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Water Quality Analysis - Science topic

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Physical, chemical and biological water quality analysis
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  • SELECTION OF SURFACE-WATER SAMPLING SITES
  • The study team is responsible for selecting sampling sites, including the specific point(s) or transect(s) at which samples will be collected. The guiding principle for site selection is that data can be collected that accurately represent the intended conditions (such as time of year and flow rate or stage) of the aqueous system being studied with respect to study objectives. Generic guidelines for selecting flowing water and still-water sites are described in this section.
  • Each body of flowing and still surface water has a unique set of conditions that needs to be identified and considered in the site selection process.
  • Field personnel must be trained in the correct and current water quality data-collection procedures and must exercise judgment gained from field experience to make site selections.
  • Careful and complete documentation of site information and the data collected must be input to electronic and paper files. In most bodies of flowing or still water, a single sampling site or point is not adequate to describe the physical properties and the distribution and abundance of chemical constituents or biological communities. Location, distribution, and number of sampling sites can affect the quality and applicability of the resulting data. When selecting surface-water sampling sites:
  • Consider the study objectives, types of data and quality of data needed, equipment needs, and sampling methods.
  • Obtain all available historical information.
  • Consider physical characteristics of the area, such as size and shape, land use, tributary and runoff characteristics, geology, point and nonpoint sources of contamination, hydraulic conditions, climate, water depth, and fluvial-sediment transport characteristics.
  • Consider chemical and biological characteristics of the area (aquatic and terrestrial).
  • Note the types of equipment that will be needed.
  • https://pubs.usgs.gov/twri/twri9a4/twri9a4_Chap4_v2.pdf
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Hi everyone, I have a question regarding the determination of dissolved aluminium by colorimetric method using pyrocatechol violet according to ISO 10566:1994. In the preparation of 'mixed reagent', we have to add 5 mL of the aluminum standard solution (10 mg/L) into 100 mL of this mixed reagent (total volume).
My question is:
- What is the role and function of the addition of standard solution for this method? In this standard it only says "accurate addition of the aluminum standard solution is essential in order to allow a linear calibration at low concentrations".
Note: if we calculate the concentration of this aluminium standard solution in the sample is about 15 µg/L.
Thank you for your answers.
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This is a typical calibration procedure. You will need multiple concentrations to develop a quantitative response relation that you will use to estimate concentrations in your samples
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Alklinity can be calculated by titration of acid on pH endpoint. I have a data set with bounches of water quality parameters, only without Alklinity. Is there a way to get Alklinity only by calculation from other parameters (pH, TIC, Dissolved CO2, temp, and cations, onions, ect.)
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The following H and OH ion calculation procedure may also be seen.
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Several methods have been suggested in many studies
One of these solutions is to use the guidelines
Which of these guidelines are used and can they be provide (Name , Lien, PDF...) to me?
Thanks
Azzeddine
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Excess of fluoride content in drinking water (more than 1.5mg/L) sourced from inland water bodies causes dental fluorosis and skeletal fluorosis. Although reverse osmosis (RO), electrodialysis, and distillation are available for deflouridating inland water bodies. However am not sure that how effective these methods can be used to deflouridate groundwater. I would like to hear some suggestions on the mechanisms effective at deflouridation of groundwater.
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Deflouridation techniques are simple and can be explained like Bone charcoal, contact precipitation, Algona, activated alumina, ion-exchange technology, membrane filtration, nanofiltration, and clay are all methods for defluoridating water that can be used. Reverse osmosis (RO), electrodialysis, and distillation are examples of cutting-edge treatment methods.
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We are seek alternatives to Qual2kw in water quality simulation models based on R program. Present day, we use .xlsx based model. Our objective is calibrate/simulate water quality scenarios of river, with point/nonpoint sewage sources. Thanks a lot!
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Thanks a lot, Jochen Hack! Your answer is helpful.
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Water quality analysis is a costly affair where a large number of parameters are involved and each parameter requires a significant number of samples to be analyzed.
How we can quality check the data values when only one sample is analyzed for each parameter?
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Dear Nirankar Singh,
One sample is not enough to represent the water sample that you are analyzing, Remember that composition of water (both physical and chemical) varies at different sampling point/location in the water body. It is advisable to take at least 3 samples, and even replicate the samples to be sure of your results.
Even the multivariate analysis (PCA, HCA, etc) mentioned by Mostafa F. Mostafa can only be achieved when you have a substancial data to give precise variations in the water compositions.
Regds.
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I wanted to ask that if we have to develop a modelling tool to anticipate the impacts of weather extreme events on the water quality of a lake but the amount of information collected in the field is scarce. What kind of models would be better to use and which are the natural processes we should include in the models. Please guide me briefly if possible.
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I think mike she will be best suited for integrated hydro metrological and water quality modelling purpose
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600 mg/ lit in waste water.
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What should be the optimum vale of nitrogen (in ppm) in activated sludge system.
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Please, can you suggest a high graphical resolution software for creating hydrogeochemical graphs, especially for Gibb's diagrams?
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Much chemical process modelling and/or simulation work can be done with the widely-used Microsoft’s Excel.
Application example ― Simulations carried in Excel 5.0 with Visual Basic for Applications (VBA) macros ― The recursive least squares algorithm (RLS) allows for (real-time) dynamical application of least squares regression to time series. Years ago, while investigating adaptive control and energetic optimization of aerobic fermenters, I have applied the RLS algorithm with forgetting factor (RLS-FF) to estimate the parameters from the KLa correlation, used to predict the O2 gas-liquid mass-transfer, while giving increased weight to most recent data. Estimates were improved by imposing sinusoidal disturbance to air flow and agitation speed (manipulated variables). The power dissipated by agitation was accessed by a torque meter (pilot plant). The proposed (adaptive) control algorithm compared favourably with PID. Simulations assessed the effect of numerically generated white Gaussian noise (2-sigma truncated) and of first order delay. This investigation was reported at (MSc Thesis):
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Dear researchers,
Does anyone know how to use BASINS for Water Quality Analysis Simulation Program (WASP) model? Since the database in BASINS is mainly from US, how can I apply it for other countries or area?
Thank you in advance.
Regards,
Khaliesah
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Maybe this information could be helpful. It has been several decades ago when we used BASINS for some of our watershed analysis on US and local National Forests, and I probably do not recall all the specifics. As I remember, EPA uploaded all their (including local, county, state and agency) georeferenced point and non-point pollution data and overlaid the basin and watershed boundary coverages such as those developed by the USGS as appropriate, so it could be interrogated for watershed type analysis or other uses as project planning or addressing water quality questions, classifications or uses. I would assume it to be a major work to expand elsewhere, but perhaps your resource agencies already have this information uploaded into their management or GIS data base, and might make it public for use, analysis and application. As I remember our use of BASINS involved more for qualitative watershed analysis condition and rating, and did not necessarily address quantitative analysis of water quality. Some locations are data rich, others lack quantitative specifics. I don’t remember if it included land use, but we also used that, as well as any specific information we had accumulated. I cannot remember the titles of a couple documents I put into Researchgate that likely used some of BASINS information, but one was Indian Creek Watershed Analysis, and another had to do with Watershed Analysis for National Forest Planning.
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Hello all! What equipments are used to identify chemical and biological contaminants and measure their concentrations in a water? Thank you
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Modern coupling techniques are widely used for the determination of chemical contaminants, for example: GC / SM-SM; HPLC / MS; IRTF / MS, UV-VIS
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I am researching which wavelength I have to select to detect the metals gallium (Ga) and zirconium (Zr) by inductively coupled plasma mass spectrometry (ICP-MS), but it is being difficult to find. Does anyone have any material to share?
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Hello. Which matrix do you have for the analysis planned?
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Hello, I'm new to Fuzzy Logic System and i want to learn prepare dataset for fuzzy logic.. I have data for physicochemical parameters of a river. usually, I'm using physico-chemical water parameters for assessment of water quality. Actually, the things I want to ask are for advanced users, but the only thing I need now is how can I adapt the data I have for fuzzylogic (MATLAB) or how do I transfer parameters consisting of 17 columns to fuzzy logic? Thank you in advance for your help.
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im waiting your mail
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I am interested in hearing about the experiences from researchers who have successfully used Google Earth Engine (Python Version)for water quality determination (chlorophyll, turbidity etc.).
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Hatirzhil Lake: Water Quality estimate of turbidity through NDTI using the Google Earth Engine Platform. The higher value of turbidity yields a high value of NDTI and vice versa. It has also been reported in the literature that relying on a single band or algorithm sometimes results in overestimation or underestimation of suspended sediment concentration(Kuhn et al. 2019; Pahlevan et al. 2019)
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Beryllium is exceedingly toxic and known to interfere with Human enzymes.
Analysts have developed techniques to measure Beryllium in parts per Quadrillion.
Beryllium is present in Fluoride industrial waste dumped into drinking water supplies in Australia, measured by one supplier to be 95 gram per tonne (see attached analysis).
I wonder if anyone has studied the concentration of Beryllium in drinking water, its absorbed dose range and risk factors for various diseases, including cancers, as a result of this "Fluoridation" waste disposal? What are the effects on the Human foetus?
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Dear Prof.Geoff.,
It's a nice discussion. I have never heard that the effects of Berrylium at a certain dose can cause a lethal effect on human health and containing some carcinogenic effects upon the human cells.
Beryllium has some useful but undoubtedly harmful effects on health and well-being. Measures need to be taken to prevent hazardous exposure to this element, making its biological monitoring in the workplace essential.
Regards,
Md OSim,India
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What reference studies (Book, Article, Tesis etc) you know used ER Method was applied using the Vertical Electrical Survey (SEV) technique (Wenner-Schlumberger, dipole-dipole arrays) for definition of intrinsic vulnerability index to water contamination underground?
Are there any studies that have used this method to set parameters for analyzing groundwater vulnerability to contamination por geoelectric layers?
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Hello,
Our lab is currently adapting a previous working method (designed for the Turner TD-700) for the quantitative analysis of chlorophyll-a in water by fluorescence to be used with a new instrument (Cary Eclipse Fluorometer). Details in full about the method below. In testing our new method, we were able to produce a reliable standard curve up to 100 ug/L chl-a with a raw fluorescence of 781 (Attached Fig 1.)
In order to test this method with environmental samples, we prepared filters of increasing filtered volume from a single collected sample (e.g. 1 filter @100ml, 1 filter @250ml, 1 filter @400ml, etc). My thought was that we would see a proportional increase in fluorescence, based on filtered volume (i.e. the 400ml filter would have ~4x the fluorescence of the 100ml sample.) Instead, we saw what looked like quenching (or at least reduced fluorescence) around the 400ml mark (raw fluorescence ~500). Our 600ml sample had roughly the same fluorescence as the 400ml sample and our 800ml sample had significantly lower fluorescence than both of them etc. (Attached Fig 2.)
We do not see any similar effect in our standard curve and the fluorescence reading for these samples are well below where our standard curve tops out. Has anyone ever seen a similar phenomenon? Do you know what causes it or how to fix it?
Brief Method Description:
Water samples are filtered on GFF filters and stored with desiccant in a freezer. Samples are extracted in ethanol in a dark environment. Extracted samples are excited @434 and emission is measured at 673 nm.
Thank you.
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My guess is that you may be seeing an inner filter effect, whereby the absorbance of excitation and/or emitted light by the sample reduces the fluorescence intensity. To avoid this problem, dilute each sample with solvent so that they all have the same absorbance at the peak absorbance wavelength, preferably less than 0.1. Then correct for the dilution after measuring the fluorescence.
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Am doing my research on impact of urbanization on surface water quality. I want to compare the impact the last 30 years with the current and to forecast future deterioration of lake water quality. I do analysis the current water quality for different parameters by taking samples and analysis in laboratory.
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Dear Nega,
The question you asked depend on the region of your study location. If its under the government authorities they may analyze water quality for determine the current condition of quality of water regularly. Further, some publications have raw data or you can request raw data form that authors.
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What is the most economical and efficient method of analyzing surface and underground water quality?
Especially nitrate, thermotolerant coliforms, Total Dissolved Solids TDS.
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I think that the EPA National Service Center for Environmental Publications: nepis.epa.gov is a good choice on economic methods
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Am doing my research on three water supply reservoirs concerning impact of urbanization on water quality of these reservoirs. I want to use modeling.would you please suggest me what kind of modeling shall use?
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You can use QUAL2K, it is the revised version of the QUAL2E model developed by the US Environmental Protection Agency.
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Wetland is very important however it is now degrading conditions due to anthropocentric and industrial pressure at many status and cities. we have baseline data of some of the wetland of Vadodara District
thank you
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offcourse......I have ready a review paper for leading journal.
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Bottle drinking water contained many floc. What is the reason? This water produced from fully automated systems.
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Normal flocs which form during coagulation-flocculation in alum treatment can be removed by sand filtration. But some flocs form in bottled water, reason is not clear how it can be removed. Please find out it.
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I am currently working on black-water events that occur in reservoirs (south China) in certain times of the year. The sediments in the reservoir contain manganese and iron content. Apart from analysis of DOC (dissolve organic content) in the reservoir, i want to investigate the role microbes and bacteria play in this phenomenon.
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Nice discussion...
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I have 7 years of data outputs for a model I ran to test water quality response to Phosphorus loading. I have base model outputs as well as manipulated model outputs (in which I increased Phosphorus loading). The watershed is broken into 31 sub-watersheds and I am looking to find which sub-watersheds are most sensitive to Phosphorus loading. I have begun performing linear regression of base~manipulated outputs and am not seeing the results I expected. Is there a better way to analyze the sensitivity of manipulated model outputs for large data-sets?
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Change the Xs a little bit and look at the corresponding change in y. You might also want to try a plackett- burman experimental design. See the attached file. Best wishes, David Booth
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I just want the name of the methods....
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If you fix it with %30 formalin it is not possible...
All best
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What is the best (easiest, cheapest) way to get degassed water to run some hydraulic measurements? I currently use a vacuum pump but it takes some time and it very noisy.
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I have always wondered why one would want to use completely degassed water. It makes no sense. You just need to remove large air nuclei (someone should calculate and measure which size class of air nuclei changes resistance). I think the main goal is to remove any large gas nuclei so that you are not introducing bubbles to bordered pit fields while perfusing, which may increase R. Since degassed water does not exist in the xylem system, using completely degassed water may even remove gas from the plant hydraulic system during perfusion since the water in the xylem should be in gas equilibrium with the surrounding tissue. Furthermore, I notice that many go through the pain of the degasding procedure, then pour the solution into a container which regasses it and then this solution sits for hours, sometimes longer, and thus allowing gas to diffuse back into the perfusion solution. With that being said, I use autoclved KCl solution, that I then put under vacuum using small amounts of solution at a time. Using a 60 cc hydraulic syringe i lock off the tip with a luer loc then pull back the plunger and agitate the system, repeat several times until the bubbling stops. Each time I push the air out, then relock it etc. Then i attach my syringe to the big hydraulic system and slowly push the fluid into the hydraulic head container that is closed in a plastic bag system (sort of like a baby bottle) to reduce contact with air. I am using a SSFM or pressure transducers to measure deltaP across a hydraulic resistor system. For me, I am really only concerned with having any bacteria and reducing the abundance of air nuclei as much as possible in my perfusion solution. Seems to work.
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Blue, green and red - how does the reflectance change in turbid water compared to clear water?
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...and here the graph of spectral reflectance of water in aquarium tank, i.e. still waters without turbulence, please have a look at the attached jpg. If compare with previous image, there is difference in the diapason of wavelength 700-800 nm (in this case decreasing). But one should consider other possible environmental factors. You can find more graphs in my MSc Thesis.
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I have collected a sample of water from a small stream for a section of my masters dissertation but I am struggling to find literature regarding whether or not the water is of good quality quality/polluted or not, as I have little experience with water quality. I have compared them to guidelines, but need to know more information about their levels actually signify
These are my results:
Magnesium - 0.5ug/l; Copper - 3ug/l; Maganese - 0.1ug/l; Cadium - 0.9ug/l; Lead - 7.1ug/l and nickel - 18.8u/l
I am also struggling with my results for ammonia N-NH4 (0.42mg/l); nitrate NO3-N (0.1mg/l) and SRP PO4-P(0.13mg/l)
Any help or references towards papers would be much appreciated
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Choice of water quality parameters is guided by intended use e.g drinking purpose, irrigation purpose, industrial use (say boiler), environmental discharge, surface water body, bathing purposes (swimming pool) etc. Countries have different sets of max permissible limits of parameters for different uses. I am not sure exactly for which purpose the parameters are sought. However, in general the parameters like pH, EC, BOD, SS (suspended solids), and coliforms play important role to assess water quality. Ample literature are available. The problem is when for a particular intended use say, 7 parameters are within permissible limits and 1 is beyond the limit, then defining suitability is confusing. Some water quality suitability indexes have been attempted using several parameters, yet I am not very confident. If someone can put more light on that.
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Water Quality analysis 
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pH of Ganges water varies from 6.5-8.7 however it may not constant because different types of contaminants are soluble in this water so that pH is not constant some time weathering of rocks like limestone which soluble in this water to form a carbonate and bicarbonate ions, it causes acidity of water & some times industrial discharge goes to Ganges water and this water may be alkaline.
On the basis of this above reason pH of Ganges water varies.
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I want to estimate the sulfide concentration in the wastewater. What is the sensitivity of methylene blue method (detection limit - how much ppm?, maximum how much i can quantify the sulfide?). Please anyone suggest easy and reliable method for sulfide estimation in the wastewater containg high sulfide concentration.
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Check first the Standard Methods for Water and Wastewater analysis....then chosee.
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Ground water, surface water and wastewater always contain dissolved solids. Most of researchers used electrical conductivity (EC) meter for measuring dissolved solids. But the results are always different from that measures with gravimetrically. Question arises, how to testify, which one is authentic.
Gravimetric method is time consuming. If we use EC meter, what cares may be taken?
Is ion-balancing is of some use?
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The answer is clear: only the gravimetrically determined method provides reliable results. The EC/TDS method is a calculation using a conversion factor which ranges from 0.25 to 1.34 [µS/cm and mg/L] . If – and only if – you predetermined the conversion factor for a given site THEN you can use the EC/TDS ratio and it will also be reliable. Please see my paper
Hubert, E. & Wolkersdorfer, C. (2015): Establishing a conversion factor between electrical conductivity and total dissolved solids in South African mine waters. – Water SA, 41(4):490-500, 6 fig., 8 tab.; doi:10.4314/wsa.v41i4.08.
for details and more references.
So, to answer the last part of your question: determine the EC (at 25 °C = κ / TDS ratio for several samples of your site(s) using the gravimetrical method (ensure you calibrate your EC meter) and then use this factor f to calculate TDS as follows:
TDS [mg/L] = f × κ [µS/cm]
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Bihar is the states that is recognized widely as highly affected with Fluoride in drinking water and affected with Fluorosis. A test conducted an on-the-spot of underground water confirmed the alarming presence of fluoride content which has caused physical deformities and accelerated the ageing process of the villagers. I am looking for the solution for this issue and hot spot locations? Suggest me where I can get the relevant data?
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Dear Vikram,
Please also have a look at these useful PDF attachments.
Good luck!
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Hi everyone,
I have analyses the on-site and major and trace elements some river water samples , and now I want to calculate several water quality parameters like pollution index, water quality index, metal index, ..etc. In the equations I encountered variables like Si and C0 to calculate the Pi and Cf values. I wonder if they are the same or different meanings. Also can I calculate pollution Loading Index (PLI) for water samples, not the sediments.
Thanks in advance
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Hi Mohamed,
yes, you can calculate heavy metal pollution index (HPI) . Please find the paper attached by Al-Hejuje et al (2017 )
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I'm about to do a water quality analysis, I was wondering which model to use?! WASP, Ce-Qual-W2, Mike ?! What do you recommend?
What are the advantages and disadvantages of WASP over the others?!
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I have studied all the publications suggested by my colleagues- what I feel is both the publications suggested by Dr Anoopkumar are important , the WASP model would be relevant- can be used by you.
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I want to do water quality analysis using Landsat images. Can anyone help show me how to estimate Chl-a from the Landsat images? In-situ data is required for this analysis or not?
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@Konuko, there are several globally developed Landsat chl-a algorithms found in literature that you can use to estimate chlorophyll. Fin attached one document I recommend you to read
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I'm working on retrieval of turbidity from remote sensing approach and for validation want to compare in-situ data with satellite derived product so need conversion of NTU to mg/l.
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I think the national turbidity unit and FTU are the only way to describe the turbidity of the solution
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Generally we use WQA for drinking water using WHO standard or national water quality indexes. Some countries also following river water quality analysis as per plankton, algae, benthos and invertebrates (aquatic flora and fauna. Fish species and their feeding ground would be the another parameter we can assume for WQA. Besides these what are the scientific standard as we can use the best method for river water quality analysis?
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Dear,
For assessing water quality and pollution levels, I recommend the following parameters to be measured in water; pH, turbidity, ammonia, nitrite, nitrate, salinity, total phosphorus, total nitrogen, DO, BOD, COD, toxic heavy metals (e.g. Pb, Cd, Ni, Cr) and crude oil. This will cover the impact of agricultural, industrial and domestic activities on water quality.
Regarding the threshold limit of these parameters in water or others, you will not find all identified in the WHO law or in other laws. You can propose a threshold limit for the non-identified parameters in water and this will be value added. Use the impact assessment to set the limit and verify your result. Correction coefficient analyses between the parameters that their threshold limits are identified and the non-identified ones are helpful for this.
Good Luck,
Ahmed
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I found a variety of methods in the literature (single representative pixel, mean of 3X3 pixels, etc). Has anyone done a comparison?
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Hi Gwen
What do you want to evaluate specifically?
There is no ideal method of sampling. It should be chosen based on what you specifically want to evaluate, to reduce the occurrence of gross and problematic errors in each case. For example: can depth affect the variable you want to measure? What is the natural variability of the variant you want to estimate? Temperature usually has less spatial variability than turbidity or the content of algae and microorganisms.
Anyway, the ideal method will depend on what you intend to evaluate, quite specifically. Search the literature for studies that are as close as possible to yours.
Hugs, Luís
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Could you please anyone can suggest me,
what are the Best field testers (instruments) low cost price for pH, EC, TDS, Temperature testing in the water?
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We use for fieldworks horiba U-52(53). multi-parameter water quality meter
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We recently aproved a grant for a project, and now we are searching the best equipment. Besides the already mentioned parameters, analysis of water hardness, nitrates, nitrites and phosphate would also be welcome. Some collegues told me already about equipments from Horiba and Hanna. Other suggestions?
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hello
I recommend НАСН products to measure water pollutants
regards
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-Have anyone quantify the sensitivity: contribution of temperature and precipitation in long-term algae biomass variation?
-In other words, how much more algae blooms would we see in the future? 
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Good information but it is unpublished.
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If we use phosphate solubilizing bacteria as biofertilizer in farms, may this bacteria cause adverse effect on natural ecosystems like rivers and lakes?
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Such effects need to be evaluated only in terms of inorganic - P as phosphates as a measure any possibility towards process like eutrophication , not as PSBs as pollutants.Such PSBs would play in scavenging inorganic phosphates , in case , P is in surplus...
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Hey, I would appreciate if somebody help me “what is the Max permissible limit for Na+, Ca2+, Mg2+, K+, Ca2+, Cl−, HCO3−, in drinking and irrigation water according to WHO standard. Thanks
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I have a 350 ft borewell in my home. Physio- chemical parameters were analysed for the same. Almost all the parameters are above the permissible limits. I have attached the analysis report for more details. TDS  is 3220 ppm, Total Hardness 1350 ppm, also facing with odor problem . I want to make this water safe for daily utilities bathing, dish-washing and clothes washing. can we use any chemicals or Is there any alternate solutions?
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Hi Jaya,
Coagulation is key. I would prefer you conduct a Jar test to know the amount of coagulant (Alum, Ferric chloride)  that is necessary. This is a cheap process compare to the more technical and fairly expensive membrane process. I would also advise you check the breakpoint chlorination to prevent unnecessary contamination with excess chlorine.
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parameters are Temperature,PH,Conductivity,Turbidity,TDS,Salinity,Dissolved Oxygen,BOD,COD,Hardness,Nitrate,Phosphate,Total coliform and Fecal coliform
Is the same model can apply for surface and ground water quality?
Is there any universal standard method available for this?
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here you can find the calculation of water quality index for ground water
regards
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What parameters should be included?
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Computation of WQI of groundwater - Please see the attached paper.
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I want to have some reference materials regarding the physico chemical parameters ( pH, salinity, conductivity, depth , nitrate , phosphate , DO, BOD , chlorophyll a concentrations, , COD, sediment carbon, sediment pH, sediment conductivity, texture) and environmental conditions preferred by several species given in word document.If you have some information that will be much helpful.
Thank you.
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please see the information that provided by DR. Ton
thanks for sharing this Atlas.
regards
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I have been unable to find anything that seems to even remotely answer this question.
Doesn't have to necessarily be a precise method; approximation would suffice.
Lake - BOD: 1.31, DO: 10.54 (mg/l)
Effluent - BOD: 20 mg/l
I realise that factors such as temperature and pH will come into it, and I do have some data for those... 
Dilution is also to be considered separately via CORMIX modelling. 
Thanks 
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So the biological oxygen demand of you effluent is 20 mg O2/litre of effluent - that means 1 litre of effluent will consume 20 mg of oxygen during 5 days of incubation at 20 °C. Say you had a 1 in 10 dilution (ie 9 lake and 1 effluent) you would have  a BOD of (20 x 1 plus 1.3 x 9) = 31.7 mg O2 demand. Your your lake water contains 10.54 (mg/l) (we'll have to assume the effluent does not contain any DO), so your mixture would initially contain 9 x 10.54 mg O2 (or 94.9 mg). Very simplistically, the DO, if all the BOD is realized instantaneously (unlikely) and lake is at 20oC (unlikely where you are), would be 94.9- 31.7 or 63.2 mg or 6.32 mg/l. So you will have to model the dilution to get the answer (ie at any one point you will need to know how much effluent is present per unit volume of receiving water and either make assumptions or model other factors such as kinetics of BOD, temp effects on DO and BOD kinetics, primary production inputs etc). BTW 20 mg/l BOD is pretty low strength effluent so I would imagine only very localized impact if there is good mixing. Hope this helps
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I am measuring NO3- in drainage waters from arable fields and for some drainage samples the sensor is dead on the true value from lab analysis, while some other samples results in it measuring too much
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I have YSI 1300 for wAter quality parameters such as ( ph,EC, TDS,temp).
I don't have NO3 sensor but It's easy to measure it by spectrophometer. 
But you need to calibrate it before using with drainage water samples may be the detection limit s or the concentrations of NO3 is very high or very low and this make the problem to sensor.
So try to calibrate it before using in the field samples
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There is a stream/river with permanent white (milky) water color in Southern part of Blue Nile, Ethiopia. The Gumz tribes living around it call this river " Impua Aya" in their language. Impua mean "White" and Aya " Water" in English. The color of water doesn't change with time and space according to the people who told me. I appreciate any one who can tell me the probable causes for the permanent whiteness (milky) color of the water of this stream.
With kind regards.
Kassahun Birhanu
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Thank you Sir for your answer
kind regards
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I am looking for best ways to analyze data for water quality parameters, pH, conductivity, TSS,TDS, COD, SS, Salinity, Zinc, ammonia Nitrogen NH3, cloride, turbidity, and Total and free chlorine residual, Total coliform and E.coli, what is the best test in statistics and best method to follow to analyze, the water quality is for harvested rainwater.
Thank you 
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 Thank you so much for all answers, but how to recognize to use the best STAT analysis, I mean to use Descriptive data analysis, or t-test one sample t-test or two samples t-test, or  one-way ANOVA test, or PCA, or multivariate as I have many water parameters and I want to compare it to WHO standards so how to chose the correct and best test, as my water samples are from harvested rainwater tank, any further suggestions, please, Thank you?
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The colloid is stick on cation Al+3/Fe+3  or them is stick to colloid?
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I agree with Farooq,
... but let me add some text to point out what to look for....
DLVO theory will explain that trivalent ions may absorb onto your colloid, but their effect is mostly in raising the ionic strength of the dispersion, thereby compressing the double layer of your colloid. If the double layer is sufficiently depressed it looses its function in stabilizing the colloid and thus aggregation will occur. The ionic strength can be calculated with this formula:
Ionic Strength(I) = 1/2 * ∑ z² * c
Where,
Z = Valence of the species
C = Concentration of the species
Since Iron and Aluminum are trivalent and the valence is raised to the power 2, they are nine times more potent in depressing the double layer thus causing aggregation or flocculation of dispersed colloids.
Kind regards, Leo
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I would like to know what would be a good method development for the analysis, as my previous method has resulted in no results appearing for the Mg analysis.
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Hi did you check APHA method ? APHA chapter 3120 - Metals by Plasma Emission Spectroscopy, Method B - Inductively Coupled Plasma (ICP) Method. 
Here is the link, hope it helps.   
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and i wish to apply for the same
i am in need of an US personal to be collaborated with me in this project
anticipating the best from you
thanking you 
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Dr. Kumar, Consider contacting the University of Washington, Department of Industrial Hygiene, Seattle WA USA. You could ask them if they might have a masters degree student or several students to cooperate with you. They might be the best on on air quality, and are very good on other pollution subjects. Likewise they are in the same university with a large fisheries school. Good luck.  
PS: Maybe Emeritus Professor Lee Montief is still there and you could ask him to direct you to the appropriate person in his institution.  He might remember me as Dr. Lewis E. (Mac) MacCarter, former MPH student.  I am sorry that I do not have funding to offer to collaborate with you myself.
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In laboratory test, COD value is obtained with minus value.
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The only way that the value could be negative is if oxygen increased in your incubation. This could result from several errors, but most likely light was allowed to penetrate your bottle allowing photosynthesis to occur, otherwise you have to check the calibration of the instrument.
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I am studying the treatment on drinking water from an undergound water source. It is high in Fe2+ and Fe3+ content. The drinking water that is supplied to residents is full of Ferric chloride that leaves significant stains on clothes and other items.
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I am new to piper plots. After going through reviews for freeware available to plot water quality data, I found Grapher to endorse an easy UI for novices such as me into piper plots. However,  am unable to understand the exact procedure as to how may the percentage of cations and anions be normalized to 100 before plotting the graph. Answers and suggestions for alternate freeware with plotting SOP are most welcome.
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Just divide each ion (in milliequivalents per liter) by the total summation of ions (either cations or anions) and then multiply by 100
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We would Iike to determine water quality  by measuring the reaction of bioluminescent organism when they are added to a water sample.  Can anyone provide us with a reproducible procedure?
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 Thank you to everyone who has sent information.  I appreciate you taking the time to help out.
Mahalo from Hawaii.
Barb
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Stedman had a design that took the solids off ahead of digestion and converted the removed solids to a fuel source. I liked this process as it pulled out a lot of material, which if it had gone through bacterial digestion, would have been converted into solution which is more difficult to control. Is anyone working along these lines? I ask because a lot of the pharmaceuticals are broken into more toxic daughter products either by bacterial digestion or later oxidative processes, and many are mitochondrial toxins (MT). Thus using the effluent as an irrigation source or drinking water augmentation sees these MTs bioaccumulating in irrigated crops or being chronically delivered with drinking water.  Thanks------------Edo
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The plant is a typical municipal secondary plant treating 8 million gallons per day, and equipped with a 4.3 million gallons per day Tertiary Treatment for recycled water. The idea is to suggest sending a cleaner influent through plant by removal of solids up front. This would substantially diminish bacterial digestion of solids, including pharmaceuticals. Plant is down-gradient from level 4 teaching hospital and surrounding labs and other clinical facilities. Recycled water is slated to be augment source for groundwater recharge. A cleaner end-influent would presumably make the raw stock becoming recycled water less of a hazard and easier on equipment.
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Dear my colleagues,
I am working on article regarding hydro-geochemistry and water quality analysis of a groundwater basin in Afghanistan. I have the water quality test results and I want to show the results in Piper and other diagrams. Please kindly kindly let me know that by which software can I draw Piper diagram.
Thanks and advance
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Dear Abdulhalim,
You can use Aquachem that can be downloaded for one month free trial or use GW_Chart. You can also use this excel spreed sheet. See also the attached paper.
With my best regards
Prof. Bachir ACHOUR
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I want to sterilize water at rate of 1 liter per second.
there is two main question:
1. which process has lower cost (for this rate or higher)
2. which process has highest accuracy. in fact it is very important for me to kill all living organism in water !
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 Dear Saeed Taji,
The market is literally flooded with water treatment options. Reverse osmosis systems, loose granular activated carbon, solid carbon block filters, and distillers all promise sparkling, clean water, but how do you know which one is really best? With a little research, you can find the ideal water treatment system for you.The UV treatment is best and low cost. Scientists have known for nearly a century that ultraviolet light of certain wavelengths is an effective germicidal agent.
All UV units have a maximum flowrate capacity and lower cost and less maintenance but some operation instruction ,e.g.
1.       At high Flow rate water will pass through without enough UV exposure.
2.       If Flow low then heat may build up which can damage the UV lamp
3.       The flow must be at constant Flow.
One application where ultraviolet disinfection is used is in recirculating delivery systems. In a recalculating system, water flows constantly from a storage tank, out to the pressure stations (or through the stations and through the piping in the animal rooms), then flows back to the storage tank. These installations use in-line UV units in the recirculating loop to provide control of bacterial growth.
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I'm running an experiment to see how pH and NaCl concentration affect desorption of metals, using pond water as the solvent. Because I'm changing pH and NaCl concentration, I wanted to keep the original pH intact in the sample taken, so took two 10 litre samples and compared the difference between an acidified sample and non-acidifed sample, as expected most metals decreased in the non-acidified samples, but only by a small amount (I'm assuming sample size helped). However the Sodium content was much higher in the non-acidified sample, any idea why?
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Are your  calibration standards matched to the acid content of the samples or are you running both acidified and non-acidified samples against the same calibration standards.. You may have a sample transport interference as the acid can change the particle size distribution of the droplets from the nebuliser. Long shot but worth thinking about.
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Dear all ,  
In our well water fishes all has died due to what reason ? Please share your idea? I have checked water some parameter. 
pH = 7.83
TDS=266ppm
COND=377 micro s
SALT=182 PPM
DO= 14.96 ppm.
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I agree it is unlikely to have so high oxygen concentration in well water. I recommend to measure it again. Makes sure the electrode is calibrated.
Fish are much more sensitive than humans to ammonia which often occur in groundwater and it is easy to measure.  
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When this rainwater sample was kept at the room temperature for several months, it turned from colourless to brown/ green color in the water sample. Why is it so?
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I agree with the other answers -- algal growth is probably what's going on.  Shielding the sample from light may alleviate this problem.
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Hello,
I know that there is a squeezing technique to sample pore water of mudrocks. But this technique is very sophisticated and potentially time consuming. My question if it is possible to evaluate the pore water chemistry of mudrocks from a chemical analysis of water sampled from boreholes?
The water samples would be from a depth of about 20-25 m. Is it possible to assume that the groundwater is in equilibrium with the pore water inside the hydraulic active pores of the mudrock and that the groundwater is representative for the composition of the pore water?
Unfortunately I can't rule out that there is a hydraulic connectivity to a quartenary aquifer.
Best Regards
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There are other techniques involving pumping with nitrogen. This requires you to seal the sample longitudinally, I believe this should be along the general flow direction. there wll be sealed in parts of the pore volume but you get the effective pore volume. Pumping nitrogen in one side and collecting water or everything, then remember to account for N2 and the pore volume it displaced. Nitrogen is small enough to displace pretty much everything, and can be modeled using something akin to the Buckley -Leverett Solution. This will destroy your sample in a way, since it's difficult to displace the nitrogen. Vacuum techniques are one way to get close to removing it. 
Other considerations are anisotropic conditions, although shallow sample wells will allow you to characterize that.  A Petroleum Engineering professor,  Dr Jafarpour at USC is working on characterizing subsurface conditions with limited data, but I've not worked with him so I don't know it well.
If you only wish to chemically characterize your pore water then displace it with other water and model the diffusing effects. This is relatively simple to model, using the error function, to determine the mixing of your components and your input water.
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What Should be the maximum total hardness concentration in feed water of Sea water membranes RO? Which range will help me to maintain the good life of membranes?
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It is preferable to speak about calcium carbonate scaling ou saturation index rather than total hardness in RO Desalination. The saturation index depend on many parameter as [Ca2+], water pH, Ionic Strenth, Temperature and RO rate conversion.
please find in attached file 2 papers : "A New Index for Scaling Assessment" published in IDA word Congress 2007 and "Reconsidering Water Scaling Tendency
Assessment" published in AICHE J. on 2006.
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Simple mixing of organic manures with water increases bicarbonate value. 
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What Henrik said is correct, but if you use the Gran method, which is an extrapolation method which use a strong acid to titrate well beyond the equivalence point. But the problem does not change. We have to find out alternative method.
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How calculate water quality index for irrigation purpose if you have concentration of all cation, anions ,SAR, SP, RSC EC and pH.
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From water quality data , the water quality index can be evaluated and for this published work is available along with softwares.
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I need to prepare some polymerized coagulant for turbidity removal from wastewater. Under various pH change from 4-10, will it change its state i.e. will polymerized content decrease and converted to unpolymerized form? If so how and why?
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Dear Muhammad,
The activity of coagulant depends upon the types of coagulant. So you can apply different coagulant in different pH conditions. 
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I need a chemical method with less chemical use for determination of Arsenic in drinking water. The work is focused on developing low cost and field portable sensor for detection of Arsenic in drinking water resources, which may be used by the people from rural areas. 
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Hi Iftak, While doing research on arsenic in well and stream water in Chile & Argentina I used the Hach system.  The arsenic problem is as bad in South & Central America as Assam, and Bangladesh.
The best results were managed by using a temperature controlled box. 18 degrees C was the optimal for carrying the samples from the point of extraction to the test center. As a lot of this was in the Atacama then in Patagonia, I only managed three test site extractions per day. And got a good repeat accuracy as I learned about the test equipment.   I would not recommend this to untrained persons as the results can be changed with temperature changes over time from extraction to test.
I understand that Cambridge are working on a new test kit that will be more accurate. But it's still in the planning stage.
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Is there any standard colorimetric method to determine Antimony concentration (Sb-III and Sb-V) in water? Also, describe the minimum detection limit.
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I am getting COD value too much higher than BOD of river sample is it correct ???
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thank you, Anders, for your preciuos comment. Ammonia can be oxidised by dichromate only at high potassium dichromate concentration (0.25 N) and in presence of chloride.
see Effect of Ammonia on COD Analysis
Byung R. Kim
Journal (Water Pollution Control Federation)
Vol. 61, No. 5 (May, 1989), pp. 614-617 
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I am trying to link the presence of heavy metals in drinking water sources or the biomagnification of these metals up the food chains for example when waste waters are used in irrigation and the plants take the metals up or when waste water mixes with aquatic ecosystems like rivers and lakes and fish take them up..and then there is the risk of humans consuming the contaminated fish or plants. could these processes be linked to the rising cases of cancer? how can such a research be designed?
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You can measure the dose of heavy metals in tissues of plants, fish and animals that drink the water or who eat that water plants and that fish.
If you study the water from the tap, you can give it to some animals (lab mice) and look at their tissues.
I'm not sure about human level (human tissues). Using medical statistics is a good idea.
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I use Loopamp Real Time Turbidimeter LA500,
It was working and my results were going very welll.
I don't know whether the cause of problem is about the turbidimeter or not?
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How old is the lamp? They can give unsteady readings as they get old. Try replacing t