3.2 Sewerage and Wastewater System Overview
This document provides an overview of the On-site Wastewater Management System (OWMS) at Lake Bennett Estate, based on the LBC OWMS O&M Manual V1.1 prepared by ENVR Solutions Pty Ltd.
Superseded Assessment
The 2019 Irwinconsult "Review of Wastewater Treatment Facilities" report identified critical deficiencies in the pre-upgrade system. That legacy infrastructure has been decommissioned and replaced by the upgraded OWMS described in this section.
System Status
Current Assessment
The upgraded OWMS is operational, treating wastewater to Class A recycled water standards via an AdvanTex® advanced secondary treatment plant with subsurface dripline irrigation disposal.
System Architecture
The OWMS comprises three subsystems:
- Wastewater Treatment Plant (WWTP) — AdvanTex® treatment, peak design 37,800 L/day
- Land Application Areas (LAA) — Two subsurface dripline irrigation zones (7,620 m²)
- Recycled Water Storage (RWS) — Four 27 kL tanks (108,000 L total)
Design Capacity
| Parameter | Value |
|---|---|
| Average daily flow | 12,000 L/day |
| Peak daily flow | 37,800 L/day |
| Primary treatment capacity | ~84,000 L (existing septic + 66,000 L new WWTP tanks) |
| Recycled water storage | 108,000 L (~2.8 days at peak flow) |
| LAA irrigation area | 7,620 m² operational (9,425 m² design total) |
| Allowable daily discharge | 22,860 L/day (3 mm/day DLR) |
Collection Network
Wastewater from 64 bungalows is collected via three zones:
| Zone | Bungalows | Route |
|---|---|---|
| Zone 1 | 17–59 | Gravity sewer → SPS1 (SSP1 ~18 kL septic) → WWTP PT-1 |
| Zone 2 | 1–16 | Gravity sewer → SPS2 (SSP2 STEP tank 22 kL) → WWTP PT-1 |
| Zone 3 | 65–66, 75–80 | Gravity → SSP4/SSP5 → SPS3 (SSP3) → rising main under lake → SPS1 |
System Components
Collection Network
- 3.2.1 SSP1 — Main Septic Tank & Lift Well (SPS1, Zone 1)
- 3.2.2 SSP2 — STEP Tank (SPS2, Zone 2)
- 3.2.3 SSP3 — Transfer Pump Station (SPS3, Zone 3)
- 3.2.4 SSP4 — Everhard Septic Tank & Lift Well
- 3.2.5 SSP5 — Modified AquaTreat Systems & Lift Well
- 3.2.6 Sewer Gravity Mains & Access Chambers
- 3.2.7 Rising Sewer Mains
Treatment Plant
- 3.2.10 Wastewater Treatment Plant Overview
- 3.2.11 Primary Treatment Tanks
- 3.2.12 AdvanTex Secondary Treatment
- 3.2.13 Disinfection and Final Polishing
- 3.2.14 Recycled Water Storage
- 3.2.15 OWMS Operations, Maintenance and Contingency
Disposal and Related
- 3.2.8 Effluent Disposal Area (Land Application Area)
- 3.2.9 Water Reservoir & Potential System Impact
Treatment Standards
The WWTP produces Class A recycled water suitable for:
- Subsurface irrigation within two designated LAA zones
- Future community nursery propagation and estate greening programs
| Parameter | Discharge Target |
|---|---|
| BOD | ≤ 30 mg/L (max) |
| TSS | ≤ 20 mg/L (max) |
| TN | ≤ 60 mg/L (avg) |
| TP | ≤ 20 mg/L (avg) |
| E. coli | ≤ 10 CFU/100 mL (max) |
| pH | 6–9 |
Key Contacts
| Role | Contact |
|---|---|
| Designer, Installer, Remote Monitoring | ENVR Solutions — 0402 524 033 |
| Site Caretaker | Tim Earl — 0417 892 281 |
| Liquid Waste Removal | McMinns Pumping — 0408 895 171 |
See 3.2.10 Contacts for the full contact list.
Version Control
| Version | Date | Description |
|---|---|---|
| 1.0 | 2025-10-06 | Initial Release (legacy system, Irwinconsult 2019) |
| 2.0 | 2026-06-22 | Updated for AdvanTex WWTP upgrade per O&M Manual V1.1 |
Next Review Date: 2026-12-22