E. AVSAR *, I. TOROZ *, A. HANEDAR **, E. USLU *** Campus, 34469,İstanbul, TURKEY TURKEY - PDF


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INVESTIGATION OF THE USABILITY OF AUTOMATIVE INDUSTRY CHEMICAL WASTEWATER TREATMENT SLUDGE AS AN ADDITIVE TO BRICK RAW MATERIAL IN TERMS OF FIRING PROCESS STACK GAS EMISSIONS E. AVSAR *, I. TOROZ *, A. HANEDAR **, E. USLU *** * Department of Environmental Engineering, İstanbul Technical University, Ayazaga Campus, 34469,İstanbul, TURKEY ** Department of Environmental Engineering, Namık Kemal University, Tekirdağ, TURKEY *** KİLSAN Clay Company, 34075, İstanbul, TURKEY SUMMARY: Gradually decreasing the capacity of landfill sites necessitates the usage of alternative disposal methods instead of storage for the disposal of industrial treatment sludges which are not classified as hazardous waste and are non combustible. Usage of these wastes on another industrial area as raw material or raw material additive is one of the actual research area at the present time. By the way disposal cost reduction and landfill usage period increment will be provided. In this study firing process stack emissions investigated in case of the automotive industry treatment sludge was used as an additive to the brick raw material. Chemical treatment sludge which is non hazardous characteristic according to General Fundamentals Relating to Waste Management Regulation (GFRWMR) Appendix-3-B and not adverse effect on product quality at 5 and 10 percent additive to raw material according to experimental studies was used on field scale experimental brick production. During the firing process stack gas emissions were being sampled and measured according to Industry Originated Air Pollution Control Regulation (IOAPCR) and Hazardous Waste Control Regulation (HWCR). According to measurement results, chemical treatment sludge usage as an additive to the raw material was determined as an useful recyling application however it should be monitored according to variable process conditions. 1. INTRODUCTION The usage of wastes as additive to the raw material in different industries is an important and common research subject around the world. Usage of the various wastes as an additive to road and construction materials is defined as win win strategy in the literature because by implementation of this strategy is provided not only converting wastes to the useful materials but also decreasing the disposal problem and diposal cost In Turkey, usage of the wastes of various sectors in another sectors as additive to the raw material is called as waste market implementation and coordinated by The Union Chambers and Commodity Exchanges of Turkey (TOBB) 2. LITERATURE REVIEW Various studies were performed about usage of treatment sludge as an additive to the raw material in brick manufacturing process. Common conclusion of these studies that the product is produced with addition of the specific amount of treatment sludge to the raw material is suitable by means of quality and environmental aspects but this process have to be monitored in respect to changing operating conditions (Weng 2003, Cusido 2003, Feenstra 1997). Due to the brick manufacturuing process is carried out with high temperature, contaminants comes from treatment sludge such as heavy metals are enclosed in the brick structure, organic matter content and patogens are being oxidized and patogens According to Cusido (2003), specific percentages of clay, untreated urban sewage sludge and forest debris (for homogenization of other two component) was mixtured for production of the new ceramic material that is called as ecobrick. For the brick quality up to 40% of sewage sludge plus forest debris become the material not suitable for structural applications. For that study monitoring exercise at laboratory scale was performed both of the normal brick manufacturuing and ecobrick manufacturuing (15% dry sludge, 80% clay and 5% forestwastes in weight) and firing step gaseous emissions were being sampled and analysed according to EPA Reference Metods. VOCs and inorganics (CO, PM, SO x, NO x, HCl, HF, heavy metals) were monitored. As expected, VOC and inorganic emissions (except HF) were higher for ecobrick than normal brick but only NO x, PM and HCl emissinons exceeded the limit values. 3. MATERIALS AND METHOD It was noticed that studies should be carried out step by step in order to determine air pollutants which are occured from the usage of waste sludge as a component of brick and the stages that are briefly explained below should be carried out within this context of this study. At the first step of this study; wastewater resources of automative industry, wastewater characterization and wastewater treatment plant were investigated. Metalic and oily wastewaters that are generated from production processes in the lines of dye-house, welding factory, fuel storage dying process and bumper factory are discharged into the chemical wastewater treatment plant within the automative plant. Heavy metals within the wastewater are coagulated and flocculated through chemical treatment and then settled in the settlement tank in the chemical treatment plant unit. Sludges that are settled in the settlement tank are transmitted to the centrifuge sludge dewatering system (decantor) through pumps and dewatered in this system. At the second step, sludge that is occured from chemical wastewater treatment plant was analyzed according to GFRWMR that was published in Official Gazette on with the number of by the Turkish Ministry of Environmental and Forestry (MofEF). Analysis of chemical treatment sludge was made by TUBITAK-MAM Chemistry and Environmental Institute according to GFRWMR Annex-3B. As heavy metals in the chemical treatment sludge are within the context of GFRWMR Annex-3B, they are characterized as hazardous as a result of the analysis. However, the concentrations of heavy metals in the sludge are under the limit concentrations that are indicated in GFRWMR Annex-3B and the sludge was not been determined as hazardous. Figure 1. Automative industry chemical treatment sludge and decanter unit At the third step, product analyses were made in laboratory scale in order to determine the effects of sludge on product quality. laboratory scaled brick production was realized through putting chemical sludge in 5 and 10 percentages as raw material additive. As a result of analyses, any negative impact was not monitored except of the requirement of the determining the performance of dried material in full scale production process. Due to the positive results of the laboratory scale experiments about product quality, full scale production was experienced. At the last step, measurement and evaluation of air pollutant emissions that will occur during the passage of full scaled mixture through brick drying oven were made. 4. EXPERIMENTAL STUDIES When 42 tones of sludge production from chemical wastewater treatment plant of automative factory and soil preparation capacity of the brick production plant with monthly 60,000 tones and averagely 26% of humid are taken into consideration within the context of study, it is calculated that the molar ratio of chemical treatment sludge in total raw material will be extremely under 1%. For this reason, chemical sludge was added into raw material in 1 percentage on molar based during the experimental production. Measurements for possible air pollutants during the recovery period were made by taking into consideration the gaseous and particulate air pollutant emissions from oven stack during firing process are the most important matter in terms of environment witin the context of experimental production. Within the context of pilot study, chemical treatment sludge was subjected to brick production processes consisting of mixture that is composed by adding 1% by weight into the brick raw material shaping drying and firing processses. Brick production flow diagram is briefly given in Figure 2. %1 sludge Emission sampling and measurement point Brick Firing Oven Raw material preparation Shaping Drying 120 o C 750 o C 950 o C 600 o C o C 60 meter 60 meter 80 meter Heating area Firing area Cooling area Figure 2. Brick manufacturing flow chart Emission sampling and measurements in firing unit oven are realized within the framework of IOAPCR and HWCR. 5. LEGISLATIVE LIMITATIONS AND EXPERIMENTAL RESULTS Limit conditions for the brick production plant where experimental production was made, was determined in IOAPCR in order to evaluate air pollutants from the plant. It is noticed that the plant is subjected to the constraints for plants where firebrick, ceramic pipes, building bricks, tile clinker and similar coarse ceramic products are fired that is indicated in Annex-5 C.8.1 of the regulation. Constraints for these plants; Inorganic floride compounds in stack gases should not exceed 30 mg/nm 3 by taking into consideration the volumetric CO 2 as 3%. SO 2 and SO 3 (in terms of SO 2 ) emissions in waste gases should not exceed 500 mg/nm 3 in 10 kg/hour or more mass flows in the plants which use raw material having sulphur ratio less than 0.12% and SO 2 and SO 3 (in terms of SO 2 ) emissions in waste gases should not exceed 1500 mg/nm 3 in 10 kg/hour or more mass flows in the plants which use raw material having sulphur ratio at 0.12% or more. If gas formed Inorganic chloride emissions in waste gases are 3 kg/hour or more, concentration of these compounds (C1 - ) is waste gases should not exceed30 mg/nm 3. NOx emissions (in terms of NO 2 ) should not exceed 500 mg/nm 3 if the mass flows of SO 2 is 10 kg/hour or more in waste gases. Limitations in Annex-1 of the regulation should be provided. Characteristics of oven stack where emission measurements were made are given in Table 1. Table 1. Emission sampling and measurement point specifications Stack dimensions (m) 3mx2,5 m Stack Name Drying oven stack Gas velocity (m/s) 13,2* Stack cross section area (m 2 ) 7,5 Gas temperature ( o C) 134* Gas flow rate (Nm 3 /h) * O 2 % 19* Gas pressure (mbar) 1006* H 2 O % 8,7* * average of the 3 measurements Emission parameter values that were determined as a result of emission measurements and samplings in drying oven stack were given in the Table 2 and Table 3. Table 2. Inorganic emission levels and limitations Combustion Gases Analysis Results (mg/nm 3 ) Parameters 1 st Average CO 2 % 1,2 1,3 1,3 1,3 CO, mg/nm SO 2, mg/nm 3 85,8 91,5 91,5 89,6 NO, mg/nm 3 14,7 16,1 14,7 15,2 NO x, mg/nm 3 22,6 24,7 24,7 24 Dust, mg/nm ,4 34,4 32,9 Table 3. Halogenous emission levels and limitations Concentration (mg/nm 3 ) Parameters 1 st Average HCl 3,38 4,21 2,20 3,26 HF 0,54 0,19 0,19 0,31 It is noticed that constraints of IOAPCR are enabled in terms of SO 2, NO x and dust parameters. However, there is no limitation for CO parameter in C.8.1 group where the analysed plant takes part of Annex-5 for the activity groups in the regulation. So, it is not possible to make any assessment based on this parameter in terms of the process. This situation shows that the regulation can not be directly used for the evaluation, when firing and process are together for this and similar plants.carbonaceous materials come from the materials within the brick compounds during the firing process as CO gas, as well as CO emissions occur from waste stack of cogeneration unit that is used for drying and from combustion gas as a result of natural gas that is used as fuel for firing. When these occurances of CO are taken into consideration, it is very hard to determine how much CO occurs from which process. Usage of 100 mg/nm 3 value which is the limit value of CO emission for the combustion of only natural gas will not be meaningful and technical evaluation for this process. Moreover, usage of air in high amounts for the requirement of the process will not enable to make an evaluation in terms of CO. As it is shown in Table 3, Cl - and F - measurement results are under the limit values of the regulation, so the limitations of IOAPCR are povided. Table 4. TOC emission levels and limitation Concentration (mg C/Nm 3 ) Parameter 1 st Limit Average TOC IOAPCR Annex-1 (99% of the raw material is soil oriented because of this organic matter limitation was choosen according to this point) Table 5. Dioxin and Furan emission levels and limitation Concentration (mg C/Nm 3 ) Parameters 1 st Average Limit PCDD 0,0016 0,0009 0,0031 0,0019 0,01 1 PCDF 0,0027 0,0031 0,0106 0,0055 0,01 1 Total 0,0043 0,0040 0,0137 0,0073 0,1 2 1 IOAPCR,Annex-1, 2 Restrict about the General Rules of the Waste Usage as an Additive Fuel Annex-2.d Table 6. Heavy metal emission levels and limitation Concentration (mg /Nm 3 ) Parametreler 1 st Average 1 Limit Thallium, Tl 0,001 0,001 0,001 0,0005 Cadmium, Cd 0,001 0,001 0,001 0,0005 0,05 2 Mercury, Hg 0,0097 0,0039 0,0034 0,0056 0,05 2 Total chromium, Cr 0,0043 0,0057 0,0051 0,0050 Copper, Cu 0,0024 0,0019 0,0016 0,0019 Cobalt, Co 0,0011 0,0013 0,0010 0,0011 Mangenese, Mn 0,0115 0,0314 0,0266 0,0231 Nickel, Ni 0,0024 0,0029 0,0048 0,0033 Lead, Pb 0,002 0,002 0,002 0,0010 0,5 2 Antimony, Sb 0,001 0,001 0,001 0,0010 Stannum, Sn 0,010 0,010 0,010 0,0050 Arsenic, As 0,0018 0,0034 0,0036 0,0029 Vanadium, V 0,0005 0,0005 0,001 0, Average values were estimated via taking in to account of the half values of measurement under the detection limits. 2 Restrict about the General Rules of the Waste Usage as an Additive Fuel Annex-2.c Table 7. PAH Component emissions and limitation Concentration µg/nm 3 PAH Component 1 st Measurement Measurement Average Naphtalane 1,203 0,446 0,8245 Acenaphtalane 0,262 0,14 0,201 Acenaphtene 0,031 0,003 0,017 Fluorine 0,133 0,129 0,131 Phenanthrene 0,42 0,514 0,467 Anthracene 0,044 0,02 0,032 Fluoranthene 0,005 0,003 0,004 Pyrene 0,005 0,012 0,0085 Benz(a)anthracene 0,002 0,009 0,0055 Chrycene 0,027 0,046 0,0365 Benzo(b)fluoranthene 0,002 0,009 0,0055 Benzo(k)fluoranthene 0,003 0,003 0,003 Benzo(a)pyrene 0,002 0,003 0,0025 Dibenzo(a,h)anthracene 0,005 0,003 0,004 Dibenzo(g,h,i)perylene 0,008 0,181 0,0945 Indeno(1,2,3-c,d)pyrene 0,002 0,003 0,0025 TOTAL 2,15 1,52 1,835 Measurements were made for other pollutants that will possibly occur from the combustion of chemical treatment sludge sludge at high temperatures according to judgements of Restrict about the General Rules of the Waste Usage as an Additive Fuel within the context of the study. When the analyses results are compared with the limitations in this restrict, it is seen that there is no restricting situation in terms of parameters given in Table 4, Table 5, Table 6, Table 7 and Table RESULTS AND DISCUSSION In case of usage of chemical treatment sludge that is occured from automative industry as a brick compound at 5-10 percentages, it is noticed that there is no negative effect on the product quality through pre-experiments. When waste is put into the brick raw material at 1% percentage, following explanations are determined in the pilot study that is made to understand that the mixture has an effect on emission values that will occur during drying and firing period or not; CO, SO 2, NO x, Dust, HCl, HF, Dioxin and Furan, Heavy metals and PAH measurement and analyses were made in oven stack, There is no limitation for conventional parameters, SO 2, NO x and Dust, there is no value for CO in the regulation Annex-5 C.8.1 to make an evalution, it is hard to make an evaluation in terms of CO and these kind of processes should be distinctively handled because evaluation in terms of emission limitations is not clear and distinct in the regulation for the situations that combustion and process are together. Inorganic gases, HCl and HF, are under the limit values of the regulation (Annex-5 C.8.1). Legal limitations (Rescript, 2005, Annex-2.d) are provided for carcinogenic materials, dioxine and furan. However, although waste was not determined as hazardous waste according to analyses results that were made within the context of GFRWMR Annex-3B by TUBITAK-MAM, discussion is required to determine the comparison of measurement results for dioxine and furan in the stack with the limitations in Restrict about the General Rules of the Waste Usage as an Additive Fuel that is published in 2005 within the context of HWCR. There is no limitations for heavy metal and PAH emissions in terms of limit values that are given in the Rescript. Usage of chemical treatment sludge in brick production is a recovery application that should be monitored and controlled in terms of Turkish Environmental Law as a result of measurements and analyses. REFERENCES Cusido, J.A., Cremades, L.V., Gonza lez, M., Gaseous emissions from ceramics manufactured with urban sewage sludge during firing processes. Waste Management 23, p: Feenstra, L., Ten Wolde, J.G., Eenstroom, C.M., Reusing water treatment plant sludge as secondary raw material in brick manufacturing. Waste Materials in Construction: Putting Theory into Practice, p: General Fundamentals Relating to Waste Management Regulation, Turkish Official Gazette on with the number of Hazardous Waste Control Regulation, Official Gazette on , with the number of Industry Originated Air Pollution Control Regulation, Turkish Official Gazette on: , with the number of Restrict about the General Rules of the Waste Usage as an Additive Fuel, Turkish Official Gazette on , with the number of TUBITAK-MAM Chemistry and Environmental Institute, Technical Report, Report Date: , Report No:2815. Weng, C.H., Lin, D.F., Chiang, P.C., Utilization of sludge as brick materials. Advances in Environmental Research 7, p:
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