Environmental Science and Pollution Research

, Volume 20, Issue 11, pp 7863–7877

Co-treatment of acid mine drainage with municipal wastewater: performance evaluation

Mining and the Environment - Understanding Processes, Assessing Impacts and Developing Remediation

DOI: 10.1007/s11356-012-1303-4

Cite this article as:
Hughes, T.A. & Gray, N.F. Environ Sci Pollut Res (2013) 20: 7863. doi:10.1007/s11356-012-1303-4

Abstract

Co-treatment of acid mine drainage (AMD) with municipal wastewater (MWW) using the activated sludge process is a novel treatment technology offering potential savings over alternative systems in materials, proprietary chemicals and energy inputs. The impacts of AMD on laboratory-scale activated sludge units (plug-flow and sequencing batch reactors) treating synthetic MWW were investigated. Synthetic AMD containing Al, Cu, Fe, Mn, Pb, Zn and SO4 at a range of concentrations and pH values was formulated to simulate three possible co-treatment processes, i.e., (1) adding raw AMD to the activated sludge aeration tank, (2) pre-treating AMD prior to adding to the aeration tank by mixing with digested sludge and (3) pre-treating AMD by mixing with screened MWW. Continuous AMD loading to the activated sludge reactors during co-treatment did not cause a significant decrease in chemical oxygen demand (COD), 5-day biochemical oxygen demand, or total organic carbon removal; average COD removal rates ranged from 87–93 %. Enhanced phosphate removal was observed in reactors loaded with Fe- and Al-rich AMD, with final effluent TP concentrations <2 mg/L. Removal rates for dissolved Al, Cu, Fe and Pb were 52–84 %, 47–61 %, 74–86 % and 100 %, respectively, in both systems. Manganese and Zn removal were strongly linked to acidity; removal from net-acidic AMD was <10 % for both metals, whereas removal from circum-neutral AMD averaged 93–95 % for Mn and 58–90 % for Zn. Pre-mixing with screened MWW was the best process option in terms of AMD neutralization and metal removal. However, significant MWW alkalinity was consumed, suggesting an alkali supplement may be necessary.

Keywords

Acid mine drainageActivated sludgeCo-treatmentMetalsNeutralizationSewageRemediationWastewater treatment plant

Abbreviations

AMD

Acid mine drainage

BOD5

Five-day biochemical oxygen demand

COD

Chemical oxygen demand

DO

Dissolved oxygen

f/m

Food-to-microorganism

HRT

Hydraulic retention time

MLSS

Mixed liquor suspended solids

MWW

Municipal wastewater

SBR

Sequencing batch reactor

SRT

Solids retention time

SS

Suspended solids

SVI

Sludge volume index

TN

Total nitrogen

TOC

Total organic carbon

TP

Total phosphorus

WWTP

Wastewater treatment plant

Supplementary material

11356_2012_1303_MOESM1_ESM.pdf (18 kb)
ESM 1(PDF 18 kb)
11356_2012_1303_MOESM2_ESM.pdf (25 kb)
ESM 2(PDF 25 kb)
11356_2012_1303_MOESM3_ESM.pdf (265 kb)
ESM 3(PDF 264 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Water Technology Research Group, Centre for the EnvironmentTrinity College DublinDublin 2Ireland