Mondi plant gets water wise

MONDI Richards Bay is saving every drop of water after it replaced quench-to-drain flushing and lubricating systems fitted to mechanical seals with AESSEAL systems, which incorporates a continuous loop water management design.

The new systems will cut water usage at the plant by more than 60 000 kilolitres per month, helping to conserve scarce water resources in Zululand.

Mondi placed its order for the replacement systems in February on fluid sealing and wear resistance company Easy Coat, the AESSEAL agent for Richards Bay.

The order provides for 167 AESSEAL type-SWO2 and SWO3 water management systems that will use recycled water to cool, lubricate and flush mechanical seals in the local plant.

This will replace through flushing designs that need a constant supply of fresh water.

The order follows successful trials of 152 such systems installed over the last 12 years.

AESSEAL’s SWO2 system uses an integral vessel to store flushing water for continuous recycling.

Besides lowering costs by conserving water, the system is superior to the once-through format in three ways – there is an indicator that shows when any inboard seal failure occurs; the system is kept pressurised by a non-return valve which helps to prevent cross contamination of sealing water in the event of a failure; and the system is fitted with a regulating valve which maintains water pressure and flow rate without further settings or adjustments after installation.

Mondi’s own environmental department at the Richards Bay mill supported the new systems proposal because of a proven mechanical seal and potential water savings of just under four million kilolitres.

An installation some 10 years ago of mechanical seals and water management systems at Mondi’s Merebank mill just outside Durban, had resulted in multi-million Rand water savings and substantially reduced downtime on rotating equipment.

In the case of the Richards Bay contract, the 167 competitor cooling and lubrication systems to be replaced are consuming an average of 63 210 kilolitres of water every month.

With the cost of water calculated at R2.50 per kilolitre, excluding the effluent treatment costs, water savings of R158 025 per month will deliver a return on investment in the new AESSEAL systems in under a year.