Effect of calcium nitrate on odor and properties of chemistry in sediment of Shenzhen River

Abstract

For the purpose of appropriate nitrate dosage, experiment was conducted to evaluate the performance of control of acid volatile sulfide (AVS) with calcium nitrate and to investigate the changes of related properties including total organic carbon (TOC), redox potential (ORP), pH, water content, ammonia nitrogen and bioactivity. Injection dosage of nitrate-nitrogen at 1.27 g/kg fresh sediment can obtain 97% removal of AVS in 14 days. There was no affect of increase of nitrate-nitrogen dosage on removal efficiency of AVS, and higher nitrate-nitrogen dosage could keep treatment effect stable for a longer time. ORP increased significantly to -100 mV when injection dosage of nitrate-nitrogen was more than 1.58 g/kg fresh sediment. The nitrate-nitrogen dosage more than 2.53 g/kg fresh sediment resulted in significant decline of pH value, and the nitrate led to increasing in ammonia nitrogen and decreasing in sediment micro-bioactivity. The appropriate range of nitrate-nitrogen dosage is from 1.58 to 2.22 g/kg fresh sediment (0.70-0.98 g/g S).