Optimization of oxygen-releasing materials and pH regulation in groundwater remediation system
地下水修复系统中释氧材料的改进及pH调控

Using oxygen-releasing materials to supply oxygen for groundwater remediation system can result in pH increase of groundwater. To solve this problem, three kinds of oxygen-releasing materials were made by blending cement, calcium peroxide (CaO2), sand, bentonite, KH2PO4 and water together with certain proportion. Column experiments were conducted to evaluate the influence of oxygen-releasing materials on dissolved oxygen (DO) and pH of groundwater. The experimental results showed that cement has a good effect on controlling oxygen-releasing rate. High proportion of cement in oxygen-releasing materials can delay the oxygen-releasing rate and avoid high pH of water caused by the fast reaction of oxygen-releasing materials. Adding KH2PO4(mass fraction less than 10%)in oxygen-releasing materials can decrease pH of system and total phosphorus concentration in water can meet the drinking water standard. Using granular tourmaline (1~2 mm in diameter) as the buffering zone can decrease high pH from 11.3 to 10.2