Investigation of colloidal biogenic sulfur flocculation: Optimization using response surface analysis.

Area of Science:

• Environmental Science
• Chemical Engineering
• Water Treatment

Background:

• Biogenic elemental sulfur (S(0)) presents significant solid-liquid separation challenges in wastewater treatment, including poor settling and membrane fouling.
• Effective separation of S(0) is crucial for efficient wastewater management and potential resource recovery.

Purpose of the Study:

• To compare the flocculation efficiencies of polyaluminum chloride (PAC), polyacrylamide (PAM), and microbial flocculant (MBF) for biogenic S(0).
• To optimize S(0) flocculation using response surface methodology (RSM), evaluating the impact of flocculant dose, pH, and stirring intensity.
• To determine the feasibility of PAC for S(0) recovery in sulfate-laden wastewater treatment.

Main Methods:

• Flocculation experiments were conducted using PAC, PAM, and MBF to treat S(0) in wastewater.
• Response surface methodology (RSM) was employed to optimize flocculation parameters: flocculant dose, pH, and stirring intensity.
• Treatment efficiency was assessed by S(0) flocculation rate and supernatant turbidity removal.

Main Results:

• The flocculation efficiency order was determined as PAC > MBF > PAM.
• Optimal S(0) flocculation was achieved at pH 4.73, 129 r/min stirring speed, and 2.42 mg PAC/mg S flocculant dose.
• Under optimal conditions, the S(0) flocculation rate reached 97.53%.

Conclusions:

• Polyaluminum chloride (PAC) is a highly effective flocculant for biogenic elemental sulfur (S(0)) separation.
• Response surface methodology (RSM) provides an efficient approach for optimizing S(0) flocculation processes.
• The study provides essential parameters for sulfur recovery during sulfate-rich wastewater treatment.