scholarly journals A new UVC‐LED system for disinfection of pathogens generated by toilet flushing

Indoor Air ◽  
2020 ◽  
Author(s):  
Alvin C. K. Lai ◽  
Sunday S. Nunayon
Keyword(s):  
Toilet Flushing

scholarly journals Exposure to SARS-CoV-2 in Aerosolized Wastewater: Toilet Flushing, Wastewater Treatment, and Sprinkler Irrigation

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 436
Author(s):  
Muhammad Usman ◽  
Muhammad Farooq ◽  
Muhammad Farooq ◽  
Ioannis Anastopoulos
Keyword(s):  
Wastewater Treatment ◽  
Public Awareness ◽  
Sprinkler Irrigation ◽  
Short Review ◽  
Etiologic Agent ◽  
Respiratory Pathway ◽  
Oral Transmission ◽  
Toilet Flushing ◽  
Epidemiological Monitoring ◽  
Rapid Characterization

The existence of SARS-CoV-2, the etiologic agent of coronavirus disease 2019 (COVID-19), in wastewater raises the opportunity of tracking wastewater for epidemiological monitoring of this disease. However, the existence of this virus in wastewater has raised health concerns regarding the fecal–oral transmission of COVID-19. This short review is intended to highlight the potential implications of aerosolized wastewater in transmitting this virus. As aerosolized SARS-CoV-2 could offer a more direct respiratory pathway for human exposure, the transmission of this virus remains a significant possibility in the prominent wastewater-associated bioaerosols formed during toilet flushing, wastewater treatment, and sprinkler irrigation. Implementing wastewater disinfection, exercising precautions, and raising public awareness would be essential. Additional research is needed to evaluate the survival, fate, and dissemination of SARS-CoV-2 in wastewater and the environment and rapid characterization of aerosols and their risk assessment.

scholarly journals Design and Optimisation of Home Scale Greywater Recycling Package

2018 ◽  
Vol 152 ◽  
pp. 02005 ◽  
Author(s):  
Kalaichelvan a/l Arugam ◽  
Azadeh Ghadimi ◽  
LH Chang
Keyword(s):  
Suspended Solids ◽  
Developed Countries ◽  
Wire Mesh ◽  
Water Usage ◽  
Mechanical Parts ◽  
Biological Water ◽  
Toilet Flushing ◽  
Physical Chemical ◽  
Final Design ◽  
Biological Water Treatment

Water crisis is becoming one of the biggest challenges in some countries due to over population and drought. Therefore, government and non-government organisations in well-developed countries are encouraging industries to install water recycling package to reduce water usage and consume greywater instead. However the home scale is not yet available in the market. This research focuses on design a home scale greywater treatment system for toilet flushing within 3,000 to 5,000 USD as a collaboration with DD Techniche Sdn Bhd. Greywater is the waste water produced from laundry, kitchen and bathroom except the toilet waste and contains suspended solids, microorganisms, oil, nitrates and phosphorus which needs to be treated using suitable types of treatment for safe reuse. The treatments include physical, chemical and biological water treatment in which in this study the proposed system is a combination of all three. The design is evaluated using experimental methods to meet the standard of toilet flushing quality. The greywater system consists of the mechanical parts to control the flow of greywater and store the treated water including pumps, sand filtration tank, wire mesh chassis and collection tank. The final design has dimension of 6 m3 and optimised price within the budget.

scholarly journals An Analysis of the Effectiveness of Two Rainwater Harvesting Systems Located in Central Eastern Europe

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 458 ◽  
Author(s):  
Agnieszka Stec ◽  
Martina Zeleňáková
Keyword(s):  
Sensitivity Analysis ◽  
Net Present Value ◽  
Rainwater Harvesting ◽  
Payback Period ◽  
Practical Aspect ◽  
Financial Ratios ◽  
Present Value ◽  
Toilet Flushing ◽  
Harvesting Systems ◽  
The Impact

Decentralized water systems are perceived as solutions that not only save water, but also as a way to partially or completely become independent from centralized suppliers. Taking this into account, an analysis of the effectiveness of rainwater harvesting systems (RWHS) for toilet flushing in existing academic facilities located in Poland and in Slovakia was carried out. The tests took into account the different volumes of storage tanks collecting rainwater. On the basis of two financial ratios, namely Net Present Value and Discounted Payback Period, the profitability of these systems was also assessed. The research was extended by the sensitivity analysis, which allowed determination of the impact of changes in individual cost components on the financial effectiveness of the investments considered. The results obtained clearly showed that the implementation of RWHS in the dormitory in Rzeszów was unprofitable for all tank capacities tested, and the payback period significantly exceeded the period of 30 years accepted for the analysis. Completely different results were obtained for RWHS in a dormitory located in the city of Košice, for which the financial ratios NPV (Net Present Value) and DPP (Discounted Payback Period) were very favorable. It was also confirmed by the results of the sensitivity analysis. The use of rainwater for toilet flushing caused that it was possible to achieve water savings of an average of 29% and 18%, respectively, for facilities located in Slovakia and Poland. The results of the research have a practical aspect and can provide an indication for potential investors and managers of academic facilities, similar to those analyzed in the article. Taking into account that in many countries water and sewage rates are significantly higher than in Poland and Slovakia, the cost-effectiveness of using the analyzed installation options in these countries could be even higher.

Combined seawater toilet flushing and urine separation for economic phosphorus recovery and nitrogen removal: a laboratory-scale trial

2014 ◽  
Vol 70 (6) ◽  
pp. 1065-1073 ◽  
Author(s):  
H. R. Mackey ◽  
Y.-S. Zheng ◽  
W.-T. Tang ◽  
J. Dai ◽  
G.-H. Chen
Keyword(s):  
System Integration ◽  
Batch Reactor ◽  
Low Cost ◽  
Water Source ◽  
Ammonia Removal ◽  
Phosphate Removal ◽  
Laboratory Scale ◽  
Phosphorus Recovery ◽  
Toilet Flushing ◽  
Urine Separation

Freshwater toilet flushing consumes 20–35% of typical household water demand. Seawater toilet flushing, as practised by Hong Kong since 1958, provides an alternative water source. To maximise the benefits of this unique dual water supply, urine separation could be combined to allow low-cost struvite production and subsequent urine nitrification – in-sewer denitrification. This paper reports on a laboratory-scale study of seawater urine phosphate recovery (SUPR) and seawater–urine nitrification. A laboratory-scale SUPR reactor was run under three phases with hydraulic retention time between 1.5 and 6 h, achieving 91–96% phosphorus recovery. A urine nitrification sequencing batch reactor (UNSBR) was also run for a period of over 650 days, averaging 90% ammonia removal and loading of up to 750 mg-N/L.d. Careful control of the SUPR phosphate removal was found necessary for operation of the downstream UNSBR, and system integration considerations are discussed.

scholarly journals Probabilistic and Economical Design of Roof Top Rainwater Harvesting Tank by Simulation Technique

2018 ◽  
pp. 1-17
Author(s):  
J. Ramachandran ◽  
V. Ravikumar
Keyword(s):  
Rainwater Harvesting ◽  
Design Method ◽  
Daily Rainfall ◽  
Daily Basis ◽  
Annual Runoff ◽  
Balance Model ◽  
Graphical Form ◽  
Exceedance Probability ◽  
Toilet Flushing ◽  
Economical Design

Introduction: Rainwater harvesting is the collection of rainwater directly from the surface(s) it falls on. Rainwater harvesting through collection tank is an effective method. Numerous methods are available for determining the size of the storage capacity required to satisfy a given demand. These methods vary in complexity and sophistication. Methods: The tank design method includes general thumb rule (5% of annual runoff), sequential peak analysis (simulating twice the length of the record), optimization (best one that suits objective criteria), simulation, probabilistic and economical design. Simulation water balance model which works on daily basis, normal probability distribution and economics are used in designing the capacity of tanks and it is presented in a graphical form. The tanks are designed for two different purposes like domestic use and toilet flushing only. Place and Data: Trichy city daily rainfall records from 1951-2011 is used. If a person living in Trichy city wants to construct a rainwater harvesting tank for toilet flushing purpose (6 Nos * 25l = 150l demand per day), the graphs can used. Results: At a chosen exceedance probability (EP) of failure (how much time the tank fails to supply water), the engineer can decide the storage size under a preset deficit rate and also the cost of each tanks (per 1000 l) from the curves generated in this study. These relationships can be used by engineers in the design process.

Collected rainfall as a water source in Danish households - what is the potential and what are the costs?

1999 ◽  
Vol 39 (5) ◽  
pp. 49-56 ◽  
Author(s):  
P. S. Mikkelsen ◽  
O. F. Adeler ◽  
H.-J. Albrechtsen ◽  
M. Henze
Keyword(s):  
Drinking Water ◽  
Water Consumption ◽  
Water Source ◽  
Point Of View ◽  
Local Context ◽  
Economic Reason ◽  
Toilet Flushing ◽  
Sustainable Water Supply ◽  
Drinking Water Production ◽  
Alternative Water

The water resource, energy and economy aspects of rainwater collection are assessed to evaluate rainfall collection as an alternative option for sustainable water supply. A maximum of 229 million m3/year of rainwater can be collected from Danish roofs, provided that all possible surfaces are used and all rain falling on the surfaces is collected. This is equivalent to 24% of the total present production of drinking water, which is mainly based on groundwater. From household roofs 64.5 million m3/year can be collected if used for toilet flushing and washing of clothes. This is 68% of the actual demand for toilet flushing and washing of clothes in households and 22% of the total water consumption in households, but only 7% of the total present drinking water production in Denmark. From the society point of view there is neither an environmental nor an economic reason to systematically promote rainfall collection on a larger scale in Denmark. Thus it is important to see rainfall collection in a local context, and in each case to evaluate whether there are cheaper alternative water sources or options for minimising the water consumption.

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