Feature Project (Treatment Plant Design and Optimisation)
| Client: | | Rotorua District Council |
| Location: | | Rotorua, NZ |
For a number of years we have been assisting Rotorua District Council (RDC) with their wastewater treatment needs. In 2010, we completed a feasibility study to investigate increasing the wastewater treatment plant (WWTP) capacity from 65,000 Population Equivalent (PE) to 105,000 PE. Following an options evaluation, it was decided to use some of the existing WWTP water retaining structures to minimise construction risks associated with poor ground conditions. A side stream Membrane Bioreactor (MBR) process was selected as this process can achieve high and consistent effluent quality output at a low footprint area.
For this project we established a collaborative working partnership with RDC engineers and operational staff including developing a project plan “boundaries definition” for membrane supply. Contractually, the membrane supply came under AS/NZS 4911. Our detailed design team, project managed by Raj Valabh, then provided bespoke design work and contract documentation for the upgrade works.
A number of innovations were conceived and incorporated in to the design and contract procurement, such as: - Retrofitting all treatment processes and hollow fibre membranes into an existing structure,
- Use of 3D CAD for clash management and detailed design,
- Procurement of membranes, aeration blowers, aeration diffusers, pumps and mixers under AS/NZS 4911,
- Design / Build of blower building, tank retrofit and chemical storage by the contractor under NZS 3910,
- Process simulation modelling for design verification using BioWin®.
This project will be the first large scale MBR in New Zealand using hollow fibre membranes and will also be the largest municipal MBR in New Zealand treating a maximum daily flow of 11.3 ML/d.
The project is currently in construction, with commissioning scheduled for mid 2011.
Design Concept
Flat Sheet Membrane Bioreactor Operational Experiences, presented at 2010 Water New Zealand Conference
Rotorua District Council web site
www.rdc.govt.nz