To achieve a pH adjustment of 8.4 for nitrification in a rotating biological contactor (RBC), which chemical would be most effective?

Soda ash is the most effective choice for achieving a pH adjustment of 8.4 in a nitrification process within a rotating biological contactor (RBC). Soda ash, or sodium carbonate, is a strong alkaline substance that can effectively raise the pH of water. This is particularly important for nitrification, as a pH range of 7.5 to 8.5 is optimal for the bacteria involved in this process.

Soda ash dissociates in water to release carbonate ions, which can neutralize acidity and lead to an increase in pH levels. The high buffering capacity of soda ash makes it suitable for quickly and consistently maintaining the desired pH level, ensuring that the nitrifying bacteria can thrive and perform efficiently.

In contrast, sodium bicarbonate, while also capable of raising pH, works more slowly and achieves a less significant increase compared to soda ash. Calcium carbonate can also raise pH; however, it tends to dissolve more slowly and might not be as effective in rapid pH adjustment in this specific application. Ammonium sulfate is not suitable for pH adjustment as it actually can lower pH due to its acidifying properties. Thus, soda ash stands out as the optimal choice for ensuring effective