqueous suspension was obtained and processed by crossflow microfiltration (40 °C) using tubular ceramic membrane with 0.2 μm pore diameter. Permeate flux, which increased with transmembrane pressure, could be maintained above 100 L·h−1·m−2 at high volume reduction ratio by coupling mechanical extraction with enzyme liquefaction. The concentration step led to an increase of the carotenoid content by up to 19-fold and the diafiltration step allowed the carotenoid purity to be multiplied by 5. The impact of the process on the retentate characteristics was assessed using a model based on simple assumptions. This calculation tool can easily be implemented and is helpful for choosing the operating conditions, to minimize water consumption as well as effluent production.

Mathematical modeling and study on the application of cross flow direct evaporative cooler under different indoor and outdoor environmental conditions

Performance of a cross flow direct evaporative cooler under different indoor and outdoor conditions was investigated by a thermodynamic model and using finite difference scheme. Unlike the previous studies, the temperature variation of water film during the evaporation process was included among the modeling, and the error of the mathematical model to estimate the effectiveness of the cooler became lower than the error reported in the literature. To achieve the comprehensive results and evaluation of the applicability of the system under real conditions, the performance of the cooler in ambient temperatures of 25, 30, 35 and 40 °C, relative humidities of 10, 30, 50 and 70% and cooling demand of 1–5 kW for a building with air changes of 5, 10 and 15 per hour was investigated. Lastly, the study on the performance of the cooler in different Iranian provincial capitals showed that for air change of 15 per hour and cooling demand of 1 kW, the system could provide thermal comfort conditions in 24 provincial centers while for air change of 5 per hour and cooling load of 5 kW, this goal cannot be achieved in any centers. Moreover, comparing the water consumption of the coolers showed that the maximum and minimum daily water consumption was for Yazd in September and for Kermanshah on July, respectively. Investigation of the coefficient of performance of the system for air changes of 10 and 15 per hour revealed that Khoramabad and Bandar Abbas had the maximum and minimum coefficients of performance, respectively.

Analysis of the heat budget of standard, cool and watered pavements under lab heat-wave conditions

The thermal behavior of 12 standard and cool pavement structures (asphalt, granite, stabilized sand, cobblestones, reflective paints, pervious concretes, dry grass, etc.) coupled with pavement-watering is studied in the lab under heat-wave-like conditions. Watering is fine-tuned for each structure to maximize cooling and minimize water consumption using two linear cooling regimes, before deployment in the field. The surface heat budget is closely studied and the partitioning of irradiance and net radiation into conductive, convective, radiative and cooling flux at surface is analyzed for each structure. Energy partitioning, surface temperature increase and optimal watering rates all exhibit good correlation with overall surface absorptivity. The transmitted flux at varying depths is also characterized using a transmission index that includes surface absorptivity and apparent conductivity of the traversed layers. Results of this study intend to improve our understanding of the energy balance of cool pavements compared to traditional ones under given weather conditions, as well as that of processes involved in the optimization of their evaporative cooling versus watering rate. Benefits of each pavement, efficiency of the method, limitations of the protocol and its potential transposition to the field are all discussed in this contribution.

Minimum water consumption method screening of velvet bean (Mucuna sp.) processings to produce functional food ingredients

Velvet bean (Mucuna sp.) has been proven containing many beneficial compounds that can be implemented in pharmaceutical and medicines but less noticed for functional foods even though traditionally it is consumed as daily foods or snacks. The indigenous food preparation such as velvet bean Tempe warrants scientific investigation to help society with better public health management. The objective of the review is to select the best method for functional food ingredient product development using velvet beans and provide hypothetical health-oriented food processing e.g. velvet bean flour as functional food ingredients with a focus on less water consumption during processing. Steaming is the selected method.

Cover Crop Selection by Jointly Optimizing Biomass Productivity, Biological Nitrogen Fixation, and Transpiration Efficiency: Application to Two Crotalaria Species

Crotalaria spectabilis and Crotalaria juncea are cover crops (CC) that are used in many different regions. Among the main attributes of these species are their high potential for biomass production and biological fixation of nitrogen (BNF). Attempting to maximize these attributes, while minimizing water consumption through high transpiration efficiency (TE), is a challenge in the design of sustainable agricultural rotations. In this study, the relationship between biomass productivity, BNF, and TE in C. spectabilis and C. juncea was evaluated. For this purpose, an experiment was carried out under controlled conditions without water limitations and using non-inoculated soil. BNF was determined by the natural abundance of 15N, while TE was estimated by several different methods, such as gravimetric or isotopic method (13C). C. juncea produced 42% less dry matter, fixed 28% less nitrogen from the air, and had 20% less TE than C. spectabilis. TE results in both species were consistent across methodologies. Under simulated environmental conditions of high temperature and non-limiting soil water content, C. spectabilis was a relatively more promising species than C. juncea to be used as CC.

Toward the reduction of water consumption in the vegetable-processing industry through membrane technology: case study of a carrot-processing plant.

The food industry consumes large amounts of clean, potable water and in turn generates a significant amount of wastewater. In order to minimize water consumption, membrane technologies represent a suitable solution for the treatment of wastewater before it is recycled as process water. Many studies have shown the effectiveness of this technology in the dairy industry, but there are few studies in the fruit- and vegetable-processing sectors. A recently developed methodology for the reduction of water consumption was tested here. Compounds to be eliminated were identified through chemical analysis of several wastewater samples from a carrot-peeling process. Drinking-water quality was selected as our target. Total suspended solids (TSS), fructose, glucose and sucrose were identified as key parameters. Salts (particularly Ca2+ and Mg2+), pH and carbonate hardness (CH) were identified as indicators for evaluating the risk of scaling and corrosion. Based on these results, sieving followed by a 0.5-μm microfiltration (MF) was chosen as the process for pre-treatment. Four nanofiltration (NF) membranes (NFW from SYNDER, DK from GE, NF270 from DOW and SR3D from KOCH) and three reverse osmosis (RO) membranes (ESPA4 from Nitto Group Company, BW30 from DOW and HRX from KOCH) were then tested for the capacity to minimize chemical oxygen demand (COD) and to principally remove sugars. These membranes were then evaluated in terms of permeability and rejection rates. High-quality water could be obtained with RO membranes at low pressure (up to 15bar) while limiting fouling risks. Rejection rates up to 98.3, 98.0, 99.2, 99.2 and 99.4% for conductivity, COD, fructose, glucose and sucrose, respectively, were achieved. These results are very encouraging for future reuse in vegetable processing before the blanching step, after an additional disinfection treatment.

Design of a water curtain to reduce accumulations of float coal dust in longwall returns

Accumulation of float coal dust (FCD) in underground mines is an explosion hazard that affects all underground coal mine workers. While this hazard is addressed by the application of rock dust, inadequate rock dusting practices can leave miners exposed to an explosion risk. Researchers at the National Institute for Occupational Safety and Health (NIOSH) have focused on developing a water curtain that removes FCD from the airstream, thereby reducing the buildup of FCD in mine airways. In this study, the number and spacing of the active sprays in the water curtain were varied to determine the optimal configuration to obtain peak knockdown efficiency (KE) while minimizing water consumption.

HYDROPHILIC POLYMER CHANGES THE WATER DEMAND IN THE IMPLEMENTATION OF A DWARF CASHEW ORCHARD

Abstract: Important losses of dwarf cashew seedlings during the establishment of orchards in the Brazilian semiarid are related to the relatively short rainy season. This study aimed to evaluate biochar and hydrophilic polymer as soil amendments to increase water retention and reduce plant death in the first year. An experiment was conducted at the Curu Station, Paraipaba, CE, Brazil, using the clone BRS 226. The experimental design consisted of randomized blocks, with amounts of 0.5, 1.0, 2.0, and 4.0 kg of cashew wood biochar and 20, 40, 60, 80 g of hydrophilic polymer applied per pit, as well as a control treatment (no soil amendment). Seedlings were submitted to an irrigation regime to avoid water stress (5 L water seedling-1 when the tensiometer installed at a depth of 0.15 m reached 60 kPa). The variables of plant development number of leaves, plant height, stem diameter, and canopy diameter were evaluated up to 374 days after transplanting to the field. The analysis of variance showed no treatment effect on plant development. However, minimum water consumption was observed when 29.56 g of hydrophilic polymer was applied per pit, providing 100.0% seedling survival.

Assessing the socio-demographic, economic and water source types that influences households drinking water supply in Debre tabor town, north-west Ethiopia

Background: Human life depends on clean and healthy environment. However, low environmental standards lead to reduced life expectancy. Most peoples who live in the developing countries are under risk of getting clean water and any form of sanitation services. Because of this, millions of peoples are suffering from diseases associated with water. Nowadays, it needs emphasis on the accessibility of drinking water and factors which determine the supply of safe drinking water for urban households. Objectives: This study aimed to assess socio-demographic, economic and water source types that influences households drinking water supply in Debre Tabor Town, North-West Ethiopia. Methods: A community based cross-sectional study design was conducted among households from February to March 2019. An interview-based pre-tested and structured questionnaire was used to collect data. Data collection samples were selected randomly and proportional to each kebeles. Epi info version 7.2.1.0, and SPSS Version 24 were used to enter and analyze the data; respectively and descriptive statistics with frequency counts and simple percentages were performed. Results: 418 households were participated. On average there were about 4.53 persons per each household. The most frequently used water source is pipe water (78.95%). Fetching water was the responsibility of females and children. Majority of the population of the town had no alternative sources, since traditional water sources were polluted by animal and human wastes. Due to high scarcity of water supply, traditional water sources were used by the residents. The time taken from home to traditional water sources was about 55.74% of the population had got their water for a trip of 15-30 minutes and 35.17% of the population 31-45 minutes, was much longer than the country average. 44.50% of the population got their water supply partially per week. 91.15% of the population was under the problem of water scarcity in the town. About 85.65% scarcity was happened due to weak administration of the concerned government bodies. Conclusion: The water supply was inadequate, and the quality was low. The median consumption was found to be 30 liters per household per day and 6.62 l/p/d, lower than the national and WHO minimum water consumption level of 20 l/p/d. Nine out of ten persons was under the problem of water scarcity in the town. The concerned government bodies should provide adequate and quality potable water facilities for the town residents.

Electricity savings by reducing water consumption in a whole city: A case study in Joinville, Southern Brazil

This paper aims to propose a method to estimate the electricity savings in water supply and sewage systems due to the reduction of potable water consumption on a city scale. The method was applied in a case study in Joinville, a city located in Southern Brazil. The strategies considered to promote water savings were: replacement of toilets, greywater reuse, rainwater harvesting and combination of these three strategies. Single-family residential, multi-family residential, public and commercial sectors were assessed. For each building sector, minimum and maximum potable water consumption and sewage generation reductions due to each strategy were determined, so the range of possible electricity savings in water supply and sewage systems were estimated. The financial feasibility of adopting these strategies was verified using data from the National Information System on Sanitation and local utility. The most significant energy savings were provided by the simultaneous adoption of the three strategies (from 2136.8 MWh/year to 8951.5 MWh/year). However, greywater reuse and rainwater harvesting presented savings similar to those provided by the three strategies. The single-family residential sector led to the highest energy savings, corresponding to more than 50% of total electricity savings in seven of eight cases analysed, while the smallest contribution was from the public sector. The local utility would not fail to profit in any of the scenarios analysed. Thus, in addition to the environmental benefits of water savings, lower sewage generation and electricity savings, the local utility would also profit from adopting these strategies on a city scale.

Short-Term Optimal Operation of Baluchaung II Hydropower Plant in Myanmar

The short-term optimal operation model discussed in this paper uses the 2016 to 2018 daily and monthly data of Baluchaung II hydropower station to optimize power generation by minimizing water consumption effectively in order to get more revenue from optimal operation. In the first stage, run-off-river type Baluchaung II hydropower station data was applied in a mathematical model of equal micro-increment rate method for optimal hydropower generation flow distribution unit results. In the second stage, dynamic programming was used to get optimal hydropower generation unit distribution results. The resultant data indicated that optimized results can effectively guide the actual operation run of this power station. The purpose of the optimal load dispatching unit was to consider the optimal power of each unit for financial profit and numerical programming on the actual data of Baluchaung II hydropower plant to confirm that our methods are able to find good optimal solutions which satisfy the objective values of 17.75% in flow distribution units and 24.16% in load distribution units.

Mechanocatalytic Synergy for Expedited Cellulosic Ethanol Production Compatible with Integrated Biorefinery

Developing economically viable cellulosic ethanol process requires concentrated fermentable sugars and minimum water consumption. Biorefinery economics requires highly integrated efficiencies in the full utilization of all biomass components. Toward this objective, we have developed an enzyme-free mechanocatalytic saccharification process that combines mix-milling of P2O5 with lignocelluloses and successive hydrolysis into fermentable sugars. Demonstrated with corn stover (CS) and CS-xylose residues, after recovery of valuable hemicellulose, fermentable glucose in 75% yield at a high biomass loading (92 mg/mL) was obtained with concomitant precipitation of pristine lignin. The undetoxified concentrated hydrolysate allows for fermentative upgrading, achieving 42 g/L ethanol (a benchmark (40g/L) for an economically feasible bioethanol process) in 52 h after hemicellulose is converted into xylose. P2O5 is essential in fragmentation of cellulose in the milling stage and subsequent accelerated hydrolysis to gl...

Stochastic Economic Dispatch of Hydro-Thermal-Wind-Photovoltaic Power System Considering Mixed Coal-Blending Combustion

This paper proposes a stochastic economic dispatch (SED) model for hydro-thermal-wind-photovoltaic power system (HTWPPS) considering mixed coal-blending combustion (MCBC) to improve the operational efficiencies of thermal power units (TPUs) with deep peak-regulating operation (DPRO). Firstly, the rations for different types of coal can be acquired by meeting the operational requirements of boilers. Three functions including the cost of coal consumption, polluting gas emission, and the life loss cost for TPUs could be obtained by fitting coal quality. Besides, they would be strictly piecewise linearized, respectively. Consequently, the objective function involving the above three kinds of costs as well as the cost of oil injection can be presented. Secondly, there is a two-stage framework for reducing the coupling of HTWPPS and improving the solving efficiency. In the first stage, the Monarch Butterfly Optimization (MBO) algorithm is employed for obtaining the power outputs of hydro-power units (HPUs) taking the minimum water consumption as the objective. In the second stage, the load curve can be updated according to the results from the first stage. Besides, the Latin Hypercube Sampling method and the backward scene reduction technique are utilized to acquire a set of scenarios of wind power. In this way, the SED model considering MCBC can be achieved. The case studies have been carried out on a simplified provincial power system in China with the help of MATPOWER and CPLEX. The results show that the proposed model can effectively increase the economic and environmental benefits for TPUs.

Effects of water harvesting and organic fertilizer on vineyard (Vitis vinifera L.) yield and soil moisture content under arid conditions

Water harvesting techniques increase the amount of rainfall per unit area, directing the rainwater to the crop area. The rain water is stored in the soil profile with mulch and similar applications and helps the plant to benefit during the arid periods. Water harvesting techniques can be supported with mulching and fertilizing practices in order to crop yield increase. This study was carried out on 20 years old vineyard in farmers' garden in 2015 - 2016, produced on dry conditions, with economical prescription for Kilis province. Four different doses of leonardite fertilizer were applied in combination with soil bund rainwater harvesting in the experiment. The highest soil moisture was obtained from 370 mm to 7 kg/vineyard leonardite application. The maximum plant water consumption was determined to be 389.5 mm on average from the application of 7 kg/vineyard fertilizer. The minimum plant water consumption was obtained from the control with 310.7 mm. In terms of yield, there was no difference between 5 and 7 kg/vineyard leonardite fertilizer.

FORECASTING OF THE EXTREME WINTER LOW FLOW FOR THE NORILKA RIVER

The object of the study is the Norilka River, located in the North of the Krasnoyarsk territory. Only 45% of the norm of precipitation fell in the basin of the Norilka River for the period from October 2012 to May 2013, that resulting in an extremely low spring flood formation. The feeding of the large lakes that form the river flow was also limited, as dry weather set in during the summer. This caused great concern regarding the water availability of water intakes of mining and processing plant in the city of Norilsk for the winter of 2014. The situation required the solution of a complex of hydrological tasks, the main of which is the development of a forecast of minimum water consumption for the winter of 2014. The forecast was developed using relationship between area pre-winter moistening with intensity of the winter runoff depletion. Since the capacity of the ice cover can significantly affect to decrease of the river flow, the hydrological forecast takes into account the long-term air temperatures forecast for 2013-2014 winter period. It was obtained the forecast that the minimum monthly discharge for April would be at about 22 m3/s, meanwhile daily discharge 20 m3/s. The received results were a basis for carrying out the measures directed on maintenance of steady water supply with need discharge in 7 m3/s. The low ground dam below water intakes was arranged at backwater on a site of water intakes for August-September 2013. The actual flow discharge for April 2014 was about 14 m3/s. Therefore, the construction of the dam was justified and interruptions of water supply of the plant did not happen. The methodological approaches applied to the solution of this problem can be useful in case of similar situations in the Northern regions of Russia.

Minimizing beneficiation wastewater through internal reuse of process water in flotation circuit

Cost-effective methods for reducing freshwater requirement and wastewater emission in beneficiation processes (particularly in flotation process) are greatly important in the modern mining industry. This study aims to minimize water consumption and wastewater generation in dressing plants by internally reusing process water at certain stages of flotation circuit . Laboratory scale tests demonstrated that locked cycle recycling of process water built up chemical reagents in water, which in turn influenced the flotation performance of valuable minerals and significantly decreased the grade and recovery of concentrates. Changing flotation reagent regimes in response to flotation fluctuations can reliably and feasibly maintain mineral recovery efficiency during the reuse process. Industrial scale tests validated that the quality of concentrates obtained with and without process water reuse did not show any considerable difference and satisfied the product specifications by carefully adjusting the dosage of flotation reagent. The required reagent dosages in the flotation circuit were reduced by more than 10% after using recycled water. Among the required reagent dosages, sodium sulfide (Na 2 S) was sharply reduced by 18.56%. Most importantly, the internal reuse of process water in the flotation circuit minimized freshwater consumption by 34.62% (i.e., from 5.2 t/d to 3.4 t/d), indicating that 525.6 tons of wastewater would no longer be generated every year. Overall, the proposed internal reuse process is a cost-effective and eco-friendly alternative for greening flotation process. • Internal reuse of process water in the flotation process is feasible and reliable. • Changing reagent suite reduces the negative effect of process water on flotation. • Internal reuse of process water minimized water consumed and wastewater emission. • Internal reuse of process water promotes the reutilization of chemical reagents.

Pinch Methods for Efficient Use of Water in Food Industry: A Survey Review

The implementation of sustainable water management practices, through the recycling and reuse of water, is essential in terms of minimizing production costs and the environmental impact of the food industry. This problem goes beyond the classical audit and housekeeping practices through developing a systemic water-using reduction strategy. The implementation of such an approach needs R&D development, especially for the food industry, where there is a lack of knowledge on: (a) process integration and (b) data on the pollutant indicators or (c) volumes of water used and discharged at specific steps of the food processing line. Since energy pinch analysis emerged, different variations of pinch methods have been developed. As a variation of pinch, Water pinch analysis is a global and systematic approach to minimize water consumption and discharges, especially for the most energy-intensive and water-consuming factories. Based on the nature of the food industry, the real systems are complex, multi-source multi-contaminant systems, the problem should be well formulated, including mathematical constraints (inequalities thresholds). Current work has reviewed comprehensive literature about different variations of pinch analysis. In continue, water pinch method deeply discussed and some relevant data concerning the water using process and pollutant indicators have been reviewed with emphasis on the food industry sector.

Experimental studies of furfural production from water hyacinth (Eichhornia Crassipes)

AbstractFurfural is a very promising product of lignocellulosic biomass‐based biorefineries and has the potential to become a useful resource for further conversion and utilization. Aquatic plants show an enormous potential as feedstock since they do not compete for land use, and they require minimal water consumption in a biorefinery concept due to their very high water content. This work is focused on experimental studies of furfural production from water hyacinth (Eichhornia crassipes) by means of aqueous, acid‐catalyzed dehydration. The temperature range of the process, and the acid and seawater presence were chosen based on the previous relevant studies. The aim of the study was to determine whether water hyacinth is suitable for furfural production. The experiments were performed between 160°C and 200°C with a water hyacinth concentration of 2 wt%. The results suggest that the effects of acid catalyst presence on biomass dehydration are similar to the case of pure pentose dehydration. Furthermore, the addition of seawater did not have a positive catalytic effect in terms of the furfural yield. The maximum yield was 53.2 mol% based on the C5 sugar content in the original biomass. The furfural yield of 7.9 wt% of water hyacinth input was comparable to the yield of feedstocks such as corn cob, bagasse, and oat's residue and higher than the cases of rice straw or hulls. Thanks to the comparatively high pentose potential, water hyacinth shows promising results as a candidate feedstock for furfural production. A certain variability of pentosan should be taken into account, as the chemical composition of the plant depends on the source and harvesting seasons.

Process Integration and Feedstock Optimisation of a Two-Step Biodiesel Production Process from Jatropha Curcas Using Aspen Plus

Abstract Jatropha curcas oil (JCO) has been recognized as a viable non-edible feedstock for biodiesel production with the focus of achieving lesser reliance on fossil fuels. The aim of this work is to integrate and simulate the production of biodiesel from Jatropha curcas oil by a two-step process; a hydrolysis step and a trans-esterification step. The challenge is then to optimise the feedstock ratios to obtain the minimal water and methanol consumption to give optimal biodiesel yield. For this purpose, steady-state simulation model of a two-step production process of biodiesel from Jatropha curcas oil was prepared using ASPEN Plus V8.8. The response surface methodology (RSM) based on a central composite design (CCD) was used to design optimisation experiments for the research work. From the ANOVA, methanol/oil ratio of the trans-esterification step was found to have a significant effect on the biodiesel yield compared to the water/oil ratio of the hydrolysis step. The linear model developed was shown to be a good predictor of feedstock ratios for biodiesel yield. The surface plot revealed that both feedstock ratios do not show a significant combinatorial effect on each other. Numerical optimisation gave the optimum values of the feedstock ratios as a methanol/oil ratio of 2.667 and a water/oil ratio of 1. The optimisation results also indicated a predicted optimum biodiesel yield of 10.0938 kg/hr.