Deri endüstrisi atıksularının biyolojik arıtılabilirliği ve kinetik karakterizasyonu /
Yazar: ESRA ATEŞ GENCELİ
Danışman: PROF. DR. ORHAN DERİN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Çevre Mühendisliği Ana Bilim Dalı
Derece: Doktora, 1997
Konu: Çevre Mühendisliği = Environmental Engineering
Dizin: Biyolojik arıtma = Biological treatment ; Deri endüstrisi = Leather industry ; Endüstriyel atık su = Industrial waste water ; Çevre kirliliği = Environmental pollution

Özet:
ÖZET Deri ve deri ürünleri işlenmesi ve üretimi sanayii Türkiye'nin en önemli endüstriyel faaliyetleri arasında yer almaktadır. Günümüzde deri sanayii üretiminin toplam imalat sanayii üretimi içinde % S dolayında bir paya sahip olduğu bilinmektedir. Deri üretim ve iş gücü potansiyeli yanındaki kayda değer önemli özelliğide, yeterince kontrol edilememesi halinde, yaratması söz konusu olan çevre sorunlarıdır. Deri sanayinin çevre kirlenmesi yönünden en önemli sorunu üretim prosesinden kaynaklanan atıksulardır. Üretim ve atıksu kontrolü açısında karmaşık bir yapıya sahip olan bu atıksular yüksek miktarda organik madde içermesinin yanı sıra, yüksek miktarda azot konsantrasyonuna da sahip olmaları dolayısıyla ileri arıtma teknikleri gerektirmektedir. Bu suların arıtımında doğru sistem seçimi ve tasarımı, atıksu karakterizasyonu ve arıtılabilirlik verilerine dayandırılarak gerçekleştirilebilir. Deri endüstrisi atıksularının arıtımında yaygın olarak kullanılan aktif çamur sistemleri, atıksu karakteri ve arıtılabilirlik açısından son zamanlarda getirilen yeni yaklaşımlar çerçeveside değerlendirilmiştir. Bu çalışmanın amacı; deri endüstrisi atıksularının biyolojik arıtılabilirlik açısından karakterizasyonunun ve aerobik-anoksik koşullarda kinetik ve stokiometrik sabitlerin belirlenerek, yeni verilerin oluşturulmasıdır. Birinci bölümde, deri endüstrisi atıksularının arıtılmasının önemi belirtilerek, çalışmanın amaç ve kapsamı tanımlanmıştır. İkinci bölümde, geniş bir literatür araştırması ile deri endüstrisi atıksuları üzerinde yapılan çalışmalar özetlenmiş, biyolojik arıtılabilirlik ve kinetik karakterizasyon konusundaki araştırmalar incelenmiştir. Nitrifikasyon ve denitrifikasyon ile ilgili çalışmalar özetlenmiştir. Üçüncü bölümde, teorik yaklaşım ve çalışmada kullanılan deneysel yöntemler özetlenmiştir. Analizlerin yapıldığı atıksuların temin edildiği bölge ve atıksu karakteri, ön arıtmanın atıksu karakteri üzerindeki etkisi belirtilmiştir. Dördüncü bölümde, heterotrofik ve ototrofik mikroorganizmalar ile yürütülen deneysel çalışmanın düzeni ve analiz yöntemleri verilmiştir. Beşinci bölümde, heterotrofik ve ototrofik mikroorganizmalar ile biyolojik sistem girişi ve kimyasal olarak çöktürülmüş atıksular üzerinde yürütülen deneyler ile elde edilen sonuçlar detaylı olarak verilmiştir. Deri endüstrisi atıksularında bulunan yavaş ayrışabilir organik maddenin hidrolizi modifiye edilmiş içsel solunum modeli kullanılarak değerlendirilmiş ve hidroliz sabitleri belirlenmiştir. Altıncı bölümde, deneysel sonuçlar atıksu cinsine bağlı olarak değerlendirilmiş ve literatürde mevcut olan bilgiler ile karşılaştırılmıştır. Yedinci bölümde, sonuçlar ve öneriler tartışılmıştır. xxvi

Abstract:
THE BIOLOGICAL TREATABILITY AND KINETIC CHARACTERIZATION OF LEATHER TANNING INDUSTRY SUMMARY Tannery industry is one of the most important industries in Turkey. The wastewater management of tannery industry, has great importance in the word and in Turkey both economically and pollution-wise. The production methods used in the industry thoughout the world are more or less the same. Due to the high pollution potential based on the variable structure of the industry, treatment studies necessitate systematic approach and optimization techniques. This approach enforces the establishment of organized industrial zones and the application combined treatment instead of separate treatment. Depending on the different production processes the wastewaters originating from the tannery industry have variable flowrates with different characteristics. Therefore wastewater management should be performed in a way to consider this variability. Industrial subcategorization is a useful tool to accomplish a sound wastewater management The determination of the sub-categories of a complex industry like tannery, has some basic aspects. The aspects to be considered in tannery industry sub-categorization are, the amount of wastewater, the characterization of wastewater and treatability. Since these factors depend on the raw materials and processes used in the industry, the production processes should also be considered. The raw material, process relation and sub-categorization of tannery industry in Turkey are tabulated in Table 1. The comparision of the subcategories defined for Turkey & USA (EPA, 1979) is given in Table 2 Table 1 The raw Material- Process Relation and Sub-Categorization of Tannery Industry in Turkey Cattle Sheep Goat Raw- finished (chrome tanned) Raw- finished (vegetable tanned) Raw- finished Raw- shearling Raw- finished Raw-pickle Raw- wet blue Pickle- finished Raw-pickle Raw- wet blue Wet Blue- finished Wet blue- finished Pickle-finished XXVUTable 2. Subcategory comparison TURKEY EPA(1979) Cattle raw hide-finished chrome Hair pulp-chrome tanning- retanning-wet finishing Cattle raw hide-vegetable chrome Cattle wet blue-finished Retanning-wet finishing Sheep raw to finished Sheep pickle to finished No beamhouse Sheep fur-suede Shearling Hair save-chrome tanning- retanning-wet finishing Hair save- non chrome tanning- retanning-wet finishing Through-the-blue ' In this context the aim of this study is conduct wastewater characterization and treatability studies of Istanbul Organized Tannery Industry District. Treatability studies, involve, chemical settling and biological treatability, kinetic and stochiometric constants determination and the investigation of nitrification- denitrification kinetics. Istanbul Aydınlı Organized Tannery Industry District, has 217 parts reserved for tannery industry. 107 plants are in operation. 9 of the plants perform dry processes. 49 of the plants in operation process cattle hide, 35 of the plant sheep skin, 5 of the plant both and 9 of them process half processed products. One of the plants in the district is a confectionary warehouse, another is a shoe producer and one produces velvet car covers. The district involves 6 deposit areas. Istanbul Aydınlı Organized Industry District has a production potential of 600 t/day. This figure covers Turkeys whole production for the present time. This production level is forcasted to be 2000 t/day with a two shift production system. Although detailed information is not available on production, wastewater production is estimated to be 12000-15000m3/day. The treatment plant planned to receive the wastewaters of 200 (tannery) tannery industries as a member of Istanbul Kazhçeşme Organized Tannery Industries Union rebuilt in Istanbul Aydınlı Organized Tannery Industry District. Total daily capacity is planned to be 300 tons salted cow leather and 300 tons sheep leather ( HARRISSART,Ph., 1992 ) For the Turkish tannery industry the combined treatment requirement led to the development of organized industrial districts. In Turkey many leather producers are grouped together. Table 3 compares the characteristics of raw wastewaters of organized industrial districts in Turkey. XXVlllîle 3. The Comparison of raw lustrial Districts in Turkey wastewater characteristics of Organized uneter Tuzla Mean Org. Dist Range Çorin Mean Jmg/Q_ Org. Dist Range Biga Org. Dist Mean Range (men) (mem Manisa Org. Dist Mean Range (mg/1) (me/1) can seen in Table 3 although the wastewater characterization of Turkey Organized ustrial Districts do not exhibit significant variation, the differences present in ferent districts are due to the raw material-product relationships. s determination of wastewater quality is important for the development of itment alternatives. The first step of wastewater management is a detailed iracterization study. The literature values and the wastewater characterization ults of a 2 year study for two organized industrial districts (ATEŞ et al., 1997) are en in Table 4. Table 4. Wastewater characterization cording to the Table 4, average total COD is in the range of 5000-6000 mgA, rage soluble COD is 2000 mgA, average SS is in the range of 2000-6000 mg/1, XXIXsulfur is between 50-300 mg/1, total chromium is between 1 15-225 mg/1 and TKN is in the range of 215-380 mg/1. Depending on the chemicals used in the industry, wastewaters show highly alkaline characteristics. pH is around 8.2 and chloride varies around 10000 mg/1. Tuzla Organized Tannery Industrial Districts treatment plant which consists of homogenization, primary settling and activated sludge units is fed with 3 separate streams. Furthermore chromium and sulphur wastewater lines have chemical settling, and chemical oxidation unit respectively. Nevertheless, stream separation is not performed at the moment and all the wastewaters are fed to the primary settling unit and treated in activated sludge unit (ORHON et al. 1995). In this study the wastewater character is monitored and the effects of homogenization and primary settling are examined. Homogenization Due to the great fluctuations of wastewater loads and flowrates of leather industries difficulties are encountered in the operation of treatment plants. For this reason homogenization process is inevitable for the treatment of tannery industry wastewaters. The unit collects separate streams and homogenize the wastewater. Primary Settling: In wastewater treatment, the distribution of settliable solids gives important information about primary settling process. Primary settling reduces the parameters like SS, BOD5 and chromium at a considerable extent. The removals are 40-90 % for SS, 30-50 % for BOD5 and more than 10 mg/1 chromium levels are experienced in the effluent stream. The effects of homogenization and primary settling out the wastewater quality are given in Table 5. Table 5 The effects of homogenization and primary settling in wastewater quality (ATEŞ et all., 1997) Parameter Raw wastewater Homogenization Primary settling effluent effluent XXXThe Effect of Chemical Settling on Wastewater Quality: Since tannery industry wastewaters are complex and strong wastewaters, they need to pass through pre-treatment before biological treatment. Readily biodegradable COD is determined by the methods proposed by EKAMA et al. (1986). Inert COD fractions are found by the methods proposed by GERMİRLİ et al. (1991) and ORHON et al.(1994). Experimental results show that 18 % of total COD is inert, 36 % is readily biodegradable and 46 % is slowly biodegradable COD. The Effect of Biological Treatment on Wastewater Quality: In order to meet the discharge limits, tannery wastewaters require biological treatment The most important point in the reduction of organic matter by biological treatment is the biodegradation rate of organic matter. Tannery wastewaters have two main problems; a portion of the organic matter is not biodegradable and the biodegradable portion has different rates of biodegradation. The non-biodegradable part not only reduces the efficiency of the treatment plant but also makes it harder to meet the effluent standards. For this reason residual COD should be determined in order to have sound design and to determine the system efficiency. Likewise, the treatment of slowly degradable COD needs low loads, and long residence times. Since learner tanning wastewaters include complex materials that hydrolyze slowly, these wastewaters need long residence times for treatment. For the design and operation of the biological systems, the organic loads should be determined. For biological treatability, the examination of aerobic and anoxic growth kinetics of heterotrophic organisms and the determination of readily biodegradable COD is the first step. Respirometric measurement methods, showing biomass electron utilization rates, are used to determine these parameters. With the respirometric measurements, maximum growth rate, decay rate, readily biodegradable organic matter are determined as shown in Table 6. In the determination of readily biodegradable organic matter, COD is measured in parallel with respirometric measurements, in order to identify the yield coefficient of heterotrophic and autotrophic microorganisms. For the identification of wastewater characterization for biological treatability, soluble and particular COD are determined. Oxygen uptake rates for raw and filtered wastewater are measured according to the method proposed by EKAMA & MARAIS (1986). Since filtered wastewater contains readily biodegradable COD and soluble slowly biodegradable COD, the experimentally determined values and OUR profiles are used to determine the kinetic constants, Ks, khs and Kxx by curve fitting. Using these kinetic constants, kh, Kx are determined from the raw wastewater profiles (Table 7). The hydrolysis rate of slowly biodegradable organic matter present in tannery wastewater, is examined for the two cases where, slowly biodegradable matter is composed of on particular form and of particular and soluble forms. The hydrolysis rate of soluble slowly biodegradable organics is, 1.08/ day primary settling effluents and 1.18/day for the effluent of chemical settling. The parameter Kxx is determined to be 0.226 mg COD/ mg COD. day after primary settling and 2.83 mg COD/ mg COD day after chemically settling. The hydrolysis rates of slowly biodegradable COD after primary XXXI* £ # l $ i İl î S a S I S e» H i S S £ £ i <5 i § U MI e Vj oo ^; rö es Ö en Ov Ö t-» oo oo m vı es o o m ^ ON Sf * m oo on 05 «i K es £! ö O ^ ««? 00 ^; vq r{ en, 00 On t** t*» <*? 06 oö »?M IH «-^ ı-« *"" *-4 *M VI ON VI es v» VO es eS vî K}iqON S3S 332 8«i o 9 «o o vo v> v» o 00 00 v> ^- v> vo 8r2£8£ Sn-££8 Tf.«* tt tS 00 V) o en V) VI s § en 00 S o 00 ON ö o VI 00 o 00 3- on es on t-» r» ö ö ö ^ o 2 v».« r- E: r» 00 v> es es ss 9 _ _ es en en 8 S.o es S V) O VI es -H es o es V) 5 vı e§ "2 v> -H es es es § 88 _ Vl - 1 es v> 00 § v> VO en § S 58 MS e e e 8 «e SS8 ö d ö o o gg ONVov»oONV>^- vıgesgmS VlONVl^HTt-*^J-Vl^-t~^t~^V100 ©d©<-^dd©©ddd©-^o©.. r- ve e »h e en O B9EOI» 'BO CO CO P, O «1 C0 CO 00 CO CO ».UbUUU CO O -« es (T) Tt V) vo o ON «-H xxxiio m «r> oo O O >n O oo o OO I^H^H ı - ı - I O.-" O - öö © ö ö öööööö ? s «s t-; VO «O IO, 00 o\ - < es m ^ c4 -. »* -; »j -< o o OS OS o\ ö «o «5 ^* ı m5 i o o. 3 o, oo ©o.m.ooooom ol mm cin h 'MmmnnN «O O O O. O O. O. O. V>.. N N m m « 'mm m m.?* ' S I III » m es m o t- ı «5 ı '3 3 5 3^0^.VO VOV0 t^^VoSsOvO vo^ ö ö ööd ö öö öööööö öö.. _.. ^o^acmoftmHOımmpMpm* ööööö°ööö-^öööööööö^öö m Os şo o O, CO t» 00 «3 CO O CO CO CO CO CO CO CO CO CO fS nt m ON 2 SS XXXUland chemical settling are 0.161/day and 0.267/day respectively. Half saturation constant is determined to be 0.067 mg COD/ mg COD day for primary settling wastewaters and 0.058 mg COD/ mg COD day for chemical settling wastewaters. Experiments performed on the effluent of primary settling show that 16 % of wastewater is readily biodegradable organic matter, 37 % is readily hydrolyzable organics, 24 % is slowly hydrolyzable organics, 15 % soluble inerts, and 11% is particular inert organic materials. The chemically settled wastewater contains, 22 % readily biodegradable organics, 47 % readily hydrolyzable organics, 16 % slowly hydrolyzable organics, and 19 % soluble inerts. After chemical treatment, slowly hydrolyzable particulate organics are reduced. The reason for this is that the particular matter present in wastewater is effectively reduced by chemical settling. The System Components and Kinetic Constants Heterotrophic Growth Under Anoxic Conditions: The determination of readily biodegradable substrate under anoxic conditions: By using the proposed by EKAMA and MARAIS (1986), NUR (nitrate utilization rate) and OUR(oxygen utilization rate), are examined in batch reactors under anoxic and aerobic conditions with selected (F/M) CTı/XTı ratios. In parallel to this study, OUR is measured batch-wise under aerobic conditions by the method of KAPPELER and GUJER (1992). The results of the experiment on maximum growth rate ( jxH ) is determined independent of the biomass concentration. By the comparison of two methods the determination of the biomass activity is aimed. By measuring electron acceptor consumption rates, Ssuiig, T|h, ki, k2, k3 values are estimated. Similar to the aerobic conditions heterotrophic yield coefficient under anoxic conditions is determined with COD measurements parallel to electron acceptor consumption rates. The yield coefficients found experimentally, are used to estimate the amount readily biodegradable organic matter and similar results for the effluent of primary settling are optained. The value of readily biodegradable COD, for aerobic conditions is 350 mg/1, for anoxic conditions it is 346 mg/1 and for chemical settling effluent in aerobic conditions the value is 228 mg/1 and for anoxic conditions it is 289 mg/1. The average yield coefficient for primary settling effluents is 0.66 mg COD/ mg COD and for chemically settled effluents it is 0.655 mg COD/ mg COD under aerobic conditions, the average yield coefficient under anoxic conditions, for primary settling effluents is 0.45 and for chemically treated wastewaters is 0.485 mg COD/mg COD. The Ssi concentrations determined with the experimental studies using the yield coefficients, gave very similar results. Determination ofr\z In order to determine electron acceptor consumption rate under aerobic and anoxic conditions 5 sets of experiments are performed on the leather tanning wastewaters after primary settling and chemical settling,. The results have shown that primary settling effluents have Tjg between 0.25-0.81. The average value is 0.46. Chemical settling effluents have % between 0.45-0.59 having an average 0.52. xxxivDetermination offy The experiments performed on tannery wastewaters have shown that t|h values for primary settling effluents are between 0.55-1.27. An average value of 0.83. The results of similar experiments on chemical settling effluents have given r\h values between 0.43-1.12, and an average of 0.82. No previously determined t|h value is found for tannery effluents. Determination ofDenitrification Rates. Denitrification rates based on active biomass concentration during growth phase for primary settling effluents are found to be in the range of between 0.016-0.0758 mg N03"-N / mg VSS. hr. Denitrification rates are between 0.015-0.032 mg N03"-N / mg VSS. hr. for chemical settling effluents. In the second hydrolysis phase, the denitrification rates of primary settling effluents are between 0.0045-0.0189 mg NO3" -N / mg VSS hr. and 0.0031-0.0186 mg N03"-N / mg VSS.hr. for chemical settling effluents. The average values are 0.096 mg NO3-N / mg VSS.hr. and 0.0087 mg N03"-N / mg VSS. hr. respectively. The third phase (endogenous decay phase) is not observed for chemical treatment effluents whereas it is monitored on the two sets conducted for primary settling effluents. The Determination of The Inert Components in Tannery Wastewaters The inert components are determined by the methods proposed by GERMİRLİ et al. (1991) and ORHON et al. (1994). The results of the 6 set of experiments showed S 1 values of 212 mg/1 and 173 mg/1 for primary and chemical settling effluents respectively. Xi average value of 253 mg/1 is observed for primary settling effluents. The raw wastewaters 1 1 % of the raw wastewaters is made up of particulate inert matter and 10 % is made up of soluble inert matter. Kinetic Constants of Autotrophic Growth The second part of the study aims to identify the growth rate of autotrophic microorganisms and the factors affecting this rate. For this purpose, for the determination of the maximum net growth rate of autotrophs NOx-N measurements are performend in batch reactors. The data obtained experimentally are determined by Fibonacci non-linear equation solution technique. Autotrophic maximum net growth rate is determined to vary between 0.25-0.36 / day"1. Chromium and chloride present in the wastewater do not affect the autotrophic maximum net growth rate. XXXV