Biological denitrification of drinking water using various natural organic solid substrates

Area of Science:

• Environmental Science
• Water Treatment Engineering
• Microbiology

Background:

• Nitrate contamination in drinking water poses significant health risks.
• Conventional denitrification methods can be costly and energy-intensive.
• Sustainable and cost-effective alternatives for nitrate removal are needed.

Purpose of the Study:

• To evaluate natural organic solid substrates (NOSS) as carbon sources for drinking water denitrification.
• To determine the most effective NOSS for nitrate removal in a laboratory setting.
• To assess the performance of a biodenitrification reactor with subsequent sand filtration.

Main Methods:

• Batch studies using various NOSS (poplar, hornbeam, pine shavings, wheat straw) as carbon sources.
• Biodenitrification in an upflow laboratory reactor using wheat straw as the optimal carbon source.
• Post-reactor sand filtration for solid particle removal and powdered activated carbon adsorption for color, DOC, and residual nitrate reduction.

Main Results:

• Wheat straw demonstrated the highest nitrate removal efficiency among the tested NOSS.
• Effluent nitrate concentrations remained below the acceptable limit of 50 mg/l NO3-.
• Soluble dissolved organic carbon (DOC) levels influenced denitrification efficiency.

Conclusions:

• Natural organic solid substrates, particularly wheat straw, are effective carbon sources for drinking water biodenitrification.
• A multi-stage treatment process involving biodenitrification, sand filtration, and activated carbon adsorption can achieve high-quality effluent.
• This approach offers a sustainable and efficient method for nitrate removal from drinking water.