On the Pukete Wastewater Treatment Plant inlet works in Hamilton, where Importance Level 4 requirements demanded certified seismic and structural performance, APD delivered two custom HazSure® HDPE tanks totalling 60,000 L, redesigning the tank openings before fabrication after its engineering review found the issued drawings breached BS EN 12573.
McConnell Dowell required two custom 30,000 L HDPE service water tanks for the Pukete inlet works, part of a municipal infrastructure upgrade for Hamilton City Council. As part of an IL4 facility, the tanks needed verification for seismic loading and long-term structural performance.
This project required engineering coordination far exceeding standard storage tank specifications. Every nozzle, inspection opening, and anchor location had to integrate seamlessly with the civil infrastructure and mechanical pipework. Achieving PS1 certification demanded close, continuous collaboration with McConnell Dowell and a Chartered Engineer.
During our internal engineering review, APD identified a critical compliance discrepancy in the original project specifications detailing the side inspection ports. Manufacturing to the initial specifications would have resulted in non-compliant assets. Consultation was made with the client and Chartered Engineer where the design was engineered to achieve compliance.
| Attribute | Specification |
|---|---|
| System type | Custom HDPE tank (HazSure®) |
| Application | Service water storage (filtered river water), wastewater treatment inlet works |
| Total Safe Working Volume | 60,000 litres |
| Tanks per site | Two |
| Material | UV stabilised HDPE PE100 |
| Diameter (Internal) | 3500 mm |
| Operating liquid height | 3118 mm |
| Design temperature | 30°C |
| Design pressure | +0.5 / -0.3 kPa |
| Importance Level | IL4 |
| Seismic design | Site Class D with engineered hold-down restraint system |
| Construction standards | BS EN 12573, EN 1778, SWI 2017, Health and Safety at Work (Hazardous Substances) Regulations 2017, AS/NZS 1170, NZSEE |
| Verification | Independent PS1 |
| Design life | 25 years |
APD delivered two custom 30,000-litre storage tanks for the Pukete Wastewater Treatment Plant, meeting all municipal structural and earthquake safety requirements.
APD identified a compliance discrepancy regarding the side-entry inspection ports in the original specification documents. After reviewing the issue with the Client and Chartered Engineer, APD resolved their engineering concerns, ensuring the final assets met all safety regulations before manufacturing began.
When the client later issued late-stage piping changes, APD reissued documentation and secured immediate approval. This fast-tracked adjustment ensured the tanks met the target delivery date.
What happens if the project specifications conflict with the standards?
How are HDPE tanks certified for Importance Level 4 infrastructure?
Through independent verification. The Pukete tanks were validated by an independent Chartered Engineer PS1 assessment, covering seismic loading and long-term structural performance for a Site Class D site.
Can APD accommodate design changes after fabrication has started?
Yes. When late piping revisions were issued at Pukete, APD froze production at the fittings stage, updated all CAD models and STEP files, and reissued drawings for approval. The updated documentation was fast tracked, so the changes went through without delaying fabrication.
What are custom HDPE tanks for wastewater infrastructure made from?
The Pukete tanks were built from HDPE PE100 (black).
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