Water Engineering - Science topic

"Researchers are hunting for new ways to strip salt from water as the world’s freshwaters are becoming more salty and industries are producing more briny waste. Current methods are often energy-intensive or create problematic waste. Some scientists are using electricity to pull salt from water through specialized membranes. Others are working with a solvent that traps water — but not salt. With battery-makers clamouring for lithium-rich salts, future desalination companies could even turn a profit selling salts while offering clean water as a free byproduct..."

Thank you from my heart, dear Jamel; I did not tell you that I visited Tunisia probably 20 times or more during the PLO stay there. In 1982, I and 3 other colleagues came up with the idea of establishing an organization for Arab Human rights. I was in charge of sending the invitations and answering the questions of everyone who feared attending. About 30 distinguished personalities met at Al Hammamat at the Institute for Social Studies and issued a statement after difficult discussions. But we caused the director of the Institute, Dr. El Taher Labib, to, unfortunately, lose his job.

Thanks a lot!

Hello dai, you can check this thesis, regarding the use of DSSAT

The phenomenon in the difference in pile settlement along the length is typical for long piles. Especially this phenomenon occurs in long bored piles.

Sig

SAP2000 has two types: Student version and professional version. The latter is better as it has considerable capacities and it is adaptable for the design and calculations of great structures.

Other software such as AutoCAD 3D, FLAC 3D, ANSYS, ABAQUS, HecRas and so on, can be used. It should be noted that any software has its peculiarities. The selection depends on what you want to achieve witch accuracy! Sometimes, you can use 2 software to compare the precision level of the results!

This is a good question.

Excellent question flagged here. Would be eager to know more.

follow

you can use the following link to search the related journals

https://jcr.clarivate.com/JCRLandingPageAction.action?Init=Yes&SrcApp=IC2LS&SID=H4-QgqmTkTHLg5K2FckC2OpCXFlrDhMYOx2Bn-18x2dhFz2PourQgcILyGpmx2Fh9wgx3Dx3DnSEsVHix2BV4sFX4Dacv2RVAx3Dx3D-WwpRYkX4Gz8e7T4uNl5SUQx3Dx3D-wBEj1mx2B0mykql8H4kstFLwx3Dx3D#

Dear Hanif

You can try to these journals:

1- ISH journal of hydraulic engineering

2- Modeling earth system and environment

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.

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:

http://www.pure-earth.com/softcalc.html

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...

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.

Some more links about Matlab code. 

Hi

I hope this may help,

Kind regards

Refer to manufacturer for the FO module

Reverse Osmosis is the commercially available and quite cost effective technique

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.

Hi, I do not know

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

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:

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).

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

Thanks Ms. R Schirhagl.

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

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.

Don,

1894 book with penstock waterwheels if you have not found it yet. PDF with text smaller and still retains good images.

JAG

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

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

See attached publication.

Best wisches,

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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

Damen is a well-known dredger manufacturing company in Gorinchem, the Netherlands.

 I'm sorry but your question is, uncertainty

in the condition of high temperature, it may be produced some kind of acid, butylic acid, propionic acid and acetic acid.

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.

Thanks Mr. Kushal for your valuable input.

Terminalia chebula of Combretaceae family could be helpful in reducing ground water hardiness.

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.

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

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.

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

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

Thus, your membrane might be contaminated by fluoride anion? Try to pre-wash it with NaCl 

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.

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

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. 

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!

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.

@ Dear Dr. Telvari,

It's probably too late to answer, but go through this recently updated Q:

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.

It spent three $6000 for laboratory equipment in China. 

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

I think it is different, because the stability of the submerged groynes material is different with not submerged groynes.

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.

Thank you so much for your response. Is there any manual or guidelines for sampling Methods and analysis. 

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

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.

Some time, we may not get optimal solution. 

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.

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

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.

Another suggestion, something like

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.

@Fatemeh,

The attached excel file may be helpful, but just for uniform trapezoid channels.

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.

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.

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.

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

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.

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.

Hi Chitta,

SBRs are best suitable for low wastewater volume, needs to be automated (cycle control), better for high load and to control filamentous growing (in highly degradable wastes), not suitable for wastewater containing toxic substances (no possiblity to equalize the toxic load to appropiate levels). It works like a plug flow reactor in time instead of space, so it basically has all the advantages of this kind of flow.

Continuos reactors on the other hand can be design to work in complete mix regime or plug flow and are best for higher wastewater volume.

Anyway, to answer your question about which one is more often used: continuos reactors.

I hope the answer helps you.

Dear Talib,

Do you know the EU-project 'Water in Historic City Centres'? It run between 2003 and 2007 with partners in Belgium, the Netherlands and UK.

Goal of the project was to reopen old canals in the centre of the participating cities.

If you are unable to use a pump with smaller nominal flow rate, or you have not the possibilities of reduce the speed of rotation, I think you will applicable only a "creative ways"...

One such the "creative ways" is to dividing the flow of liquid downstream of the pump into two parts. Next - experimentally - can adjust the flow rate of the two streams, so, that one of them will be identical to what you need, and the other - redundant - can be returned to the original container of the liquid.

www.qc.cuny.edu/.../2012%20Blanford%20and%20Gao%20JEM%20D...‎