As a follow up to laboratory work completed under the project A0305 (Process Improvements to Starch Products from Root and Tuber Crops) and a process audit of starch and sago production (Trim and Curran, 1993) a visit was undertaken to carry out a preliminary field test of a hydrocyclone unit and evaluate its potential for application in the sago and starch industry. The commissioning trials showed that the unit performed marginally better than predicted during laboratory tests. Solid recoveries from the unit were in the range 91-95% compared to 88-92% with similar underflow volume splits of around 45%. Integrated factory trials demonstrated the possibility of re-cycling up to 60% of the water required for root crushing and sieving of the starch milk with equivalent reduction in the volume of waste water produced. Composition of factory waste waters when the hydrocyclone unit was used was little different from that of the waste waters produced under normal operation. However, the reduction in pollution load possible from using hydrocyclones to re-cycle process water may be more than 50%. There appeared to be a positive effect on the quality of the starch, in terms of the colour and level of impurities, produced when using the hydrocyclone. This offers the possibility of eliminating subsequent washing of the starch. A slight improvement in the whiteness of the polished sago was recorded which may be reflected in higher prices. Based on these highly successful results and the positive reaction showed by producers and local authorities, proposals are made for full-scale trials of a hydrocyclone unit over a full processing season, and to assess the implications at the macro level, both in economic and environmental terms, of introducing the technology. It is also recommended that collaboration be made with a hydrocyclone manufacturer in order to facilitate uptake of the technology by producers, and to collaborate with SAGOSERVE on the development of strategies for introduction of the technology and its wider dissemination across the industrial sector
