Makalenin Adı: Pestisit endüstrisi zararlı atıklarının arıtılmasında İnhibisyon
Yazarlar: Yalçın GÜNEŞ , İlhan TALINLI
Kaynak: itüdergisi/e, su kirlenmesi kontrolü, Cilt:17, Sayı:2, 79-86
Özet: Bu çalışmada bir zararlı atık niteliğinde olan pestisit endüstrisinden kaynaklanan sıvı formdaki atıkların atıksu arıtma sistemi içerisinde en uygun arıtım mekanizmasının tespitine çalışılmıştır. Çalışmalar sırasında endüstrinin dengeleme tankından farklı tarihlerde üç adet numune alınmıştır. Uygulanan deneysel plan çerçevesinde numunelere kimyasal arıtma, ozonlama ve bakteriyel çoğalma inhibisyon testlerinden oluşan deneyler yapılmıştır. Kimyasal arıtma uygulanmalarında en uygun koagülan, doz ve pH tespitleri yapılmıştır. Ozonlama işleminde ise 477 mg/l ozon akısı kullanılarak 15, 30, 45, 60 ve 90. dakikalarda numuneler alınmış ve KOİ (Kimyasal Oksijen İhtiyacı) giderim verimleri hesaplanmıştır. Deneylerin son aşamasında numunelere bakteriyel çoğalma inhibisyon testi deneyleri uygulanmıştır. Deneylerin ilk aşamasında toplam KOİ giderimi bazında her ne kadar önce kimyasal arıtma uygulayıp daha sonra ozonlama yapmak daha iyi bir arıtma performansı sergilemiş olsa da, sadece KOİ giderimine bakarak numunelerin zehirlilikleri hakkında bir yorum yapabilmek mümkün değildir. Bu sebeple ortaya çıkan bütün arıtma alternatifleri için (kimyasal arıtma, ozonlama, kimyasal arıtma + ozonlama ve ozonlama + kimyasal arıtma) ve hamsular için bakteriyel çoğalma inhibisyon testi deneyleri yapılmıştır. Elde edilen sonuçlarla EC50 değerleri ve literatürdeki yaygın substrat inhibisyonu modelleri kullanılarak Ki inhibisyon sabitleri bulunmuştur. Elde edilen sonuçlardan sadece ozonlama işlemi uygulanmış numunelerin EC50 değerlerinin (sırasıyla %24, %9 ve %8) hamsuyun EC50 değerlerinden (%21, %6,5 ve %6) çok farklı olmadığı tespit edilmiştir. Tek başına kimyasal arıtma ve kimyasal arıtma ile birlikte ozonlama seçeneklerinin EC50 değerlerini belirgin bir şekilde arttırdığı görülmektedir. Ki inhibisyon sabiti açısından da durum çok farklı değildir.
Anahtar Kelimeler: Zararlı atık, inhibisyon, ozonlama, kimyasal arıtma, pestisit endüstrisi atıksuları.
Adres bilgileri: İTÜ Fen Bilimleri Enstitüsü, Çevre Bilimleri ve Mühendisliği Programı, 34469, Ayazağa, İstanbul
Tel: (282) 652 94 75
Yayımlanma tarihi: 2007
Üniversite: İstanbul technical university
Article: Inhibition on treatment of pesticide industry hazardous wastes
Abstract: According to the stipulations of the RCRA hazardous waste program, the majority of pesticide active materials have been given in priority pollutant lists. They are categorized according to their environmental effects such as biodegradability, toxicity, carcinogenity and persistency. Particularly, toxicity characteristic of pesticides by bioaccumulation may affect most of animals and hold health effect by appearing in food chain. Spent forms of those pesticide active materials have been considered as hazardous waste according to EPA and the Turkish regulations. In this study, a best practical technology was searched to treat a waste which is hazardous according to EPA lists and Turkish regulations in wastewater treatment system, generated by a pesticide industry. During the study, three samples were taken from industry's equalization tank in different dates. Samples were characterized and than treatment alternatives were applied. First, coagulation and ozonation were applied to the raw sample separately. And than combinations of ozonation and coagulation were performed, than bacterial growth inhibition test was carried out after each treatment alternative. In combination coagulation and flocculation with ozonation chemical treatment was performed first by using and and proper coagulant, optimum coagulant dose and pH were determined. NaOH and were used for pH adjustment and non-ionic polyelectrolyte was used. Than these samples were ozonated and COD removal efficiencies has been determined by taking samples in 15, 30, 45, 60, 90. minutes. Ozone generator, used in this study, reaches the optimum operating efficiency by 5 L/min oxygen flux and with this flux it produces 477 mg ozone/min. In the next stage of the experiments chemical treatment was performed after ozone oxidation. Thus, treatment efficiencies of each system were determined in the terms of COD. A series of Jar-Test experiment applying 2 min rapid mixing at 200 rpm, 15 min slow mixing at 15 rpm and 30 min for settling was conducted on wastewater. Chemical treatability test results showed that treatment efficiency was better than . Furthermore the COD values of the samples after chemical treatment by using and ozonation were reduced to 540 mg/L from 9500 mg/L with a %94 treatment efficiency for first sample, 1830 mg/L from 25000 mg/L with a %92 treatment efficiency for second sample and 2200 mg/L from 29000 mg/L with a %92 treatment efficiency for third sample. With an opposite procedure, when ozonation was applied before chemical treatment overall removal efficiencies were found % 78, %75, and %79 respectively in terms of COD. In the last stage of the experimental procedure bacterial growth inhibition test was performed to the samples. In this study it was found that the treatment efficiencies of ozonation following coagulation were higher than other alternatives. In spite of this, it is not possible to interpret toxicity potential of samples depending on only COD values. Therefore, bacterial growth inhibition test was carried out to the effluents of each treatment alternatives (coagulation, ozonation, coagulation + ozonation and ozonation + coagulation) and raw wastewaters. This test was done in a constant temperature shaker and 250 ml narrow-neck, round bottle was used as reactor. The test mixture in the bottles consisted of specific dilutions of wastewater, buffer solutions, nutrients and microorganisms. The dilution water in the standard biochemical oxygen demand (BOD) test was used as dilution water. In addition one reactor was only fed with glucose for blank sample. The bottles incubated 16 hours at 22 2 0C temperature. After this time bacterial growth has been measured as mg/L with suspended solid experiments. values were evaluated by using graphs in which per cent of SS plotted versus the log of the dilutions. In order to determine the kinetic constants, four substrate inhibition models were evaluated by Least square technique. The results showed that samples that are performed only ozonation have similar values ( %24, %9, and %8 respectively) compared to raw wastewater (%21, %6,5 and %6 respectively). It was seen that only chemical treatment or chemical treatment with ozonation alternatives increases apparently the values. Similar results can be concluded for inhibition constant, Ki. Ki values of ozonated wastewater (1021, 848 and 1283 mg/L respectively) and raw wastewater (1484, 1177, 1113 mg /) are quite similar as indicated before.
Keywords: hazardous waste; industrial waste water; inhibition; waste water treatment