I. The basic principle of the restoration cost method [130]
According to the principle of environmental economics [65] and the theory of value of natural resources [5], the cost of restoration or protection from pollution can be taken as the economic loss brought about by the destruction of environmental resources, and the method of assessing the loss caused by this environmental pollution and damage is called the restoration cost method. The formula is as follows:
Economic evaluation of urban geo-environmental risk
Equation (6-2-1) in: S1 for the prevention and control of environmental pollution or damage to the cost; F1 for the protection and restoration of its original environmental function of the unit cost; Q for the pollution, damage or will be polluted, damaged by some kind of Q is the total amount of environmental quality or environmental goods that are polluted, damaged or will be polluted or damaged. Here refers to the amount of polluted groundwater.
Restoration cost method is applicable to the estimation of economic losses caused by environmental pollution. Including: ① increased costs due to water treatment; ② corrosion and damage caused by building materials and economic losses; ③ additional costs due to the prevention and control of groundwater pollution; ④ shipping channel siltation and losses.
Because of the treatment or remediation of contaminated groundwater, there are more methods available, such as microbial in-situ remediation method, pump-and-treat system method, etc., there are differences in the treatment or restoration costs used in the different methods, and the same method, due to the different levels of technology, the costs required are not the same, and sometimes the differences are also very large. Therefore, when using the restoration cost method to calculate the economic loss caused by the pollution of groundwater, the method with low cost should be selected according to the specific situation, or several methods with lower cost should be selected for simultaneous assessment, and the one with the lowest cost should be taken as the final assessment result.
This section chooses the polluted groundwater pumping and "into the city sewage treatment plant treatment" and "near-site plant treatment" two methods [131] to calculate the cost of restoration.
The principles of the two methods of "input to municipal sewage treatment plant" and "near-site treatment"
1. Input to municipal sewage treatment plant
The contaminated groundwater will be extracted and input to the established municipal sewage treatment plant for treatment. The cost is calculated according to the following formula:
Economic Evaluation of Urban Geo-Environmental Risks
Equation (6-2-2), F is the total cost of inputting into the municipal wastewater treatment plant; F is the cost of extracting the groundwater; F is the cost of conveying the wastewater; F is the cost of treating the water; F is the cost of treating the water; F is the cost of transporting the wastewater. .
2. Near-land plant treatment
The total cost of near-land plant treatment (F total) consists of groundwater extraction costs (F mining), sewage conveyance costs (F conveyance), the cost of building the plant (F plant), the cost of running the water treatment plant (F operation) four major components, that is, the formula is
Economic evaluation of urban geo-environmental risk
Equations (6), (6), (6) and (6). -2-2) and (6-2-3) in several costs, are involved in the calculation of the total amount of contaminated groundwater, accurate calculation of the amount and scope of contaminated groundwater has become the key to the restoration cost method to calculate the economic loss of contaminated groundwater.
Shijiazhuang Hutuo River groundwater source of polluted water has been calculated in the previous section.
Three, the treatment project cost calculation
1. Input city sewage treatment plant treatment costs (F loss)
According to the (6-2-2) formula for calculating the input city sewage treatment plant treatment costs, you need to calculate the cost of groundwater extraction, input sewage treatment plant costs and water treatment costs, respectively.
1.1 Groundwater extraction costs (F open)
The amount of groundwater contaminated by the two sources mentioned above, i.e., the amount of groundwater to be pumped out, is Q=1.2957×108 m3. The total cost of development consists of the cost of extraction of groundwater contaminated by the two sources. It can be decomposed into well drilling cost, material cost, pumping cost etc. The total cost of polluted groundwater extraction is calculated as:F open=B1+B2+B3=$245,480+$132,556.3+$10,487,205=$10,865,200. Each calculation is shown in Table 6-2-1.
Table 6-2-1 Groundwater Extraction Costs Table
Continued
1.2 Conveyance Costs for Input to Wastewater Treatment Plant F Sending
The conveyance costs for input to the Wastewater Treatment Plant F sending consists of the cost of the storage tanks and the lifting costs A1, and the cost of pipe laying A2.
F send = A1 + A2 = 1,907,850,000 yuan + 15,414,000 yuan = 17,321,700 yuan. Each calculation is shown in Table 6-2-2.
Table 6-2-2 Calculation of Water Transmission Costs for Input to the Wastewater Treatment Plant
1.3 Water Treatment Costs F Service
After entering the City's Wastewater Treatment Plant, the WTP will charge according to the water quality conditions and treatment requirements of the input water. The groundwater is only nitrate ion exceeds the standard, the concentration is 40mg/L on average. such a concentration of water to be treated to nitrate ion is less than 2.5mg/L, the unit price of water treatment is 0.55 yuan/m3 (Wang Hao et al., 2004). The volume of sewage water to be treated Q=1.2727×108m3, so the cost of water is
C=0.55 yuan/m3×(2.245×107+1.0507×108)m3=70,136,000 yuan
Therefore, the total cost of inputting polluted groundwater into the municipal wastewater treatment plant for treatment is
F transmission = F opening + F send + F at = 3,384,448,000 yuan + 17,321,700 yuan + 70,136,000 yuan = 90,842,139,000 yuan
2. Near-site plant treatment costs F build
Use the formula (6-2-3) to calculate the near-site plant treatment costs (F total), which consists of groundwater Mining costs (F mining), water conveyance costs (F conveyance), plant construction costs (F construction), water treatment plant operating costs (F operation) and other four major components.
2.1 Groundwater extraction costs (F extraction):
has been calculated from the above as
F extraction = $10,865,241.3
2.2 Wastewater conveyance costs (F conveyance)
i.e., the cost of pumping groundwater into the wastewater treatment plant, consisting of the cost of storage tanks, A1, and the cost of pipeline laying, A2.
(1) storage tank cost A1:
A1=20000 yuan;
(2) pipe laying cost A2: A2 that is, from the well to the storage tank pipe laying costs. Selected dm800 pipe diameter pipe drainage, the price of 432.34 yuan / m, the distance of 17,000 m, pipe laying costs A2 = 432.34 × 17,000 = 7,349,780 yuan.
So, F conveyance = B1 + B2 = 20,000 yuan + 7,349,780 yuan = 7,369,780 yuan
2.3 The cost of building a plant in the vicinity of the site (F building)
The use of simple processes, chemical method wastewater treatment equipment and other construction of wastewater treatment plants. The cost composition includes a one-time investment in plant construction costs, plant operating costs. One-time investment in plant construction costs F construction of the plant.
According to the scale of 72,000 cubic meters of water per day, in situ construction of sewage treatment plants, the cost of building a plant is about 300 yuan/m3, that is, a one-time investment in plant construction costs F plant for
F plant = 300 yuan/m3 × 7200 m3 / d × 10 mouth = 21,600,000 yuan
2.4 Treatment plant operating costs (F operation)
Wastewater treatment running costs are calculated according to the unit price of water treatment is 0.2 yuan/m3, then the running cost C2 is
C2 = 0.2 yuan/m3 × (2.245 × 107 + 1.0507 × 108) m3 = 25,504,000 yuan So, the total cost of near-site construction of the plant treatment total F is
Total F = F mining + F conveying + F construction + F running = 10,865,240,000 yuan + 7,369,780,000 yuan + 21,600,000 yuan + 25,504,000 yuan = 65,339,020,000 yuan
Fourth, Discussion
(1) The use of the restoration cost method to assess the economic loss of groundwater pollution is in line with the principles of environmental and natural resource economics. The evaluation process and results show that this method is feasible.
(2) There are many methods for restoration or treatment of groundwater pollution, and the results of various evaluation methods may differ, and some of them are very different, such as the difference between the two evaluation results mentioned above (35,330,800,000 - 65,330,902,000 = -30,000,000,000) 30,001,000,000. In the selection of methods, should choose the advanced technology, engineering design, the lowest cost of the kind of method, its evaluation results as the economic loss of groundwater pollution value is reasonable.
(3) Regardless of which technology is chosen to restore groundwater, the amount of contaminated groundwater must be calculated when calculating the cost, and the calculation of the amount of contaminated groundwater depends on the grasp of hydrogeological conditions and water quality parameters, hydrogeological parameters of the accurate acquisition. Therefore, when using the restoration cost method to assess the economic loss of contaminated groundwater, geological investigation is still an important basic work.