Innovative sludge pretreatment technology for impurity separation using micromesh.

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Solid-Liquid Separation

Background:

• Sludge treatment facilities face operational challenges due to impurities like fibers, hair, plastic, and sand.
• Effective pretreatment of primary sludge is crucial to mitigate these impacts and improve treatment efficiency.

Purpose of the Study:

• To introduce and evaluate an innovative primary sludge pretreatment technology: the sludge impurity separator (SIS).
• To determine the key operational parameters and their optimal values for the SIS.
• To assess the performance, efficiency, and economic viability of a full-scale SIS.

Main Methods:

• Development and implementation of a sludge impurity separator (SIS) utilizing a non-woven micromesh with a 0.40 mm pore size.
• Laboratory-scale testing to identify and optimize critical operational parameters: impurity concentration, aeration intensity, and channel gap.
• Full-scale trial of the SIS with a treatment capacity of 300 m³/day to evaluate real-world performance.

Main Results:

• Optimized operational parameters for the SIS were determined to be: impurity concentration < 25 g/L, aeration intensity < 0.8 m³/(m²·min), and channel gap < 2.5 cm.
• The full-scale SIS achieved over 88% removal of impurities from the influent sludge.
• The micromesh cleaning cycle exceeded 16 days, indicating robust performance and reduced maintenance requirements.

Conclusions:

• The sludge impurity separator (SIS) is a highly effective technology for removing impurities from primary sludge, significantly reducing impacts on downstream treatment processes.
• Optimized operation ensures high impurity removal efficiency and extended micromesh cleaning intervals.
• The SIS demonstrates economic feasibility with low energy consumption (1.06 kWh/m³) and operational costs (0.6 yuan/m³).