Bulgur cooking process: Recovery of energy and wastewater

The cooking process in the grain industries (bulgur, parboiled rice, wheat, pulses, etc.) is an important operation, which requires high levels of energy and water. The wastewater from the cooking process in the bulgur industry is discharged without any recovery measures. In this study, the recovery of energy and water from the wastewater of the bulgur cooking process was investigated, including; i) recovery of the wastewater from the initial cooking process using filtration, centrifugation, a packed-filtering column (containing sand, activated carbon and resin) and ultraviolet-light (UV), and ii) the re-use in the subsequent cooking process by mixing with fresh water. Dissolved Oxygen (DO), 5 days-Biochemical Oxygen Demand (BOD5), pH, turbidity, conductivity, total solid content and Brix were measured to determine the effects of the wastewater treatment operations. It was found that these treatments were significantly (P ≤ 0.05) effective in the reduction of the BOD5 values from 429.5 to 93.7 mg/L. The total solid content, Brix, conductivity and turbidity values decreased. The energy requirement to heat up the water for cooking may be reduced to 57% of current energy usage. It was found that the re-use of wastewater may be possible for the subsequent cooking operations. [Display omitted] •The recoveryand reuse of wastewater and energy from the cooking operation is possible.•The wastewater of bulgur cooking system can be treated by using filtration, centrifugation, packed-filtering column and UV.•Energy requirement to heat up water for cooking might be decreased to 57% of current energy use.