Australian Water Management Review Vol. 1 2014 | Page 135

MHL, also known as ‘Milk of Magnesia’, is a critical
product added to sewage by Unitywater to reduce odour
and protect underground assets against corrosion.

1

Recycled water is
supplied to the plant
hot water tank where it
is heated and stored,
ready for use in the
batching process.

Hot water is sent to
one of two hot mixing
tanks where additive
B and Magnesium
Oxide are added.

2

3

After two years of careful development with local expects, Wise Waste
Solutions, Unitywater now has the ability to cheaply manufacture MHL
directly on site using recycled water. The innovative and efficient approach
is creating significant savings for Unitywater in chemical costs.

The emulsified solution
passes through a heat
exchanger to be cooled
and is then transferred to
the 2000L cooling tank, for
further cooling and mixing.
The hot mixing tanks can
also be programmed to act
as cooling tanks.

4

The MHL solution is
transferred from the
cooling tank (or hot
mixing tank) to the
storage tank.

5

When required, the
MHL solutions is
transferred from the
storage tank to a truck
and transported to a
Sewage Pump Station
for further storage
and dosing of the
sewerage network.

Batching plant process
Magnesium Hydroxide Liquid
(MHL)

MgO

B

A

Magnesium
Hydroxide
liquid

2

1

HoT
WaTER
Tank

Stores and heats up to
4000L of recycled water
ready for use in the
batching proceess.

HoT
Mixing
TankS

The 2000L hot mixing
tanks mix and emulsify the
additive B and Magnesium
Oxide agents together with
the heated water.

5

4

3

Cooling
Tank

Once the temperature of
the solution has reduced
to 30°, additive A is added
into the tank and mixed to
create the MHL solution.

SToRagE
Tank

The MHL solution is The 20,000
litre storage tank receives the
final MHL product. Two mixer
devices (agitators) fitted inside
the storage tank rotate to
maintain the MHL composition