1、Characteristics of odor pollution near landfill site LU Peng1 YU Changkang1 WANG Guiqin1 DAI Zhifeng1* CHEN Wei1 REN Limei2 Beijing, China (1.Beijing environmental sanitation engineering research institute, Beijing, China, 100028； 2. MSW landfill of Chao Yang District, Beijing, China, 100018) e-mail
2、 address: Abstract Odor released from landfill is one serious point sources of air pollution in urban place that damages the surrounding environment, injures peoples health, induces villagers angrily and is not easy to be resolved. Sampling points near landfill and its ambient villages were selected
3、 at different direction from the central of landfill site. During one week observation period, odor concentration, ammonia and sulfide hydrogen are checked at different time every day. The results show the odor concentration has vibrate fluctuation between day and night during observation period. Ne
4、ither sulfide hydrogen and ammonia concentration has remarkable relationship with odor concentrations. Odor pollution is serious in night than that of in daytime at landfill area. Odor protection distance from landfill boundary should be more than 500m by analyzing the reduction regular of odor conc
5、entration in the research. Keywords- landfill; odor; diffusion; regular I. INTRODUCTION Large-scale industrial enterprises move out of Beijing Administrative Region to achieve the city planning and construction. Sanitation facilities, faraway from the center of the city, are surrounded by residentia
6、l area now. Its negative influence on city air environment became more seriously and was taken extremely concerned by municipal government. Odor pollution all occur in every steps of municipal solid waste (MSW) treatment process, such as collection, transportation and final disposal. Much odorous ma
7、terials are incomplete decomposition products that produced in anaerobic conditions. These materials including a lot of sulfur or nitrogen based compounds, like thiols, sulfides or amines, and much of it has toxic characterization 1-3. In China, more than 90% of municipal solid waste (MSW) was taken
8、 to sanitary landfill. At that place, odor pollution and other seriously environment problem occurred. In landfill area, the intensity of odor pollution has significant seasonal variation and the composition the unpleasant smell materials were analyzed by scholars 4-6. But the dynamic of odor pollut
9、ion changes during 24 hours of a day was rarely reported. Odor protection distance of landfill area generally according to practical experience because its pollution influence distance from landfill boundary was not very clear. The research was to detect the pollution changing regular of whole day a
10、nd the influenced distance from landfill boundary to ambient area. II. MATERIALS AND METHODS A. Testing sites A large of municipal solid waste sanitary landfill was selected at the east of Beijing, which include one first phase bury area and one second phase bury area covered 30hm2 and 16.5hm2 respe
11、ctively. The MSW pill is mounted to 40 meters in designed and it can accept 2000 tons of garbage per day continually for 17 years and contain 12 million m3 MSW during lifetime. Several villages at different directions neared the landfill (Fig.1) were selected in the scope of 600 meters distance from
12、 landfill boundary. According to the main wind direction was northwest during testing period, testing results at open space near Xiaotuncun village were used as background values. The center of village A is about 476 meters from the east boundary of landfill. The center of village B is about 500 met
13、ers from the south boundary of landfill. Village C is on the north direction of landfill. Because village A and village B is on the down wind direction, 5 testing points are selected on the odor dispersion direction at different distance near the villages. Point 1 is on the boundary, other four moni
14、toring sites are selected according to its relative position from landfill center to the village. Here includes the site between the village and landfill (point 2), the site in front of the village to landfill (point 3), the site in the center of village (point 4) and the site behind the village (po
15、int 5, the furthest position to landfill site). B. Analyzing method Air samples at every point were collected respectively from November 24 to Dismember 1 of 2006. Samples collected three times in one day that at 4:00am, 12:00 am and 10:00 pm respectively. The whole monitoring period prolong to 7 da
16、ys (172 hours). * Corresponding author: Sponsor: Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, Tsinghua University, 100084 Beijing, China, No. SWMES 2009-12 The samples of ammonia and sulfureted hydrogen in environmental air were collected by auto
17、environmental air collector (type KB-6120, Beijing central western Ltd.). Sample of ammonia concentrations were analyzed by sodium salicylate-sodium hypochlorite spectrophotometry method 7. The sulfureted hydrogen concentrations of the samples were analyzed by methylene blue spectrophotometric metho
18、d 8. The emission threshold of the concentration of ammonia and sulfureted hydrogen according to “Comprehensive emission standard of air pollutants” 9, odor samples were collected by 2L volume aluminum foil sample collecting bags (produced by Delin ltd., every bag could endure 3kPa pressure). Odor s
19、ample collecting methods and emission threshold were according to China National Standards “Emission standard of odor pollutant” GB/T14554-1993 10. Odor concentrations were determined by triangle odor bag method liked that dynamic olfactometry both use the human nose as a sensor 11. Meteorological f
20、actors changing were detected in testing period. Changes of wind directions and velocities during day were detected by verification regulation of portable 3-cup anemometer (type is DEM 6, produced by meteorological instrument factory in Tianjing). Air pressure was detected by aneroid barometer (Chan
21、gchun meteorological instrument factory, type DYM3). All data were analyzed by SPSS 13.0 software. Fig 1 Relative position of testing points to landfill area III. RESULTS AND ANALYZING A. Meteorological data during testing period During experiment period, air pressure generally below 103kPa except t
22、wo peaks appeared at 22 and 118 hours respectively which have the same values as 103.5kPa (Fig. 2). Three wind velocity value peaks appeared at 60hour, 4ms-1; at 100hour, 3.6ms-1; and at 156hour, 5ms-1 respectively and it is less than 2.5 ms-1 in other testing times. The mean value of velocity was 2
23、.4 ms-1. Fig 2 Changes of wind speed and air pressure during testing period B. Odor concentration changes during testing period In 5 testing points at south diffusion direction near village B, the site between village and landfill was influenced by odor pollution remarkable, because the odor concent
24、ration is over through the emission limits of “Emission standard of odor pollutant” (20 dimensionless)7 several times during observation period which at 4h, 28h, 52h,72h,94h and 118h respectively(Fig.3). There have same phenomena in testing points on east diffusion direction near village A. From the
25、 odor concentration curve we find the strongest odor pollution occurred at time of 28 hours (4:00 am in November 25). B1 and A1 point both over emission threshold seriously on east dispersion direction, The testing result at point A2 (between village and boundary) and A3(before village) over thresho
26、ld seriously (20, dimensionless), but it has less influence on the point in village (point A4) or behind village (point A5). On south dispersion direction, The testing result at point B2 (between village and boundary) over threshold seriously, but it has less influence on the point before village(B3
27、),in village (point B4) or behind village (point B5). Fig 3 Change of odor concentration at different testing site at downwind direction of landfill 01020304050600 12 24 36 48 60 72 84 96 108 120 132 144 156 168 180odor concentration/dimensionlessV illa ge A01020304050600 12 24 36 48 60 72 84 96 108
28、 120 132 144 156 168 180time/hoursodorconcentration/dimensionlessbou n da r y be t w e e n l a n df ill a n d v illa g ebe f or e v illa g e in v illa g ebe h in d v illa g e e m is s ion t h r e s h ol dV illa g e B1021 0 2 . 41 0 2 . 81 0 3 . 21 0 3 . 61044 12 22 28 36 46 52 60 70 76 84 94 100 108
29、 118 124 132 142 148 156 166 172t i m e / ( h )airpressure(kPa)0123456windvelocity/(ms-1)air pressure wind velocity0.1km Fig. 4 fluctuation of odor concentration on landfill boundary and temperature during testing period By statistical analyzing, there have remarkable relations (P0.01, 2 trail test)
30、 between odor concentrations on the landfill boundary in different directions. But, there have no remarkable relationship between the air pressure and odor concentration, neither the air temperature. The wind velocity has some effect on odor concentration for the lower odor concentration always appe
31、ared at the time that higher wind velocity occurred. But there have not remarkable relationship between wind velocity and odor concentration by statistical analyzing. There have two characteristics about odor concentration changing during the observation period. Firstly, odor concentrations have sim
32、ilarly fluctuating trend in different testing points; Secondly, remarkable relationship between odor concentrations on the landfill boundary in different directions at the same time. According to the two characteristics, data of odor concentration at landfill boundary were picked up to analyzing the
33、 dynamic of odor pollution intensity of whole day (24 hours of a day). The mean odor concentration changing on landfill boundary show that the lowest values always appeared at 12 am in the daytime and the highest value generally appeared at 4 am in the evening. The trend of odor concentration changi
34、ng was reversed to that of air temperature during whole monitoring period. The odor concentration curve show vibrate changing regular that was as same as the feeling of the residents who living in the village during the observation period. It is show that odor pollution in night was seriously than i
35、n the day time near landfill area (Fig.4). IV. DISCUSSIONS A. Distance of odor pollution influence By statistical analyzing, odor concentration (Table 1) and its standard variation decreased with the distance increasing. These phenomena inferred that the polluted intensity was get down during odor d
36、ispersion and the odor concentration difference between day time and at night time decreased too. There have remarkable relationship of odor concentration between landfill boundary and other sites in different diffusion directions that neared village A or neared village B respectively (table 1). Pro
37、tected distance from landfill to ambient area is very important in odor pollution research. In China, 500 meters protect distance was provided at downwind direction from landfill site in an old environment protection demand on landfill site selection 4, 12. The new standard for pollution control on
38、the landfill site of municipal solid waste(GB16889-2008) change the “500 meters downwind” to “by environment evaporation” 13. Some scholar suggesting the protection distance is between 500 meters to 800 meters around small scale landfill site, 800 meters to 1000 meters around middle scale landfill s
39、ite, 1000 meters to 1500 meters around large scale landfill site 14. B. The influence of ammonia and sulfureted hydrogen on odor pollution There has no relationship between the concentration of ammonia and odor concentration. And the ammonia concentration has no regular vibration like the change of
40、odor concentration in 24 hours of the day. The lowest value appeared at the testing point between village and landfill site (point 2) and highest value appeared at the siteTable 1 Descriptive statistics of odorous air concentration of different distance sampling points near landfill area Point No. S
41、ampling site distance from landfill boundary (m) Mean value /dimensionless Std. Deviation Sample content N Correlations coefficient between point on landfill boundary and other testing sites A1 East boundary 0 20.27 10.48 22 - A2 Between landfill and village 238 17.05 6.81 22 0.910* A3 Before villag
42、e 476 13.00 4.39 22 0.746* A4 In the village 506 10.32 1.49 22 0.101 A5 Behind village 536 10.00 0.00 22 - B1 South boundary 0 19.59 8.27 22 - B2 Between landfill and village 250 16.09 5.74 22 0.764* B3 Before village 500 14.23 4.17 22 0.491* B4 In the village 550 11.82 2.79 22 0.430* B5 Behind vill
43、age 600 10.59 1.40 22 0.539* *correlation remarkable (0.01 level, 2 trail); *correlation remarkable (0.05 level, 2 trail) - 1 001020304050604 12 22 28 36 46 52 60 70 76 84 94 100 108 118 124 132 142 148 156 166 172t i m e / hodorconcentration/dimensionless- 1 001020304050temperature/m e n o d o r co
44、n cen t r a t i o n o n la n d f i ll b o u n d a r y a i r t e m p e r a t u r eFig.6 odor concentration changing regular with distance increasing from landfill boundary in front of village (point 3) from one week testing values (data not show). There have no remarkable relationship of ammonia conc
45、entrations between different test sites. And neither has remarkable relationship between ammonia concentration and odor concentration by statistical analyzing results. The mean concentrations of ammonia in the middle of village were higher than on the landfill boundary inferred that ammonia produced
46、 from livestock that culture by villagers themselves was probably more than that produced from landfill. So, it can deduce that ammonia concentration is not the main factor, which influence on odor concentration. Generally, there have three periods during odor pollution process, production, effusion
47、 and detection by human beings 15. The materials have molecular weight light than air is easy to evaporate to atmosphere and molecular weight above than air has more influence to the downwind area of landfill site. Transport of the odor is affected by factors such as the season, time of day and the
48、atmospheric conditions influencing dispersion of the odor (e.g. turbulence, wind speed and wind direction). The hydrogen sulfide concentration is one main odor pollution factor that influenced on the ambient area of landfill site. But, the hydrogen sulfide concentrations were too low to detect (less
49、 than the instrument testing limitation) during testing period. The two important odorous materials, ammonia and hydrogen sulfide that in china national standard “Emission standards for odor pollutants” GB14554-19937 were not have remarkable relation with odor concentration in experiment. V. CONCLUSIONS Three results were concluded from the research: (1) Odor pollution in landfill area has vibrated changing regulation from day to night, which is lower in the day time and higher in
