What is the effect of adding CO2 to a septic tank?

Adding carbon dioxide (CO2) to a septic tank primarily results in a decrease in pH. This occurs because CO2 reacts with water to form carbonic acid, which can lead to a more acidic environment in the septic system. The lower pH can influence microbial activity within the septic tank, potentially affecting the overall effectiveness of the treatment process.

In septic systems, maintaining an appropriate pH is crucial for the health of the microorganisms that break down waste. A significant shift in pH can hinder these beneficial bacteria, possibly leading to reduced treatment efficiency and a backlog of waste within the tank.

While other options might suggest potential outcomes related to septic systems, they do not directly correlate with the introduction of CO2. For instance, increasing dissolved oxygen would generally occur through aeration rather than CO2 addition. Similarly, CO2 would not typically raise the temperature; instead, the biological processes within a septic tank can naturally produce heat. Increasing solid waste retention is more about the tank's capacity and flow rates than the chemical changes induced by CO2. Thus, the lowering of pH is the most significant and accurate effect of adding CO2 to a septic tank.