Proceedings

Manganese occurs naturally in the upland raw water sources of Britain. Although not of toxicological
concern, low manganese residuals in the public water supply give rise to black mains deposits and dirty
water complaints. This causes significant capital expenditure in the water industry.

The process engineering of manganese removal has become regarded as a bolt‐on unit process;
essentially oxidation of soluble manganese to the insoluble form and removal by filtration. Historical
practice has been to use chlorine, which causes other water quality problems, or adsorption onto active
media (green sand or manganese dioxide). The latter preferred process is not well defined.

Laboratory experiments and plant data reported here, demonstrate the conditions for the adsorption and
oxidation of manganese on sand without chlorination. Inclusion of this process within conventional Rapid
Gravity Filtration is proposed to avoid unnecessary capital expenditure and enhance the efficiency and
sustainability of the overall treatment process.