Effect of Fe (II) concentration on filter headloss and effluent water quality

Bu çalışmanın amacı sulardaki Fe(II) konsantrasyonunun filtre yük kaybı ve çıkış suyu kalitesine etkisini deneysel olarak incelemektir. Çalışma laboratuvar ölçekli iç çapı 30 mm ve yüksekliği 1000 mm olan pleksiglassdan imal edilmiş silindirik filtre kolonları kullanılarak gerçekleştirilmiştir. Kolonlara 0.50-0.59 mm çapları arasında ve 40 cm yüksekliğinde silisli kum doldurulmuştur. Çalışmada musluk suyu, dört farklı Fe (II) konsantrasyonu (0.5, 1.0, 2.5, 5.0 mg/L) ve iki farklı yükleme hızı (5.6, 11.20 m3/m2.saat) kullanılmıştır. Ham suyun alkalinite değeri, ani pH değişimlerine karşı 150 mg/L CaCO3 değerine ayarlanmıştır. Alkalinite ayarlamasında sodyum karbonat ve pH düşürmede karbondioksit kullanılmıştır. Filtre çıkış suyunda su kalitesini temsilen bulanıklık değeri ve filtrenin demir giderim verimini belirlemek için çıkış suyunda toplam demir(TFe) ölçülmüştür. Filtrede oluşan yük kayıpları ve filtre yatağı boyunca yük kaybı değişimi incelenmiştir. Sonuç olarak,  2.5 ve 5.0 mg/L gibi yüksek TFe konsantrasyonlarında yük kaybının 0.5 ve 1.0 mg/L’ye göre çok daha hızlı meydana geldiği ve tıkanmanın tüm filtre yatağı boyunca değil yoğun bir şekilde filtrenin üst kısmında olduğu, 0.5 ve 1.0 mg/L gibi düşük TFe konsantrasyonlarının yük kaybı oluşumunu çok az etkilediği, filtre çıkışında TFe’nin standart değerinin (0.2 mg/L) altında kalması açısından 2.5 ve 5.0 mg/L TFe konsantrasyonlarında 5.60 m/saat ve daha düşük filtre hızlarının uygulanmasının uygun olacağı belirlenmiştir. Anahtar Kelimeler: Filtrasyon, demir (II) oksidasyonu, yük kaybı,  demir giderimi.The aim of this study is to determine the effect of Fe(II) concentration on filter headloss and effluent water quality. In the scope of the study, a plexiglas cylindrical columns having inner diameter of 30 mm and height of 1000 mm were employed in laboratory scale studies. These filter columns were filled with silica sands having 0.59 mm equivalent diameter, 2.64 g/cm3 density and shape factor of 0.80. It was ensured that the ratio between inner diameter of filter column and diameter of sand was greater than 50. Settling velocity of silica sand was calculated as 8.07 cm/s by column settling experiment results. The porosity of the sand was determined in the experimental study as 0.36. Filter columns were fed by a 100 L-tank. The oxygen required for the oxidation process was provided by a fine bubble diffuser set on the bottom of the tank.  In this study, tap water having 2.5-3.5 mg/L of total organic carbon, 9.5-11 mg/L of dissolved oxygen and temperature of 15-16 0C was used. Alkalinity value of 90-110 mg CaCO3/L of tap water was adjusted to 150 mg CaCO3/L with sodium carbonate (Na2CO3). Increased pH value was decreased to 7.0 injecting carbon dioxide. To ensure Fe(II) concentration, desired ferrous ammonium sulfate (FeSO4(NH4)2SO4.6H2O)  was added to water. Nitric acid ((HNO3)) was used to preserve iron samples for metal analysis.  Perkin Elmer 2100 DV Induced Coupled Plasma Optical Emission (ICP-OES) was used for iron measurement. Cations and anions of tap water were measured by using DIONEX ICS?1500 Ion Chromatograph (IC). Experimental studies were carried out at four different Fe(II) concentrations (0.5, 1.0, 2.5 and 5.0 mg/L) and two different filter velocities (5.60 and 11.20 m/h). Turbidity and total iron concentration were measured at the influent and effluent of the filter. 0.81, 1.2, 7.0 and 15.0 NTU of turbidity in the filter influent were obtained by oxidation of  Fe(II) in the feed tank. Turbidity in the filter effluent for 2.5 mg/L of iron concentration was increased for first 150 minutes and than decreased. It is thought that this was due to longer ripening period of the filter for 2.5 mg/L of iron concentration. On the other hand, it was observed that low filter velocities had to be applied for high iron concentrations and turbidity removal efficiency was not changed importantly in the high filtration velocities in the course of time. Total iron concentrations in the filter effluent were apparently decreased by the increasing filtration period. Although filter headloss was increased linearly at all iron concentrations, it was apparently high for 5.0 mg/L of iron concentration according to other concentrations (0.5, 1.0 and 2.5 mg/L). Headloss changes among filter bed height were investigated and it was noted that headloss curves among filter bed were very different. While headloss curves among filter bed height were parabolic for low filter velocities, they were in the shape of two linear curves at 90 minutes and longer for high filter velocities. While headloss was decreasing to 35 cm deep from top of the filter bed linearly, it was suddenly changed its direction following more step linearly. It was observed that headloss was increased by elevated filter velocities. The results obtained in this study can be summarized as follows: In the case of 0.5 and 1.0 mg/L total iron concentrations and a porosity of 0.36, iron removal can be achieved by rapid sand filters (5-15 m/h) ensuring water quality standards described in TSS-266 (TS-266, 1997) In the higher total iron concentrations such as 2.5 and 5.0 mg/L, headloss occurrence was more rapid than for 0.5 and 1.0 mg/L and clogging happened in top layers of the filter rather than among all the filter height. It was observed that low concentrations of total iron such as 0.5 and 1.0 mg/L did not affect filter headloss occurrence. It was determined that filter velocities lower than 5.60 m/h were more appropriate for 2.5 and 5.0 mg/L total iron concentrations to ensure filter effluent quality and TSS-266 standard. Turbidity removal efficiency was affected by Fe(II) concentration rather than filter velocities. Maximum filter operation time was calculated according to net headloss occurrence rate, filter velocity and raw water iron concentration using experimental results. It was found that the ratio between velocities 11.20 and 5.60 m/s was 0.5 for maximum operating times. Keywords: Filtration, ferrous oxidation, filter headloss, iron removal

Determining dissolved oxygen change using artificial neural networks: An example of Kızılırmak River

Bu çalışmada nehirlerdeki çözünmüş oksijen konsantrasyonun değişiminin modellenmesinde yapay sinir ağlarına (YSA) dayanan yeni bir yaklaşım sunulmuştur. Genişletilmiş delta-bar-delta ile geriyayılım  öğrenme algoritmaları bu ağları eğitmede kullanılmıştır. Bu uygulama için en basit YSA yapısını oluşturmada 5 farklı veri yapısı ve 2 farklı transfer fonksiyonu test edilmiştir. Elde edilen sonuçlar, YSA’nın çözünmüş oksijen konsantrasyonunu belirlemede başarılı bulunmuştur. İşlemlerin hızlı hesaplanması, basit yapıda olmaları, matematiksel modellemesinin çıkarılması zor problemlere kabul edilebilir sonuçlar sunmaları, su kalite modellemesinde ekonomik çözümler sunmaları bu zeki yaklaşımın karşılaşılan üstünlükleridir.Anahtar Kelimeler: Çözünmüş oksijen, Kızılırmak Nehri, modelleme, yapay sinir ağları. In this study, a new approach based on artificial neural networks (ANN) to determine dissolved oxygen concentration change in rivers is presented. The dissolved oxygen concentration in rivers plays dominant role in determining the water quality. This parameter constitutes a significant criterion of ecological stability and activity of water. The ANN structures with the inputs of 27, 5, 4, and 3 have been constructed. The parameters that are most simplistic and easy to measure are used as inputs to the neural network structure to be able to observe the changes in the dissolved oxygen concentration in Kızılırmak River. The Multi Layer Perceptron (MLP) structure has been used in the phase of modeling. ANN models were trained with the extended delta-bar-delta and backpropagation learning algorithms. To achieve the task with simple configuration, 5 different data structures and two different transfer functions were tested. The best result of ANN applications is obtained with the neural network structure that uses the EDBD algorithm. The results obtained from the simulations have shown that, ANN models achieved the modeling of dissolved oxygen change with high accuracy. Providing fast computation, simple structure, economic and plausible solutions determine the water qualities are the advantages of ANN encountered in this work.  Keywords: Dissolved oxygen, Kızılırmak River, modeling, artificial neural network

Using alternative instruments in the solid waste management and environmental cleaning tax

Bu çalışmada, uluslararası düzeyde katı atık yönetiminde ne tip ekonomik araç ve/veya araçların kullanıldığı incelenmiş ve Türkiye’de kullanılabilecek en uygun ekonomik araçların belirlenmesi konusunda öneriler geliştirilmiştir. Bu amaçla, öncelikle yurtiçi ve yurtdışındaki mevcut durum incelenerek, halen kullanılan çevre yönetimi araçları belirlenmiştir. Hâlihazırda Türkiye’de uygulanan sistemin etkinliği değerlendirilmiştir. Söz konusu araştırmalar sırasında geçerli mevzuatın ve yönetim sisteminin durumu göz önünde bulundurulmuştur. Türkiye’deki önemli çevre sorunlarından biri katı atıkların yönetiminde yaşanan eksikliklerdir. Katı atıklar konusunda Türkiye’de halen uygulanan Çevre Temizlik Vergisi (ÇTV) hem katı atıkların uzaklaştırma maliyetini karşılamamakta hem de atık miktarının azaltılması konusunda bir teşvik sağlamamaktadır. Bunun nedeni verginin, katı atık emisyon miktarı ile atık bertarafının marjinal maliyeti arasında teşvik edici bir ilişkinin olmadığı bir biçimde düzenlenmesidir. Mükellefleri daha az atık üretmeye zorlayacak veya teşvik edecek herhangi bir mali mekanizma yoktur. ÇTV tahsilatı tüketilen su miktarı (m3) başına yapılmaktadır ve bu da üretilen katı atık miktarıyla ilişkilendirilmediğinden hem atık bertaraf maliyetini karşılamamakta hem de çevre sorunlarını arttırmaktadır. Katı atıklarla ilgili mevcut ve olası sorunların çözümünde ÇTV ile finansman olanakları ve yapılabilirliği irdelenmiş, dışsallıkların da göz önünde bulundurulduğu vergilendirme sistemlerinin uygulanması durumunda elde edilecek avantaj ve dezavantajlar ortaya konulmuştur. Sonuç olarak ÇTV’nin zaman içinde kaldırılarak, üretilen atık bedeline göre ücret alınmasına yönelik bir sistemin oluşturulmasının uygun olacağı düşünülmektedir. Anahtar Kelimeler: Katı atık yönetimi, ekonomik araçlar, çevre vergileri, Çevre Temizlik Vergisi, dışsallık.In this study, a proposal was developed on the use of most appropriate economic instruments by solving conceptual problems emerging on the definition and use of main economic instruments for environmental management and was applied on solid waste management particularly. To this end; first of all, all available environmental management tools were determined while present situation had been investigated in national and international scale. Effectiveness of the current system in Turkey was evaluated. Legislation and management system in use were taken into consideration during aforementioned study. Economic instrument can be described as any instrument that aims to induce a change in behavior of economic agents by internalizing environmental or depletion cost through a change in the incentive structure that these agents face rather than mandating a standard or a technology. Generally accepted classification of economic instruments is made by OECD. According to this classification main economic instruments for environmental management can be classified as user fees, emission charges, product taxes, non-compliance fees, tradable permits, deposit refund systems, performance bonds, voluntary agreements and environmental subsidies. User fees, emission charges, product taxes, deposit refund systems, voluntary agreements and environmental subsidies are frequently used ones in solid waste management. They can be used individually or together to reach an efficient solid waste management system. There is some misusage of economic instruments both in definition and in practical use. Economic instruments can be used for revenue raising purposes or earmarked for environmental quality goals. Taxes and tax-like charges are the powerful tools in solid waste management if they are applied correctly. However, price elasticity of solid waste collection and disposal are found as inelastic by some researchers. This fact causes that taxes are not too successful to decrease the solid waste amount produced by individuals. Despite environmental cleaning tax is named as tax; it is a user charge according to OECD classification. One of the most important environmental problems in Turkey is the lack of appropriate solid waste management system. In solid waste management, besides a number of Ministries and institutions, more than 3000 municipalities are responsible and authorized in Turkey. Except for municipalities, number of directly responsible institutions and authorities is 36. Legislation is also very scattered. Direct and indirect law and regulations about environment are above one hundred in number. This structure is also an important obstacle and hampering the effectiveness of successful application of economic instruments and achieving the environmental quality goals. Municipalities allocate a significant portion of their budgets for solid waste management. Environmental Cleaning Tax (ECT), stipulated by the Municipal Revenues Law has been using since 1993 in Turkey to compensation of waste management financing in municipalities. However it is able to compensate only less than 30 percent of waste management costs. ECT is collected per m3 consumed water per household. It is not designed for environmental protection purpose. It is designed such as there is no relationship between solid waste emission and external marginal cost of solid waste disposal in a stimulating manner. Taxpayers have no incentive and/or enforcement for producing less solid waste. Externality can be defined as the impact of costs and benefits generated from economic activity on the people not related to this activity. In market economy, it is generally explained that the occurrence of externality caused by the activities of one person or company on other person or company beside of market prices. Environmental externalities are related to external costs that are described as the misuse of environmental resources in a harmful way to others without any financial indemnification. All alternative strategies about solid waste management cause some environmental externalities during collection, transfer and final disposal of solid wastes to some extent. These externalities create a number of local, regional and global problems. Human health effects, disturbance of ecosystem, depletion of resources and global warming can be sorted among them. Disamenities are also important problem for human welfare. When these externalities are not internalized by using some instruments, there will not be reached sustainable development goals. Therefore, it is believed that adoption of new economic instruments is necessary for municipal solid waste management by considering externalities and giving up the use of ECT in the future will be useful for sustainable solid waste management.  Keywords: Solid waste management, economic instruments, environmental taxes, externalities

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

Mevsimsel nüfus değişiklikleri ve atıksu yönetimi üzerine bir inceleme

One of the most critical issues in terms of management of touristic areas is the variability of population throughout the year. The population increase during the peak season due to tourism imposes a stress on water resources and leads to pollution risks in the coastal areas. Coastal tourism is widely regarded as one of the fastest growing areas of the world?s tourism industry. All over the world, coastal areas are developing rapidly and are attracting more and more tourists each year. The Mediterranean is the main tourist destination in the world. The main problems of Mediterranean destinations are the seasonal and coastal concentration of tourism activities. Every year more than 250 millions of people flock to the Mediterranean coasts. Additionally, second housing increases the population during the peak season.  This increase in population brings about a peak in water demand for domestic use. Tourism activity peaks in summer, coinciding with the time when natural water availability is at its lowest. According to European Environmental Agency (EEA, 2000), tourists consume up to 300 litres (up to 880 litres for luxury tourism) and as apposed to a use of 150-250 litres of water per person per day by a regular user. Extensive landscaping, water parks, swimming pools and golf courses are typical tourist facilities that require water during the dry season. Taking the example of Bodrum, a touristic summer town in the Eastern Mediterranean region, the top reasons for preference were reported to be the sea, the sun, the beaches, its natural beauty and cultural heritage. In this case study, the resident population of the Bodrum peninsula is 118237 and this is regularly and officially recorded. However vast increases in population are observed during the peak season due to national and international tourists and second housing in the area in addition to the busy pleasure craft traffic. No doubt, knowing the correct number people in town throughout the year is one of the prerequisites of water and wastewater management. However no information about second housing and tourism population seems to be officially recorded. This work focuses mainly on the prediction of the variations in the total population of Bodrum throughout the year. Predictions were based on an investigation to quantify the monthly percentages of resident, second housing, touristic and pleasure craft populations, based on currently available data to lead to a relevant wastewater management approach and an evaluation of its implications on wastewater management. The predictions have indicated that dominated by the tourists and second housing in July and August, the population is more than fourfold of that of February. As a result of the vast seasonal variations in population together with the topographical conditions of the peninsula, wastewater disposal of in Bodrum consists of central facilities and a large number of individual biological treatment systems serving second housing sites, hotels and marinas. Treated effluent is reused for irrigation of gardens in these areas. Holding tanks, which are widely used throughout the peninsula, also provide an alternative to individual biological treatment plants. Despite the quality of reclaimed domestic wastewaters is judged by the fecal coliform standard in the Turkish environmental legislation and international guidelines (WHO 89/2006 and USEPA2004), at this time, regulatory agencies allow the use of reclaimed domestic wastewater that has been treated to essentially secondary level followed by disinfection, for landscape purposes, park and golf course irrigation. The reclaimed effluent is monitored for BOI5, COD, pH and SS. but not for pathogenic microorganisms, which may lead to health concerns.The allocation of revenues of the general budget which is determined according to residential population, is the most significant financial source for municipalities. However this allocation does not seem fair for touristic summer towns like Bodrum as the population increase during the peak season is almost four times that of resident population. Environmental protection and pollution prevention is obviously one of the main factors in the sustainability of Bodrum peninsula as a popular and preferred touristic town, as well as other towns of similar character. A thorough recording of its demographical status and a serious well-planned monitoring and control strategy regarding wastewater management and water quality will provide powerful tools towards sustainability of the area. Keywords: Seasonal population, tourism, second housing, wastewater management, Bodrum.Turizm; yerleşimlerin nüfusunu arttıran ve yıl içinde mevsimsel nüfus hareketliliklerine neden olan bir aktivite olup, özellikle Akdeniz kıyılarındaki birçok yerleşimin ekonomisinde belirleyici olmaktadır. Mevsimsel nüfus hareketlilikleri de daha çok kıyı turizmi yapılan bölgelerde görülmekte, yerleşik nüfusla birlikte ikinci konut nüfusu, turizm nüfusu ve günübirlik nüfusun toplamından oluşan yaz nüfusu, kış nüfusunun birkaç katına çıkmaktadır. Turizmin neden olduğu mevsimsel nüfus hareketlilikleri özellikle atıksu yönetimi açısından önemli problemler oluşturmaktadır. Yerleşik nüfus göz önüne alınarak yapılan tesisler yaz aylarında yetersiz kalmaktadır. Bodrum Yarımadası son 30 yılda dünyanın önemli turizm merkezlerinden biri haline gelmiştir. Yarımada da yerleşik nüfus ile ilgili kayıtlı verilere ulaşılabilmekte ancak, ikinci konut ve turizm nüfusuna yönelik sınıflandırılmış veri bulunmamaktadır. Bu çalışmada yapılan kestirimlerde yarımada genelinde toplam nüfusun yerleşik nüfusun 4, ortalama nüfusun da 2 katına çıktığı hesaplanmıştır. Bodrum’da topoğrafik yapı ve mevsimsel nüfus değişiklikleri nedenleriyle merkezi ve bireysel arıtma tesisleri ile foseptikler bir arada kullanılmaktadır. Özellikle bireysel arıtma tesisleri çıkışları sulama amaçlı kullanılmakta olup denize deşarj edilmelerine izin verilmemektedir. Bodrum yarımadasındaki 397 arıtma tesisinin 387’si bireysel arıtma tesisi olup bunların işlevlerini yerine getirdiklerinin dikkatle planlanmış bir izleme denetim mekanizmasıyla takibi halk sağlığı ve sürdürülebilirlik açısından önemlidir. Mevsimsel nüfus hareketliliklerinin belirgin olduğu turizm yörelerinde teknik bakımdan pik nüfusun, finansal bakımdan ortalama nüfusun dikkate alınması uygun görülmektedir.  Anahtar Kelimeler: Mevsimsel nüfus hareketliliği, turizm, ikinci konut, atıksu yönetimi, Bodrum