Effect of storage time on swine manure solid separation efficiency by screening

Area of Science:

• Environmental Science
• Agricultural Engineering
• Animal Science

Background:

• Confined animal feeding operations (CAFOs) in Brazil have expanded, increasing swine production scale.
• Swine manure management significantly impacts air quality and treatment system efficiency.
• The form and volume of manure are critical factors in environmental management.

Purpose of the Study:

• To evaluate the efficiency of manure solid-liquid separation using screening.
• To investigate the impact of different screen opening sizes and pit storage times on separation efficiency.
• To analyze manure characteristics under tropical climate conditions.

Main Methods:

• Solid-liquid separation was performed using screening with varying aperture sizes.
• Manure samples were analyzed after different pit storage durations.
• Ammoniacal nitrogen production and chemical oxygen demand (COD) were measured.

Main Results:

• A notable ammoniacal nitrogen production rate of 24 mg/L per storage day was observed.
• Screen separation efficiency decreased within the first eight days of storage.
• Storage time directly correlated with the degradation of the organic fraction, indicated by increasing COD.

Conclusions:

• Shorter manure storage times enhance solid-liquid separation efficiency.
• Early separation minimizes organic matter degradation and ammonia volatilization.
• Optimizing separation timing is crucial for improving air quality and treatment efficacy in swine CAFOs.