Antibiyotik türevi üretimi atıksuyunun anaerobik arıtımı

Abstract

İlaç endüstrisinde.antibiyotik üretiminden kaynaklanan atıksuların, yüksek organik madde içerdiklerinden dolayı; çevreye bırakılmadan önce arıtılmaları gerekmektedir. Bu çalışmada antibiyotik türevi üretimi atıksularının, yüksek organik kirliliklerinin giderilmesi için etkin biyolojik arıtım sistemlerinden olan anaerobik arıtma prosesinde arıtılabilirliği incelenmiştir. Antibiyotik türevi üretimi atıksuyu ile organik yükü ekstraksiyon yöntemi ile azaltılmış olan atıksu beş değişik KOİ değerine seyreltilmiş ve anaerobik olarak arıtılabilirlikleri incelenmiştir. Düşük KOİ konsantrasyonlarına ( 10000, 15000, 20000 mg02/l ) seyreltilmiş her iki atıksu için arıtmanın gerçekleştiği görülmüştür. Orjinal atıksuda 25000 mg02/I ile 30000 mg02/l KOİ konsantrasyonlarında substrat inhibisyonundan dolayı arıtma gerçekleşmemiştir. Orjinal yükü ekstraksiyon yöntemi ile azaltılmış atıksuda ise 30000 mg02/I KOİ konsantrasyonunda yeterli oranda arıtma sağlanamamıştır.

Enviromental problems have been dramatically increasing and efficient uses of the natural sources have been decreasing in our world due to the increasing population and industrial development. As a result of technological development different characteristics of the wastewater become. For this reason, wastewater has to be discharged after pretreatment and treatment. In this way, the negative influence effect on the ecological balance in the nature decrease. Wastewater characteristics vary widely from one type of industry to another and even among plants within the same industry category. Generally, the pollutional characteristics of industrial wastes have been divided into three main categories; the physical and mechanical, the chemical, and the biological. The physical characteristics of wastewaters are; - temperature - color - turbidity -odor - flow variability - conductivity - radio activity - insoluble components - foamability -corrosiveness - settleability. The chemical characteristics of wastewaters are; - chemical oxygen demand -pH - alkalinity - solids - total organic carbon - surfactants - hazardous matters - heavy metals - pesticides -carbonhydrats - phenols - nitrogen, chlorine, sulfide, phosphorus -fats, oils and greases. The biological characteristics of wastewaters are; - biochemical oxygen demand - viruses, pathonegic bacteria. Physical processes include flow equalization and solids seperation using screening, sedimentation, or flotation. Chemical processes are neutralization, oxidation, coagulation, extraction and precipitation. They are generally used for reduction of heavy metals or incompetible pollutants such as cyanide. Coagulants include lime, costic soda, and certain sulfides. Oxidants generally used are chlorine, hydrogen peroxide, ozone, or oxygen. Extraction technologies are used to treat wastes containing a variety of organic constituents and a broad range total organic content. The basic principle of operation in extraction technologies is to remove constituents from a waste by mixing the waste with a solvent. That solvent will preferentially dissolve the waste constituents of concern from the waste. Biological treatment is used for influence containing simple organic materials, and for producing high-quality influence from general waste streams. The majority of the organic chemicals present in this type of waste are biodegradable, allowing for an acclimatized microbial population to develop. Biological processes include both aerobic and anaerobic systems, in aerobic treatment, as represented by the activated sludge and trickling filter processes, the waste is mixed with large quantities of microorganisms and air. Microorganisms use the organic waste for food, and use the oxygen in the air to burn a portion of this food to carbondioxide and water for energy. Since these organisms obtain much energy from this oxidation their growth is rapid and a large portion of the organic waste is converted into new cells. Anaerobic wastewater treatment is a biological process in which organic matter is decomposed in the absence of molecular oxygen. The primary products of anaerobic process are methane and carbondioxide; however, some intermediate organics are also produced. Usage anaerobic treatment techniques, as primary treatment followed by aerobic processes as post treatment seems to be more practical alternative. The advantages of anaerobic treatment are; - A possibility of a high degree of waste stabilization - Low production of waste biological sludge - Low nutrient requirements - No oxygen requirements - A useful end product which is methane. XI The major disadvantage is that relatively high temperatures are required for optimum operation; temperatures in the range from 30 °C to 37 °C are preferred. Another disadvantage of anaerobic treatment is related to the slow rate of growth of the methane producing bacteria. Because of it, longer periods of the time are required for starting the process. This slow rate of growth also limits the rate at which the process can adjust to change waste loads, temperatures, or other enviromental conditions. The advantages of anaerobic treatment are quite significant, while the disadvantages are relatively few. The advantages normally far outweigh the disadvantages for more concentrated wastes. Antibiotics, is produced on a very large scale. It is obtained by mould- fermentation of a mash containing starchy materials, lactose and nutrient inorganic salts. After fermentation, the mycelium is seperated from the mash by filtration. The mash is next acidified to a suitable pH using phosphoric acid, and the antibiotics removed by extraction with amly acetate. The solution of antibiotic is again extracted, but this time with a buffered solution of sodium chloride; the isolated antibiotic is finally purified by extraction with an organic solvent. If the mycelium is very carefully and exactly seperated from the mash, the waste liquors are fairly clear. The combined content of organic and inorganic suspended solids in a filtered antibiotic mash is about 400 mg/l., but in spite of this the wastes are milky-yellow in colour and are clarified with difficulty. Antibiotics is the most important pharmaceticals. The biodegradable of antibiotics are; Antibiotics > intermediates components I Simple organic components I C02 + NH3 + H20 + S02 Antibiotic production wastewaters can be divided into the following groups: - Spent fermentation mash - Waters from washing or floors and equipment - Wastes containing acids, bases and solvents - Wastewaters from recovery process. Because wastewaters consist of complex organic matters and it is impossible to measure the organic content each of them individually, it is necassary to use collective parameters such as chemical oxygen demand (COD), biological oxygen demand (BOD), volatile fatty acids (VFA). The chemical oxygen demand specifies the volume related oxygen quantity required to completely oxidize the organic constituents of the wastewater. The COD value is suitable as a summary measure for determining the pollution of the wastewater or the quality of the purification procedure. It is the most important parameter in the wastewater. Oxidation is carried out in a defined sulfiric acid- potassium dichromate solution (K^C^Oz). Potassium dichromate is reduced by the organic constituents of the wastewater to Cr+3. The excess potassium dichramate quantity is inversely proportional to the COD. XII In this study, anaerobic treatability of antibiotic derivative wastewaters were experimentally investigated. The properties of the wastewater are determine at the beginning of the study and the values are given below: Chemical oxygen demand (COD) ?pH. SO42- ? PO43- ? Color ? Total solids (TS). Total suspended solids (TSS) ? Volatile suspended solids (VSS) : 76400 mg02/I :4.47 : 15235 mg/l : 4240 mg/l : dark yellow : 112000 mg/I : 4540 mg/l : 2240 mg/l In the experimental study, the anaerobic reactors (oxoid) were used. The reactors were operated in an incubator at which the temperature was kept at 37± 1°C during experimental studies. The anaerobic reactors have one liter volume and in the all experiments the anaerobic reactors were fed with diluted wastewater (180 ml) and anaerobic sludge. The biogas formation in anaerobic treatment was measured with a gas measuring system. At the beginning of all experiments samples of 3 ml were taken in the system, in order to determined COD, VFA( volatile fatty acids), alkalinity and pH parameters. In this study the original wastewater of antibiotic production was extracted with ether to remove an organic matter as it was shown in Fig.1. Wastewater ( COD= 76400 mg 02/l) Ether i L T Extraction (24 hours) r Ether Liquid phase _i Small particles Centrifuge Liquid phase ( COD= 52200 mg 02/l) Fig. 1 Flow Diagram of Extraction Process A COD= 24200 mg 02/l % 31.68 XIII Original wastewater was diluted to five different concentrations of COD (10000, 15000, 20000, 25000 and 30000 mg 02/l). The diluted original wastewater which had 10000, 15000, 20000 mg O2/I COD values were treated anaerobically and the COD values of the diluted wastewaters decreased to 3072, 3571, 5332 mg O2/I. But in the other studies an inhibition was observed. In the same way, the diluted extracted wastewater which had 10000, 15000, 20000, 25000 mg O2/I COD values were treated anaerobically and the COD values of the diluted wastewaters decreased to 1535, 2533, 3999, 10814 mg O2/I. But the diluted 30000 mg O2/I COD wastewater was inhibited.