Sentetik biyogaz tesisi sıvı atığının karışık mikro alg bakteri kültürleri ile arıtımı

Öz

Biyogaz üretiminin sıvı yan ürünü olan biyogaz tesisi sıvı atığı (BTSA), yüksek KOİ, N ve P içeriğiyle alıcı ortamlarda ciddi kirlilik ve ötrofikasyon riski oluşturmaktadır. Bu çalışmada, yaklaşık KOİ 1065 mg/L, NH₄⁺-N 350 mg/L, ve PO₄³⁻-P 26,3 mg/L olarak hazırlanan sentetik BTSA üçlü paralel kesikli reaktörde mikroalg-bakteri karışık kültürü ile arıtılmıştır. Reaktörler sabit sıcaklıkta, kontrollü ışık altında ve sürekli hava pompası ile karışım sağlanılarak işletilmiştir. Deneysel izleme, biyokütle üretiminin devam ettiği 78 gün boyunca sürmüş; pH, klorofil a (Chl-a), optik yoğunluk (OY660) KOİ, NH₄⁺-N ve PO₄³⁻-P düzenli olarak ölçülmüştür. Biyokütlenin ve Chl-a’nın sürekli artışı, mikroalg-bakteri biyokütlesinin geliştiğini ve besin maddelerinin esas olarak asimilasyon yoluyla giderildiğini ortaya koymuştur. Maksimum 397 mg/L uçucu askıda katı madde (UAKM) derişimine ulaşılmıştır. KOİ başlangıca göre %88,3 azalmış, bu da bakteriyel oksidasyonun yanı sıra fotosentezle desteklenen simbiyotik metabolizmanın etkinliğini göstermiştir. NH₄⁺-N de %38,9’luk giderim gözlenmiş, bunun yaklaşık %12’sinin biyokütle asimilasyonuna, geri kalanının ise volatilizasyon ve olası nitrifikasyona bağlı olduğu hesaplanmıştır. PO₄³⁻-P konsantrasyonu 24,45 mg/L’den 12,15 mg/L’ye düşmüş (%50,3 giderim) olup, bu azalımın da büyük ölçüde alg biyokütlesine fosfor dahil edilmesiyle açıklanabileceği görülmüştür. Sonuçlar, mikroalg-bakteri kültürleri ile BTSA’nın arıtımında asimilasyon temelli bir mekanizma ile etkili KOİ, N ve P giderimi sağladığını göstermektedir.

Anahtar Kelimeler

• Atıksu arıtımı
• Asimilasyon
• Biyogaz tesisi sıvı atığı
• Mikroalg-bakteri
• Ötrofikasyon kontrolü

Treatment of synthetic biogas slurry with mixed microalgae-bacteria cultures

Öz

Biogas slurry (BS), a liquid by-product of biogas production, poses a significant risk of pollution and eutrophication in receiving environments due to its high concentrations of COD, nitrogen (N), and phosphorus (P). In this study, synthetic (BS) prepared with approximately 1065 mg/L COD, 350 mg/L NH₄⁺-N, and 26.3 mg/L PO₄³⁻-P was treated in triplicate batch reactors using a mixed microalgae–bacteria culture. The reactors were operated under constant temperature, controlled light conditions, and continuous aeration to ensure proper mixing. Experimental monitoring was conducted for 78 days, during which biomass production persisted, and pH, chlorophyll a (Chl-a), optical density (OD₆₆₀), COD, C, and PO₄³⁻-P were regularly measured. The continuous increase in biomass and Chl-a confirmed the growth of microalgae–bacteria biomass and revealed that nutrient removal occurred primarily through assimilation. A maximum volatile suspended solids (VSS) concentration of 397 mg/L was achieved. COD decreased by 88.3% compared to the initial value, demonstrating the effectiveness of the symbiotic metabolism supported by both bacterial oxidation and photosynthesis. NH₄⁺-N removal reached 38.9%, of which approximately 12% was attributed to biomass assimilation, with the remainder likely due to volatilization and potential nitrification. PO₄³⁻-P concentration decreased from 24.45 mg/L to 12.15 mg/L (50.3% removal), primarily explained by phosphorus incorporation into algal biomass. The results demonstrate that BS treatment with microalgae–bacteria cultures provides efficient COD, N, and P removal via an assimilation-based mechanism

Anahtar Kelimeler

• Wastewater treatment
• Assimilation
• Biogas Slurry
• Microalgae bacteria
• Eutrophication control

Kaynakça

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