How it works
OMA App provides a rapid field indicator of effluent quality to assist Council in the management of onsite facilities by providing a guide of the presence of suspended solids (Turbidity/TSS – Total Suspended Organic Solids).*
OMA App does not replace the need for laboratory testing for those facilities Council may consider high risk.
The most accurate method of measuring suspended solids is a laboratory process that is expensive, time-sensitive, time-consuming (transporting samples to the laboratory) and impractical for application in the field. A long-established and accepted alternative utilises a Secchi disk and visual interpretation by the person conducting the test.**
OMA draws on the principals of the conventional Secchi tube, which needs to be filled to a depth of 1 metre, for the OMA sample tube that requires only 100mm.
The Basic Process
A small sample of effluent is placed in the OMA tube to the level indicator on the side of the tube.
A cap is placed on the top of the tube with a focal distance of 150mm to the Secchi disk. This allows a smart device camera to focus on the Secchi disk in the base of the tube through a consistent depth sample.
The OMA app instantly analyses a photo of the Secchi disk and calculates a grey-scale percentage relative to a baseline photo of the empty tube.
This value is correlated against a known TSS sample of effluent prepared by a NATA laboratory with accurate mg/litre of TSS to the values of 5, 10, 15, 20, 25, 30, 35 and 40.***