Bu çalışmada, fosforun yapay sulakalan sistemlerinde giderimi incelenmiş, ortam malzemesinin giderim verimine olan etkisi adsorpsiyon izotermleri ile açıklanmaya çalışılmıştır. Bu etkinin anlaşılabilmesi için ortam malzemesi olarak toprak, demir-çelik endüstrisi yüksek fırın cürufu, perlit, çakıl ve kum kullanılmıştır. Dane büyüklüğü açısından çakıldan sonra en iri yapılı malzemeler sırası ile cüruf, perlit, toprak ve kum olarak bulunmuştur. Atomik absorpsiyon spektrometre analizlerine göre en fazla katyon içeren malzeme, her üç katyonu da (Al, Fe, Ca) içeren yüksek fırın cürufu olarak belirlenmiştir. Yüksek fırın cürufunu sırası ile çakıl, toprak, kum ve perlit izlemektedir. Ancak her bir katyon için değerlendirme yapıldığında Ca içeriği en yüksek malzemeler çakıl ve yüksek fırın cürufu’dur. Fe içeriği en yüksek malzeme yüksek fırın cürufu; Al içeriği en yüksek malzeme ise toprak ve yüksek fırın cürufu’dur. X ışını difraktometre cihazı ile yapılan tam element analizi ile bulunan sonuçlar, atomik absorpsiyon spektrometresi sonuçları ile benzerlik göstermiş, fosfor tutulması açısından en umut verici malzemeler cüruf, çakıl, toprak ve kum olarak bulunmuştur. Sulakalanlarda kullanılma potansiyeli olan yüksek fırın cürufu, kum, çakıl, toprak ve perlitin 21 °C ve 4 °C’de yaz ve kış şartlarında adsorpsiyon denge zamanı, Jar-Test düzeneğinde gerçekleştirilen deneyler ile tespit edilmiştir. Aynı düzenek kullanılarak yukarıda verilen ortam malzemelerinin 21 °C ve 4 °C’de, 12 mg/l toplam fosfor (TP) konsantrasyonu için Freundlich, Langmuir ve BET izotermine uygunluğu araştırılmıştır. Kullanılan malzemelerin tümünün Langmuir izotermine uygun adsorpsiyon davranışı gösterdiği saptanmıştır. Anahtar kelimeler: Langmuir izotermi, yapay sulakalan, fosfor, adsorpsiyon.Constructed wetland systems, a low cost and low technology option, have been successfully used for recycling and managing domestic and different types of industrial wastewater. The capacity of these systems is widely documented and because of their relative low cost, easy operation and maintenance the use of constructed wetlands as wastewater management solution, has extended rapidly as a choice for treatment of domestic wastewater. Such naturalized treatment systems have been shown to have a significant capacity for both wastewater treatment and resource recovery. Most studies on constructed wetlands have focused mainly on the net removal of pollutants such as bacteria, suspended solids, biological oxygen demand and nutrients such as nitrogen and phosphorus from wastewater. Although such studies have generally confirmed the effectiveness of constructed wetlands for pollutants removal, they provide little information on the processes involved in pollutant removal. The mechanisms of phosphorus removal in constructed wetlands are incompletely understood. Settling and retention of particulate forms of phosphorus is generally considerable in the slow moving waters of wetlands. Uptake of soluble forms of phosphorus occurs by sorption, complexation, precipitation and assimilation into microbial and plant biomass. In this study, removal of phosphorus, which is one of the most important elements in wastewater and causes to eutrophication was examined; the effect of media material on removal efficiency were detailed investigated. The mechanisms of phosphorus removal in constructed wetlands such as adsorption (onto media material), precipitation, plant uptake, system geometry, climate, wastewater composition are insufficiently understood. As to the removal mechanisms for P also include biological transformations. Although wetland capacity to remove pollutants is considered good, water quality discharge limits are becoming more stringent; and therefore the performance demand of constructed wetlands capacity is increasing. The discharge of nutrients to the environment is one of the water quality parameters that are becoming increasingly restricted, since nutrients are responsible for eutrophication of waters. The capacity of constructed wetlands to remove phosphorus is an issue that has not been satisfactorily solved. The aim of this study is to understand the effect of media material on phosphorus removal on constructed wetlands. To understand this effect, the Jar-Test system was fed batch and all supernatant analysis after one hour settling time was made according to standard methods. As the media material the most important parameter in constructed wetlands, its effect on phosphorus removal efficiency was explored by means of adsorption experiments. Soil, slag, perlit, gravel and sea sand were selected as media materials in this experimental study. Soil was provided from a construction site, slag was supplied from iron and steel foundry, perlit obtained from mine, gravel was provided from Municipality of Gebze, sea sand was taken from Gebze seaside. According to the sieve analysis, perlit was found as the most uniform and suitable material for the study. The others were exhibited changeable grain size distribution. To determine the effect of cation contains of the materials which is considered very important in the literature, atomic absorption spectrometer analysis was conducted on the materials. According to the results of this analysis, slag was evaluated the most suitable material as it contains all three cations (Al, Fe, Ca). Gravel, soil, sea sand and perlit are followed to the slag. The element analysis showed that gravel and slag have the highest amount of iron among the tested materials; slag has the highest aluminium content. Therefore it is decided that slag, gravel and soil are the most proper media materials for the adsorption of phosphorus. Equilibrium times of all materials used in the wetlands were determined under summer and winter conditions (21 °C and 4 °C) using to Jar-Test equipment. The experiments were conducted on at constant temperature for each condition. The reactor was continuously mixed at 50 rpm until the system reached to equilibrium. The suitability of the materials to Freundlich, Langmuir and BET isotherms are searched by using the same jar-test equipment for 12 mg/l total phosphorus concentration as for representing medium organic loaded wastewater. The results of the adsorption experiments indicated that isotherms obtained for all materials used in this study fit Langmuir isotherm. According to these findings, soil, slag and sea sand has been evaluated most promising media materials either phosphorus adsorption capacity or easy and fast availability. Keywords: Langmuir isotherm, constructed wetland, phosphorus adsorption
