131001 Minor Change Request · 132006.268.03

4377-131119-1.0


3.0 EFFLUENT QUALITY AND QUANTITY
3.1 ASSESSMENT OF SOIL AND GROUNDWATER CONDITIONS
The soil and percolation test results indicate that the soils at the site are relatively
impermeable but is however still suitable for on-site sewage treatment and effluent disposal.

Groundwater or seepage was not observed within the boreholes carried out during the recent

site investigation.



Given the relatively poor permeability of the site soils and the presence of medium to heavy
clay soils which are more representative of Category 6 soils, the on-site wastewater

assessment for this site is based on Category 6 soils although the Borehole logs indicate the

presence of Categoiy 5 top soils.


3.2 SYSTEM SELECTION
In order to minimise potential impacts on local water quality and to maximise the potential

reuse of treated effluent, it is recommended that all wastewater generated from the

development be treated to a minimum secondary standard. It is understood that all wastewater

generated from the dwelling and factory office facilities will be diverted to the existing septic
tank located geographically downslope of the waste generating facilities. It is proposed that
the existing septic tank will be converted to a pump station, with all collected wastewater to

be pumped to a SIP capable of treating the wastewater to a minimum secondary standard.



Typical quality criteria for secondary and advanced secondary treated effluent nominated in

the Department of Infrastructure and Planning, Queensland Plumbing and Wastewater Code

are summarised in the following table:


Table 1: Quality Criteria for Secondary and Advanced Secondary Treated Effluent
                                                                                Advanced Secondary
                                                    Secondary Treatment
                  Parameter           Units                                         Treatment
                                                      Acceptable Limit
                                                                                 Acceptable Limit
             Suspended Solids          mg/L                  30                         10
                     BODS              mg/L                  20                         10
                Faecal Coliforms    cfu/IOOmL                200                        10




February 2014                          Site & Soil Evaluation Report                                 6
                                   Wastewater Treatment and Effluent Disposal
                                   314 Cooroy Mountain Road, Cooroy Mountain