Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area

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1 Soil and Environ., December 2003, Vol. 6, No. 4, p 183-p 192. Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area 1 2* 2 Wuchou yu 1 Chenfang Lin 2* Chia M. Chang 2 ABSTRACTS Landfilled dumping method is the most common way for garbage disposal; however, if the watery leakage, riched of organic substances, is not collected and processed, it will migrate into soil and eventually pollute the underground water. Based on the principles of mass conservation and system analysis, tried to builds up a mathematical model for assessing the transport of the organic leachate and its potential contamination to the groundwater. The sampling area was targeted at the garbage dumping site in the Ta-du mountain located in the suburban of Taichung city. All the soil in the experiment was taken from the layer upon which the garbage is to be dumped. The watery leakage was taken from the collecting pool of the dumping area. In order to idenitify the parameters for the mathematical model, some studies on the decompositions of organic substances in the leachat-saturated soil were carried out. The non-decomposable organic fraction and the rate constant of the decomposable fraction under constant temperature were measured. In the decomposability studies, the effects of the soil on the organic decomposition and retention were investigated. Different lengths of soil columns were used and different 1. Instructor of Department of Environmental Engineering and Science, National Pingtung University of Science and Technology, Pingtung, Taiwan. 2. Department of Soil and Environmental Sciences National Chung Hsing University, Taichung, Taiwan. * Corresponding Author : clin@sun.besa.nchu.edu.tw

2 184 Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area flow rates of leachate were enforced and accelerated to flow through the colums. The results showed that the organic substances passed through the soil colums of three different lengths and flow rates were approximately at the constant fractions of. 24% ( 1985) Keywords: Municipal solid waste, Underground water contamination. (1990b) ( 1976) % kg/ kg % % 36% g 600 ml P.V.C g 20 g 40 g 5.6 cm ( ) ml hr ml hr ml hr -1

3 Soil and Environ., December 2003, Vol. 6, No. 4, p 183-p ml hr ml hr ml hr -1 6hr 3hr 5 min C.O.D. 8 (Franson, 1985) (Walkley-Black Method) Sommers, 1982) (Nelson and (Gray, 1989) Fig. 1. Experimental setup of column leaching. C.O.D 3. C.O.D. 5 Griffin (1976) CO2 H2O ml hr ml hr ml hr ml hr ml hr ml hr dct K (Ct Cmin)...(1) dt Ct mg g -1 K

4 186 Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area Otha (1986) [C s 0 +Q C1 t] [C s 0 +Q C1 t] P C1 Q t Cobs Q t...(3) Fig. 2. Scheme of mechanism of elimination of organic matters from soil matrix. Ct min T mg g -1 (1) C s 0 mg Q ml hr -1 t T P C1 mg L -1 Cobs mg L -1 (3) (Q C1 t) C s 0 dct Ct min K Ct K K ( ) dt Ct Ct dct t C 0 t Ct Ct min K dt Ct Ln (Ct Ct min) -Kt C t 0 (Ct Ln Ct min) (C 0 t Ct min) (Ct Ct min) (C 0 t Ct min) -Kt exp(-kt) Ct =Ct min +(C t 0 Ct min) exp(-kt)...(2) (3) (Cs 0 + Cobs Q t) P (4) (Cs 0 + Q C1 t) C s 0 Ws C s 0 (Ws Cs 0 + Cobs Q t) P (5) (Ws Cs 0 + Q C1 t)

5 Soil and Environ., December 2003, Vol. 6, No. 4, p 183-p C s 0 mg kg -1 Ws (5) P kg ph 8.27 (Chemical oxygen demand C.O.D.) 2920 mg L mg L mg L -1 1mm ph % 17.0% 50.0% 33.0% {[Ws Cs 0 + Q C1 t] Ws[Ctmin+ (C t 0 Ct min) exp(-kt)]} {[Ws Cs 0 + Q C1 t] Ws[Ct min + (C t 0 Ct min) exp(-kt)]} P=Q C 1 t C obs Q t...(5) 25 P C 0 t mg g-1 K day -1 (1987) Ctmin mg g -1 C 0 s mg kg -1 Q ml hr -1 t T C1 mg L -1 Cobs mg L -1 Ws kg Fig. 3. Content of organic matter in soil verses incubation time.

6 188 Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area ( 1987) K C min [C(t) Cmin] Ln Kt (Ct Cmin) Ct (t) OM OM Cmin=2.27(mg g -1 ) K 0.144(day -1 ) Fig. 4. Plot of Accumlation depth of leachate verses leaching time. K 0.5 day -1 ( 1994) K=0.144 day -1 Cmin=2.27 mg g -1 C t 0 =4.0 mg g -1 ( ) mg g mg g m ml hr ml hr ml hr C.O.D. 0.29% mg L -1 Cmin 0.063% P (4)

7 Soil and Environ., December 2003, Vol. 6, No. 4, p 183-p C.O.D Fig. 5. Plots of Acc. OM. in leachates v.s. Acc. Depth of leachates. Fig. 6. Plot of Acc. Depth of leachate v.s. P values Table 1. Experimental results of infiltration effect in 0.5 cm length of soil column Acc. Time Acc. of leachate Acc. of leachate Acc. leachate P T(hr) (ml) (cm) C.O.D (mg L -1 ) K=0.144 day -1 Cs 0 =2.9 mg g -1 Ct=4.0 mg g -1 Ct min=2.27 mg g -1 Ws= g P= ml hr ml hr ml hr -1 r=0.998

8 190 Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area Table 2. Experimental results of infiltration effect in 2.4 cm length soil column Acc. Time Acc. of leachate Acc. of leachate Acc. leachate P T(hr) (ml) (cm) C.O.D (mg L -1 ) Table 3. Experimental results of infiltration effect in 4.9 cm length soil column Acc. Time Acc. of leachate Acc. of leachate Acc. leachate P T(hr) (ml) (cm) C.O.D (mg L -1 ) ml hr ml hr ml hr -1 r= ml hr ml hr ml hr -1 r=

9 Soil and Environ., December 2003, Vol. 6, No. 4, p 183-p C.O.D C.O.D Fig. 7. Correlation between experimental C.O.D. and model predicted C.O.D. in 0.6 cm length of soil column. Fig. 9. Correlation between experimental C.O.D. and model predicted C.O.D. in 5.4 cm length of soil column PP b C.O.D P.70 Fig. 8. Correlation between experimental C.O.D. and model predicted C.O.D. in 2.7 cm length of soil column. 1994, day OM 52 Franson, M.A.H. et al.(eds).1985.standard

10 192 Assessment on the Transport and Groundwater Contamination of Organic Leachate in a Garbage Dumping Area Methods for the Examination of Water and Wastewater, prepared by APHA, AWWA and WPCF, Washington, D.C., Sixteenth edition. PP Gray, N.F., Biology of Waste water Treatment. Oxford University Press. Oxford. P.208 Griffin, R. A., N.F. Shimp, J.D. Steele, R.R. Ruch, W. Arthur White, and G.M. Hughes Attenuation of Pollutants in Municipal Landfill Leachate by Passage Through Clay. Environ. Sci. Technol., 10: Nelson, D. W. and L. E. Sommers Total Carbon, Organic Carbon, and Organic Matter. P In A. J. Page et al.(ed.). Methods of soil analysis. Part2. 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI. Otha, S., A. Suzuki, and K. Kumada Experimental Studies on the Benavior of Fine Organic Particles and Water-Soluble Organic Matter in Mineral Soil Horizsons. Soil Science and Plant Nutrition. 32:15-26.