Assessment of Treatment Effect of Heavy Metal Pollution from Sewage Sludge in Wastewater Treatment Plant Discharge in China’s Nanjing MV Industrial Park

To explore methods for a comprehensive assessment of the treatment effect of heavy metal pollution in the sewage sludge from China’s industrial parks, we studied the wastewater treatment plant of the Nanjing MV Industrial Park as an example. Eight common heavy metals in sewage sludge – Zinc (Zn), Copper (Cu), Lead (Pb), Mercury (Hg), Chromium (Cr), Nickel (Ni), Arsenic (As), Cadmium (Cd) were studied. The treatment effect of these containments was comprehensively assessed using the absolute niche fitness model, the relative niche model and the spatial niche fitness model. All three models showed that Pb > Cu > Ni > Hg > Cd > Cr > Zn > As in the samples. However, they produced – different numerical values – the absolute niche suitability model < the spatial niche suitability model < and the relative niche suitability model. Therefore, we concluded that special attention should be paid to the carcinogenic risk of As and Cr heavy metals to the person exposed to the sewage sludge.