1. Cross-border network for knowledge transfer and innovative development in wastewater treatment WATERFRIEND HUSRB/1203/221/196 2nd Training course – Industry wastewater treatment

2. .. 2nd Training course Waterfriend WASTE WATER CONSIDERATIONS IN GRAIN MILLING INDUSTRY Aleksandar Fišteš & Dragana Šoronja Simović

3. .. 2nd Training course Waterfriend

4. .. Cereal processing industry  any industry that takes a cereal or a cereal product as it raw material  diverse as the range of products it produces (food and non-food)  grain milling can be designated as a mainstream process

5. .. 2nd Training course Waterfriend Pollutant parameters Major control parameters:  biochemical oxygen demand (BOD)  suspended solids (SS)  acidity (pH) Additional control parameters:  chemical oxygen demand (COD)  inorganic dissolved solids  temperature  phosphorus  ammonia

6. .. 2nd Training course Waterfriend Corn dry milling

7. .. 2nd Training course Waterfriend Water use in corn dry milling Washing:  remove any remaining impurities and mold  lot of the mills does not use water to clean corn  the resultant waste waters: high BOD (1500-2000 mg/l) concentrations high SS (1500-3500 mg/l) concentrations significant pollution problem Treatment of the waste stream:  collection of waste water from washing operation if practiced  primary solids separation by sedimentation  biological treatment using activated sludge or a comparable system  final separation of solids by sedimentation prior to discharge  solids are added to the hominy feed  clarified waste waters could be recycled into corn washing operation

8. .. 2nd Training course Waterfriend Tempering:  raises the moisture content of the corn to the level necessary for milling  only enough water is added to reach the desired moisture content  no waste water is generated Water use in corn dry milling The best way is to avoid generating any waste water by replacing the wet methods with dry cleaning techniques

9. .. 2nd Training course Waterfriend Wheat milling

10. .. 2nd Training course Waterfriend Water use in wheat milling Washing:  very few mills today use a water wash as a final cleaning step  adds about one percent moisture to the wheat  reduce microbiological contaminants  waste waters contain moderately high levels of BOD and SS Tempering:  the vast majority of mills use dry cleaning techniques  modern wheat flour milling uses water only in tempering  adding water to bring the moisture content up to desired levels (14-17%)  no process waste waters are discharged

11. .. 2nd Training course Waterfriend Rice milling  the product is whole grain rather than flour (byproduct)  does not use any process waters  no process waste waters

12. .. 2nd Training course Waterfriend Parboiled rice process

13. .. 2nd Training course Waterfriend Water use in parboiled rice process Waste waters:  from the parboiling and steeping operation  steep water is not reusable for steeping because of the color pick-up which would discolor the rice  high in dissolved BOD (1200-1300 mg/l)  low in SS (30-80 mg/l) Treatment of the waste stream:  collection of waste water  biological treatment using activated sludge or a comparable system  final separation of solids by sedimentation prior to discharge  the biological solids from treatment process could be included with the bran and hulls as animal feed

14. .. 2nd Training course Waterfriend Presentation/lecture has been produced with the financial assistance of the European Union. The content of the presentation/lecture is the sole responsibility of University of Novi Sad, Faculty of Technology and can under no circumstances be regarded as reflecting the position of the European Union and/or the Managing Authority. The best way to deal with the waste waters is to avoid generating them