Case studies

Progressive Cavity Pump Solution for South Canterbury ByProducts Ltd

South Canterbury ByProducts relocation to their Timaru site in 2009 bought about a requirement for a new Odour Control and Raw Material Transfer solution, with a key challenge being the 100 metre distance the raw materials were to travel. With a 5-10 metre distance being typical, this presented a significant challenge and whilst they were aware of what a solution might look like based on overseas examples, nothing like it had been attempted at the time in New Zealand.

Previously the DAF (Dissolved Airflow Flotation) system collected the top solids which were then treated by pumping them through a steam heated decanter (centrifuge), spinning out the liquid before collecting the solids and transporting them to a composting operation. Shaun Morath, the Maintenance Manager at Levin said that they had long suspected that these solids were not being treated well. The solution was to replace the decanter with a Filter Belt Press.

Prior to the Belt Press installation, approximately 8 tonnes of solids had been collected daily and the liquid centrate going back into the effluent system had approximately 4% solids causing overloading issues with the treatment system, in turn causing problematic odours and additional disposal costs. In extreme cases it also caused problems for the municipal waste treatment plant where the final effluent was discharged.

The new filter Belt Press improved effluent quality overnight. Liquid centrate from the system dropped to around 0.2 to 0.3% solids, having a significant positive effect on the final effluent quality and operation of the DAF plant. Odour was no longer an issue and there was a 30% uplift in solids collected. Onsite, the self cleaning belts and simple wash down at the end of day added to its ease of use and maintenance costs have been vastly reduced.

Positive flow-on effects saw overall chemical use dropped by 50%, again contributing to cleaner waste water and reduced operating costs.

The entire system became a lot easier to operate and has required considerably less labour input to run so from our perspective and that of the local council and our neighbours the installation of the belt press has been a real success story.

Shaun Morath, Maintenance Manager