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https://www.researchgate.net/project/Ancient-Hydrological-Knowledge-and-Old-Hydraulic-Structures Can we share information about ancient hydrological knowledge, old hydraulic techniques, and ancestral water management methods
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The Central Bank of Tunisia (BCT) has put into circulation a new banknote of 5 dinars (type 2022) with a dimension of 143 mm x 73 mm, bearing the image of the engineer and left-wing activist and agricultural engineer , Slaheddin Amami (1936-1986); Tunisian agricultural engineer who had initiated the reform of the Tunisian hydrological system. He has made important contributions, in particular to the agricultural problems of arid and semi-arid zones, and more particularly, to the genius of local populations to adapt to them by developing ancestral knowledge on the management of water and soil resources, explaining the foundations of dryland farming in southern Mediterranean countries.
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dear all,
I'm a student and I'm in "Civil and Environmental Engineering" department.
please, can you tell me what are software programs that I will need when I graduate in (water desalination, irrigation systems, water distribution systems)?
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Hello Ahmed .
Top 12 Best Open Source Software in Water Resources are listed below:
1. QGIS
QGIS is the most popular GIS tool with an impressive trajectory and a vibrant community. It also even has a particular ecosystem of complements called “plugins”. QGIS is a completely open source alternative that reduces the cost barriers since it does not need a paid license and can be executed in any operative system.
2. SAGA GIS
SAGA GIS is a GIS platform oriented to spatial analysis. SAGA GIS is a simple but powerful tool, with a big library focused on spatial analysis and characterization of basins. The interpolation options in SAGA GIS are better implemented than in other free and commercial software.
3. HEC-RAS
The numerical model HEC-RAS is developed by the U.S. Army Corps of Engineers. This model uses the gradient and topography to evaluate the flow depth, velocities and flooded zones. It is also useful to calculate sediment transport and water temperature.
4. iRIC
iRIC (International River Interface Cooperative) is a software developed with the purpose of offering a complete simulation environment of the riverbed and its results can be exported and used to analyze, mitigate and prevent disasters, through the visualization of the results of the river simulation.
  • Hydrologic modeling
5. HEC-HMS
The Hydrologic Modeling System (HEC-HMS) is designed to simulate the hydrologic processes in basins. The software includes traditional procedures of hydrologic analysis, such as infiltration events, unit hydrograms and routing. HEC-HMS also includes modules for evapotranspiration, snow melting and calculus of soil humidity.
6. PRMS
The modeling code PRMS (Precipitation Runoff Modeling System) is a modular system of spatially distributed parameters, which represent the physical processes of a basin. It was developed by the United States Geological Survey (USGS) to evaluate the effects of several combinations of geomorphology, type of soil, soil use, vegetation and climatic parameters in the hydrological response of a basin.
7. SWAT
SWAT is a tool to evaluate soil and water at a basin scale. It is focused in precipitation-runoff modeling and transport of water and solutes through surface flow. It predicts the impacts of soil management practices in water resources and sediments
  • Hydrogeological modeling
8. MODFLOW
This code performs groundwater modeling based on finite differences developed by the United States Geological Survey (USGS). It is capable of simulating groundwater 2D and 3D flux and simulate the principal physical processes related to the groundwater regime such as recharge, evapotranspiration, pumping, drainage, etc.
9. MT3DMS
The MT3DMS package is a mass transport model coupled to a flux model in MODFLOW. The MT3DMS code simulates advection, dispersion/diffusion and chemical reactions of adsorption/absorption of contaminants in groundwater.
  • Computational fluid dynamics modeling
10. OpenFOAM
Pretty much any physical phenomenon associated to fluid dynamics can be represented with this software. The amount of packages incorporated and also its condition of an open source code make it useful to explore the possibilities of modeling several types of problems including the addition of a reactive model.
11. Python
This is the favorite code for scientific, water resources and environment analysis. It has several packages for different tools such as GIS, mathematical analysis and artificial intelligence.
If a complete tool for manipulation, processing and plotting of data is needed, Python – Scipy is an effective, versatile and free code solution.
12. R
R is a programming language for statistic calculations and graphics generation. It is easy to understand and makes it possible to make complicated analysis with just a few lines of code.
It is the best option to perform spatial analysis since it incorporates several interpolation options.
Thanks
📷
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I would be grateful if you could help me find out one or few case studies in the Pacific region where soil erosion in pineapple fields is efficiently managed.  As part of a regional project (www.spc.int/resccue) dedicated to integrated coastal zone management  in the Pacific region, I would like to identify few case studies where soil erosion in pineapple fields is correctly managed in order to organize a technical exchange between pineapple producers in French Polynesia and producers in other places of the Pacific region.
Many thanks for your answer.
Do not hesitate to contact me if you need further information.
Best,
Mr CHARLES mahe / RESCCUE project coordinator in French Polynesia
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This is a good question.
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In the computer modeling and simulation of floatovoltaic systems in marine environments or freshwater reservoirs, a floating PV photovoltaic array performance model and simulation need to characterize the FSPV or FPV irrigation reservoir water evaporation benefits in sustainability assessment for sustainable development energy projects. Quantifying evaporative water-saving is a key project viability metric in a techno-economic model for FPV hydropower hybrid performance models for hydroelectric facilities, or to estimate floating PV array operating temperature or floating PV module internal cell temperature changes in comparative studies for floating FPV and ground-mounted PV or GPV.
Computer estimation of evaporation from a water surface of a water basin or wastewater basin is often calculated in Matlab or Python through mathematical evaporation models, by using parameters such as solar radiation, air temperature, humidity, water temperature, wind velocity, etc. While various applications and modifications of the Penman method, Penman-Monteith equations or Priestley-Taylor evaporation rates are used to predict or determine evapotranspiration rates in various solar water pond cover configurations, and PV floater design types as a sustainability indicator.
However, most water surface modeling or reservoir evaporation methodologies seem to be based on average daily solar irradiation rates, meaning real-time simulation model predictions need to be adapted to account for more instantaneous hour-to-hour solar irradiation data model inputs, ambient temperature variations, wind variations, airmass, relative humidity, water temperature or weather prediction data obtained from remote sensing and weather prediction data.
In a recent publication (link below) on environmental impact assessment of floating solar PV, we propose a method to time-normalize the hourly predictions of floating solar PV evaporation rates in a water-energy-land-food nexus metric, but would like to know from researchers and scientists if literature is available to discuss other scientific data engineering options for hour-to-hour or even-minute-to-minute evaporation rate estimations on open water surfaces as a means to quantify the evaporation savings of an FPV prototype in a real-time simulation model:
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Excellent question flagged here. Would be eager to know more.
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Please suggest a high graphical resolution software for Water Quality Modeling of Water Supply Pipe Networks which includes the ability to analyze chemical decay. Thank you.
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There are several good and free software to mention including SWAT, HEC-HMS... but since you mention about Water Quality Modeling of Water Supply Pipe Networks, I would recommend you to use MIKE URBAN by DHI, which is integration with ArcGIS that you can model the water quality in the collection system in MKE URBAN CS with MOUSE and also MIKE URBAN CS with SWMM.
You can refer to this attachment of MIKE URBAN Collection system User Guide:
You can find out more about MIKE Product by DHI in link below:
MIKE URBAN also provide 1-year free license for student , but since this software integrates with ArcGIS, you have to have license from Esri.
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Dear researchers and experts
My first paper about numerical validation of spur dikes (1-2) in Drinking Water and Engineering Science journal (3) didn't accept cause they don't have reviewer in the field and after a long time, they said that it's not in their scope. Although, sadly, they published it due to their law and put a "This preprint has been retracted." with a red mark! on it. since this paper didn't accept, if available, we want to improve and publish it in a journal or a valid conference.
as our facility doesn't support us in international conferences could anyone sponsored us? and could anyone help us to improve the paper for publishing?
If anyone likes to contribute, Please contact me for further discussion and queries, I would be appreciated.
Regards,
Hanif Pourshahbaz
2-Pourshahbaz, H., Abbasi, S. and Taghvaei, P., Numerical scour modeling around parallel spur dikes in FLOW-3D.
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Dear Hanif
You can try to these journals:
1- ISH journal of hydraulic engineering
2- Modeling earth system and environment
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Due to environmental impacts of dams such as:
- problems for the surrounding area, for plant life,
- dams block up flowing bodies of water, such as rivers, any animals that depend on the flow to reproduce or as part of their life cycle are put in danger.
- Harm water quality and temperature.
- Block fish migration
- ...
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From the previous answers, a lot has been said regarding the potentials usefulness of dams, which is really good. I would like to adress in this answer, for the sake of discussion, some key points regarding why dams can be problematic to us.
It appears that during the past decades, wild river streams (ones that run free from headwaters to confluence) have nearly been wiped and then replaced by river dams. Fact is, dams disrupt natural systems and subsequently thwart the work of rivers. They block fish runs, seasonal flood patterns, affecting redistribution of nutrients (like marine nitrogen delivered by salmon to feed the inlands).
Dams encourage unsustainable growth, displace people, often indigenous people
Very often, dams are built through grants of institutions and rarely benefit the local people. Most of the generated hydropower (if any) is delivered to big cities, not the rural villages displaced by the dams.
Even from a design perspective, it appears dams are made to fail. A huge reservoir surfaces mean terrible annual evaporation losses. Silting is unavoidable. Even the largest reservoirs silt up. When they collapse, it is nightmarish.
Some researchers point out dams are not the solution to our energy crisis. Solar and wind can provide far more reliable, long-term energy than hydropower with far fewer environmental costs.
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Ex: Think total hardness is 200ppm. Total treated water requirement is 5000L/day.
Then how calculated the
a) Softener vessel size?
b) Required resin volume?
c) Salt regeneration time?
d) Dosage of salt?
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Ideally, a water softener should be sized so that it does not regenerate any more often that every three days (wastes water and salt), nor go longer than 14 days before regenerating (can cause compacting of resin, and fouling with sediment or iron). 7 days between regenerations is probably best - especially if iron is present. For the majority of homes, our 1 cubic foot unit is more than enough capacity. There are conditions that would create a need for a larger unit: larger family (6 or more) and/or very hard water (over 15 grains). Use the following formula to calculate the proper size: 1. Multiply the number of people in your family times 70 (gallons of water used per day, national average). 2. Multiply the answer by your water hardness in grains per gallon (to convert mg/l or ppm to grains, divide by 17.1). If iron is present, add 5 grains for every ppm (mg/l) of iron (iron MUST be dissolved iron - it appears clear from the tap but leaves reddish-brown stains). 3. This is your "grains per day" number. Divide this number into each of the softener capacities until you find the best size.
You can find additional data on:
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I am going to perform a membrane autopsy of a reverse osmosis membrane to investigate fouling. I know how to do it based on research papers that i have read but I need a standard procedure describing the steps to be followed.
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AMC is the moisture condition of soil before 5 days actual rainfall.
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Antecedent Moisture Content means the preceding wetness condition of the area under study. Rainfall-dependent inflow and infiltration (RDII) into sewer systems is highly affected by antecedent moisture conditions . The travel paths for RDII entering the sewer system are very complex because the transport mechanisms include both surface runoff and subsurface transportation. This adds additional complexities to the hydrologic effects and antecedent moisture effects such as the saturation levels of the soils in the subsurface, groundwater levels, and subsurface hydraulics. Curve number is a coefficient that reduces total precipitation to runoff potential after losses. Therefore higher the CN value higher is the runn off potential.It is crucial to use CN value that best represents the ground cover type and hydro-logic condition
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Water disapearance from drinkers in piggery can be partitioned into the water consumed by the pigs and water spillage. The percentage of water spillage is usually too high to be ingored particularly if using nipple drinker, so the water disapearance cannot be simply recorded as the water consumption. Is there any method or technology can seperately quantify the water intake and spillage in individually housed pigs (eg: one pig with one nipple drinker)? Thanks.
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The problem can be partly solved with installation of some sort of tray bellow nipple (metal tube cut in half), to distinguish between consumed and spilled water. The tray should be inclined out of the cage, where you can catch "spilled water".
Hope my answer help...
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To determine the mean river Width in sections, there are different methods. As you know, rivers shape isn't an unique shape and I can't calculate it by mathematical methods that usually we used in numeral shapes. I can calculate the area that covered by channel (A) and the length of flow (L) in study section, can I use this typical equation "A/L=w"?
Regards.
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Have a look at this R solution. It calculates the channel width locally for any given river shape. https://github.com/AntoniusGolly/cmgo
It does this by first calculating a centerline and then transects. You can later set the spacing of the transects.
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I need a supervised fuzzy regression sourse code for MATLAB to forecast the groundwater level. Can anybody tell me how and where can I get a sample source code for fuzzy regression?
Best Regards
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Some more links about Matlab code. 
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please explain the advanced methods to cure or treat the fouling 
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usually in power plant pH and Conductivity is main parameter to predict condition in BTG, can you provide ORP values for water sample in Power plant? in all the type of dosing system i.e. AVT(O), AVT(R), Oxygenated etc.
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Thank you Premji..
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How to calculate the cross sectional area required of Forward Osmosis membrane for treating any wastewater?
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Refer to manufacturer for the FO module
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I want details of sustainable technologies used in sea water treatment and how to use them in a wastewater treatment plant of a hotel  
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Reverse Osmosis is the commercially available and quite cost effective technique
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Looking for any recent research or innovations on the water treatment. Work with poor communities in rural Africa and most current treatment systems are very expensive for the community. Would there be any appropriate technology solutions? Recently drilled two boreholes near Lake Turkana with good yield but water is too salty for drinking and farming as well. Also ideas of how to use this water would be welcomed.
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For my project i want to know how to increase the evaporation rate, and what are the factors  majorly contribute for evaporation in solar still?
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The most important factor that affects level of production of the solar still is the amount of solar radiation on the glass cover, called irradiance. Not all of the solar energy that contacts the glass will actually be used for evaporation of the water in the basin because it gets reflected and absorbed by anything it passes through. An energy flow diagram that shows that part of the sunlight is reflected and absorbed by the glass, the water, and the basin surface. If the still is not perfectly sealed and insulated there will be heat losses to the surroundings.
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If I am doing disinfection of water with chlorine and the initial concentration of free chlorine is 3 mg/L before spiking the water with bacteria. The initial demand of free chlorine immediately after adding bacteria is 2.8 mg/L. The reaction occurs for 1 minute, measure again free chlorine after the contact time (2.6 mg/L) and then I stop the reaction with Sodium thiosulfate. The CT value would be the mean value (3+2.8+2.5)/3= 2.76 mg/L * 1min? Or just considering the initial demand? (3+2.8/2=2.9 min mg/L) thanks in advance!!
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Hi again Beatriz. First, I apologise for making the mistake with the units. I should not answer questions when I am too tired!! You are correct, the units are mg/l.min.
With regards the Ct value. By definition, this is the concentration C(mg/l) of free chlorine measured at the end of the contact period, multiplied by the contact time t(min). Your question was "am I calculating correctly the Ct value in the disinfection experiment?" so strictly applying the definition, no.
Integration to find the area under the decay curve will allow you to find the actual change of concentration over time, not just how quickly the change is happening, i.e. the way the concentration changes, instead of the rate of change.
As I understand it, Ct is an indicator of how long a given concentration of disinfectant has been in contact with microorganisms in the water, rather than a rate of change of concentration with time, or the way the concentration changes. 
John
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I want to work for the leakage assessment of intermittent water distribution system. Epanet is mainly used for pressurized water supply system. But in my country the DMA's are not implemented. So when I will start to assess leakage, what kind of tools I should use for intermittent water supply system. I will be grateful, if kindly the researchers help me. 
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If you are looking for a tool that quantifies the leakage or what is so called real losses in water supply systems, then you can check the following tool that quantifies the leakage and analyses its sub-components: 
You can also check this software that analyses the water losses and its components (including real losses; leakage) in water supply systems:
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I require an sensor which will detect the presence and absence of water through analog signal. I will be installed it inside pipe and it should be small and not too costly.
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There are low level sensors for fuel tanks in vehicles. Often they are NTC thermistors. If heating energy don't have dissipation through liquid then resistance is decreasing (and lamp turn on).
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As per a WHO report, by the end of 2012, 64% of the global population used improved sanitation facilities which means almost 1 of every 3 person still have less / no access to proper sanitation. What steps should be taken to make it a near 100% of the same?
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It has also been noted that lack of knowledge about the essence of improved sanitation is one of the main reasons for the low uptake of improved sanitation in developing countries. Thus, in trying to meet the quest for access to improved sanitation by all, development agency and governments should create demand for sanitation through sensitisation of the community. On strategy would be to use the 'name it and shame' approach which has been shown to trigger the community realise the need for improved sanitation. A sensitised community is more likely to contribute through various means including labour during sanitation projects and this turns to be more sustainable
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I work on the MIP to detect the testosterone in water. Colloidal crystals of silica particles were fabricated on the glass slide. Then, I used acrylic acid as a monomer, EGDMA as a cross linker and AIBN as an initiator. My problem is when I made the incubation to detect the hormone, the concentration of testosterone before and after the incubation is the same ( I used 30 mg of MIP in 15 ml of different concentration solution of hormone). This mean there is no detection, or my MIPs not work. Also, I got the same results for NIP. 
Notes: 
1-  I used the hydrofluoric acid (HF) for removal of silica particles after polymerization and acetic acid for removal of testosterone from the MIP. 
2- Also, my MIPs is a thin film, not particles
Does anyone have the same problem when worked on the MIP or anyone can advise me, please?
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Thanks Ms. R Schirhagl.
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What is the best method to estimate water resistivity knowing the salinity/chlorinity and formation temperature?
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Dear Matteo,
The simplest method is the measurement of the resistivity by reading a resistivity device. In the absence of such a device, you can take the measure
of the resistivity by the "method of the pipe", the results are relatively
imprecise, especially for conductive water and whose implementation
work requires certain precautions.
With my best regards
Prof. Bachir ACHOUR
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Should it be exactly 0.45 um or can we use pore size lesser than 0.45 um? 
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Dear Kasun,
I confirm that is often used filters with pores of 0.45 µm. But are also used tighter pore size filters of 0.22 µm.
With my best regards
Prof. Bachir ACHOUR.
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I would like to discuss with anyone who has studied and surveyed water mills and their interactions with the river beds, or I would have some suggestions of publications to read or download from the network. It would also be nice to be able to exchange research experiences gained in the different countries of origin. Thank you.
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Don,
1894 book with penstock waterwheels if you have not found it yet. PDF with text smaller and still retains good images.
JAG
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Dear all,
I got results from pressure plate on the relation between the water content and pressure head. I want to use RETC to obtain soil hydraulic properties. Can anyone help me in this issue?  I need a quick guide to get these properties.
Thanks
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Dear Ahmed,
If you just want to characterize Soil hydraulics such as water comtent vs. pressure head, etc... while you have done it using pressure plate, and you want compare between them ? however, in either cases , the problem is not difficult. you will bring your data points and input them to your retec program, you get results. Here is a simple sample, which I'm sinding you here
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Has the angle of deviation of water bars effect on their efficiency?
I needs some references about efficiency of water bars on skid trails in forest area.
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Dear Ramin
The angle of deviation of water bars has effect on their efficiency.
But unfortunately have not done many research in this term.
Regards
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Is it possible that any Water Treatment Plant Operator or Scientist can share some historical data (a few years)?
  • Specially daily data of: raw water quality parameters, treated water quality parameters, Alumine dose, Chlorine dose, Ozone dose,....) from any Water Treatment Plant in USA, Western Europe, or another region.
  • Water treatment plant those using specially using Ozonation in pretreatment, PAC, and GAC in water treatment process.
Thanks in advance for all your contributions.
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Dear Nicosia,
Thank You for your contribution, the good news is that I met Mr. Angelo SIRAGUSA at Essen in Germany on June, 2014 in IWA conference at the celibration 100 years of activated sludge.
Best regards
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I need some references about the effect of protection layer that is added on the surface of sand filter (especially on slow sand filter).
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See attached publication.
Best wisches,
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I'm doing a water quality research. I have parameters like nitrogen DO etc. While having those date as x-axis and Concentrations as Y-axis, when i log-transformed the concentrations, the graph pattern appeared to be the same as previous one. Why is this happening? What is the other way to make my graph linear instead of using log-graph?
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Yes always include outliers and explain them away if you need to, such as the outlier was the first storm after an extended drought, and the intensity of the event flushed an abnormal amout of nitrigen buildup into streams.  Remember the high r2 line is not the goal, and if you can explain the outliers, that is sometimes as important as the trend.
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dear all, i am a chemical engineer working in International petrochemical (pvt) limited. We have a sodium sulfate plant and we have 3 evaporators at site. About 1.3 tons of water is being evaporated per hour. And the heated vapors are being wasted in air. I want to recover those vapors some how. For that i am considering 2 Options right now.
1- Mechanical Vapors re-compressor.
2- Thermal Vapors Re-compressor.
The pressure of steam available is about 75 psi. Kindly tell me the Right proposal for the right action in terms of cost and optimization.
Best Regards
Muhammad Fahd
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I think that if you have a steam at 75 psi is more convenient a TVC.
MVC use only electrical power and the steam can not be used.
With 1.3 ton of steam you can produce 8 -10 tons per hour of distillate water.
Giorgio
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please give information about usuage of different sand media in water treatment?
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Dear Chiru Chiranjeevi,
Sand filters are used for water purification. There are three main types;
1-Rapid (gravity) sand filters
2-Upflow sand filters
3-sSlow sand filters
All three methods are used extensively in the water industry throughout the world. The first two require the use of flocculant chemicals to work effectively while slow sand filters can produce very high quality water free from pathogens, taste and odor without the need for chemical aids.
A sand bed filter is a kind of depth filter. Broadly, there are two types of filter for separating particulate solids from fluids:
Surface filters, where particulates are captured on a permeable surface
Depth filters, where particulates are captured within a porous body of material.
In addition, there are passive and active devices for causing solid-liquid separation such as settling tanks, self-cleaning screen filters, hydrocyclones and centrifuges.
There are several kinds of depth filter, some employing fibrous material and others employing granular materials. Sand bed filters are an example of a granular loose media depth filter. They are usually used to separate small amounts (<10 parts per million or <10 g per cubic metre) of fine solids (<100 micrometres) from aqueous solutions. In addition, they are usually used to purify the fluid rather than capture the solids as a valuable material. Therefore they find most of their uses in liquid effluent (wastewater) treatment.
Particulate solids capture mechanisms
Sand bed filters work by providing the particulate solids with many opportunities to be captured on the surface of a sand grain. As fluid flows through the porous sand along a tortuous route, the particulates come close to sand grains. They can be captured by one of several mechanisms:
Direct collision
Van der Waals or London force attraction
Surface charge attraction
Diffusion.
Operating regimes
They can be operated either with upward flowing fluids or downward flowing fluids the latter being much more usual. For downward flowing devices the fluid can flow under pressure or by gravity alone. Pressure sand bed filters tend to be used in industrial applications and often referred to as rapid sand bed filters. Gravity fed units are used in water purification especially drinking water and these filters have found wide use in developing countries (slow sand filters).
Overall, there are several categories of sand bed filter:
rapid (gravity) sand filters
rapid (pressure) sand bed filters
upflow sand filters
slow sand filters.
Rapid pressure sand bed filter design
Smaller sand grains provide more surface area and therefore a higher decontamination of the inlet water, but it also requires more pumping energy to drive the fluid through the bed. A compromise is that most rapid pressure sand bed filters use grains in the range 0.6 to 1.2 mm although for specialist applications other sizes may be specified. Larger feed particles (>100 micrometres) will tend to block the pores of the bed and turn it into a surface filter that blinds rapidly. Larger sand grains can be used to overcome this problem, but if significant amounts of large solids are in the feed they need to be removed upstream of the sand bed filter by a process such as settling.
Operating parameters for rapid pressure sand bed filters
Rapid pressure sand bed filters are typically operated with a feed pressure of 2 to 5 bar(a) (28 to 70 psi(a)). The pressure drop across a clean sand bed is usually very low. It builds as particulate solids are captured on the bed. Particulate solids are not captured uniformly with depth, more are captured higher up with bed with the concentration gradient decaying exponentially.
Uses in water treatment
All of these methods are used extensively in the water industry throughout the world. The first three in the list above require the use of flocculant chemicals to work effectively. Slow sand filters can produce very high quality water free from pathogens, taste and odor without the need for chemical aids.
Multimedia Filtration
Pressure vessels with sand or other loose media are widely used in industrial filtration applications. During the cleaning cycle, called "backwash", the bed is lifted (or "fluidized") to loosen the filter media and release trapped dirt which is removed in the backwash flow.
After the backwash cycle, the bed is allowed to settle before the filter is returned to service (i.e., normal flow). A "filter-to-waste" cycle is used following the settling to assure the filtration media has sufficiently re-stratified and that any loose dirt is removed from the underdrain / collectors.
Multimedia filtration refers to a pressure filter vessel which utilizes three or more different media as opposed to a "sand filter" that typically uses one grade of sand alone as the filtration media. In a single media filter, during the "settling" cycle, the finest or smallest media particles remain on top of the media bed while the larger, and heavier particles, stratify proportional to their mass lower in the filter. This results in very limited use of the media depth since virtually all filterable particles are trapped at the very top of the filter bed or within 1-2 inches of the top where the filter media particles have the least space between them. The filter run times are thus very short before the filter "blinds" or develops so much head pressure that it must be backwashed to avoid seriously impeding or stopping the flow.
Multi media filters typically utilize three layers of media for multimedia filtration: anthracite, sand and garnet. These media are often chosen for use in multi media filters due to the distinct differences in their densities. Anthracite is the lightest filtration media per unit volume, followed by sand, and then garnet.
The idea behind using media with differing masses is that during backwashing the lightest media with the largest particles (anthracite) will naturally stratify at the top of the filter, while the intermediate sized media (sand) will settle in the middle, and the heaviest media with the smallest particles (garnet) will settle to the bottom.
This layering of the filtration bed encourages the very largest contaminants to become trapped in the first layer of the filter, with smaller particulates sifting farther down into the lower layers. Trapping contaminants in this manner allows for more efficient turbidity removal and for longer run times between backwash cycles. A simple sand filter can be expected to eliminate particles down to 25-50 microns in size, as compared to a multi media filter that can remove particles down to 10-25 microns.
Operating at higher pressure differential is liable to drive particles so deeply into the media bed that backwash is not able to remove them all. Over time the build-up of dirt deep in the filter will cause shortened filter runs and high differential pressures. Filter backwash may include air scour to help loosen packed dirt in the media bed. When this step is included, it is preceded in the backwash cycle by a "drain down" period for water to be bled out of the filter vessel.
Flocculants / coagulants may be used upstream of the filter to induce the tiny dirt particles to join together to form particles large enough to be removed by the filter. This process is called "agglomeration" and, with proper chemical dosage, adequate mixing and adequate contact time, it will enable the filter to remove particles below 10 microns in average diameter.
The Benefits of Multimedia Filtration over Conventional Sand Filters
Unlike traditional sand filters, multi-media water filters are composed of three filtration media, ordered in decreasing porosity. Because of their multi-layer design, multi-media water filters are able to trap and retain a far larger number of particles than traditional sand filters before backwashing becomes necessary.
Trapping sediment and particulates throughout the entire depth of the filter bed, allows multi-media water filters to operate for much longer periods of time than conventional sand filters. The process of multimedia filtration produces high quality, filtered water at much faster flow rates than traditional sand filtration.
Rushton, A, Ward, A S and Holdich, R G (1996). Introduction to Solid-Liquid Filtration and Separation Technology. Wiley VCH. ISBN 978-3-527-28613-3
Coulson, J M; Richardson, J F; Backhurst, J R and Harker, J H (1991). Chemical Engineering. Vol.2, 4th Ed. ISBN 0-7506-2942-8.
 Ives, K J (1990). "Deep Bed Filtration." Chap. 11 of Solid-Liquid Separation, 3rd Ed., Svarovsky L (ed). Butterworths. ISBN 0-408-03765-2
The following links contain studies using different sand types for the filtration of water from variety of sources:
Abstract
 Water samples were taken from three different shallow wells in Abeokuta, Ogun state Nigeria (West Africa). These wells are represented by as raw water A, B and C and were filtered using sand as filter media, sand grains of different sizes was used. The raw water was filtered with fine sand (column 1), coarse sand (Column 2) and very coarse sand (column 3), these loadings are homogenous and the fourth column contains there three sand layers. The filtered water was subjected to laboratory analysis which includes the following: pH value, TDS (Total dissolved solids), EC (Electrical conductivity), TS (Total Suspended Solid), Calcium, Magnesium, Potassium, Hardness and Sodium. The obtained laboratory test results were compared with W.H.O standard for highest desirable and maximum permissible. One way ANOVA and bar Chart are the statistical tools employed in analyzing the data. The fine sand homogenous filter gives the best output, and then followed by the coarse sand, and then the mixture of the sand also gives preferable outputs. The homogenous fine sand media flow rate was slower but give the best output. In situation where sand particles is very small, bed depth is very high, minimal or no chemical treatment will be required after filtration.
2-https://www.google.ps/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiM9qbwpqjMAhXkFZoKHc3iDlYQIAgvMAI&url=http%3A%2F%2Fwebcache.googleusercontent.com%2Fsearch%3Fq%3Dcache%3AV-yq9ZDIv7QJ%3Awww.hach.com%2Fasset-get.download.jsa%253Fid%253D18374278952%2B%26cd%3D3%26hl%3Den%26ct%3Dclnk%26gl%3Dps&usg=AFQjCNHCw7DmGvzRp6JtCVPdpUaWrBWREg&sig2=jMH-ZAtNdrrKL-ZYBv1omQ
Granular Media Filtration for Water Treatment Applications
Terry Engelhardt
Application Development Manager – Drinking Water
Hach Company
Drinking Water Treatment - Filtration
How drinking water filtration works
Filtration systems are used most often in home water treatment to remove sediment or iron, manganese, or sulfur particles. Filtration can also remove some bacteria from water. In mechanical filtration systems, water passes through a medium such as cloth or sand. Particles become trapped on the surface of or within the medium. The pore size, or space between media granules or fibers, determines what size particles a filter can remove.
Filters are rated according to the smallest particle they can trap. The filter opening size to use depends upon the material to be removed by the filter. A smaller size will satisfy removal requirements but will require more frequent cleaning or replacement of the filter. When these filters are used to pre-treat water for other water treatment devices, such as a reverse osmosis unit, follow the manufacturer’s recommendations.
Surface or screen filters remove the particles at or very near the filter surface. They function very much like a screen; particles of a certain size and larger are retained at the surface while smaller ones move through the openings.
Depth filters have a thick filter medium. Particles are retained throughout the thick filter mat. Depth filters have a gradation in the size of the filter media so that the largest particles are held at or near the filter surface, while progressively smaller particles are captured deeper in the filter where the filter media becomes smaller.
Either filter type may be used for a wide range of particles sizes.
Types of drinking water filters
There are many different types of filters used in drinking water filtration units. They differ in design, cost, and effectiveness. Before purchasing a system, verify that the treatment system you are purchasing has been tested and certified by a third party (for example, National Sanitation Foundation)to ensure manufacturer’s claims. Mechanical filtration systems include cartridge sediment filters, media and multimedia filters, and precoat filters. Which filtration method to select depends on the concentration and size of the suspended solids in the water and the rate at which water needs to be treated. Media filters such as sand filters have a greater contaminant removal capacity than other types of filtration devices. However, cartridge filters with fiber or ceramic filter material are made with a smaller and more uniform pore size and can be more reliable in removing small particles.
Hoping this will be helpful,
Rafik
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Do you know any dredger manufacturing company in the Netherlands or EU countries? Or can you give me any contact of such a company? Please find me a dredger manufacturing company from the Netherlands or other EU countries to work with my husband's company to participate a Tender. The company has to have 20 years dredger manufacturing experience. We will form joint Venture (JV) and all works will be done in Bangladesh in our shipyard. All technical and Machinery supports for 20” and 18” Cutter Suction Dredger will be provided by the dredger manufacturing Company.
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how can I get aware of the newest researches about river water quality and uncertainties about it?
please help me by answering
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 I'm sorry but your question is, uncertainty
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I am working on a practical project with waste activated sludge under thermal hydrolysis process. After the thermal incubation and centrifugation of sludge sample, the sludge sample is separated in three phase: sludge, supernatant and a yellow intermediate. This intermediate is found at 120 degree and disappear at 140 degree. I assume this is a kind of EPS after huge amount of literature review. But i still not completely sure, there does not any literatures found same situation with thermal condition.
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in the condition of high temperature, it may be produced some kind of acid, butylic acid, propionic acid and acetic acid.
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with minimum required data
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The USACE HEC- packages are powerful tools for the hydrology (http://www.hec.usace.army.mil/).  Although, USDA/TAMU's SWAT package may provide you with more water quality tools (http://swat.tamu.edu/).  Both of these are free.  The HEC tools (HEC-RAS if you are only interested in river flow, HEC-HMS for precipitation data to runoff) will provide more with less input; however, you tagged this question as water quality, so you may need to explore SWAT.  Nevertheless, each model has its own limitations, big limitations.
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suggest me some commercially adapted technologies to treat effluents produced from onion, garlic and other vegetable dehydration plants.
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Thanks Mr. Kushal for your valuable input.
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Is Terminalia Arjuna help to reduce ground water hardness?
if there is any specific standard method to monitoring water hardness ?
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Terminalia chebula of Combretaceae family could be helpful in reducing ground water hardiness.
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My waste water contains higher concentration of ammonium ion, magnesium ion, phosphate ion and nitrate ion.The pH of my sample range from 7 to 11 and i use 1M NaOH to control pH. I want to detect Mg²⁺ + NH₄⁺+ PO₄³¯  by using metrohm 83 ion chromatography. I diluted my sample 10000 times but could not get good result. can anyone tell what is the problem and how can i solve it? Thanks in advance.
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When you say you do not get a good result upon dilution, what specifically is problematic about your result? Are you observing low recovery for ammonia? If so, the problem could be your filter material. Most natural materials contain cation-exchange sites due to oxidation and/or scission of chemical bonds during the preparation process. You might improve the situation by acidifying the sample with MSA.
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What is the mechanism of TiO2/UV application's in removal colour pollutants from aqueous?
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photocatalytic mechanism in which electron are transfered fro the HOMO to the LUMO of TiO2
then H2O reacts in the emptied HUMO : H2O --> HO° + H+
and O2 reacts in the LUMO with the electron : O2 + e- --> O2°-
both HO° and O2°- are very oxidizing species "destroying" any organic molecules
regards
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we have three cases
-the spillway upstream dam axis
-the spillway downstream dam axis
-spillway with the dam axis
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As spill way is the measure structure which controls the safety in High floods
definitely it will have its bearing on the design of Dams.
The spill way even though conceived and designed may have to be changed when actual construction starts based on the geological, structural and Hydraulic data. to suit the conditions.
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I am just planning for my master thesis. my Idea is to do research on urban flood modeling of Kabul City. 
I have DEM with resolution of 1 meter and rainfall data with 1 day resolution, 
Kabul has no underground sewer system. water drains in the open, concrete lined ditches alongside the roads. i also have the data about land use. 
Kindly give me suggestions which model i should use for urban flood simulation in this case. 
thanks for your attention 
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Dear Fazli Rahim Shinwari ,
In early December, 2015, at Chennai, India there was an incidence of heavy rains in the flood plain, with upstream over flows and the lakes got over filled, and the channels not able to permit the outflow of rain floods caused heavy inundation in the city. Chennai being on the coast had the effects of high tide,,and low tides for allowing outflows of rain water. This had a  very devastating effects. Some data and study are emerging  if you are keen, pl remain in touch on email - seshadri.ajit@gmail.com  -
well wishes, Ajit Seshadri
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For low head (1-5 m) and various discharge (2-50 cms ) rivers, a conventional small hydroelectrical power plant does not seem feasable. I am considering water wheels and looking for theoretical and practical guide. Thanks in advance.
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Dear Mustafa, 
Yes, for low head applications water wheels are technically and economically most suitable solutions. I have been working on water wheels model testing and numerical simulation. Some useful literature for you:
Müller, G. and Kauppert, K. (2002). Old watermills- Britains new source of energy? In Proceedings of ICE, Civil Engineering, volume 150, pages 178–186.
Müller, G. and Kauppert, K. (2004). Performance characteristics of water wheels. Journal of Hydraulic Research, 42(5):451–460.
Müller, G. and Wolter, C. (2004). The breastshot water wheel: Design and model tests. In Proceedings of the institutions of the civil engineers:Engineering Sustainability, volume 157, pages 203–211.
Paudel, S., Linton, N., Zanke, U. C., and Saenger, N. (2013). Experimental investigation on the effect of channel width on flexible rubber blade water wheel performance. Renewable Energy, 52(0):1–7.
Best regards,
Shakun
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PVDF membrane used in a simple NaNO3 solution, and we detected a release of fluoride from the membrane.  We can't explain the mechanism for how the fluoride can be broken off from the PVDF matrix.
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Thus, your membrane might be contaminated by fluoride anion? Try to pre-wash it with NaCl 
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I have some problem measuring ORP-value in reverse osmosis permeate. The ORP value in the this RO permeate in all case was determined in the range 200-300 mV which is quite high. The calibration was OK. I've also used the same probe and instrument for surface water and boiler condensate, the values were 190 mV and 100 mV, respectively, which are correct values. The conductivity of the RO permeate is 10-14 uS/cm and 200-300 uS/cm for the surface water and 8-12 uS/cm for the boiler conensate. I do not understand why is this high values of the RO permeate because even sodium-metabisulfit is added to remove all the chorine constituent from the RO feed and no actiive chlorine was determined in the RO feed. It is related the low dissolved solid content? What is the reliability of the probe and the instrument in such a low dissolved solid concentation. Or this is because of the dissolved oxigen? Please give me some suggestions.
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You can check about ORP reading of RO permeate and the impact of pH in the following link: http://www.ethanolproducer.com/articles/5833/common-mistakes-in-design-use-of-reverse-osmosis-systems.
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The policy planners are emphasizing to increase the water use efficiency. However, I understand a minimum leaching fraction is essential even for canal water irrigation under arid climates. Arid regions are already facing shortage of good quality water, to meet this shortage poor quality irrigation waters are in use everywhere. I fear, unless magnitude of LR is not considered and met, there must be problems of soil salinity followed by sodicity that is even more difficult to reclaim and manage for crop production for food security.
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use modern irrigation system is first step, also, cover soil surface by polyethylene mulch, save about 20 % of water for plants, adding organic compost for soil is the third option because compost has high water holding capacity and then save water
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I have a river water that may have a potential to form fluorapatite, is there a possibility for scaling on UF dead-end membrane?
for information, the UF membrane cut-off is 10 kDa.
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Dear Islam,
From my experience there is no way that such compound will not removed by ultrafiltration membrane having cut-off of 10 kDa unless there is a fouling in your membrane.
Studies have showed that very small colloids, ranging from about 3−20 nm in diameter, appeared to be important membrane foulants . The colloidal foulants include both inorganic and organic matter. When the colloidal fraction of material was removed, the remaining dissolved organic matter (DOM), which was smaller than about 3 nm and included about 85−90% of the total DOM, caused very little fouling. Thus,  small fraction of DOM may be responsible for fouling.
An appropriate cleaning of your membrane will provide experimental evidence.
Hoping this will be helpful,
Rafik
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how can we reduce water while curing?
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several activities go on at construction sites  that make use of water: mixing of concrete, wetting of dry surfaces, washing of equipment etc. to reduce water wastage during mixing of construction materials, proper equipment should be used such as mixers with which only the required volume of water is used. To also reduce wastage and recycling at construction sites, washing and cleaning of equipment should be done in a reservoir. water storage and delivery  facilities should be safe and leakage free to reduce water wastage. 
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How does the physical,chemical and biological characteristics of aquatic plants in a constructed wetlands affect their performance in wastewater treatment in constructed wetlands?
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dear mr Lepcha
I think I woudl try to look at the traits = characteristics of plants , native wetland plants of your region  - and choose for your purpose  the ones that are most likely to grow and to 'do the work' in a contracted wetland. From the species pool of native , wetland plants I would filter out the good candidates. I assume that the vegetation will be regularly removed (for composting or so).  Of course it would be nice if a group of them woudl be somewhat resemble an occurring communities - but i guess that's of secondary importance.  As for traits I woudl look (filter) plants that have a high rate of nutrient acquisition = usually these with high SLA, low LDMC, high N% and high P% in leaves. Rather larger plants as well. The plants with aerenchyma would do better (providing O2 to the rootzone) and in general plants with higher tolerance for NH4 etc. Although the tolerance is probably not included in the traits databases.  Than I woudl think of 'layered'  and multi-species structure: so to optimist the use of space and of light. Probably here the roots are important - so pick species with different rooting depth and root systems (to keep surface stable and provide an optimal resorbtion of nutrients). It the wetlands is partly shallow ponds - you probably should choose the plants growing (and tolerating ) different deaths. The layered above ground  vegetation would help to optimally use light (so plants that are both -  medium to large plants - with diverse growth forms?). Next  I woudl choose plants that have a good clonal spread. If possible I woudl also include plants with flowers, diverse flower types and attractive / valuable for pollinators= they your wetland can also provide extra service as a additional food source for the insects. Of course you need to think of the plants with good fitness in your local conditions (abiotic , climatic) - but this you need to decide based on local conditions.
I hope it helps - good luck!
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How can I avoid negative pressure in a closed tank where a tube brings water and another tube discharges it for gravity? Input and output are at same level and I  get bubbles in output together with liquid. Is there any way I could keep the water level higher than output point so that it is constantly submerged? I cannot increase the influent flow.
Many thanks for your help,
Simone
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I agree with the answer. You should partially fill the tank and put an airhole on the top. the tank should not fill more if the outflow is lower or equal to the inflow.
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I want to estimate surface runoff over a large city using SWMM model but there is not any runoff data for calibration. There are digital map scaling 1:25000 and rainfall data for nearly rain recorder site.
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@ Dear Dr. Telvari,
It's probably too late to answer, but go through this recently updated Q:
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Actually I am going to research on drought monitoring in Bangladesh and I want to use MODIS tool. But I do not have an idea how to use that. Can anyone help me and show me some guidelines? Thanks in advance.
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Hi Sudipta Kumar Hore
Please find the attachment. Hope it will be helpful for you,
Moreover, it is necessary  to have some basic knowledge about MODIS products, MODIS Processing Levels, MODIS Temporal Resolution, MODIS Spatial Resolution etc.
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I am performing a thermoeconomic analysis  to asses the performance of a combined cycle and looking for a formula that simulate feed water deaerator price, if there is any.
Thanks for help in advance
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It spent three $6000 for laboratory equipment in China. 
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I am currently doing a case study on pump efficiency and looking at the thermodynamic method which uses differential temperature and pressure to measure losses. I am searching for literature on this subject to form an academic report backed up with results from the pump tests to identify if the thermodynamic method should be used.
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You may find this article useful:
Papa and Radulj (2013) 'Thermodynamic method used for pump
performance and efficiency testing program' Environmental Science & Engineering Magazine March 2013
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I am trying to design submerged groynes in lowland rivers, is the same as the not submerged but with different high?
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I think it is different, because the stability of the submerged groynes material is different with not submerged groynes.
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Using saline water in agriculture has been investigated by various researchers. But can we use saline water in industry? Can you suggest me some references on my relevant topic?
Industrial machines, pipes and containers is typically work at temperatures above 100 oC. The salts may be deposited in these places and disrupt manufacturing. Also saline water may be unhelpful to produce and the ideal product not be made.
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It depends on the type and concentration of saline content in the water. For example, Calcium sulfate has inverse solubility so operation beyond 50-60 C is hard to achieve without using anti-scale additives which are an additional cost component.
If you have more info on the exact concentrations of different salts in the water you intend to use, maybe I can help you.
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Whats the simple method to estimate T90 for the sewage river, dumping effluent to sea through estuary. Whats Methodology should be adopted?   
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Thank you so much for your response. Is there any manual or guidelines for sampling Methods and analysis. 
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We are a group of academics working on how we can improve water supply and sanitation in the city of Masvingo, Zimbabwe
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Dear Maxwell
we have made a system to sanification drinking water by ozone. You can see the System in my Linkedin profile. It is a mini-container in which are  : 1) an ozone production system at low power ( 150 watt/30 g. X h ) , 2) a contact column  water -ozone by special nozzles , 3) a tank of 1000 litres, 4) a gasoli e power system
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Can anyone guide me through numerical dam-break modelling with finite difference methods?
I know that in finite volume methods, boundary conditions must agree with zero velocity at upstream, but since I can't find a head-velocity relationship at boundaries, I wanted to use FDM (with all is disadvantages in shock capturing).
If there is a training code, so I can learn more, I'd also appreciate it.
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Dam break problem is also a Riemann problem type. It does not have b.c. but initial values only. It is similar to a shock tube in gas dynamics. For further reference see Leveque, R.J., 2002. Finite Volume Methods for Hyperbolic Problems. Cambridge University Press.
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I am working on the interaction of three water source factors and my response is the supply, I want to know the advantages and disadvantages of using CCD.
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Some time, we may not get optimal solution. 
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What should I do if I want to do acting snowmelt runoff using neural networks or management of water resources
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ANN model is a black-box model that allows you to establish a complex relationship between a set of input and output data. ANN works by training the model using set of known input and output. But as others mentioned, there is uncertainty associated with it, like over-simulation. As I understand, for your case, you want to create a relationship between snow-melt and runoff and then do some prediction scenario analysis for management application. Of course it is possible using ANN, where your input will be snow melt data and output - runoff, you can add other parameters like precipitation, temperature as input during training which improves your simulation and decreases uncertainty. The advantage of ANN is that they require less parameters/data compared to process-based models. However you need enough time series data for training and validation purposes.
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The wastewater has very high COD (2000mg/l), low BOD (300mg/l), Total Nitrogen (900mg N/l). Should I do pretreatment before using anamox? If so, what is good pretreatment method in this case? What should I consider when installing an anamox reactor?
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Dear Hoang,
The partial nitrification/anammox (you need to oxidize half of the ammonia to nitrite) combination has mainly been applied for wastewaters with high ammonia concentrations and low concentrations of biodegradable COD such as digester supernatant, in which the ratio of biodegradable organic carbon to ammonia nitrogen (COD/N) is lower than 0.5 g COD∙g N−1. The growth of heterotrophic bacteria can compete with the low growing autotrophic bacteria (AOB and anammox).
However, recent studies show the possibility of using anammox processes to waters with higher rates. An interesting paper regarding this topic is:
Successful application of nitritation/anammox to wastewater with elevated organic carbon to ammonia ratios. http://www.sciencedirect.com/science/article/pii/S0043135413009007
, where ratios up to 1.4 g COD∙g N−1 were tested.
In your case, an important question is the nature of the non biodegradable COD, as the possible effects of COD on the anammox and nitrification processes depend on the type of COD.
In this study, the anammox was used to treat a landfilll leachate, with low BOD/N ratios, but COD/N >2.5
Coupling anammox and advanced oxidation-based technologies for mature landfill leachate treatment. http://www.sciencedirect.com/science/article/pii/S0304389413002823
The application of Anammox processes in the WWTPs allows to reduce the energetic needs of the facility, as remove the N with less oxidation. It produces less biomass. Moreover, by the application of the anammox processes (as the ELAN (R) process) no organic matter is needed for denitrification, and therefore this organic matter can be used either to achieve less nitrogen content in the final effluent of the plant (by increasing denitrification in the water line) or to generate more methane in the anaerobic digester when available in the plant.
You can read about some experimental implications of the anammox based processes in:
Implications of full-scale implementation of an anammox based
process as post-treatment of a municipal anaerobic sludge digester operated with co-digestion. http://www.iwaponline.com/wst/up/wst2013795.htm
Full-scale partial nitritation/anammox experiences- An application survey. http://dx.doi.org/10.1016/j.watres.2014.02.032
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Chloride is a common inorganic anion in dye wastewater, ranging from 1.5 to 80 g/L. Could you please give me some suggestions for chloride removal in both industrial scale and lab scale? Thanks~
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I would not suggest salinity reduction unit as your first treatment method because I think only evaporator can match your requirement; however, when evaporator is once used, then you also do not have to worry about the COD. RO and EDR can be utilized in salinity reduction, but I do not think it can work well in high salinity dye wastewater (up to 80g/L) which you mentioned.
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Relative humidity of 45% is observed during day time and increases slightly at nights in the location
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see above
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Hi Helen,
Above has pretty much listed what I know. There is another recently published higher resolution dataset - http://sharaku.eorc.jaxa.jp/GSMaP/ you may want to take a look.
Anyway, just be cautious when using remotely sensed data. Experience tells that they can be problematics at certain areas.
Cheers.
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see above
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@Fatemeh,
The attached excel file may be helpful, but just for uniform trapezoid channels.
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Nutrient removal
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HRT is not a critical design and control parameter to consider but solids retention time (SRT). This is depending upon the wastewater temperature. For example a total SRT of 10-12 days would be sufficient at wastewater design temperature of 20oC whereas total SRT of more than 20-25 days is needed at 10oC. Anoxic and aerobic SRTs are depending on feed wastewater quality, target effluent nitrogen configuration and process configuration. IWA based simulation models (i.e., Biowin, GPSX) are available to determine anoxic and aerobic SRTs.
Design engineers provide adeqaute tank volume to keep the biomass in suspension and allow proper mixing and oxygenation all of which dictate the minimum HRT. Although HRTs may vary, typical minumum anoxic and aerobic HRTs in MLE systems are 1.5-3 and 6-10 hrs.
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Civil engineering, hydraulics division.
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Dear Ahmad Alghwail,
Depends on the purposes.
There are some elements of counterflow in the construction given by Peterka in Section 6 as Stilling basin for pipe or open channel outlets, described as impact energy dissipator. The other you can see in JHE Johnson и Dham (2006) where it comes to back splash effects.
1. Peterka, A. J., (1984) Hydraulic Design of Stilling Basins and Energy Dissipators, A Water Resources Technical Publication, Engineering Monograph No 25. Eighth Printing: May 1984. USBR, (1987) “Design of Small Dams”, Third Edition, US Government Printing Office, Denver, Colorado: 1987.
2. Michael, C. J., R. D. Dham, (2006) Innovative Energy-Dissipating Hood, Journal of Hydraulic Engineering, ASCE, August, 2006.
I could orient you only according my practice. I had made several stilling basins or energy dissipators using some element of counterflow. Stilling basins for horizontal Tel Hosh Dam - Syria, Iadenitza Dam - Bulgaria, and for vertical cone (cylinder) valves Rakov Dol Dam - Bulgaria, two levels stilling basin Jebel Dam - Bulgaria and etc.
If you can give me some details maybe I can give you more information. There are some Russian constructions; several are mine I have tried to prepare a criterion for effectiveness of the stilling basins. Some of mine publications are in Bulgarian.
3. Tadger, J. (2007) Hydraulic Jump Effectiveness and their Influence on the Design Process of the Stilling Basins, Jubilee Scientific Conference of UACEG, Sofia, 2007.
4. Tadger, J. (1999) Howell- Bungеr valves and some conceptions of their stilling basins’ structures. Aniversary Scientific Conference, 50 Years Faculty of Hydrotechnics at the University of Architecture, Civil Engineering and Geodesy, Sofia, 6-8 October 1999.
You have to have in mind the cavitation problems because more of these constructions are given without cavitation model investigations.
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I am using the UASB reactor but it seems not working effectively. The wastewater has COD=4000 and BOD=400.
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Hello Hoang - as the other contributors have remarked there are a number of AOP options such as ozone, fenton, elecetrochemical, etc that can be used. In general the decision on which to use would be based on a number of factors that are often site specific. For example the final discharge limits required are important to consider, the downstream treatment technologies etc. In general I would advise a batch experiment if possible to see which AOP process might be most effective.
These papers might be useful "Removal of Organic Matter from Landfill Leachate by Advanced Oxidation Processes: A Review" by Li et al. and "Coupling anammox and advanced oxidation-based technologies for mature landfill leachate treatment" by Anfruns et al.
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I would be grateful for any suggestions.
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I think the method in your Excel sheet is for reservoir routing rather than flood routing in a channel. I did not work on that, I can not help.
Amro
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I have an interest and at the same time I need to get an information, helps and cooperation or other comments about the future of water engineering.
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Dear Bashkim,
your question should be divided to more than one question. I dont know what hence is your mean, but with deficiency of water in all over the world the water engineering will be more scientific and more proficiency with all of details.
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What about after constructing?
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I believe your question is relating to soils with soluble salts. All such areas where soluble salts are present in soil and irrigation is to be introduced must include drainage as integral component. Surface irrigation with inefficiency will have every chance to lead to soil salinity problem over a period of time and needs to be taken care of. Planning and execution of main drains (which may also act as escape canal) at the time of construction of irrigation canals may be advised as economic, however, secondary and tertiary level drainage can be introduced at the time of problem actually faced to make it more economic.
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