Deri sanayii sıvı artıklarının aktif çamur metodu ile tasfiyesinin kinetiği üzerine bir araştırma

Abstract

I- ÖZET Bu çalışmada,deri sanayii sıvı artıklarının özellikleri ve tasfiye imkânları araştırılmış, `Aktif Çamur` metodu ile tasfiye işleminde çamur yaşı ve havalandırma süresinin etkisi incelenmiş «kinetik katsayı ve sabitelerden yararlanılarak giriş BO1,. yükü ve istenilen çıkış suyu kalitesine göre havalandırma havuzu (Reaktör) hacmini veren abaklar hazırlanmıştır. Birinci bölümde «deri işleme teknikleri hakkında genel bilgi verilerek sıvı artıkların meydana geliş zamanı «yeri ve miktarı, özellikleri, her bir işlem kısmında ve toplam akışda kirlilik yükü, zararla etkileri «tasfiye metodları ve bu konuda önceki yıllarda yapılmış çalışmalar gözden geçirilmiş, aktif çamur metodunun esasları ele alınarak; mikroorganizma çoğalması ve besin (Substrat) kullanılması, aktif çamurun özellikleri, tasfiyeyi etkileyen başlıca faktörler belirtilmiş, tasfiye kinetiğinin temel ifadeleri Michaelis-Menten ve Monod Kinetik modeline göre çıkartılarak verilmiş ve bu ifadelerden yararlanılarak kinetik katsayı ve sabitelerin grafik olarak tayin edilişi gösterilmiştir. İkinci bölümde, Beykoz Deri Fabrikası ana kanal de şarj yerinde inşa edilen savak ve yaklaşım havuzundaki ölçümlerle debi değişimi, ana kanaldan alınan numunelerde yapılan analizlerle kirlilik özelliklerinin 24 saatlik ve 6 aylık değişimi, ana kanal üzerinde kurulan model tesisâe yapılan deneylerle çeşitli imâlat işlemlerinden gelen değişik özellikteki sıvı artıkların 6; 12; 24 saat ve `ön havalandırmalı 12 saat bekletme` halleriII için dengelenmesi incelenmiş, laboratavar ölçekli aktif çamur sisteminde 9 = 3;5;10;15 ve 20 günlük çamur yaşları için yapılan deneylerle çamur yaşının ve uygun çamur yaşı ile çalıştırılan model aktif çamur tesisiyle yapılan deneylerle t =2;% ve 3 saatlik sürelerde havalandırmanın tasfiyeye etkisi araştırılmıştır. Üçüncü bölümde, deney neticelerinin değrelendirilmesi yapılarak; biyolojik yük, çamur yükü ve hidrolik yüklü hesaplanmış, çamur yaşı, çamur yükü, çamur konsantrasyonu ve havalandırma süresine göre tasfiye verimi ve çıkış değerlerinin değişimi grafik olarak gösterilmiş, kinetik katsayı ve sabiteler tayin edilerek diğer sıvı artıklarla mukayesesi yapılmıştır. Kinetik katsayı, sabitelerien ve temel ifadeden yararlanılarak reaktöre bir günde giren B0İ_ miktarı, istenilen B0Î_ tasfiye çıkış değeri ve seçilen çamur konsantrasyonuna göre reaktör hacmini veren abaklar geliştirilmiştir.Bu abaklar kullanılarak Beykoz Deri Fabrikası için nümerik bir uygulama yapılmıştır. Dördüncü bölümde, bu çalışmada elde edilen sonuç lar özet halinde verilmiştir.

Ill SUMMARY Tannery liquid wastes is known as one of the diffi cult industrial wastewater to deal with. If one remembers that equivalent population value of the tannerey industry in Turkey is 970 000 «significance of the efforts towards to the reduction of the pollution loads originating from the tanneries becomes obvious. There fore, this study is specifi cally focused on the treatment of Sümerbank, Beykoz Tannery Industry liquid waste by activated sludge method. In the first chapter, the leather manufacturing techniques are introduced. The amount, the characteristics and the places of liquid wastes at various manufacturing levels are searched. An enormous amount of liquid wastes are generated, due to the fact that a large part of leather ma nufacturing is in water media. The liquid wastes contain small leather pieces, dis solved proteins, hairs, blood, a large amount of lime, so dium sulphate 9 sodium hydroxite, sodium sulphite, chrome salts, vegatable tanning materials, neutral salts, protein ©riginated compounds of nitrogen, productions of chemical reactions of these materials, aliphatic acid, glycerine and dysstuffs. The BOD- value of the liquid wastes of leather in dustry starts from 500-2000 mg/l rises up to k5 000 mg/1. Total solids (TS) is 7000 mg/1 and the half of it is orga nic materials. Total suspended solids (TSS) is 2000-3000 mg/1.According to manufacturing process, the value of pH varies between 3-13 «If the liquid wastes of various pro cesses are accumulated and equilized, then the value of pH varies between 8-10.IV la the total effluent, the values of polio tioa lo ads caused by the above pollutants as a (gr) for per (kg) raw hides are: BOD =75-90 gr/kg, G0D»200-220 gr/kg, ©xi- dable materialsallO-130 gr/kg, Suspended saterials-1%® gr/kg salinity=250-350 gr/kg. The harmful effects of liquid wastes of leather in dustry «the treatment techniques and the previous work car ried on this subject in recent years are summarised. By emp loying the activated sludge method, the increase of microor ganisms, the utilization of substrate and the basic factors influencing the treatment are explained. Kinetic coefficients and constants are graphically obtained by using the following basic equations of Mieaaelis- Henten ana Monad's kinetic model; S -S °>-İî - * In the second chapter, the change of the flow found by the measures in th© stilling basin and its wier which is built en the main canal of Beykos Leather Factory. The hour ly pollution changes for 2k hours period and the daily pol lution changes for 6 months period according to the main pa rameters is found by analysing the samples taken from the main canal. According to the results of the measurments,the minimum value of the flow in main canal, stays almost cons tant during night times, between 17.00/07.00 hours. Duringthe mama period the average flow ie ^i-u.^e.0^»6 1/see and Btmmds.ru deviation is CoİQ, 87 l/sec.The flew has var ying maximum values during the day t in» between S.00/I6.00 hoars aad above values for this case are Q.`` `M =23,6 1/ se«,o'sîy,)y 1/sec. According to the results of the measure- aemts of 2k hours period, pollution loads generally has a ©oMstaat Minimum level during the nighttimes of 21.00/07. 00 hewfi^but it takes fluctuating large values during the day- tite> b©tw@®a 8s©o/200©o fe oars, aad the largest value is ob served betwee® 10e@@/lloO@ h@urs.The pollution changes of 2k hours period is shown graphically in this ehapter.âecor- ding to the results of the measurements of 6 months pariod, the average pollution load values of main canal are; pH=7- 11, BOB =»600-1600 mg/1, COD=1500-^500 mg/1, Cr+3=20-80 rag/1, S%1Q0-3Q© ag/1, Settlable material6»1500-2500 mg/1, TSS= 650-1^00 mg/1, C©l©ur»650-1%00 ppm, Turbiditys80-150 FfB. A model activated sludge treatment plant is estab lished on the main canal of the factory, The two units of this plant made by steel barrels are the `Stirring and pri mary aeration tank` and `equalizing tank` which have a vo lume of 400 1 and kSQ 1 respectively. The equalizing of the different liquid wastes comes out from various manufactu ring processes is observed in these tanks for the detenti on times of 612î2*f hours and `with primary aeration 12 ho urs detention time`. It may be concluded that among thas® the last one is the best. The pollution removal values for this situation are; 62 % B0D5,62 % COD, 91 % Gr+3, 72 % S=, 91 % TSS, kZ % colour and 35 # turbidity. The lab-scale activated sludge unit consist of se dimentation chamber of 13 liters and aeration chamber of 25 liters is made out of plexiglass. Completely mixed andVI continues flowing is established `in order to carry out the experiments for finding out the effect of sludge age to treatment and to collect the necessary data for calculation of the kinetic coefficient and constants, and the «ay in which system works for the sludge age of 9 =3 ;5.10; 15 and 20 days is explaine The model activated sludge plant consists of `stir ring and primary aeration tank`, `equalizing tank`, `primary sedimentation tank`, `activated sludge tank` and `final se dimentation tank`. The last three units of the model are ma de out of trasparent plexiglass and have the volume of 153 1, 128 1 and 153 1 respectively. This continuous flowing plant is established in order to find out the effect of ae ration on treatment efficiency. The way in which the system works by applying suitable sludge age for t=2;4 and 8 hours of aeration times is explained. In the third chapter, the assesment of the experi mental results is carried out. The biological load (B. ) is calculated by using the influent BOD. value at steady state for each sludge age(0 ), the wastewater flow and the volume c of aeration chamber in the lab-scale activated sludge unit» Sludge lead (H ) is obtained by dividing the biological lo- ad to the sludge concentration (MLVSS) of Steady-state. In the same manner; biological load and sludge load are calcu lated by using the influent BOS- value of each aeration ti me, the sludge concentration and the volume of reactor in the model activated sludge plant. The suitable sludge age 6C=15 days is selected by comparing the treatment efficien cy of the main pollution parameters in each sludge age. Which is obtained from the analysis of the experiments carried out in the lab-scale activated sludge unit. TheVII treatment efficiencies of the main pollution parameters ac cording to the sludge age, the sludge lead and the sludge concentration are given graphically. It ia found out to be S hours aeration time and R =0,20 kg B0D_/kg VSS/day sludge load by coparing the cal- eulated influent, and effluent values of the main pollution parameters and treatment efficiencies for each aeration ti me which is obtained from the analysis the experiments car ried out in the model activated plant «The f ©lowing average pollution removal and effluent values are obtained; 85 % BOD-, 75 % COD, 100 % Sa,75 % Gr+5, 60 % colour, 60 % tur bidity, and B0D_»3O mg/l, C0D=250 mg/l, S*»0 ag/1, Cr+'= 1.3 ag/1, eelour=l60 ppm, turbidity-15 FTü.The above treat ment efficiencies and effluent values of the pollution pa rameters are represented graphically according to the ae ration time and the sludge load. It is found out that in the treatment of tannery liquid wastes by activated sludge method, by using the Ki netic basic expressions and experimental data, the values of kinetic coefficients and constants are; `Yield coeffi cient` 1=0, 6^}, `Endogenous decay rate` K, =0,186 (day)'1, `Saturation constant` I »133 ag/1* `Maximum substrate uti- lizatioa rate` k=l,^3 (day), `Specific substrate utili zation rate` k=0,0037 (mg/l)`1 (day)```1. These coefficients and constants in textile industry are; TaO, 60-0,72, K.= 0,05-0,10 (day)`1, K,«8Q mg/l, k«l, 2^-1*7© (day)`1, in chemical and petrochemical industry are; 1=0,31-0,72, Kd=O,05-O,l8 (day)`1, k=0, 003-0,018 (mg/l)`1(day)`1.VIII When these results are compered, it is seen that the valu es obtained for leather industry, is similar to those of textile, chemical and petrochemical industry. Ab the rasults of this-study, ^the- graphs are-deve»^ loped by using the kinetic eoefficiens, constants and the basic expressions »These graphs give the volume of reactor according to the influent BOD- load (kg/day), the selected effluent BOD- value (mg/1) and the sludge concentration (gr/l).A numerical application for Beykoz Tannery Indus try is carried out by using these graphs* In the fourth chapter, the conclusions obtained in this study are summurized.