Çok amaçlı filtrelerde farklı zeolit kullanımları için amonyum ve askıda katı madde giderimi

With increasing quantities of pollutants being discharged into receiving waters over the years, new and more stringent effluent quality standards have been adapted in various countries of the world. In many cases compliance with new standards may be possible by using different systems. The selection of the most beneficial treatment plant scheme will turn  out to be more and more important in the future. Available land for treatment plants are generally limited, therefore it must be used efficiently. For this reason, retention times in reactors, hence reactor volumes should be kept reasonably small to reduce area requirements. In recent years, there are more stringent standards for some parameters, especially for discharging in sensitive areas. Two of these parameters are ammonium and suspended solids which standardizied by European Council directive named "Urban Wastewater Treatment Directive",  (91/271/EEC) which is also adapted  for Turkey. Ammonium is classically removed in biological treatment units through nitrification. This is an effective removal technique when influent ammonium concentration is more or less constant, but in the case of variable and peak loads, the same pattern of fluctuations in the influent may be observed in the effluent stream. This seems to be even a more significant problem for plants at areas in which standards are altered to more stringent ones in time. Classically suspended solids are removed in secondary treatment units, but if high suspended solids removal rate will be needed, filters are used for advanced treatment of suspended solids. This study is aimed to determine the conditions which will give the highest benefits for the simultaneous removal of ammonium and suspended solids in a multi-purpose filter for different zeolite placement types, and zeolite  volume/bed volume ratios at the same filtration rate. In experimental analysis, Bigadiç clinoptilolite which is a natural zeolite from the western Anatolia is used as ion exchanger and sand is used as filtration support material. There are batch tests  and coloumn analysis in laboratory studies. In batch tests, the capacity of Bigadiç clinoptilolite was determined as  10.4 mg/g for 20 mg/lt initial wastewater ammonium concentration at pH 7.3 and 0.5-1 mm diameter zeolite is used. In column analysis, different multi-purpose filters are designed with different zeolite placement types and  zeolite  volume/bed volume ratios, at the same filtration rate. Ammonium and suspended solids removal rates are observed and compared for all multi-purpose systems. The column analysis are  aimed to determine the conditions which will give the highest benefits for the simultaneous removal of ammonium and suspended solids in a multi-purpose filter. Having that purpose, analysis are made in two stages. In both of the stages, systems are operated downflow and 0.5-1 mm zeolite and sand used as filter material. In first stage three different systems are constituted to determine the effects of zeolite placement on ammonium and suspended solids removal; 1- A  multi purpose  filter in which 25% of filter material is zeolite and zeolite is located at the upper layer of the filter bed. 2- A  multi purpose  filter in which 25% of filter material is zeolite and zeolite is located at the bottom layer of the filter bed. 3- A  multi purpose  filter in which 25% of filter material is zeolite and zeolite is mixed with sand through the filter bed. In second stage two different systems are constituted to determine the effects of zeolite quantity on ammonium and suspended solids removal; 1- A multi purpose filter in which 25% of filter material is zeolite and zeolite is located at the upper layer of the filter bed. 2- A multi purpose filter in which 50% of filter material is zeolite and zeolite is located at the upper layer of the filter bed. By the evaluation of experimental analysis,  a multi-purpose filter in which 50% clinoptilolite used as upper layer is recommended  with 100% ammonium removal and 82% suspended solids removal in working period of 120 hours .The success of this investigation could be an alternative both for the upgrading of existing treatment plants or polishing stage for ammonium and with a high removal suspended solids rate by using a multi-purpose filter. Keywords: Multi purpose filter, filtration, ion exchange, suspended solids removal, ammonium removal, clinoptilolite. Son yıllarda özellikle hassas alanlara deşarj konusunda Avrupa Birliği tarafından uygulanan ve Türkiye'de de yürürlükte olan "91/271/EEC" nolu "Kentsel Atıksu Arıtımı Yönetmeliği" ile daha sıkı standartlar getirilen parametrelerden ikisi amonyum ve Askıda Katı Madde (AKM) parametreleridir. Bu çalışmanın amacı, klasik atıksu arıtma sistemleri çıkış sularında önemli bir problem olan amonyum ve askıda katı madde parametrelerini, standartların altına düşürmek için hazırlanan "klinoptilolit+kum" malzemeli çok amaçlı filtrelerde klinoptilolit konum ve miktarının  giderim üzerindeki etkilerinin incelenmesidir. Deneysel çalışma kısmında öncelikle tez kapsamında kullanılan klinoptilolitin amonyum giderim kapasitesi belirlenmiştir. 20 mg/lt amonyum içeren atıksu konsantrasyonunda,  0,5-1 mm dane boyutunda klinoptilolit için pH 7.3'de bu çalışmada kullanılan Bigadiç klinoptilolitinin amonyum tutma kapasitesi 10.4 mg/g olarak bulunmuştur. Sürekli deneylerin ilk aşamasında, çok amaçlı filtre sisteminde zeolit farklı  konumlara yerleştirilerek amonyum ve AKM giderim verimleri belirlenmiştir. Daha sonra aynı  filtrasyon hızında %25 ve %50 oranlarında klinoptilolit içeren iki farklı çok amaçlı filtre sistemi oluşturularak amonyum ve AKM giderim verimleri tespit edilmiştir. Yapılan deneysel çalışmalar sonucunda toplam yatak hacminin %50'si oranında klinoptilolit kullanılan, klinoptilolitin üste yerleştirildiği aşağı akışlı sistem, 120 saatlik işletim süresinde %100 amonyum giderimi ve %82 AKM giderimi sağlamış olduğundan en uygun çok amaçlı filtre sistemi olarak önerilmiştir. Giriş amonyum ve AKM konsantrasyonlarına bağlı olarak pilot çalışmalar ile belirlenecek uygun filtre hızı ve temas süreleri için oluşturulabilecek çok amaçlı filtre sistemleri ile, amonyum ve AKM'nin birlikte giderimi için uygulamada verimli sonuçlar elde edilebileceği düşünülmektedir. Anahtar Kelimeler: Çok amaçlı filtre, filtrasyon, iyon değişitirme, askıda katı madde giderimi, amonyum giderimi,klinoptilolit.&nbsp