Wenderholm Regional Park – Waiwera
Wenderholm with its pohutukawa glade picnic area, safe beach and scenic walks is a great family destination. The park sits between mouths of the Puhoi and Waiwera rivers in a very picturesque part of the North Island.
A key to the wastewater treatment plant installed at this location was that no part of it impacted on the park’s surroundings.
In addition to this, the sensitive coastal environment and fluctuating loads required a robust and sustainable wastewater management solution.
The Orenco AdvanTex® system—supplied by Innoflow fitted the criteria perfectly. The unobtrusive nature of the AdvanTex® system allowed for the treatment system to be installed in the main picnic area. The recirculating textile packed bed reactor provided a robust process able to handle with ease the widely fluctuating loads encountered at this site.The following details the system components and technical specifications. Also shown are the expected and actual performance figures for this wastewater management system.
The Treatment Plant is installed completely underground, with only the AdvanTex® Pods slightly elevated due to flooding in this area. Brown access lids have been used to blend in with the barked finish chosen by the Park managers. The whole treatment plant will soon disappear when the native vegetation planted over the top of the plant establishes.| Constraint | Solution | Comment |
| Widely fluctuating flows. | Utilise large surface area of AdvanTex® Textile pods in conjunction with timer dosing | The rtPBR provides a robust treatment process producing consistent performance under widely fluctuating loads |
| Limited area for disposal | Low pressure effluent distribution installed under park area | The very high level of treatment from the rtPBR allowed reduction in disposal field size. A 50 l/m2 loading was used. |
| Issues with Groundwater and flooding | Entire treatment plant watertight | Watertight risers and lids provide access to all points of the treatment plant while protecting it from infiltration |
| Remote Location. One onsite staff member who needs to patrol entire park area | Remote Telemetry Control Panel supplied with treatment plant | All parameters can be controlled remotely via desktop computer. Pumps and alarms can be controlled and bypassed if needed. Trend analysis data can be collected |
Table 1: Design Constraints
| Parameter | Expected Performance | Actual Performance |
| BOD5 | <10 mg/ltr | 0.5 mg/ltr |
| Suspended Solids | < 10 mg/ltr | 3 mg/ltr |
Table 2: Treatment System Performance
| System Component | Specification | Comment |
| Design Flow (Peak) | 25 m3/day | Varies. Average 15 m³/day |
| Septic Tanks | 2 @ 23 m3 + Existing | Existing Septic Tank fitted with ProSTEP Pumping system for waste from Couldrey House |
| Recirculation Tank Size | 23 m3 | Installed deep underground to achieve gravity flow from Septic Tanks |
| Recirculation Pump | Orenco Multi-stage Turbine | Duty Alternating Crossover. Serving 5 sectors with 3 pods per sector |
| Packed Bed Reactor Area | 15 m2 | Installed in unusable terrain in a 5 by 3 matrix next to toilets |
| Treated Effluent Tank Size | 23 m³ | Installed downstream of Splitter valve |
| Discharge Pump | Orenco Multi-stage Turbine | Timer controlled submersible turbine pump to dose load low pressure distribution trenches |
| Disposal Trenches | Low Pressure Distribution | Installed in sand underneath park area |
Table 3: System Summary