A continuous process of persulfate oxidation and citric acid washing was investigated for ex-situ remediation of complex contaminated soil containing total recoverable petroleum hydrocarbons (TRPHs) and heavy metals (Cu, Pb, and Zn). The batch experiment results showed that TRPHs could be degraded by Fe2+ activated persulfate oxidation and that heavy metals could be removed by washing with citric acid. For efficient remediation of the complex contaminated soil, two-stage and three-stage processes were evaluated. Removal efficiency of the two-stage process (persulfate oxidation - citric acid washing) was 83% for TRPHs and 49%, 53%, 24% for Cu, Zn, and Pb, respectively. To improve the removal efficiency, a three-stage process was also tested; case A) water washing - persulfate oxidation - citirc acid washing and case B) persulfate oxidation - citric acid washing (1) - citric acid washing (2). In case A, 63% of TRPHs, 73% of Cu, 60% of Zn, and 55% of Pb were removed, while the removal efficiencies of TRPHs, Cu, Pb, and Zn were 24%, 68%, 62%, and 59% in case B, respectively. The results indicated that case A was better than case B. The three-stage process was more effective than the two-stage process for the remediation of complex-contaminated soil in therms of overall removal efficiency.

The study area is Cheonjang-ri, also called Alps village, making continuous profit after performing Comprehensive Rural Village Development Projects. This study aims to determine the development process of activities about urban and rural interchange and its characteristics for making continuous profit by residents themselves. A focus on thinking about the process is necessary to make activities in order to achieve continuous profits in the underdeveloped rural village by residents themselves. As a result of this study, Alps village has developed new activities, improving problems which are encountered on the development process of activities. And, Alps village has developed new activities by linking them with previous activities. To improve problems, Alps village has made an effort by itself and cooperated with the subject, both inside and outside of the village. This way has been effective for increasing the number of visitors in village. Increasing the number of visitors in village has been effective in making a continuous profit. Also, continuing to make new activities in order to substitute previous activities including problems has been effective to increase profit.

A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k1 was 0.07∼0.17 ℓ/㎎·hr and maximum exchange quantity q0 was 27.75∼31.81 ㎎/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 ㎎/ℓ nitrate-contained wastewater of 10,000 gallons per day to 2 ㎎/ℓ , total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.

In this paper, the individual number of the future has depended not only upon the present individual number but upon the present individual age, considering the stochastic process model of individual number when the life span of each individual number and the individual age as a set, this becomes a Markovian. Therefore, in this paper the individual is treated as invariable, without depending upon the whole record of each individual since its birth. As a result, suppose N(t), t〉0 be a counting process and also suppose Zn</Tex> denote the life span between the (n-1)st and the nth event of this process, (ngeq1〈/TEX〉) : that is, when the first individual is established at n=1(time, 0), the ZZn</Tex> at time nth individual breaks, down. Random walk Zn〈/Tex〉 is Zn=X1+X2+·s·s+XA, Z0=0</Tex> So, fixed time t, the stochastic model is made up as follows ; A) Recurrence (Regeneration)number between(0.t) Nt=maxn ; Zn≤t B) Forwardrecurrence time(Excess life) T-It=ZNt+1-t C) Backward recurrence time(Current life) T-t=t-ZNt