Hello Adi Seno Abyoga,

So far, I know Electrical conductivity (EC), also called specific conductivity or salinity or total dissolved solids (TDS), in natural water, is its capacity to conduct electric current. It refers to salinity (SAL). It is also the measurement of total dissolved solids (TDS). Whereas, turbidity (TBD), also known as total suspended solids (TSS), is the suspension of solid particles in water – either living or non-living.

I have attached a few notes for you Adi. I hope they help.

John

It is best to collect data to find out relative to the waters being compared. Generally, one might not expect a strong relationship between EC and turbidity. However, distilled water has very low if any EC, and also turbidity, and little or nothing grows in this media, so ability of organic particles to scatter light should be limited. I do not know of any organisms that can fix their own nutrients, etc. to thrive in distilled water. Groundwater can have varying degrees of TDS, and sometimes TSS, depending on geology, etc. In addition, exposing ground and treated water with dissolved nutrients with sunlight forms media for organic growth response. Turbidity is measured by particles scattering light, so whether the particles are silt or clay, or organic such as algae, they can scatter light. Numerous small, minute particles such as a suspension of clay is much more effective at scattering light than the larger silt and sand size particles with the same value of TSS. One must dilute the samples so turbidity readings are 40 NTU or less (see std methods). There relationship if any of turbidity with EC is likely to be specific to that water source, groundwater or treated water, so its ability to serve as a comparative parameter is probably limited, but may be useful in specific circumstances where the relationship appears strong from data.

Turbidity is independent of EC. Because most residents do not regularly maintain their water wells, the principal cause of turbidity is the presence of bacterial colonies and their colloidal byproducts. It is not uncommon for samples to contain more than a million colony forming units per ml. Turbidity is also due to suspended sediment. Suspended fines are either derived from infiltration through the screened interval or from chemical precipitates. Fine sediment, precipitates, and bacterial byproducts will continually accumulate at the bottom of a well below an overlying nepheloid layer. In some and particularly older wells, nepheloid layers can eventually become thick enough to be partially entrained in water circulating to the pump inlet every time the pump is turned on. Transient turbidity measured while sampling is principally due to natural degassing of either CO2 or bacteriogenic methane.

Thank you very much for the contributions to my question. I realize that it would be hard to find relationship between EC and turbidity (if anything even exists as Mr. Gorody has pointed out).

I would therefore like to close this question and move on to the next. Once again thank you very much kind Sirs for the help!

Thanks to Dr. Machell for his short note on the topic.

I feel that if it is a turbid water due to suspended sediments, then the density of such water will be more than the clear water. And denser the water, more will be the EC value (as in the case of saline/sea water).

Well,

TDS-EC relation.

As Hem, 2005 mentioned, EC related to TDS. The whole set of data fit a straight line regression closely (r=.98) with a value for A in the formula KA=S of 0.59. (K in this formula is specific conductance in micro mhos/cm and S is dissolved solids in mg/L.) For the analyses of natural waters , the range of A is about 0.54 to 0.96, which represents nearly the full range to be expected. A is mostly between 0.55 and 0.75.

Turbidity- TSS relation

As shown in the attached figure,

Turbidity is determined by the amount of light scattered off particles . While this measurement can then be used to estimate the total dissolved solids concentration, it will not be exact.

Turbidity does not include any settled solids or bedload (sediment that “rolls” along the riverbed) . In addition, turbidity measurements may be affected by colored dissolved organic matter. While this dissolved matter is not included in TSS measurements, it can cause artificially low turbidity readings as it absorbs light instead of scattering it .

Total suspended solids, on the other hand, are a total quantity measurement of solid material per volume of water. This means that TSS is a specific measurement of all suspended solids, organic and inorganic, by mass. TSS includes settleable solids, and is the direct measurement of the total solids present in a water body. As such, TSS can be used to calculate sedimentation rates, while turbidity cannot.

Sincerely

Hi, I did treat textile wastewater by vertical flow constructed wetlands and I did not find any relationship between them.

Check this out!

Conductivity and TDS (total dissolved solids) are often thought of a being interchangeable, but they are not. Conductivity is a measurement of the ability of a substance to conduct electricity.

EC is directly related to TDS in (in meq/l) and a very simple groundwater classification is based on EC (electrical conductivity [µS/l] in Germany, [µmho/l] in American papers. I'm not familiar with the acrony TSS. Should you mean non-dissolved solid matter (turbidity): it is indirectly related to EC. Sorry, that I am not further elaborating. The topic is standard textbook content and you should certainly refer to any of these (since you are working in Germany try GEORG MATTHESS: Die Beschaffenheit des Grundwassers, 1973). Furthermore, EC is easy to measure in the field, so you can use it for a quick and easy survey. If you have more detailed data (ion concentrations) better use those for correlations or calculate the EC from these (MATTHESS among many others also helps you with these calculations).

Good questions as well as discussions, apparently, it seems to me that there might not any relationships between these two components measured one by light scattering ability and other electrical conductivity.

Electrical conductivity represent dissolved solids whereas Turbidity represent suspended particles. Both are quite different.

The best is to get independent measurements of all these variables, otherwise there is no direct relationship between them. Conductivity measures dissolved salts that are able to conduct current (esp inorganics), TDS includes those that can carry charge and those that cant (e.g. organic mat), however turbidity can be caused by dissolved salts like iron etc and suspended solids which don't have the ability to carry any charge, hence not possible to detect them when measuring conductivity.

It depends upon the individual constituents of the water. If the turbidity is due the formation of solid phase from the dissolved solids, as in case of crystallization. increase in the Turbidity is accompanied by a reduction in the electrical conductivity of the sample. due to reduction in the free ions present in the liquid bulk to conduct electricity.

FYI, bacteria are also a common source of turbidity because their bioslime byproducts are also finely suspended. Slime will usually take much longer time to settle out of suspension than clay. Use a clear beaker in the field and you can often readily see the difference between suspended sediment and bioslime.

Yes, there is a general correlation between EC and TDS. But to address if there is any influence of suspended solids on EC, you need to plot EC vs. either total calculated dissolved ion concentration or vs. ionic strength and calculate a regression line. Then take the difference between the actual vs predicted EC and plot those data against NTU. You may discover sample sets when residual values will be correlated with NTU. To be confident of results, it is important to ensure that you analyze for all major ions and that the cation-anion charge balance is better than +/- 5%. It helps to have a sample set of more than 30 points to perform this type of analysis.