Aerofloat delivered an effective WWTP to ensure cost effective operations. 

Aerofloat was contracted to build a wastewater treatment facility to process the wastewater from the cardboard packaging plant after constructing similar plants at the client’s New Zealand and Melbourne facilities. It was able to draw on this experience to ensure the new Queensland facility exceeded expectations.

At the pre-existing plant, process wastewater was being treated by chemical flocculation and sedimentation prior to discharge to sewer. Waste sludge was being dewatered in a plate press prior to disposal to landfill. Aerofloat was contracted to design a low maintenance wastewater treatment plant that would ensure compliant effluent.

The wastewater at the plant needed to be treated to a level suitable for sewer discharge and accommodate growth at the site. The client wanted to improve its manual handling and safety at the site for operators. Some structures within the system had also reached the end of their lifespan and required upgrades to ensure safe and effective operations. 

“The previous construction of similar plants in New Zealand and Melbourne for the client allowed Aerofloat to ensure a well-considered, innovative design that would meet the client’s needs,” said Michael Anderson, Aerofloat’s GM.

“Aerofloat incorporated its AeroCirc DAF technology and associated process equipment, tanks and controls to treat the process wastewater to the sewer discharge standards and provided a new filter press system.”

After reaching the treatment plant from the production line, wastewater flowed over a rotary drum screen to automatically remove solids, labels and foreign matter entered the drainage network from the building. It then gravitated to a 46,000 litre balance tank to be pH corrected.

From the balance tank, the wastewater was pumped through Aerofloat’s patented AeroCirc DAF made from 304 SS material with a 60-degree hopper bottom tank. The AeroCirc DAF was able to treat flows up to 12m3 per hour.

Aerofloat also installed a progressive cavity feed pump and dosed Aerofloat’s coagulant into the suction of the feed pump. The coagulating wastewater then flowed to an inline coagulation pipe to the AeroCirc DAF which included a scum removal process to eliminate the need for mechanical scrapers, creating a self-cleaning mechanism. This also overcame the need for pumping the float material to the sludge thickening tank.

Polymer treatment completed the final coagulation process and the thickened floated solids were automatically scraped off the top of the AeroCirc DAF sludge hopper and pumped to the new 10,000 litre stainless steel  sludge storage tank.

Incoming wastewater was directed via a single line to a 2mm grated fine TORO rotating screening system on a mezzanine floor. A new automatic plate press sludge dewatering system was installed on the newly constructed mezzanine floor. Dewatered cake was disposed of off-site. Filtrate from the plate press then gravitated back to the balance tank via the pump pit.

The pH of the treated effluent was recorded and adjusted prior to discharge to sewer in the effluent tank to ensure compliancy. 

“The system was logic-controlled to ensure only compliant effluent was discharged. Both the operators and Aerofloat’s engineers can access the system remotely via the eWon remote access system to allow maximum control of the plant. The plant automatically returns any effluent that is out of spec to the balance tank to be reprocessed.  A pH probe and turbidity monitor were installed and an alarm provided in the event that the effluent was out of specification,” said Anderson.

In addition to the compliant effluent result, Aerofloat’s design was compact and had a minimal environmental footprint. Its sealed and vented tanks created an odourless plant, and the mechanical simplicity of the design, with its self-cleaning hopper bottom, ensured a maintenance-friendly system.