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3.2 Sewerage

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Superseded Assessment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:

Subsystem Detail
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

Treatment Plant

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 WWTP Overview 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