Brian Perry Civil delivered a new, state of the art Thickening and Dewatering Plant for Tauranga City Council at the operational Te Maunga Wastewater Treatment Plant.

The new facility involved the construction of:

• a two-storey architectural building,
• ground improvements,
• sludge load out facility
• two 16m diameter concrete PFT tanks,
• deep pump station installations,
• two 10,000L storage tanks,
• mechanical and electrical installations, and
• new access roads.

Working in an operational wastewater plant environment where ground conditions were poor and prone to liquefaction required careful planning to ensure we delivered the project to meet quality and programme requirements.

The site was highly-constrained, as was the programme, requiring constant coordination and problem solving to ensure the new plant was delivered safely to Tauranga City Council’s requirements whilst maintaining the existing plant operation. All subcontractors took part in a weekly coordination meeting and a logistics board was developed to ensure deliveries did not clash.

Our team was solutions-focused and innovated in their adaptation to unforeseen ground conditions by changing the ground improvement technique. The method was changed from insitu mass stabilisation to deep soil mixing piles. To achieve the original performance specification, we constructed 490 600mm diameter piles and overlapped them to form a continuous grout block.