keeping the bugs alive

keeping the bugs alive

Hi, I’m Mark Spilger, the Process Engineer in our water operations team. Having run numerous tours of our wastewater treatment centre, I know that one of the most common questions is about the role of microorganisms—what we sometimes affectionately refer to as "bugs"—in our 7-step treatment process. Here, I’d like to share why these tiny yet mighty organisms are so crucial and how we keep them alive and thriving. 

The Vital Role of Microorganisms in Wastewater Treatment 

Microorganisms are at the heart of the biological treatment stages in our wastewater treatment process. These microscopic organisms, including bacteria, protozoa, and fungi, play a crucial role in breaking down organic matter, removing nutrients, and reducing harmful contaminants. Here's why they are so important: 

• Organic Matter Breakdown: Microorganisms feed on organic waste in the wastewater, converting it into carbon dioxide, water, and biomass. This process significantly reduces the amount of organic material, which is essential for producing cleaner water. 
• Nutrient Removal: Certain microorganisms help remove nitrogen and phosphorus from the water, preventing the eutrophication of downstream water bodies, which can lead to harmful algal blooms and other environmental issues. 
• Pathogen Reduction: Some microorganisms are involved in the degradation of pathogens, helping to make the water safer for reuse. 

Our 7-Step Treatment Process 

To give you a better understanding, here's a detailed overview of our 7-step treatment process: 

1. Wastewater Screening: Plastics and rubbish are taken out of the wastewater. 
2. Anoxic Processing: Wastewater enters the biological processing tank bioreactor where natural bugs break it down. 
3. Aerobic Processing: Air is added to the wastewater creating new bugs which continue the breakdown process. 
4. Chemicals Added: Three chemicals—sodium hydroxide, sodium hypochlorite, and aluminum sulfate—are added at different stages to balance and disinfect. 
5. Membrane Filtration: Water is sucked through microscopic membranes that block out bugs, removing bacteria, pathogens, and other impurities. 
6. Ultraviolet Processing: Water is neutralized of impurities through the ultraviolet disinfection process. 
7. Chlorination: Chlorine is added to the water for the final treatment process before entering the recycled water tank ready for distribution to connected homes. 

Keeping the Bugs Alive 

Maintaining a healthy population of microorganisms is critical for the effective operation of our treatment process. Here’s how we ensure their wellbeing: 

• Optimal Conditions: We carefully control the environment within our treatment tanks to ensure the microorganisms have optimal conditions to thrive. This includes maintaining enough food for them to live and multiply, keeping the pH levels within the range that keeps them happy, and controlling the dissolved oxygen. We intentionally operate tanks at different dissolved oxygen levels to promote the growth of different species of microorganisms. In one tank we have an oxygen-rich environment which promotes the oxidation of organic carbon into carbon dioxide and the nitrification of ammonia (NH3) into nitrate (NO3). In another tank we want an oxygen-deficient environment so that microorganisms will use the oxygen bound into nitrate molecules (NO3) as their oxygen source and in doing so convert nitrate into gaseous nitrogen that dissapates harmlessly into the atmosphere. 
• Nutrient Supply: Just like any living organism, microorganisms need a balanced diet which means in addition to organic carbon they also need nitrogen and phosphorous. Fortunately, our wastewater contains enough nitrogen and phosphorous to keep the bugs happy. In fact, at some plants we actually dose extra concentrated liquid carbon in the form of glycerin to allow the bugs to chew up more of the nitrogen and bring the nutrient levels down even lower 
• Avoiding Toxic Shocks: Sudden changes in the composition of the wastewater can harm the microorganisms. We have systems in place to monitor the environment inside and downstream of the bioreactor to detect if the bugs are unhappy. We also require non-residential customers to abide by a trade waste agreement to limit what they can discharge into our system so that we don’t expose the bugs to anything that they can't handle.
• Regular Monitoring: Our team of experts regularly samples and analyses the microbial population to ensure it remains healthy and effective. This helps us detect any issues early and take corrective action promptly. 

Why It’s Important 

Keeping the bugs alive is not just about maintaining our treatment process; it’s about protecting public health and the environment. Effective wastewater treatment helps: 

• Protect Water Resources: By removing harmful contaminants, we ensure that the water we release back into the environment is safe and clean. 
• Support Sustainable Practices: Recycling water reduces the demand on freshwater resources, promoting sustainability. 
• Enhance Public Health: By treating wastewater thoroughly, we reduce the risk of waterborne diseases and protect community health. 

I hope this gives you a better understanding of the critical role microorganisms play in our wastewater treatment process and why their wellbeing is essential. Thank you for your interest in our work and for your insightful questions!