[Enhanced Coagulation as a Pretreatment for Low Temperature Wastewater]

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Coagulation Science

Context:

• Low temperatures significantly impact conventional water treatment processes, often reducing efficiency.
• Enhanced coagulation is a critical pretreatment step for removing organic matter and nitrogen.
• The performance of coagulants under varying temperatures is crucial for year-round water quality management.

Purpose:

• To investigate the effects of low temperatures on enhanced coagulation using a novel composite coagulant, SynthA.
• To compare the removal efficiencies of dissolved organic matter (DOM) and nitrogenous compounds under room and low temperatures (2-5°C).
• To assess the influence of enhanced coagulation on subsequent biological treatment processes.

Summary:

• SynthA demonstrated effective removal of particulate and dissolved organic matter and nitrogen, outperforming traditional coagulants like aluminum chloride (AlCl3) and poly aluminum chloride (PACl) under low temperatures.
• Low temperatures inhibited turbidity and COD removal for AlCl3 and PACl more severely than for SynthA.
• SynthA achieved higher dissolved organic nitrogen (DON) removal (28.5%-41.7%) at low temperatures compared to room temperature (17%-31.4%), indicating its adaptability.

Impact:

• Enhanced coagulation with SynthA as a pretreatment can alleviate the decrease in biological treatment efficiency during winter.
• This approach stabilizes nitrogen removal and reduces the required aeration time in wastewater treatment plants.
• SynthA offers a promising solution for maintaining consistent water treatment performance in cold climates.