AS 1546.3:2017 Australian Standard On-site domestic wastewater treatment units
A5.2.3 Influent distribution
Influent shall be pumped from the inlet of an STP or a suitably sized tank containing fresh domestic wastewater (i.e. £6 h since it was generated at a premises) to the inlet of the test STS by a positive displacement cavity pump, progressive cavity pump, solids handling pump or macerator pump via an appropriately sized pipe. The flow rate per minute and per hour shall be controlled by a Programmable Logic Controller (PLC) and the doses logged/measured and recorded each day in accordance with Tables A2 or A3. The dosing pump for systems £2000 L/d shall be capable of delivering from 50 L (±10%) within 5 mins to 150 L (±10%) within 15 mins. The dosing pump for larger systems (>2000 L/d to £5000 L/d) shall be capable of delivering from 50 L (±5%) within 2.5 mins to 150 L within 7.5 mins. A flow meter capable of measuring to an accuracy of 1% of the minimum flow shall be installed between the influent collection apparatus and the test STS. A Programmable Logic Controller (PLC) shall be programmed, installed for each test STS and connected to the flow meter to control the flow, time and duration that wastewater is pumped from the holding tank to the system.
A5.3.1 General
The commissioning period shall commence and be completed prior to winter (e.g. in Australia winter starts on 1st June). The commissioning period shall commence on the day the test STS is filled with wastewater. The first chamber shall be filled with raw wastewater and the remaining chambers, basins or containers filled with potable water. The supplier shall check the system for proper installation. If no defects are detected and the system is judged to be structurally sound, it shall be placed in operation in accordance with the manufacturer’s start-up procedures.
Where influent and effluent testing undertaken earlier than week six shows that the test STS has achieved the required effluent quality criteria listed in Table 2.1, testing in accordance with Appendix A may commence. Where the STS does not achieve the minimum secondary effluent quality criteria listed in Table 2.1 within eight weeks, the commissioning period may be extended.