Evaluation and Source Apportionment of Heavy Metals (HMs) in Sewage Sludge of Municipal Wastewater Treatment Plants (WWTPs) in Shanxi, China.

Baoling Duan,Wuping Zhang,Xiaomei Li,Fenwu Liu,Haixia Zheng,Qiang Zhang,Yushan Bu

doi:10.3390/ijerph121215022

Abstract

Heavy metals (HMs) in sewage sludge have become the crucial limiting factors for land use application. Samples were collected and analyzed from 32 waste water treatment plants (WWTPs) in the Shanxi Province, China. HM levels in sewage sludge were assessed. The multivariate statistical method principal component analysis (PCA) was applied to identify the sources of HMs in sewage sludge. HM pollution classes by geochemical accumulation index Igeo and correlation analyses between HMs were also conducted. HMs were arranged in the following decreasing order of mean concentration: Zn > Cu > Cr > Pb > As > Hg > Cd; the maximum concentrations of all HMs were within the limit of maximum content permitted by Chinese discharge standard. Igeo classes of HMs pollution in order from most polluted to least were: Cu and Hg pollution were the highest; Cd and Cr pollution were moderate; Zn, As and Pb pollution were the least. Sources of HM contamination in sewage sludge were identified as three components. The primary contaminant source accounting for 35.7% of the total variance was identified as smelting industry, coking plant and traffic sources; the second source accounting for 29.0% of the total variance was distinguished as household and water supply pollution; the smallest of the three sources accounting for 16.2% of the total variance was defined as special industries such as leather tanning, textile manufacturing and chemical processing industries. Source apportionment of HMs in sewage sludge can control HM contamination through suggesting improvements in government policies and industrial processes.

Highlights

Many wastewater treatment plants (WWTPs) were built during the past decades in China [1,2].In the Shanxi province, with a population of 35 million, more than 158 WWPTs were built in the past ten years
Secondary dewatered sludge was collected from 32 municipal waste water treatment plants (WWTPs) across Shanxi Province, China, as indicated in Figure 1.To enhance samples representative, subsamples were collected from four different sites in the storage pile at each WWTP
Because samples were from 32 WWTPs located in different regions, Heavy metals (HMs) concentrations in sewage sludge all varied greatly

Summary

Introduction

Many wastewater treatment plants (WWTPs) were built during the past decades in China [1,2]. In the Shanxi province, with a population of 35 million, more than 158 WWPTs were built in the past ten years. More and more sewage sludge will be produced with the increasing population and number of WWTPs. During 2010, China produced approximately 2.66 million tons of sewage. Res. Public Health 2015, 12, 15807–15818; doi:10.3390/ijerph121215022 www.mdpi.com/journal/ijerph

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