Mathematical model analysis of municipal solid waste collection and transportation system
Tong Huanhuan, Sun Xu, Zhao Youcai
(Tongji University School of Environmental Science and Engineering, Shanghai 200092)
This paper briefly expounds three forecasting methods of municipal solid waste output, namely single exponential smoothing method, linear regression analysis method and grey system model analysis method.
Methods, and referring to the optimal scheduling of transportation vehicles in logistics distribution system, the optimal model of garbage collection and transportation is established.
Keywords: domestic garbage; Collection and transportation system; system model
China Library Classification Number: X32 Document Identification Number: A Document Number:1005-8206 (2009) 04-0043-03.
Preliminary analysis of mathematical model of municipal solid waste collection and transportation system
Tong Huanhuan, Sun Xu, Zhao Youcai
(Department of Environmental Science and Engineering, Tongji University, Shanghai 200092)
Abstract: This paper introduces three methods for forecasting the output of municipal solid waste, namely single exponential smoothing method and regression method.
Analysis method and grey system model. Optimal scheduling of transport vehicles based on logistics distribution
System, the optimization model of garbage collection and transportation is established.
Keywords: domestic garbage; Collection and transportation system; model
Date of receipt: February 0, 20091
Urban garbage collection and transportation is to transport garbage from the source to the place.
The whole operation of the disposal site includes three stages: ① collection.
Collection-the process of garbage from source to public storage container; ②
Removal-refers to the removal of garbage from storage containers along a certain route by removal vehicles.
The process of transferring garbage to a garbage transfer station (in some cases
, pickup trucks can directly transport garbage to the treatment and disposal site); ③
Transshipment-refers to loading garbage into large-capacity transfer vehicles at transfer stations.
Long-distance transportation to treatment and disposal sites. The pre-1 stage needs to deal with garbage.
Investigate the source distribution, quantity and composition of garbage.
And predict; The latter two stages need to use optimization technology to clear and transport.
Optimize the garbage collection and transportation of lines and transfer stations.
1 Prediction method of municipal solid waste output
The collection and transportation mode of urban domestic waste is designed for domestic waste.
In the case of correctly predicting the garbage output, because of the design
The collection and transportation mode should not only meet the current demand of garbage production,
Should be able to cope with the changes in the next few years. At present, domestic
The commonly used mathematical statistics method is single exponential smoothing method,
Linear regression analysis, grey system model analysis.
1. 1 single exponential smoothing method
Yt+ 1=aXt+( 1-a)Yt .( 1)
Where: t is time; A is the exponential smoothing coefficient, with a value range of 0~
1; Actual observation value of garbage output when Xt is t; When Yt is t,
The predicted value of garbage output; When Yt+ 1 is t+ 1, the amount of garbage generated is
Predicted value.
1.2 linear regression analysis method
y = A0+a 1x 1+a2 x2+…+amxm .(2)
Where: y is the predicted output of garbage; Influence of garbage on Xi
Multiple factors (I = 1, 2, …, m); Ai is the tropic of cancer.
Numbers (I = 1, 2, …, m).
There are many factors that affect the generation of garbage, such as population,
Wage income, consumption level, living habits, fuel structure, etc.
For many factors, variable clustering method can be used to analyze data.
Line preprocessing. According to reports, after data processing, multiple regression scores.
Many variables in the analysis method belong to the "same solution" after being variated and processed.
After the actual operation, it is equivalent to the "population model" of unitary regression.
Prediction method [1].
1.3 grey system model analysis method
The grey system model (GM) contains the variable dimension m of the model.
And order n, denoted as GM (n, m). In the production of domestic waste
GM( 1, 1) model is widely used in forecasting. By studying the original work
After the time series data are accumulated, the data will appear bright.
The obvious exponential law, further analysis, can be garbage.
Output forecast.
In practical application, the grey system model prediction method will be produced.
Positive error, but the prediction result of linear regression analysis is small.
Therefore, we can combine the characteristics of the two forecasting methods and use them.
The weighted average of the measured values is taken as the recommended value of garbage output [2].
2 garbage removal route optimization
Garbage logistics is a "highly dispersed source and place"
It is characterized by high concentration and seasonal variation of output and quality.
The "reverse logistics" system is a process from decentralization to centralization; Hehe
The "forward logistics" of material supply is the process of goods from concentration to dispersion.
Although the two kinds of logistics have different performances, they are also related in essence.
Department. Adopting advanced domestic waste logistics management in sanitation operation
Environmental health engineering
environmental health engineering
Vol. 17 No.4
August 2009
Volume 17 Issue 4
August 43 rd, 2009
Environmental sanitation engineering volume 17
Technology can effectively improve efficiency and reduce costs. It's too rubbish
The selection of pickup trucks and route optimization can refer to the logistics distribution system.
Optimal scheduling of transport vehicles.
The vehicle scheduling problem is generally defined as: for a series of delivery points/
Organize appropriate driving routes at the receiving point so that vehicles can pass in an orderly manner.
After they meet certain constraints (such as the demand for goods,
Delivery quantity, delivery time, vehicle capacity limit, mileage
Restrictions, time and space restrictions, etc. ) to achieve a goal (such as a road)
The shortest distance, the lowest cost, the least time and the best use of vehicles.
Wait a minute) [3].
According to the vehicle scheduling problem in logistics [4], the garbage removal problem is established.
Basic modes of transportation.
Mark the garbage transfer station with 0; There are n pick-up points, which are divided into
Don't use the symbol 1, 2, …, n; Vehicles required to complete the removal task
The number of vehicles is m, and the carrying mass of each vehicle is c; Each settlement point
The amount of garbage produced is GI (I = 1, 2, …, n); Transfer station and
The transportation distance between any two points in each pick-up point is dij (i =
0， 1，2，…，n； J = 0， 1，2，…，n)； sequence
The driving route of k cars is called the k-th sub-path, which includes unobstructed roads.
The number of transmission points is nk, and Pk indicates nk clearance in the k-th subpath.
A collection of transmission points, where the element Pki
(i= 1，2，…，
Nk) represents the pick-up point with the order of I in the k-th subpath; Pk0，
Pknk+ 1
They all represent transit stations, that is, Pk0=Pknk+ 1=0.
Minz=
m
k = 1√
ni+ 1
i = 1 ∑ dPki- 1 Pk i
， 1≤nk≤n，k = 1，2，
…，m； (3)
m
k = 1∑NK = n； (4)
Neck; neck
i = 1 ∑gPk≤c，Pk= {Pki |i= 1，2，…nk}，k= 1，2，
…，m； (5)
PK 1∩Pk2 =φ； k 1≠k2 k 1= 1，2，…，m； k2=
1，2，…，m .(6)
It is proved that the general vehicle optimal scheduling problem belongs to combinatorial optimization.
Heuristic algorithms are usually used to solve NP-hard problems in chemistry.
Line solution. For example, Eugênio de Oliveira Simonetto and others.
Heuristic algorithm, auction algorithm and dynamic penalty method are used to solve the problem.
The scheduling problem of 24 pickup trucks in Porto Alegre, Brazil is discussed. should
The problem includes 1 garage, which is the same as the 60 t garbage removal in this city.
, to meet the minimum requirements of eight garbage sorting yards [5]. Anjay
Jaszkiewicz and others used the genetic local search algorithm of distance-preserving recombination operator.
This method solves the problem that 1 solid waste management company cleans up 30,000 wastes.
Vehicle transportation of garbage containers. This problem includes 1 garage, 2.
A landfill.
The optimization problem not only needs the shortest general route, but also needs to be realized.
Economy, environment and society win-win. Wei Song et al. proposed that the ring can be
The information of environmental and social factors is added to the optimization model, that is, to the reality.
The length of the path is weighted. The comprehensive route length formula is obtained.
For [7]:
C=α 1α2α3Cs .(7)
Where: c is the comprehensive route length, km; Cs is the practical way.
Line length, km; α 1 is the noise influence weight; α2 is the atmospheric influence.
Weight; α3 is the traffic condition weight.
3 Transfer Station Settings
Setting up garbage transfer stations can make more effective use of manpower and material resources.
Force, give full play to the benefits of garbage trucks, and ensure the loading quality.
Large garbage transfer vehicles can be transported economically and effectively over long distances,
Thereby reducing the total cost of garbage collection and transportation. So, generally speaking,
When the transfer distance exceeds a certain critical value, it is necessary to set up a transfer station.
At present, multi-objective evaluation model [8] and integer programming model [9] are widely used.
It is widely used in the decision-making of transfer station selection.
4 transportation optimization
The optimization of urban garbage transfer belongs to the transportation problem, which mainly includes
According to the disposal capacity of different disposal methods, as well as the transfer station for no
According to the transportation route and distance of the disposal site, the direction of each transfer station is determined.
The amount of garbage distributed and transported in different treatment plants.
If there are m transfer stations A 1, A2, ..., they will be generated separately.
The original amount of garbage is a 1, a2, …, am. Another garbage disposal.
N points, respectively B 1, B2, …, Bn, acceptable for disposal.
The quantities are b 1, b2, …, bn respectively. Transportation distance from Ai to Beijing
(reflecting the economy of transportation capacity) is cij, which is equal to production and disposal.
In the case of equilibrium,
m
i = 1 ∑ai=
n
J = 1 ∑bj, find the most economical (transportation distance
Lowest) transportation scheme [10].
Mathematical model: Let the shipment from Ai to Bj be Xiji, then
Fujian dialect
m
I = 1√
n
j = 1 ∑cijxij .(8)
n
j = 1 ∑ xij=ai，
m
i = 1 ∑ xij=bj，xij≥0，(i = 1，2，…
m； j= 1，2，…，n).(9)
5 concluding remarks
Introducing quantitative model into decision-making can improve decision-making quality.
Quantity and level, but attention should be paid to the collection and transportation system of urban solid waste.
Planning and design involves many interrelated and mutually restrictive factors.
It covers economic, environmental and social aspects. Therefore, in the establishment
Various factors should be considered comprehensively when modeling, and after repeated comparison and
Weigh and finally get the best domestic garbage (continued on page 48)
forty-four
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Methods of collection and transportation.
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About the author: Tong Huanhuan (1985-), master, mainly engaged in the optimization research of garbage collection and transportation system.
Research.
For fuzzy operations, the weights should be normalized, as shown in Table 2.
3.3 Comprehensive evaluation results
The comprehensive evaluation can be obtained by the fuzzy synthesis operation of r and a.
Price results.
Sludge sample1:ar = (0.022,0. 033, 0.945);
The value of sludge sample 2: a r cannot be realized;
Garbage sample 3: a r = (0. 747,0.253,0,0).
The evaluation results show that the sludge compost sample 1 "decomposed"
Grade membership is 0. 022, and the grade belongs to "well decomposed".
0, the "basic maturity" level belongs to 0. 033, "not rotten"
The membership degree of "cooked" level is 0. 945. According to the maximum degree of membership,
Then, the compost sample grade is "immature". Sludge compost sample 2
Because the original C/N (7. 13) is lower than the level at the end of composting.
C/N (16), resulting in a value r can not be reached, indicating that when pollution
When the initial carbon-nitrogen ratio of sludge compost is less than or equal to the final carbon-nitrogen ratio, this method is not applicable. rubbish dump
Fertilizer sample 3 was evaluated according to the principle of maximum membership.
The grade is broken down. The evaluation results are consistent with the reality.
4 Conclusion and prospect
In thermophilic aerobic composting, suitable sludge (initial carbon-nitrogen ratio)
The maturity of compost and domestic waste compost is less than or equal to c/n.
Unified evaluation indicators, such as duration of composting high temperature period, ηC/N,
Degradation rates of NH3-N/NO3-N, GI and NH3-N (ηNH3-N)
) 5
Evaluation of composting quality by fuzzy mathematics comprehensive method
Comprehensive evaluation view. Among many compost materials, this study is based on.
Fuzzy mathematical model is only applicable to pollution (initial carbon-nitrogen ratio ≤ final carbon-nitrogen ratio).
Evaluation of maturity of sludge and domestic waste compost, while other compost
The material needs further verification in order to better optimize the maturity index.
Parameters, improve its universal applicability, in order to improve the maturity of compost.
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