Wastewater from a cheese factory has the following composition: 8.0 g / L protein (C16 H24 O5

Wastewater from a cheese factory has the following...

Key Concepts

Total Organic Carbon (TOC)

Total organic carbon (TOC) is a measure of the amount of carbon bound in organic compounds present in a sample, typically expressed in g/L or mg/L. It is an important parameter in environmental engineering and water quality assessment because carbon is a primary element in organic pollutants. Determining TOC helps in understanding the level of organic contamination and the potential oxygen demand during wastewater treatment processes.

Molecular Formula Analysis

Molecular formula analysis involves identifying and quantifying the elemental composition of compounds based on their chemical formulas. In the context of wastewater analysis, the molecular formulas of components like proteins, carbohydrates, and fats are used to calculate the amount of carbon present in each constituent. This requires determining the molar mass of each compound and the fraction of that mass attributed to carbon, which is critical for accurately estimating the TOC.

Stoichiometric Conversions

Stoichiometric conversions are essential for translating the given mass concentration of compounds into the mass of specific elements, such as carbon. This process involves using the atomic masses from the periodic table along with the molecular formulas to compute the fraction of each compound’s mass that is carbon. By multiplying the concentration of each compound by its respective carbon fraction, one can sum the contributions from all components to obtain the total organic carbon concentration.

Transcript

00:01 Okay, so in this question, we're recording the total organic carbon of wastewater from a cheese factory that lets out protein, carbohydrates, and fat into the water.

00:12 All right, so just to start, we're going to break these down.

00:17 And the way i did this was i found the total organic carbon of each of these components and then just added them together.

00:23 All right.

00:26 So to start with that, we're going to do protein, where we are told that the flow is 8 .0 grams per liter.

00:38 And we're also told the structure of the protein, which is c -16, h -24, 05, and 4.

00:50 So with that information, we can actually determine most of this, right? so first thing we're going to do is calculate the molar mass, which if you do by just adding up all of the atomic masses of all of the individual atoms of this, you're going to get that this is 352 .392.

01:12 Okay, so in order to figure out how much total carbon we have, now we need to figure out what is the molar mass of all of the carbon.

01:20 So what you're going to do is you're going to multiply 16 by 12 .1, which gives you a value of 192 .16.

01:29 All right, so if i divide that number by the molar mass, right? so like that, what that's going to give me is the proportion of this molecule that is, in fact, carbon, which is equal to 0 .545 or 54 .5%.

01:51 Alright, so now what i can do is i can take that proportion and multiply it by the flow rate.

01:57 In other words, i have 8 .0 grams per liter coming out, and if i multiply that by 0 .545, that's going to give me that this is giving me a grand total of 4 .36 grams of carbon per liter.

02:21 All right, so that's for the protein.

02:23 So next we move on to the carb, which we're told has a flow rate of 12 grams per liter.

02:37 So now what we can do is we can, oh, i'm sorry, we're also told that the molecular formula is ch2o.

02:45 All right, so now finding the molar mass of this is a little easier than doing the protein just because it's a smaller molecule.

02:52 But we find it to be 30 .026.

02:56 Once we have that information, we can figure out the proportion of carbon.

03:00 There's only one carbon, so i can do 12 .01 divided by 30 .026, giving me a proportion of 0 .4 or 40%.

03:14 So from there, i can do this 12 times 0 .4...

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