She is responsible for the day-to-day operations of the Global Water Engineering Cohral plant installed by CST Wastewater Solutions, which produces waste water as it replaces fossil fuels.
The Cohral green energy initiative by Japanese meat processor NH Foods at Oakey Beef Exports in Australia has been praised as an environmental and business efficiency model for food producers worldwide.
The plant extracts methane biogas from its waste water streams to replace millions of dollars’ worth of natural gas currently consumed at the abattoir on Queensland’s Darling Downs and was officially opened by Australian Federal Industry and Science Minister and MP for Groom Hon Ian Macfarlane this year.
Hawkins tells FoodProductionDaily what a typical day is like for her operating one of Australia’s green energy plants.
‘Being a biogas technician at a wastewater treatment plant of an abattoir isn’t exactly the glamorous job most 24-year-old women dream of, but it actually brings me a great sense of accomplishment and satisfaction.
I’m responsible for keeping the plant running smoothly and efficiently, which involves a lot of testing, calibration and measurement, to ensure everything is within spec. The main aim of the wastewater treatment plant is to transform wastewater from the abattoir into biogas, which is used on site as a fuel to power boilers in the place of natural gas.
Already, this made the job more interesting for me, as it involved taking an environmental problem and turning it into green energy.
My background is in cattle, as I grew up on a breeding and fattening cattle property in Central Queensland. I attended the University of Queensland and it is here where I studied Agricultural Science, concentrating mostly on livestock.
Arriving at work at 7am, the first thing I need to do on a typical day is weigh the previous day’s Total Suspended Solids (TSS) samples and fill in the present SCADA values, looking for any alarms or irregularities. This involves filling in an Excel spreadsheet, recording the values that are presently on the screen. This is an effective way of making sure every SCADA parameter is within its specified range.
This is followed by a general check of the plant to make sure all equipment is functioning properly. I then speak to the engineering, maintenance and electrical managers to inform them of any issues that will need fixing - an example might be a busted airline.
After the initial checks are complete, I research some deeper data analysis, by calculating the previous day’s average values for pH, temperature, pressure, methane content and level transmitters based on SCADA trends. If there are any discrepancies in these averages, the instruments will need to be checked. For example, if the effluent pH is drastically below its normal readings, it needs to be recalibrated, and if the influent pH is too low, caustic soda dosing will need to be commenced.
My next task is to collect waste water samples from various stages of processing and manually test the pH and temperature, then test for electrical conductivity and sludge volume. After this, the samples are filtered and tested for Volatile Fatty Acids and the COD (total) and COD (soluble) samples are placed in a reactor to heat for two hours. COD stands for Chemical Oxygen Demand, and is a measure of the amount of oxygen needed oxidise the organic compounds in the wastewater.
Once that’s done I take infeed and outfeed samples of the DAFs (Dissolved Air Flotation) from the abattoir site. I take these and wastewater samples to the lab for FOG (Fat, Oil and Grease) testing.
By the time that’s done it’s 12 noon and time for lunch, which allows for two hours to take out the COD samples once I’ve finished eating.
When I return to the biogas plant, I need to report the FOG results to my superiors, so they know the efficiency of the DAFs and the quality of the wastewater.
After that I proceed to alter the feeding rate from the Equalisation Lagoon to the Cohral based on the COD(t) value of the EQ. This entails determining what percentage of the COD load I want to feed into the lagoon, and how much I think the bacteria can handle at that point in time. If the Volatile Fatty Acid level of the effluent is high, then it means that efficiency of the bacterial activity is down and the feeding rate should be reduced to a level it can handle.
I take the methane reading from a gas sampling point and test for the presence of oxygen. I check the liquid manometer is reading the same as the pressure transmitter on the Cohral and record all biogas parameters. An important part of testing is documentation, so once I’ve done all the testing I need to add both the biogas and wastewater results to our central operating datasheet and report on the observations and results.
At this stage, it is necessary to send all results to appropriate people within the company. I may also need to calibrate the pH meters if their levels need adjustment. Here is when I follow up on any reported issues before a final walk around and check.
On a day where everything has run smoothly I’m finished by 3pm, but if there are any issues, I may need to stay back to fix them. Not your average 9am-5pm desk job that’s for sure, but I feel very accomplished knowing that my contribution allows a world first Cohral installation to operate smoothly and turn wastewater into green energy.’