Our arrival at the GDC-owned science labs was a cool relief from the sun that scorched unapologetically. In the lab, white coats, lab equipment and the periodic table thrust us back to high school days.
It’s abuzz here. Technicians are mixing chemicals, others are carrying out titration, still others are heading to Menengai to collect samples.
Chemical analysis is critical to geothermal development. By understanding the chemical design of wells and a geothermal prospect, management can make informed investment decisions. Here, the team also conducts geo-hazard monitoring of boreholes for water, and fumaroles from prospects. The team also monitors reservoir concentration.
Today, some technicians are evacuating gas sampling flasks for sample collection. The flask is a glass container that leads to two openings each with a brown cork. It is made of hard glass designed to withstand the geothermal well conditions of high temperatures and pressures. Some are washing flasks with de-ionized water which removes all anions and cations to avoid contaminating samples.
Still, other technicians are evacuating gas sampling flasks charged with sodium hydroxide using a rotary vacuum pump to guarantee the purity of the sample. Before the team leaves for the field, the weight of the evacuated flask plus sodium hydroxide is measured using an analytical balance to determine the gas concentrations.
The Menengai team leaves. Others remain to analyse data collected earlier. After an hour or so, Anastasia Onduru, the Office Assistant, announces that mid-morning tea is ready. The scientists take a break. There is chit-chat here and laughter there.
Back to work
Teatime is over. The team goes to the balance room to measure the weight of the samples. This is done by deducting the weight of the evacuated flask from its weight when it contains the sample. This process
has to take place in a closed room to prevent exterior vibrations from tampering with the scale readings.
The balance room has two parts: for storage of chemicals and a smaller part for measuring the samples. It also hosts the fume hood chamber that expels obnoxious gas. It is in here that the compounds are mixed and weighed amid small talk and tinkling of gas sampling flasks.
The next stage is at the instrument room where sample analysis is done. This is the furthest end of the left side of the laboratories, next to the gas cylinder room. It has an extraction system which is a grey vent that
runs on one side of the room and rests atop an atomic absorption spectrophotometer, AAS, that is used for analysis of metals. The extraction system acts as an air conditioner to prevent overheating the machine.
G.C
We are fortunate to be at the lab as the technicians test-drive a newly commissioned gas chromatograph or G.C as is popularly called. It is used for the analysis of gases that are not trapped in the sodium hydroxide solution. The G.C is connected to a computer that acts as the instrument’s read-out. The G.C is like a printer with a keypad to key in information and screens to show the progress of the data analysis. It has television aerial-like knobs with one used to input the gas for analysis using a syringe, while the other knob lets out the excess sample through a small pipe into a beaker containing de-ionized water since the G.C only requires one millimetre of the sample for analysis.
Each sample’s analysis takes roughly 17-20 minutes. And for the first time, the technicians can sit. Other operations demand standing. It’s why ladies are on flat shoes. General talk on previous assignments
takes centre-stage as they wait for this results.
The G.C adds its take to the conversation: it hums through the process. The data comes in form of a chromatogram that is a plot of voltage against the relative retention times as the various components go through through the packed column.
“Hydrogen elutes first and methane last because of their molecular sizes and not weight,” explains Jared Nyamongo, the senior technician in charge of the lab. Back in the main lab, data analysis continues with the lab surfaces decorated with numerous gas flasks containing various samples ready to undergo the analysis process.
“‘We are in business!” enthuses Nyamongo, when he sees the samples on the surfaces. The air this time is filled with numbers “No. 90, No. 53, No. 62” as the technicians sort out the gas flasks for analysis.
The Menengai crew is back. It gets to work sorting out the samples for analysis. The flasks are wrapped with soft paper to prevent breakage. The samples are precious to lose. Work on the new samples starts immediately with ‘I’ll do this’ and I’ll do that’ shuttling their way around the lab. Then, the lab empties. It’s time for sun-downer tea. Afterwards, the process of analysis begins kick-starting the cycle all over.
