One of my favorite websites is www.hach.com. I have no personal or professional association with Hach. Rather, I am an end-user who has a lot of Hach laboratory equipment, and I am a very pleased end-user. When I have something good to say about a person or a company I will not hesitate to sing their praise. If I don’t have something good to say I’ve learned to just shut up. There’s enough negativity in the world as it is so why add to it? So, I will proceed to tell you about my personal experience using a wide array of Hach lab instruments and reagents. Before proceeding you need to understand that my experience is as an “operator” doing field testing. It is not as a “chemist” doing a lot of “bench top”
laboratory testing. There’s a big difference in the needs of the operator and the fairly basic testing they do compared to the needs and tools used by a chemist just as there is a big difference in the skill between the two.
I have become spoiled by Hach’s TNTplus chemistries. Using this chemistry is fool-proof which is perfect for the non-chemist (the operator!!). For wastewater testing, and testing using the TNTplus method, which I’ll explain more about in a minute, requires two fundamental pieces of equipment: 1) a spectrophotometer and 2) a digital reactor block. The Hach DR 2800 spectrophotometer is shown on the left in the photograph below and the digital reactor block is on the right. These two high-quality, highly capable instruments form a mighty strong foundation for doing just about any type of water or wastewater analysis you can think of.
Now here’s what is so neat about the TNTplus chemistries: They are the absolute easiest way to run a test. These 13 mm vials require that you only add some small volume of sample, anywhere from 0.5 to perhaps 5 mLs of sample, shake, let sit for 10 or 15 minutes depending on the test, then place the vial into a slot on the top of the DR2800 and the barcoded vial gets spun so it can be read and then your result is generated on screen. That’s it!! This form of testing minimized errors and makes even the most hardened, non-laboratory loving operator willing and quite able to carry out an extensive range of testing.
The digital reactor shown on the right is required to run several more complicated tests but my primary use is to run chemical oxygen demand tests. The purpose of the reactor is to “cook” the COD vial for two hours at 150°C for two hours. Take the hot vials out of the reactor, let them cool for about 20 minutes, then stick them in the DR2800 and you get your result. One of several COD ranges for the TNTplus chemistry is shown in the photograph below.
For a better idea of the range of tests you can run on water and wastewater samples using the Hach TNTplus chemistry approach please click here to open a PDF to read more about his testing.
I run COD on a variety of samples such as the individual waste streams that combine in an EQ tank, the flow out of an EQ tank, in and out of API separators, inlet to the biological reactor, and clarifier overflow. I also use the TNTplus chemistry to run such parameters as ammonia, orthophosphate, nitrate, sulfate, and even alkalinity. There is just no easier way to conduct an extensive analysis of a wastewater system than using this chemistry.