2016-07-12 - Item 14 - Att 1 - Effluent Disposal Planning Study

Figure 10 - A secondary treatment system serving a small dwelling




5.3        Noosa Council On-Site Domestic Wastewater Treatment Plant Audit
           Program
In October 2014, Council endorsed a program to conduct a formal audit of wastewater facilities in
Noosa Shire. At that time there were 3109 septic installations, 2161 secondary or advanced
secondary systems and a further 86 properties relying on holding tanks.

Consequently Council received approximately 8000 service reports from contractors and conducts
an average of 100 inspections annually. Normal audit practices involved a desk top study of
service reports submitted by contractors and to investigate issues as identified.

The principal aims of the endorsed audit program are to –

       1. Allow Council and system owners to identify potentially failing systems, and
       2. Audit service reports to test accuracy.

The program has provision for up to 50 detailed analysis tests to be submitted to a NATA approved
laboratory. The program will additionally test new software applications and equipment.
The audit reviews domestic on-site wastewater treatment plants and their land disposal systems.
The focus of the program is on Secondary, Advanced Secondary and Advanced Secondary
systems with Nutrient Reduction.

Council inspectors assess the land disposal system and the treatment plant for faults and record
the results on a report loaded onto a mobile app. The app records the sludge level, total
suspended solids (TSS), PH and dissolved chlorine content of the treated effluent. Comments on
the land disposal system are added to the app. There is provision for testing which will involve
sending samples to a NATA approved laboratory to check for levels of nutrients and thermo-
tolerant coliforms.

A review of 100 audit results demonstrated 41 systems were found to be not compliant.
Test results showed:-

           9 plants had total suspended solids levels greater than the permitted range,
           4 plants had PH levels out of the recommended range,
           8 plants required pump outs due to high sludge levels,

On-Site Effluent Disposal in Noosa Shire 2016                                              Page 19