Effluent Disposal Report

3.0 DESIGN DETERMINATION

We have determined the soil to have the following characteristics

 

 

 

 

 

 

 

 

 

Borehole Nos 3&4
Depth (mm) 0 - 200
Soil Category 5
Indicative Drainage Poor
Structure Strong
Texture ; Light Clay
Indicative Permeability P (metres/day) as Kat 0.12 - 0.5

 

 

For our calculations we have assessed the design flow as follows

 

 
   

 

 

 

 

 

 

DLR (mm/day) (Advanced Enviro-septic™ effluent) 5-8
Hydraulic load (litres/day/person) 120
Design flow Q (litres/day) (equivalent population 5 people) 600
Total System Footprint (m’) =75
Septic Tank minimum size requirement (litres) 3000

 

 

 

Advanced Enviro-septic™ System

 

 

Note — AS/NZS 1547-2012 (Appendix H, Table H1) lists the typical wastewater design flow
allowance for households with an on-site roof water tank supply as 120-litres/person/day (all
wastes). With the installation of standard water reduction fixtures the design flow can be
reduced substantially.

Note — In this instance we have used the maximum DLR of 8 mm/day due to the very highly
structured nature of the Category 5 soil recorded in BH 3 and that we recorded Category 4
soil in BH 4.

Where the design flow ‘Q’, nominated above, is exceeded the area (Ai) may need to be
increased accordingly. This sewerage system is not suitable for accepting waste from
garbage grinders.

 

Unearthed Geotechnical P/L. 3 Design Report 020-212