Application of controlled nutrient release to permeable reactive barriers

Area of Science:

• Environmental Science
• Geochemistry
• Bioremediation

Background:

• Petroleum hydrocarbon contamination poses risks to groundwater resources.
• Permeable reactive barriers (PRBs) are engineered systems for in-situ groundwater remediation.
• Controlled release nutrients (CRNs) can enhance microbial degradation of contaminants in PRBs.

Purpose of the Study:

• To investigate the efficacy of Polyon™ and Zeopro™ as CRN materials for promoting petroleum hydrocarbon biodegradation in groundwater.
• To assess the longevity of nutrient release, and the influence of flow velocity and hydrocarbon concentration on CRN performance.

Main Methods:

• Evaluated nutrient release from Polyon™ and Zeopro™ at 4°C and 23°C.
• Assessed nutrient release across 3500 bed volumes under varying flow velocities.
• Determined the impact of petroleum hydrocarbon concentrations (toluene) on nutrient release over 14 days.

Main Results:

• Both Polyon™ and Zeopro™ demonstrated sustained nitrogen, phosphorus, and potassium (N-P-K) release at 3500 bed volumes.
• Lower temperatures (4°C) extended N-P-K release duration.
• Zeopro™-activated carbon mixtures showed premature N-P-K depletion.
• Increased flow velocity reduced nutrient concentrations in Polyon™ but not Zeopro™.
• Petroleum hydrocarbons did not significantly alter nutrient release from either CRN material.

Conclusions:

• Polyon™ and Zeopro™ show promise as CRN materials for PRBs in nutrient-limited environments.
• CRN performance is influenced by temperature and flow velocity.
• Further research is needed to optimize CRN application in PRBs for effective bioremediation.