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Durham University

Department of Engineering

Staff Profile

Publication details for Professor Karen Johnson

Johnson, K.L. & Younger, P.L. (2006). The co-treatment of sewage and mine waters in aerobic wetlands. Engineering Geology 85(1-2): 53-61.

Author(s) from Durham


trial aerobic wetland in NE England is the first passive system ever designed to treat both a polluted mine water and a
secondary sewage effluent. Both of these discharges currently enter a small third-order stream (the River Team), significantly
degrading its water quality. As the total mine water and sewage water discharges to the river are ∼300 and 100L/s respectively, the
pilot-scale wetland (25×25 m) has been designed to treat a small portion of each discharge in the same 3:1 ratio. The main drivers
for remediation are Fe (∼3 mg/L in the mine water), BOD (∼14 mg/L in the sewage water), N–NH3 (∼2 mg/L in the sewage
water), suspended solids (∼23 mg/L in the sewage water) and PO4 (∼7 mg/L in the sewage water).
The combined treatment has many potential advantages over separate treatment of the discharges. Besides the mutual benefits
of mixing these two wastewaters (which each tend to be low in pollutants which are high in the other), the biogeochemical
properties of the wastewater types can be expected to yield real synergies in treatment. For instance, suspended solids in the sewage
water should encourage iron flocs to form by Fe entering in the mine water, expediting the precipitation of oxyhydroxides. Similar
processes may also accelerate manganese removal. Phosphate, which is generally difficult to remove using either active or passive
treatment can be removed via sorption onto iron oxyhydroxide precipitates. The same oxyhydroxides are also likely to provide
numerous ideal sites for the attachment of nitrifying and denitrifying bacteria.
Although the wetland is still immature, initial results suggest that co-treatment is highly successful. Effluent concentrations have
consistently been lower than Environment Agency effluent design standards and removal rates for all parameters are likely to
improve with time as both biological and microbiological communities become established.


Batty, L.C., Younger, P.L., 2004. The use of waste materials in the
passive remediation of mine water pollution. Surveys in
Geophysics 25, 55–67.
Cooke, J.G., 1994. Nutrient transformations in a natural wetland
receiving sewage effluent and the implications for waste treatment.
Water, Science and Technology 29 (4), 209–217.
Demin, O.A., Dudeney, A.W.L., Tarasova, I.I., 2002. Remediation of
ammonia-rich mine water in constructed wetlands. Environmental
Technology 23 (5), 497–514.
Drizo, A., 1999. Physico-chemical screening of phosphate-removing
substrates for use in constructed wetland systems. Water Research
33 (17), 3595–3602.
Gouzinis, A., Kosmidis, N., Vayenas, D.V., Lyberatos, G., 1998.
Removal of Mn and simultaneous removal of NH3, Fe and Mn
from potable water using a trickling filter. Water Research 32 (8),
Heal, K.V., Smith, K.A., Younger, P.L., McHaffie, H., Batty, L.C.,
2004. Removing phosphorus from sewage effluent and agricultural
runoff using recovered ochre. In: Valsami-Jones, E. (Ed.),
Phosphorus in Environmental Technologies — Principles and
Applications. IWA Publishing, London, pp. 321–335.
Hedin, R.S., Watzlaf, G.R., Nairn, R.W., 1994. Passive treatment of
acid mine drainage with limestone. Journal of Environmental
Quality 23 (6), 1338–1345.
Jarvis, A.P., Younger, P.L., 2001. Passive treatment of ferruginous
mine waters using high surface area media. Water Research 35,
Johnson, K.L., Younger, P.L., 2005. Manganese removal from mine
waters using a novel enhanced bioremediation method. Journal of
Environmental Quality 34, 987–993.
Morris, A.W., Bale, A.J., 1979. Effect of rapid precipitation of
dissolved Mn in river water on estuarine Mn distributions. Nature
279, 318–319.
Mouchet, P., 1992. From conventional to biological removal of iron
and manganese in France. JAWWA, pp. 158–167. April.
Nairn, B., Hedin, R.S., 1993. Contaminant removal capabilities of
wetlands constructed to treat coal mine drainage. In: Moshiri, G.A.
(Ed.), Constructed Wetlands for Water Quality Improvement,
pp. 187–195.
Rose, P.D., Boshoff, G.A., van Hille, L.C.M., Dunn, K.M., Duncan,
J.R., 1998. An integrated algal sulphate reducing high rate ponding
process for the treatment of acid mine drainage wastewaters.
Biodegradation 9, 247–257.
Surface, J.M., Peverly, J.H., Steenhuis, T.S., Sanford, W.E., 1993.
Effect of season, substrate composition and plant growth on
landfill leachate treatment in a constructed wetland. In: Moshiri, G.
A. (Ed.), Constructed Wetlands for Water Quality Improvement.
Vandenabeele, J., Vandewoestyne, M., Houwen, F., Germonpre, R.,
Vandesande, D., Verstraete, 1995. Role of autotrophic nitrifiers in
biological manganese removal from groundwater containing
manganese and ammonium. Microbial Ecology 29 (1), 83–98.
Wallace, S., Parkin, G., Cross, C., 2001. Cold climate wetlands: design
and performance. Water, Science and Technology 44 (11/12),
Weedon, C.M., 2001. Treatment for simple houses and small
communities — compact vertical flow reed bed systems.
@quaenviro Technology Transfer Conference: Alternative Uses
of Constructed Wetland Systems. December.
Younger, P.L., 1993. Possible environmental impact of the closure of
two collieries in County Durham. Journal of the Institution of
Water and Environmental Management 7, 521–531.
Younger, P.L., Rose, P.D., 2000. Using one waste stream to cancel out
another: towards holistic management of industrial wastewaters
and solid wastes in the UK and South Africa. Proceedings of the
CIWEM Millennium Conference on Wastewater Treatment:
Standards and Technologies to Meet the Challenges of the 21st
Century, vol. 1. Leeds, UK, pp. 349–356. 4–6th April 2000.
Younger, P.L., Banwart, S.A., Hedin, R.S., 2002. Mine water,
hydrology, pollution, remediation. Environmental Pollution, vol.
5. Kluwer Academic Publishers, Dordrecht1-4020-0138-X (pb).