Application of Box-Behnken Statistical Design Method in Chitosan Coagulation of Olive Mill Wastewater

Abstract

Olive oil production is one of the most important agricultural activities and is economically important for many Mediterranean countries. Olive oil mill wastewater (OMW) is an important liquid waste resulting from the numerous processes that occur during the olive oil production stages. OMW disposal is a serious environmental problem in the Mediterranean region, especially with its high organic matter, suspended solids, phenolic compound content and acidic pH value. In this study, chemical pretreatment of OMW by chitosan coagulation was investigated. The effect of chitosan coagulation on Chemical Oxygen Demand (COD) and Total Solid (TS) removal efficiencies were determined by Box-Behnken statistical experiment design. This method has been used to investigate the effects of three independent variables (chitosan concentration, slow mixing and precipitation time) on the response functions (COD and TS removal efficiencies) and to determine optimum conditions that maximize COD and TS removal efficiencies. Within the scope of the study, the Design expert program was used, and the correlation coefficient (R2) between the observed and estimated COD and TS removal efficiencies was found to be 0.979 and 0.9585, respectively. As a result of the experimental studies, the conditions in which the highest COD removal efficiency (53%) were obtained were 600 mg/L chitosan concentration, 45 minutes slow mixing time and 60 minutes precipitation time. The highest removal efficiency (73%) for TS removal was obtained at a chitosan concentration of 600 mg/L, a slow mixing time of 45 minutes and a precipitation time of 120 minutes. 

Keywords

• Box-Behnken Statistical Experiment Design
• Olive Mill Wastewater
• Chitosan
• Olive Oil Industry

Zeytinyağı Endüstrisi Atıksularının Kitosan ile Koagülasyonunda Box-Behnken İstatistiksel Deney Tasarım Yönteminin Uygulanması

Abstract

Zeytinyağı üretimi birçok Akdeniz ülkesi için en önemli tarımsal faaliyetlerden biridir ve ekonomik olarak önemlidir. Zeytinyağı endüstrisi atıksuyu (karasu), zeytinyağı üretim aşamalarında meydana gelen sayısız işlemden kaynaklanan önemli bir sıvı atıktır. Karasuyun bertarafı, özellikle yüksek organik madde, askıda katı madde, fenolik bileşik içeriği ve asidik pH değeri ile Akdeniz Bölgesinde ciddi bir çevresel sorundur. Bu çalışmada karasuyun kitosan koagülasyonu ile kimyasal olarak ön arıtımı araştırılmıştır. Kitosan ile koagülasyonun Kimyasal Oksijen İhtiyacı (KOI) ve Toplam Katı Madde (TKM) giderme verimleri üzerindeki etkisi Box-Behnken istatistiksel deney tasarımı ile belirlenmiştir. Bu yöntem, üç bağımsız değişkenin (kitosan konsantrasyonu, yavaş karıştırma ve çökeltme süresi) tepki fonksiyonları (KOI ve TKM verimliliği) üzerindeki etkilerini araştırmak ve KOI giderme verimini en üst düzeye çıkaran optimum koşulları belirlemek için kullanılmıştır. Çalışma kapsamında Design Expert programı kullanılmış, gözlemlenen ve tahmin edilen KOİ ve TKM giderme verimleri arasındaki korelasyon katsayıları (R2) sırasıyla 0.979 ve 0.9585 olarak bulunmuştur. Yapılan deneysel çalışmalar sonucunda en yüksek KOİ giderme veriminin (%53) elde edildiği koşullar; 600 mg/L kitosan konsantrasyonu, 45 dakika yavaş karıştırma süresi ve 60 dakika çökeltim süresi olarak bulunmuştur. TKM giderimi için en yüksek giderme verimi (%73) ise, 600 mg/L kitosan konsantrasyonu, 45 dakika yavaş karıştırma süresi ve 120 dakika çökeltim süresinde elde edilmiştir.

Keywords

• Box-Behnken İstatistiksel Deney Tasarımı
• Karasu
• Kitosan
• Zeytinyağı Endüstrisi

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