Repairs relieve pipeline pressure

Emergency repairs to Tauranga's ocean outfall sewer pipeline have succeeded in relieving pressure on overloaded sewage treatment ponds at Te Maunga.

Council spokesman Marcel Currin said the ponds, the last stage of the sewage treatment process, had never been so full.

The problems began when a pipeline collar broke at the air valve chamber, buried in the Omanu sand dunes at the edge of the beach. This pushed out a rubber ring joint, creating such a big leak it blew out the dunes.

Temporary repairs on Tuesday meant that pumping down the pipeline from Te Maunga was able to be increased to accommodate the full volume of effluent entering the sewage treatment works.

It took pressure off the man-made wetland ponds which had been slowly filling up because only 80 per cent of the sewage entering the works was able to be pumped down the leaking pipeline.

Once the main repair was completed by 4pm on Tuesday, the council was able to pump at 200 litres a second down the ocean outfall pipeline - matching the volumes entering the treatment works. Overnight pumping at the higher pressure meant the council was able to clear treated sewage from the brim-full ponds.

A two-hour shutdown of the pipeline yesterday was needed to complete repairs and allow pumping down the outfall to exceed 200 litres a second. This will handle the additional volumes from the rain which was forecasted to arrive this weekend.

The break in the pipeline happened last Saturday when the council boosted pipeline pressures to test repairs to leaks along the ocean part of the outfall.