Recovering energy, nutrient and water from waste water of bulgur plants

Abstract

Bu çalsmada bulgur fabrikalarnin atik sularndan enerji, besin ve suyun geri kazanmi arastrlmistir. Bulgur üretiminde yüksek miktarda su kullanmi ve atilmasindan dolayi, özellikle yikama ve pisirme islemleri önem arz etmektedir. Günümüzde, sanayide yikama ve pisirme isleminden meydana çikan atik su herhangi bir isleme konmadan atilmaktadir. Bu çalsmada, yikama (20 °C) ve pisirme (97 °C) islemi 1 oran bugday oranina sirasiyla 1 ve 2 oran su kullanldi. Yikama ve pisirmeden elde edilen atik suyu sirasiyla filtrasyon, santrifüj ve içersinde kum, aktif karbon ve reçine bulunan kolon ve en sonunda ultraviyole isiktan geçirilmistir. Bu islemlerin etkilerini ögrenmek amaciyla, atik suyun özellikleri (çözünmüs oksijen, BOt5, renk degerleri, pH, bulanklk, iletkenlik, toplam kati madde, Brix ve sadece yikama suyunda mikrobial yük) islemlerden önce ve sonra belirlendi.tstatistiksel olarak, atik su islemlerinin yikama ve pisirme sularna ait BOt5 degerlerinde sirasiyla 311.5`ten 169.9'a ve 429.5'ten 93.7 mg/l olmak üzere önemli (p<0.05) etkileri oldugu belirlenmistir. Her iki atik suda da renk degerleri olumlu yönde degismistir. Toplam kati madde, iletkenlik, Brix ve bulanklk degerleri düsmüstür.Ayrca uygulanan atik su degerlerine ek olarak, pisirme isleminden elde edilen atik su bir sonraki pisirme isleminde temiz su ile karstirlarak kullanilmistir. Ve daha sonraki pisirme islemlerinde de kullanlabilecegi anlasilmistir. Bununla beraber pisirme suyuna geçen besinler, pisirme suyundaki BOt5 degerinin yükselmesine sebep olmaktadir. Bu noktada, bu besinleri geri kazanmak için püskürtmeli kurutma yöntemi kullanlmistir. Püskürtmeli kurutma yöntemi ile elde edilen ürün %19 protein, %10 ni§asta ve %12 kül oran ile hazir çorba, bebek mamasi olarak ta kullanlabilir.Elde edilen sonuçlara göre, yikama ve pi§irme i§lemlerinden sirasiyla %73.4 ve %49.5 oraninda su geri kazanlabilmektedir. Ayrca, 50 ton/gün kapasiteli bir bulgur fabrikasi, yillk olarak $ 70524 ve 19080 ton su geri kazanabilecektir. Yatirm maliyeti, isletme maliyeti, hurda degeri ve servis ömrünün hesaplanmasinn ardindan net kar $ 51524 olarak ortaya çikmistir.Anahtar kelimeler: atik su, geri kazanm, bulgur, pisirme, yikama, enerji, su, besin.

In this study, recovering energy, nutrient and water from wastewater of bulgur plants were investigated. Especially, the washing and cooking steps are important operations in bulgur processing due to the significant amount of water usage and disposal. At present, the wastewater from the washing and cooking operations is discharged without any recovering operation in the industry. Washing (20 °C) and cooking (97 °C) were made using 1 and 2 ratios of water to 1 ratio of wheat, respectively. The wastewater obtained from the washing and cooking was treated with filtration, centrifugation and column which contains sand, activated carbon and resin, and then finally treated with UV. Before and after the treatments, the properties of water (DO, BOD5, color values, pH, turbidity, conductivity, total solid content, Brix and microorganism load only for the washing wastewater) were determined to find the effect of the treatments.It was found that these treatments were significantly (p<0.05) effective on the reduction of the BOD5 values from 311.5 to 169.9 and from 429.5 to 93.7 mg/l, for the washing and cooking, respectively. For both wastewater, the treatments improved the color values (L*, a*, b*, YI). Total solid content, Brix, conductivity and turbidity decreased.In addition to the recovering treatments, the wastewater of cooking was used in the next cooking operation by mixing with fresh water. It was found that the reuse of wastewater could be possible for the subsequent cooking operations. Also, the nutrients leached during the cooking lead to increase the BOD5 value of the wastewater of cooking. At this point, the spray drying method was used to recover the nutrients. The spray dried product can be used in ready soup, baby foods recipes, because of containing 19 % protein, 10 % starch and 12 % ash.According to the result, 73.4 and 49.5 % of wastewater can be obtained from the washing and cooking operations, respectively. Additionally, one bulgur plant, having 50 tons/day capacity, can save nearly $ 70524 and 19080 tons of water, annually. The net profit after the evaluation of investment cost, processing cost, salvage value and service life of system was calculated as $ 51524.Keywords: wastewater, recovery, bulgur, cooking, washing, energy, water, nutrient