Maximum allowable values of the heavy metals in recycled water for household laundry

Household laundry as a new end use of recycled water in dual reticulation systems has a great potential as the significant amount of potable water from urban households can be saved. However, there is still no sufficient evidence and supporting recycled water quality guidelines for this particular use. A key gap in knowledge is the impact of heavy metals in recycled water on clothes and washing machines. Thus, this study aims to determine the maximum allowable values (MAVs) of the heavy metals iron (Fe), lead (Pb), zinc (Zn), copper (Cu), and manganese (Mn) in recycled water for washing clothes in washing machines. Six different concentrations of each targeted metals were prepared in tap water for the washing machine experiments. The tearing/tensile strength tests were used for the assessment of cloth durability. MINITAB 16 as a statistical tool was used and ANOVA one way test was applied for the significance analysis (Turkey's test p. <. 0.05). The results show that the MAVs of the heavy metals Fe, Pb, Zn, Cu and Mn were found to be 1. mg/l, 1. mg/l, 10. mg/l, 5. mg/l and 1. mg/l respectively in terms of cloth durability. © 2013 Elsevier B.V

On distributional and asymptotic results for exponential functional of renewal -- reward processes describing risk models

Inspired by the double-debt problem in Japan where the mortgagor has to pay the remaining loan even if their house was destroyed by a catastrophic event, we model the lender's cash flow, by an exponential functional of a renewal-reward process. We propose an insurance add-on to the loan repayments and analyse the asymptotic behavior of the distribution of the first hitting time, which represents the probability of full repayment. We show that the finite-time probability of full loan repayment converges exponentially fast to the infinite-time one. In a few concrete scenarios, we calculate the exact form of the infinite-time probability and the corresponding premiums

Highly accurate step counting at variouswalking states using low-cost inertial measurement unit support indoor positioning system

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Accurate step counting is essential for indoor positioning, health monitoring systems, and other indoor positioning services. There are several publications and commercial applications in step counting. Nevertheless, over-counting, under-counting, and false walking problems are still encountered in these methods. In this paper, we propose to develop a highly accurate step counting method to solve these limitations by proposing four features: Minimal peak distance, minimal peak prominence, dynamic thresholding, and vibration elimination, and these features are adaptive with the user’s states. Our proposed features are combined with periodicity and similarity features to solve false walking problem. The proposed method shows a significant improvement of 99.42% and 96.47% of the average of accuracy in free walking and false walking problems, respectively, on our datasets. Furthermore, our proposed method also achieves the average accuracy of 97.04% on public datasets and better accuracy in comparison with three commercial step counting applications: Pedometer and Weight Loss Coach installed on Lenovo P780, Health apps in iPhone 5s (iOS 10.3.3), and S-health in Samsung Galaxy S5 (Android 6.01)

Effect of Tris-(hydroxymethyl)-amino methane on microalgae biomass growth in a photobioreactor

© 2016 Elsevier Ltd. One of the buffers namely Tris (Tris-(hydroxymethyl)-amino methane) was used to increase the growth of microalgae by stabilizing the pH value in microalgae cultures. The objective of this research is to determine the growth rate and biomass productivity of Chlorella sp. with and without Tris addition. Both conditions function at various N:P ratios cultured in photobioreactors (carbon dioxide of 5% (v/v), light intensity of 3.3 Klux). Daily variations in nutrient removal (nitrogen and phosphorus), cell concentration, DO, temperature and pH were measured for data analysis. The results show that the largest yield of biomass was achieved at the N:P ratio of 15:1 with and without Tris. After cultivation lasting 92 h, the algae concentration at this ratio was 1250 mg L-1 and 3568 mg L-1 with and without Tris, respectively. This indicates that adding Tris to the photobioreactor greatly reduces algae biomass due to bacterial competition

Feasibility assessment of recycled water use for washing machines in Australia through SWOT analysis

Sustainable urban water consumption has become a critical issue in Australia due to increasing urbanization, the country's dry climate and its increasingly variable rainfall. Water recycling is considered vital to alleviate the demand on limited water supplies. The demands on water utilities to develop water recycling capacity and supplies are therefore expected to intensify in Australia. Dual reticulation systems have already been introduced in many cities in Australia and this is likely to expand to many other cities in the future. Developed and proposed dual reticulation schemes in Australia demand the substantial replacement of tap water with recycled water to ensure system optimisation and the sustainability of water supplies. This study successfully applies Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis as a research tool to assess the feasibility of use of recycled water in washing machine applications. Through the identification of the reuse schemes' strengths (elements to leverage and build on) and weaknesses (areas to seek assistance and support) in addition to community opportunities (areas to leverage for program advantages) and threats (elements that could hinder the scheme), the positive aspects for the use of recycled water in washing machines is observed. Further study to address the specific concerns of the general public and the development of guidelines for this new end use is however essential to guide the implementation of recycled water schemes. © 2011 Elsevier B.V

Subject-Independent ERP-Based Brain-Computer Interfaces

© 2001-2011 IEEE. Brain-computer interfaces (BCIs) are desirable for people to express their thoughts, especially those with profound disabilities in communication. The classification of brain patterns for each different subject requires an extensively time-consuming learning stage specific to that person, in order to reach satisfactory accuracy performance. The training session could also be infeasible for disabled patients as they may not fully understand the training instructions. In this paper, we propose a unified classification scheme based on ensemble classifier, dynamic stopping, and adaptive learning. We apply this scheme on the P300-based BCI, with the subject-independent manner, where no learning session is required for new experimental users. According to our theoretical analysis and empirical results, the harmonized integration of these three methods can significantly boost up the average accuracy from 75.00% to 91.26%, while at the same time reduce the average spelling time from 12.62 to 6.78 iterations, approximately to two-fold faster. The experiments were conducted on a large public dataset which had been used in other related studies. Direct comparisons between our work with the others' are also reported in details

Applicability of zirconium loaded okara in the removal and recovery of phosphorus from municipal wastewater

© 2019 Published under licence by IOP Publishing Ltd. Recently, there is a new trend to consider wastewater as a precious resource. Since phosphorus is a limited non-renewable element, and MAP (Magnesium Ammonium Phosphate - MgNH4PO4.6H2O) is a valuable slow-release fertilizer, the recovery of phosphorous as MAP has received special attention from scientists all over the world. However, the application of this process with municipal wastewater is still a challenge, due to low concentration of phosphorus and high volume of municipal wastewater. This study investigates the potential of reclaiming MAP from municipal wastewater by combination of adsorption and crystallization. Soybean milk residue (okara) was loaded with Zirconium (Zr) to prepare the adsorbent (ZLO). Adsorption and desorption experiments were conducted in a semi-pilot scale ZLO packed colum system. Effects of P: N: Mg molar ratios, chemical sources and temperature on the formation of MAP were examined in an attempt to identify the optimal crystallization conditions. The attained precipitate was characterized using XRD, SEM, FTIR techniques. It was found that the ZLO packed column adsorption-desorption system could pre-concentrate phosphorus from municipal wastewater up to 28.36 times, fitting well the minimum requirement (50 mg P/L) for the economical MAP recovery. Up to 95.19% of dissolved phosphorus in desorption solution was recovered at pH = 9, Mg: N: P molar ratio = 2:2:1, using a combination of MgCl2.6H2O and NH4Cl. The harvested MAP exhibited high purity (92.59%), high P-availability (89% by mass), and extremely low levels of heavy metals. The results prove that it is viable to recover MAP from municipal wastewater by employing ZLO as adsorbent, followed by crystallization. This paves the way for mining phosphorus from municipal wastewater and reducing okara as an agricultural byproduct in a green way

Integration of SWAT and QUAL2K for water quality modeling in a data scarce basin of Cau River basin in Vietnam

© 2019 European Regional Centre for Ecohydrology of the Polish Academy of Sciences Water quality modeling in a river basin often faces the problem of having a large number of parameters yet limited available data. The important inputs to the water quality model are pollution concentrations and discharge from river tributaries, lateral inflows and related pollution load from different sources along the river. In general, such an extensive data set is rarely available, especially for data scarce basins. This makes water quality modeling more challenging. However, integration of models may be able to fill this data gap. Selection of models should be made based on the data that is available for the river basin. For the case of Cau River basin, the SWAT and QUAL2K models were selected. The outputs of SWAT model for lateral inflows and discharges of ungauged tributaries, and the observed pollutant concentrations data and estimated pollution loads of sub-watersheds were used as inputs to the water quality model QUAL2K. The resulting QUAL2K model was calibrated and validated using recent water quality data for two periods in 2014. Four model performance ratings PBIAS, NSE, RSR and R2 were used to evaluate the model results. PBIAS index was chosen for water quality model evaluation because it more adequately accounted for the large uncertainty inherent in water quality data. In term of PBIAS, the calibration and validation results for Cau River water quality model were in the “very good” performance range with ǀPBIASǀ < 15%. The obtained results could be used to support water quality management and control in the Cau River basin

Vision and perception of community on the use of recycled water for household laundry: A case study in Australia

This study investigates the community perception of household laundry as a new end use of recycled water in three different locations of Australia through a face to face questionnaire survey (n=478). The study areas were selected based on three categories of (1) non-user, (2) perspective user and (3) current user of recycled water. The survey results indicate that significantly higher number (70%) of the respondents supported the use of recycled water for washing machines (χ2=527.40, df=3; p=0.000). Significant positive correlation between the overall support for the new end use and the willingness of the respondents to use recycled water for washing machine was observed among all users groups (r=0.43, p=0.000). However, they had major concerns regarding the effects of recycled water on the aesthetic appearance of cloth, cloth durability, machine durability, odour of the recycled water and cost along with the health issues. The perspective user group had comparatively more reservations and concerns about the effects of recycled water on washing machines than the non-users and the current users (χ2=52.73, df=6; p=0.000). Overall, community from all three study areas are willing to welcome this new end use as long as all their major concerns are addressed and safety is assured. © 2013 Elsevier B.V

Resident's strategy survey on a new end use of recycled water in Australia

The concept of using recycled water for washing machine was introduced as a new end use. As there is a noticeable lack social research in understanding the general public perceptions of this application, the resident's strategy survey was carried out at some selective suburbs in Sydney with demographically based significant differences of general, gender, age, education, and property style and ownership. The survey indicates that the majority in the community considers the use of recycled water for washing machine is indispensable in view of continuing drought and the associated water shortages. Given safety assurance and demonstration, recycled water for washing machine has a considerable proportion within the responses. The general level of knowledge in community clearly understand that recycled water is more environmentally friendly option, whereas from cleanness and public health point of view, higher quality water is required to be reused in washing machine. Moreover, the residents reckon to have a small unit for pre-treatment (point of use) before recycled water entering washing machines might assure the quality and safety. The survey also shows the major concerns for a resident to use recycled water for washing machine are public health, water cleanness and washing machine durability. © 2009 Desalination Publications