Sludge reduction with pulse ozonation

Biyolojik atıksu arıtma tesislerinde atıksuyun arıtılmasının yanı sıra fazla çamurun da uzaklaştırılması önemlidir. Tesis işletme maliyetlerinin yaklaşık yarıdan fazlası çamur bertarafına harcanmaktadır. Bu nedenle uygulanabilir, ekonomik ve yenilikçi yöntemler araştırılmaktadır. Araştırılan süreçler arasında ozon güçlü bir oksidan olarak ön plana çıkmaktadır. Bu çalışmada 15-30 gün gibi uzun süren aerobik çürütmeyi kısaltmak için havalandırmaya ilave olarak ozon kullanılması araştırılmıştır. Benzer çalışmalardan farklı olarak araştırmada ozon sürekli olarak kullanılmamış olup bakterilerin ikileme zamanı dikkate alınarak 24 saatte bir kez pals şeklinde kısa sürelerle tatbik edilmiştir. Böylece ozonun biyolojik parçalanmaya olan etkisi de incelenmiştir. Ankara Tatlar Atıksu Arıtma Tesisi Havalandırma Tankı’ndan alınan numuneler ile yapılan deneyler sırasında günde bir kez erlenlerdeki çamurlara 2, 3, 4 ve 6 dakikalık sürelerle ozonlama yapılmış, daha sonra çamur 24 saat süreyle çalkalayıcıda bekletilmiştir. Dört gün süreyle devam eden deneylerde rutin olarak TKM, UKM, KOİ ve OTH  ölçümleri yapılmıştır. Sonuç olarak bu süre bitiminde UKM indirgenmesi 2, 3, 4 ve 6 dakika ozonlamalar için sırasıyla %22.6, %40, %75 ve %84 olarak tespit edilmiştir. Standart havasal çamur çürütme ile elde edilen çamur azaltımı %40-50 iken kesikli ozonlama ile elde edilen çamur azaltımı % 80 üzerine çıkmıştır. Yine reaksiyon süresi 20-30 günden 4 günlere inmiştir. Ozon destekli çürütülmüş çamurda yapılan koli basili analizleri de çamurdaki koli basillerinin bu süre içersinde tamamen öldürüldüğünü göstermiştir. Yine ozon destekli havasal çürütmede önemli mitarda ortama fosfor salınmadığı görülmüştür. Anahtar Kelimeler: Ozon, çamur degredasyonu, bakteri, ikileme zamanı, pals.Biological treatment is one of the most widely used treatment techniques. Although its high efficiency and easy design make it a preferable option, excess sludge production is a massive burden for the facilities. Approximately, half of the operation cost for domestic wastewater treatment plants is spent for sludge treatment and disposal. Even after treatment it may act as a secondary pollution source at the disposal site due to its heavy metal, pathogen and persistent organic pollutant contents. Therefore, several strategies are considered for excess sludge treatment. Incineration, dewatering, landfilling and use for agricultural purposes are some of them. However, since regulations on the use and disposal of excess sludge are much more stringent than past years, people tend to use methods which reduce the volume of sludge such as thermal, mechanical, chemical and oxidation pretreatment. Ozonation which is a chemical treatment method establishes disintegration by two mechanisms: first one is the destruction of the cell wall of the microorganism and the second one is the mineralization of the intracellular components. According to high degree of disintegration and cost effectiveness of ozonation make it a feasible technique among the other disintegration techniques. Consequently, ozone treatment of sludge gaining popularity and this leads to a new area of study in environmental engineering. The common point of previous studies is the continuous ozonation of the samples. However, ozone is a very expensive chemical to be wasted. Therefore it should be used properly. That led us to consider about pulse ozonation of sludge which would be economically more feasible if it can be as efficient as continuous ozonation. In this study it was planned to use ozone as a substitute to shorten the 15-30 day-long aerobic digestion process. Waste activated sludge samples from Ankara Tatlar Wastewater Treatment Plant were ozonated for 2, 3, 4 and 6 minutes respectively in Erlenmeyer flasks once a day on each of four consecutive days and left for incubation in between on a shaker. In the experiments, ozone was supplied by OSC-Modular 4HC, WEDECO ITT INDUSTRIES (2007) ozone generator. Operating pressure of the generator is 5 bar and the gas flow rate is 10-140 L/hr with a rated capacity of 4 g/hr. Ozone amount that is released to water in time interval was measured by using Standard Methods 8021 (DPD chlorine reagent) and calibration curve was obtained by spectrophoto-metric measurement (for 25 mL sample). The MLVSS, MLSS, COD and OUR parameters were measured routinely during the four days. MLSS measurements were done according to Standard Methods (2540B) (APHA, 1998). Chemical oxygen demand (COD) was measured by Hach Lange kits according to HACH 8000(US EPA approved) method. Volatile Suspended Solids (MLVSS) was measured according to 2540 solids method. Total-P was analyzed by 365.4 EPA Method and ortho-phosphate was analysed with 365.3 EPA Method. Obviously, one of the most important reasons of sludge treatment is sludge disinfection. In order to have an opinion about this concept, it was decided to count E.coli in the sludge. Also considering the possibility of phosphorus release, total phosphorus and ortho-phosphate were checked in the 6' ozonated sample. At the first day, total phosphorus of the sludge was 0.006 g per g biomass and after the first ozonation this amount increased to 0.0082. By these results, it can be concluded that ozonation does not release significant amounts of phosphorus to the medium. At the end of the experiments, MLVSS reductions for 2, 3, 4, and 6 minutes were observed as 22.6%, 40%, 75% and 84% respectively. As a result of the experiments, by the pulse ozonation of the non-digested activated sludge, both stabilization and reduction of the sludge were achieved in such short period as 4 days. Moreover, it can be ascertained that the obtained sludge was both disinfected from E.coli and phosphorus rich. Furthermore, since the COD left in the medium after the experiments was biodegradable, it was concluded that it would be feasible to return to the beginning of the system.  Hence, it became possible to save on both time of contact and the amount of ozone used in comparison with other studies where samples were ozonated on continuous bases. The obtained results show similar values for MLVSS, MLSS and COD for both 4' and 6' ozonation for first 3 days. Nevertheless, since the 6' ozonation is more effective in sludge stabilization, after the 4' ozonation for the first 3 days, 6' ozonation for the 4th day is suggested. Keywords: Ozone, sludge degradation, bacteria, doubling time, pulse

Kağıt sanayiinde ortaya çıkan organik klorlu atıksuların incelenmesi

TÜBİTAK YDABÇAG Proje30.01.1996Kağıt sanayii en çok kirliliğe sebeb olan endüstrilerden biri konumundadır. Bu sanayiden ortaya çıkan atıksular BOİ ve KOİ parametreleri bakımından normalde bir miktar biyolojik olarak arıtılabilir olmakla birlikte biyolojik arıtım genellikle tam olarak gerçekleşemez. Bu atıksulara özgü olarak ortaya çıkan organik halidler (AOX) ve renk parametreleri biyolojik arıtıma girmeden doğrudan alıcı ortama verilirler. Organik halidler toksik, mutajenik ve kanserojenik özellikler göstermekte ve bunları metabolize edecek gerekli enzim sistemlerinin doğada yaygın bulunmaması nedeniyle kalıcı özellik gösterirler. Son yıllarda kloroligninleri parçalayabilen funguslar izole edilmiştir. Bu proje çerçevesinde yürütülen çalışmalar esnasında % 60 dan fazla renk ve A0X arıtabilen bir fungus izole edilmiş ve Penicillium sp. olarak tayin edilmiştir. Erelenlerde yapılan kesikli çalışmalar sonucunda bu fungusun optimum pH'sının 5, optimum sıcaklığının 25 °C olduğu bulunmuştur. İzole edilen fungus optimum üreme için 2g/l asetata ihtiyaç duymaktadır. Çalışmalar esnasında fungusun çalkalamasız ortamı tercih etmesi, katı bir yüzey üzerine tutuklanarak daha başarılı sonuçlar ortaya koyacağını göstermiştir. Bu nedenle bir cam elyafı ile doldurulmuş yukarı akışlı dolgulu kolon çalıştırılmaya başlanmıştır. Sonuçlar, beklendiği üzere son derece başarılı olmuş, % 75 civarında A0X arıtımı ve renk arıtımı elde edilmiştir

Kluyveromyces türü mayalarda metal dirençliliği, metal biyosorpsiyonu ve metal-bağlama proteinlerinin tanımlanmasına ilişkin çalışmalar

TÜBİTAK TBAG01.09.1993Saccharomyces cerevisiae'nin Cupl bir susu ile karşılaştırıldığında, Kluyveromyces türlerinin toksik ağır metallere çok daha fazla dirençli oldukları bulunmuştur. Metallotiyonin sentezinin S. cerevisiae'da bakır ve gümüş ile indüklenmesine karşın K. marxianus'da konstitütif olduğu görülmüştür Ayrıca, gümüş ve kadmiyum ile muamele edildiğinde, K. marxianus• 'da metallotiyoninden daha küçük molekül ağırlıkta bir diğer proteinin.sentezlendiği bulunmuştur. K marxianus tarafından en hızlı ve en fazla biriktirilen metal gümüştür; bu metalin % 90'ı ilk 6 saat içinde hücreler tarafından bağlanmıştır. Bu organizmada bakır ve kadmiyum biyosorpsiyonu da oldukça yüksek olup. 14 saatlik bir süre içerisinde sırasıyla % 60 ve % 65'lik etkinliklerle gerçekleşmiştir. Kobalt, çinko ve mangan akümülasyonu her iki organizmada da oldukça düşük seviyelerdedir. Metallerin sadece çok küçük miktarlarının çözünür sitoplazma içinde olduğu , hücreler tarafından yüksek seviyede biriktirilen metallerin hücre duvarına ve vakuollere bağlandığı gösterıiMıiştir. K. marxianus'un altın iyonlarının solüsyonlardan geri kazanunında etkin bir şekilde kullanılabileceği de yine bu çalışmada gösterilmiştir

Reuse of lagoon effluents in agriculture by post-treatment in a step feed dual treatment process

The main constraint in lagoon treatment is the high suspended solids (SS) in the effluents, which is primarily due to high concentrations of algal cells in the finished effluent. The objective of this study was to remove turbidity originating from algae present in oxidation pond effluents by an easy and inexpensive method. For this reason, a novel lab-scale step feed dual treatment (SFDT) process was developed and the effectiveness of the trickling filter (TF) unit within the system in removing algae and organic matter was investigated. The SFDT process developed in this study is a unique and inexpensive way to scavenge algae from oxidation pond effluents. As opposed to earlier and somewhat unsuccessful studies where pond effluent post treatment was tested on once-through trickling filters, in this study pond effluents were directed to a step fed TF, so as to provide a dual treatment. Step feeding provided the necessary substrate to maintain a biofilm in TF, thereby affecting organic particles interception. The stabilization pond was not simulated in the study since the main focus was on the behaviour of the TF unit. The hydraulic loading rate (HLR) (0.5-2-4 m(3)/m(2) day), influent COD (150-550 mg/L) and influent Chl-a concentrations (250-600 mu g/L) were selected as operational variables. It was observed that, in general, removal percentages for turbidity, Chl-a, SS and COD increased considerably with the decreasing HLR, such as the removal efficiency of Chl-a was increased from 89.4% to about 97% when HLR was decreased from 4 m(3)/m(2) day to 2 m(3)/m(2) day. As a result, trickling filter produced clear effluents, with less than 2 NTU and the removal efficiency of turbidity being higher than 88%, and also removal percentages for Chl-a were higher than 95% for most of the cases

Water savings and sludge minimization in a beet-sugar factory through re-design of the wastewater treatment facility

The task of rehabilitating the already existing waste treatment facilities of a sugar factory was undertaken. A detailed survey of the water and wastewater streams indicated a necessity for immediate action towards water conservation within the plant. The spent waters from the beet-washing unit were first being intercepted at an integrated solids-liquid separation system (ISLSS) where they were partially recycled for reuse. Sludge from the ISLSS was going to an end-of-pipe treatment plant composed of lagoons. In order to conserve and recycle water, it was firstly deemed essential to modify the operating regime of the ISLSS. Consequently the sludge going to the lagoons could be decreased by one third. Next, the existing lagoons were re-arranged to comply with the discharge standards, at a very little extra cost. (C) 2002 Elsevier Science Ltd. All rights reserved

Land based sources of pollution along the black sea coast of Turkey Concentrations and annual loads to the black sea

Concentrations of inorganic pollutants, pesticides and PCBs were measured in 42 sources including rivers, streams, and industrial and domestic discharge points along the Turkish Black Sea coast in three seasons of the year 1993, The measured concentrations were compared with water quality standards currently effective in Turkey in order to determine the levels of pollution in the rivers and streams, Concentrations were also combined with the water discharge data to determine annual loads of pollutants discharged from each source into the Black Sea, Concentrations of measured parameters were much higher in domestic and industrial discharges, as expected, Most of the rivers and streams were polluted with organic material, nitrogen and phosphorous species due to discharges of untreated domestic wastes into these streams. Metal concentrations measured in the rivers and streams were fairly low due to the lack of extensive industrialization in the drainage areas of the streams, Some of the small streams, including the Neyren, Kilimli, Zafir and Tabakhane streams, are heavily polluted and were identified as sources having the potential to generate hot spots along the coast. annually, a total of 39.700 tons of nitrogen, 3.700 tons of phosphorous, 15 tons of Cd, 340 tons of Cu, 60 tons of Ph, 1.200 tons of Zn, 12 tons of heptachlor, 11 tons of aldrin, 31 tons of dieldrin, 180 tons of endrin and 500 tons of DDT are discharged from Turkish sources into the Black Sea. Except for trace metals, rivers and streams dominate the flux of pollutants, Large industries along the coast that discharge their wastes directly to the Black Sea account for a significant fraction of the annual metal discharges. Pesticides and PCBs were detected in most of the sources included in the study indicating their illegal use in agriculture. The Sakarya river was the most important source of pesticides. (C) 1998 Elsevier Science Ltd. All rights reserved

Keban Baraj Gölü ve Havzası çevre sorunları; Keban Baraj Gölü (Palu-Elazığ arası) sularının fiziksel, kimyasal ve biyolojik özellikleri/ Keban'da ötrofikasyon

TÜBİTAK DEBAG01.12.1992Bu rapor Keban Baraj Gölü'nün Palu-Elazığ arasında kalan kısmında yapılan ölçüm, analiz ve tespitleri sunmaktadır. Araştırma Ağustos 1991 de başlayıp, bir yıl devam ederek Temmuz 1992 sonunda tamamlanmıştır. Aylık periyodlarla gerçekleştirilen çalışma sırasında göl sularının fiziksel, kimyasal ve biyolojik özellikleri tespit edilmiştir, çözünmüş oksijen, sıcaklık, elektriki iletkenlik, pH, ışık geçirgenliği, Seçeni Derinliği ölçümleri saha tipi aletler kullanılarak yerinde gerçekleştirilmiştir. Belli istasyonlarda dip, orta derinlik ve yüzeyden alınan numuneler laboratuvarda analiz edilmiştir. Bu analizlerle çeşitli azot ve fosfor bileşikleri, $Ca^{++}$, $Mg^{++}$, $Na^+$, $K^+$, $SO_{4^{-2}}$, KOİ ve $Cl^-$ ölçümleri yapılmıştır . Göl suları için yapılan ölçüm ve analizlere ilaveten, araştırma bölgesine giren önemli nokta kaynaklardaki suların fiziksel ve kimyasal özellikleri ayrıca ölçülmüştür. Nisan ayında başlayan sıcaklık tabakalaşması Ağustos ayında en üst düzeye ulaşmaktadır. Kış aylarında doyma konsantrasyonlar! civarında seyreden çözünmüş oksijen konsantrasyonları, ötrofikasyon nedeni ile Ağustos ayında en düşük seviyelere ulaşmaktadır. Bu ayda oksijensiz tabakalar tespit edilmiştir. Araştırma bölgesinde mavi-yeşil alg zamanzaman hakim fitoplankton türü olarak gözükmektedir. Ölçülen klorofil-a, fosfor bileşikleri, azot bileşikleri ve Secchi derinlikleri ile ilgili değerlerin beraberce değerlerilmesi, araştırma bölgesinin genelde ötrofik özellikler taşıdığını göstermektedir. Ayrıca ötrofikasyona neden olan besin maddelerinin (azot ve fosfor) büyük bir kısmının Murat Nehri ile bölgeye geldiği tespit edilmiştir

Intermittent Ozone Application in Aerobic Sludge Digestion

Excess biological sludge, WAS, produced during activated sludge process is a growing problem for the utilities owing to the stringent regulations now imposed worldwide. One method of handling the excess sludge is to digest it, to reduce its amount and to stabilize it. Aerobic digestion is particularly suitable for nutrient treating plants as sludge should not be exposed to anaerobiosis since this will lead to release of accumulated phosphorus. A novel and patented ozone-assisted aerobic sludge digestion process (PCT/TR2010/000213) is shown to appreciably shorten the 15-30-day aerobic digestion period and the extent of solids destroyed. WAS samples were ozonated for different periods in Erlenmeyer flasks, once a day, on each of four consecutive days. Flasks were continuously aerated between ozone applications. The MLVSS, MLSS, COD and OUR parameters were measured routinely during the course of four days of digestion in order to optimize the process. As a result 22.6%, 40%, 75% and 84% MLVSS reductions were obtained at total ozone applications of 0.42, 0.64, 0.85 and 1.27 mg O-3 g(-1) MLSS, at the end of the fourth day. Hence, it became possible to save on contact time as well as achieving a bio-solids digestion far exceeding the standard aerobic process, which is 40-50% in 15-30 days, at the expense of a minimum of ozone dose. The developed process is deemed superior over side-stream ozonation where ozone is applied to the return activated sludge, RAS, line; in that it does not cause any reduction in active biomass amount maintained in the aeration tank. Conversely, reduction in active biomass concentration results in reduced treatment efficiency