EFFECTIVENESS OF DECOY WATER TREATMENT ON REACTIVATORS AT PT GOODYEAR INDONESIA Tbk

PT Goodyear Indonesia Tbk is a tire manufacturing industry whose main need is the provision of water for steam boiler decoys. This water is obtained from groundwater and surface water such as river water which is then treated in a reactivator using one of the coagulants, namely PAC, so that impurities from river water can be removed, so the water is cleaner and can be used for steam boilers and does not interfere with a further decoy water treatment. This study aims to determine the effectiveness of water treatment in reactivators to be a reference for further treatment considerations at PT Goodyear Indonesia Tbk. The test result data showed the efficiency value between the inlet and outlet and compared it with the control limit set by the company. The efficiency test parameters consist of pH, conductivity, clarity measurement, and color measurement. Based on the results of efficiency calculations, several test parameters show that water treatment in reactivators at PT Goodyear Indonesia Tbk is still good and has a high-efficiency value.


Introduction
Water is vital for the needs of human life, both domestic and industrial purposes, and its use cannot be replaced by other compounds. One of the uses of water for industry is steam boiler fillers. The water source itself is obtained from several places such as the sea, reservoirs, rivers, groundwater, and rainwater, depending on the location of the industry.
One of the water sources utilized by PT Goodyear Indonesia Tbk is river water, and the river water taken is the Cipakancilan Bogor River. The use of water at PT Goodyear Indonesia Tbk is for steam boiler filler and cooling water. The water used must go through a series of treatments first to comply with the standards carried out at the Powerhouse Unit of PT Goodyear Indonesia Tbk.
The initial treatment is in the Reactivator unit, to eliminate turbidity in the raw water with the addition of PAC.
The water produced in the initial treatment, namely the reactivator, must be clean so it can be used in a steam boiler. Therefore, it is necessary to conduct an efficiency test to know the effectiveness of PAC reactivators and coagulants. This efficiency test is done by comparing the measurement results of the inlet with the outlet as well as by comparing the control limit set by PT Good year Tbk. These ORIGINAL ARTICLE raw water measurements include turbidity, conductivity, pH, and color.
The selection of some of the parameters above is based on the test parameters conducted at PT Goodyear Indonesia Tbk as well as water quality and management that have been reported (Effendi, 2003;Linsley, 2003). By knowing some of the test parameters above, it can be known the effect of using PAC on the test parameters performed. The test results are compared with the standards carried out by the Powerhouse Unit of PT Good Year Tbk and water quality standards for industries processing using poly aluminum chloride. Quality standards for steam boilers for the degree of acidity of PT. Goodyear Indonesia Tbk is 6.00 -8.00, with quality standards for conductivity < 400 mmhos / cm, and turbidity quality standards < 5 FTU.

Materials and Methods
The materials (samples) tested are river water (raw water) and treated water from reactivators. The chemicals used are HACH formula solutions (trademark HACH) made by mixing KCl in the form of a solution with a concentration of 0.01 N, pH buffer 4, pH buffer 7, and distilled water. Tools used in determining test parameters include PHB-43 microprocessor pH-meter (Omega), specific conductance (Cole-Palmer Instrument Co.), DR/2000 direct reading visibility spectrophotometer (NALCO), trophy glassware, Erlenmeyer, and other glassware.
The research method of analyzing water reactivator samples at the Power House Unit of PT Goodyear Indonesia Tbk was carried out through three stages: sampling, sample measurement, and data processing. Analysis of water quality test parameters is a potentiometric measurement of pH value, conductivity value measurement by conductometry, turbidity measurement, and color measurement. The results obtained then calculated the efficiency between the inlet and outlet and compared it with the control limit set by the company.
Test samples were taken from water derived from tap water from rivers and water from reactivator treatment, samples were taken within seven consecutive days. For pH measurement, the pH-meter device was calibrated with pH 4 and pH 7 buffers. After calibration, the electrodes are rinsed with distilled water and dipped in 100 mL of inlet and outlet water samples. The pH value read on the screen is left to stabilize and then recorded, after which a conductivity measurement is made.
Conductivity measurement was where the conductometer is turned on, then the conductometer is calibrated with 0.01 N KCl solution.
The conductivity value of the measurement results read on the screen is left until stable and then recorded, after which turbidity measurements are made.
Turbidity measurement is done by measuring blanks, namely by means of 25 mL of distilled water inserted into the cuvette, then measured using a HACH DR / 2000 type Spectrophotometer at a wavelength of 450 nm then continued with sample measurements by filling the cuvette with 25 mL of inlet examples then read the absorbance / wavelength (Nalco, 1990;Port and Harvey, 1991).
The determination of silica, iron, phosphate, and chlorine levels in this experiment was carried out by ultraviolet-visible light (UV-VIS) spectrophotometry using a visible light spectrophotometer.
In this type of spectrophotometry, all molecules can absorb radiation in the UV-visible region, so that it can be excited to higher energy levels.
A spectrophotometer is an instrument for measuring the transmittance or absorption of an example as a function of wavelength or measurement of a series of examples at a single wavelength. To be measured with a visible light spectrophotometer, the solution must be colored because the visible light spectrophotometer works at wavelengths of 400 -700 nm (Day and Underwood, 2002).
Color measurement, starting with blanks by inserting 25 mL of distilled water into the cuvette, is then measured using a DR/2000 spectrophotometer with a wavelength of 455 nm. Sample measurements are carried out by inserting a cuvette containing 25 mL of inlet samples, reading and recording the results. Then proceed with the measurement of suspended solids.

Acidity/pH
The pH value shows the equilibrium between the acid and base of a solution, through the activity of Hydrogen ions (pH). pH-meter is a set of electrode potential measuring devices without current flow and at the same time amplifying the signal generated at the glass electrode with an electric vacuum tube (Khopkar, 1990). From every measurement on the reactivator water, both inlet and outlet after the addition of PAC, the pH will decrease. This is due to the PAC hydrolysis reaction that occurs in water (Hammer, 1977). The graph of acidity measurement can be seen in Figure 1. The pH decrease between the inlet pH and the pH at the outlet for the 1st to 7th consecutive experiments was 0.28, 0.26, 0.39, 0.21, 0.16, 0.19, and 0.40. It can be seen that the decrease in pH after the coagulation processing process in the reactivator is not more than 0.5, it shows that the PAC used does not significantly affect the pH. This is very beneficial because the expected pH is not too acidic, which is a maximum of pH 6 (Kemmer, 1998).
The PAC used to work in the pH range of 6-8 with a maximum control limit of 0.5 is the control limit of the PAC itself, that regardless of the initial pH value, the pH decrease after processing on the reactivator will not be more than 0.5. after it is known that a decrease in pH of 0.5 also shows that the reactivator shows optimal performance (Kemmer, 1998).

Conductivity
Conductivity measurement aims to determine the ability of water to conduct electric current. This ability shows the level of solutes that float in water that is proportional to the concentration of ions in the water. The graph of the conductivity measurement results of inlet and outlet samples can be seen in Figure 2.

Figure 2. Graph of inlet and outlet sample conductivity measurement results
The increase in conductivity values for experiment 1 to experiment 7 in a row is as follows : 11,12,17,6,5,19,8 mmhos/cm. Conductivity (DHL) is the ability of water to conduct electric current, It can be seen that after processing in the reactivator there is an addition of conductivity value. This is because some PAC grinds in the water will cause an increase in conductivity value. PT Goodyear Indonesia Tbk sets the maximum conductivity value at 2000 mmhos/cm. From the data above, outlet conductivity is far below the maximum limit which shows that the water used has a good conductivity value for steam boilers where the smaller the conductivity value, the better.
The increase in conductivity is relatively no more than 400 mmhos / cm, which means that the PAC that works is still very optimal and does not significantly affect the increase in conductivity value. The effectiveness of processing in the reactivator is still very optimal from the value of the data.

Turbidity
The most important parameter of the initial treatment of river water is turbidity, turbidity in the water is caused by the presence of the suspensions such as organics, plankton, and 6.6 6.8 other fine substances (Alearts, 1984). The turbidity testing method used in this study is the Neftelometric method (the unit of neftelometric turbidity is FTU or NTU). The principle is that the higher the intensity of light scattered, the higher the turbidity level. The standard turbidity level used is formazine polymer suspension (then the unit of determination is formazine turbidity unit). The graph of the turbidity measurement results of inlet and outlet samples can be seen in Figure 3. The efficiency of decreasing turbidity between the inlet and outlet from experiment 1 to experiment 7 in a row was as follows: 100, 98.11, 97.67, 98.63, 97.44, 95.45, 97.96. It can be seen that the efficiency of the turbidity value is very high, the outlet turbidity control limit is not more than 2 even though the maximum outlet control limit is 5. This shows that the PAC coagulant works to precipitate dissolved solids to work optimally and the effectiveness of the reactivator in reducing the turbidity value is very high.

Color
Color can be divided into two kinds: visible color and real color (Sugiharto, 2005). Color caused by the presence of suspended substances is called visible color, while real color is the color after solutes and suspended substances are removed. In this study, color measurements were carried out using the HACH Dr/2000 type spectrophotometer. The graph of the color measurement results of the inlet and outlet samples can be seen in Figure 4. The percent color efficiency from the 1st try to the 7th consecutive experiment is as follows: 97,90%, 94,64%, 97,90%, 98,23%, 99,54%, 96,17%, and 96,63%.

Conclusion
Based on the data produced, the largest pH decrease value is 0.4, the largest conductivity increase value is 19, the smallest turbidity efficiency value is 95.45% and the smallest color efficiency value is 94.64% still within the control limit allowed by the company. It can be concluded that river water treatment in reactivators is effective.