China - Second Tianjin Urban Development and Environment Project : environmental assessment (Vol. 4 of 11) : Environment impact general statement (draft) Part two

E574 Volume 4 Tianjin Second Batch of World Bank Loan: Urban Development and Environment Project Environment Impact General Statement (Draft) Part two Tianjin Academy of Environmental Sciences Tianjin Environmental Impact Assessment Center March 25, 2002 FILE COPY   9.Disposing sludge and evaluating the environmental effect During the implementation of the project of Dagu Sewage River and the construction project of pipe net, silt and sludge will be produced, and during the construction of pipe net and the running of Shuanglin Sewage Disposal Factory, raw sludge and digesting sludge can be also produced. These sludge can make a second pollution if they are not disposed properly. So there will be a special chapter analyzing how to deal with sludge and what influences to the environment. 9-1 Analyzing the amount and elements of sludge produced 9.1.1 The amount of sludge and the disposing measures lists in the subsidiary items The amount of the sludge at the bottom of the river course during the work of regulating Dagu Sewage River and the amount of M i& from the construction of pipe net, and the amount of 01 L, dregs, sand, digesting sludge when the Shuanglin Sewage Disposal factory is working, are all listed in Table 9-1. Table 9-1 Shaunglin Solid waste type Project of Tagu Pipe net Sewage Disposal way Sewage River project disposal factory Output 230.4A 104m3 7.5 R 104m3 22.8%for fertilizer 9.2% Desilting for afforesting, 36.8%for Sludge Percent of 95 hygienic stuffing water0/6 59 Output 900 m3/a 6489tUa Using special box and Percent of 55 55 bus to put it and bury it in water/% the place appointed by the department of Output 5475tUa environment sanitation as Detritus house refuse Percent of 60 water0/6 Output 5500m3/a Using special box near Pipe Sludge the Sewage factory, then Percent of dehydrating and disposing watere/o 60 with sludge together At the beginning, used for Output 1 4600Uta upgrading the soil of Digesting . Binhai road afforest area, Sludge Percent of in 2010, taken to the water0/6 20 bury place of municipal EASUR APR 2 2 2002 9-1 RECEIVED  9.1.2 Analyzing the elements of sludge The program takes samples from bottom of Dagu Sewage River (including the Xianfeng Sewage River) on the spot in September in 2001, and takes samples from the bottom of the Fengchan River on the spot on 26h,1,2002. 1 )Set up the points of collecting samples 1# the meeting place of water from pumping stations between Xianyiang road and Miyun road 2# the place of 500 meters upriver from the meeting place of waters between Dagu Sewage River and Ji village. 3# the place of 500 meters downriver from the meeting place of waters from Dagu Sewage River and Ji village 4# The section of Jinlai road of Ji village drainage river. 5# the place of 500 meters in front of pumping station of Pao shui wa: 6# The place of 500 meters behind the pimping station of Pao shui wa 7# the place of 500 meters in front of pumping station of village Jun ge 8# the meeting place of Dagu Sewage River and Xianfeng river 8A#Village Yan jia juan on the midpoint of 8# and 1 0# 9# The place of 500 meters upriver where the Xianfeng Sewage River flows into the Dagu Sewage River 9A# Ji tai Village near Xianfeng river 10# Xin cheng bridge 11# the place of 500 meters downriver where the waste water from Dagu chemical plant flows into the Dagu Sewage River 12# the place of 500 meters in the front of eastern Dagu pumping station 13# the place of 1km behind the eastern Dagu pumping station 14# the Ga feng lu bridge across the Feng chan river 15# the Chao yang bridge across the Feng chan river 2) the monitoring factors The program mainly chooses Cd, Hg, Pb, Cr, As, Zn, Ni etc. as pollution indexes. 3)The monitoring results The results are listed in the table 9-2. 9-2  Table 9-2 The monitoring results of the sludge in the river course (unit: mg/kg) nver No Depth Cd Hg Pb Cr As Zn Ni (cm) 1# 0-55 1.60 3.12 61.3 208 17.7 768 123 0-100 4.55 1.74 65.7 286 15.0 1420 102 2# 100-120 0.43 0.15 56.2 65.6 16.1 491 25.6 0-65 2.70 3.03 77.6 116 11.1 338 68.2 3# 65-100 0.60 0.95 73.2 134 20.2 263 42.1 00-90 2.88 7.64 356 472 16.0 1070 74.2 90-100 0.35 0.50 53.5 92.6 14.7 206 33.2 0-105 2.80 4.68 142 412 14.8 71.2 169 105-135 0.07 0.20 18.6 49.4 8.95 63 21.6 0-90 3.10 7.00 67.5 160 15.6 495 89.5 90-100 0.10 0.10 25.4 60.5 6.8 103 25.4 0-45 0.16 1.08 25.0 88.6 10.9 241 50.5 45-65 0.80 0.42 93.1 108 15.3 606 30.2 8# 0-80 2.95 2.51 390 570 9.05 2000 2580 0-120 0.67 0.24 64.4 90.2 16.7 675 29.6 8A# 120-150 0.43 0.15 56.2 65.6 16.1 491 25.6 0-80 0.45 0.41 58.1 126 16.1 498 34.1 cn 9# c @ 80-90 0.40 0.29 59 98.8 13.6 276 30.5 C> X) 0-40 1.83 1.82 382 753 78.6 2360 59 9A# 40-55 0.20 0.16 45.6 101 14 146 29.9 0-140 3.25 0.88 64.1 271 39.4 2850 43.1 10# _ar) 140-170 0.85 0.76 92.5 112 26.4 1170 31.2 11# 0-100 0.10 0.90 28.5 67.6 55.9 71.5 29.3 0-95 0.35 0.46 17.5 69.4 13.5 291 32.5 (D 12# en 95-140 0.17. 0.21 32.3 80.6 16.4 118 33.1 co 0-95 0.21 0.19 27.1 73.9 15.8 230 93 13# I 13 95-110 0.11 0.18 31.1 67.5 12 935 30.5 0-20 0.450 3.72 78.5 88.6 12.6 258.0 33.4 -ni CDm 14# 20-50 .0.241 0.237 31.8 78.7 11.7 99.0 34.8 Co g. 50-80 0.254 0.066 29.0 68.6 12.6 98.5 35.4 _) 0-20 0.308 0.059 35.8 55.2 9.75 132.0 38.0 cD 15# 20-50 0.215 0.696 35.2 61.3 11.2 114.0 34.2 50-80 0.232 0.089 30.5 58.9 13.3 98.0 39.8 pH<6.5 5 5 300 600 75 500 100 Standard limitation. pH 6.5 20 15 1000 1000 75 1000 200 9-3  From the table we can see that, the pollutants contain As, Ni, Zn don't go beyond the standards in the surface sludge of Dagu Sewage River. Among them, 'As" goes beyond the standard at monitoring point 9A; Ni at 8#; Zn at 4#, 8#,9A and 10#. The order of polluting degree is Ni>Zn>As. From the positions of the monitoring stations, the silt on the surface of 2#,3#,4#,5#,6#,8#,9Aand 10# has been polluted. The amount of the pollutants except Zn in the silt at the bottom doesn't go beyond the standard, and the silt at the bottom of other monitoring stations hasn't been polluted. The amount of the silt in the watercourse of Fengchan river conTables to the demand of Control Standard in Agriculture of the Pollutants in the Silt (GB4284-84). However, by analyzing the lixivium from the silt in the watercourse, Hg and As in the silt of the watercourse go beyond the standards. They should be judged as dangerous waste and disposed properly (hygienic stuffing). The amount of the silt at the bottom of Xianfeng river is an accumulative amount for many years. Thinking of the waste water in the area where the water is gathered of this program all drains into the Xianfeng Sewage River, the amount of digesting sludge will not higher than the silt at the bottom of Xianfeng Sewage River when Shuanglin Sewage Disposal Factory is built up. 9.2 The feasibility analysis of the measures of dealing with/disposing silt 9.2.1 The feasibility analysis of the desilting-sludge applying in agriculture According to the results above, the surface sludge on 1#, the bottom sludge on 3# and 7#, the surface sludge on 8A and 9# of Dagu Sewage River have the amount of heavy metal which conTables to the limitation in Control Standard in Agriculture of the Pollutants in the Silt (GB4284-84). And TN,TP and organic substances are in high content. The degree of alkalization is low. N and P in the soil are the necessary elements for plants' growing, and the organic substances are beneficial to improving soil quality. So on the premise of controlling the usage amount of the sludge properly, the pollution to the environment from N and P not only be got rid of, but also get the double goals of changing disadvantage into advantage and turn waste into.treasure. The sludge amount in agriculture of this program adds up to some 542270m3 which is 22.8% of the total sludge. 9.2.2 The feasibility analysis of disposing silt and sludge piling and afforesting According to the results of the samples taken on the spot, the amount of heavy metals and mineral oil in hard sludge at the bottom of 2#,5#,6#,8A,9#, 12#andl 3#etc. conTables to the limitation in Control Standard in Agriculture of the Pollutants in the Silt (GB4284-84), but the fertility is poor and the degree of alkalization is high. So it isn't suitable for agriculture. In order to decrease sludge piling from 9-4  occupying land to the largest extent, the silt piling area should be arranged on the salt wasteland the whole way. The amount of piled silt in the program adds up to 266040m3. If the height on average is 1.0m,the area of piling amounts to 266133m2. According to The Research on lianjin Water Resource Used properly and Comprehensive Prevention of Water Pollution. There are 2986.9mu saline-alkali soil in the irrigation area of Dagu Sewage River, and 202789.6mu wasteland. Therefore, saline-alkali soil and farm land on both banks can meet the demand of sludge piling of the program. It is possible to pile the sludge on the saline-alkali soil and farmland on both banks of Dagu Sewage River. According to the analysis of the present monitoring on the sludge at the bottom, the amount of heavy metal and mineral oil in hard sludge and soft sludge of 7#,11#,12#and 13# conTables to the limitation in Control Standard in Agriculture of the Pollutants in the Silt (GB4284-84).The fertility is comparatively good and the degree of alkalization is relatively higher. It is a good way to dispose sludge that they can be used to make afforest zone on both sides of the watercourse. The amount of desilting-sludge used on afforesting adds up to 695352 mu. 9.2.3 The feasibility analysis of digesting sludge used in the farmland Whether the sludge can be used in the farmland depends on two sides of elements: one is the amount of poisonous substances in sludge, the other is the present situation of the soil in agriculture. The main pollution element restricting the usage of sludge in the farmland is heavy metal. The amount of heavy metal in the sludge of this program assured by Shuanglin sewage disposal factory according to the project analysis compared with the demand in Control Standard in Agriculture of the Pollutants in the Silt (GB4284-84). Referring to table 9-3: Table 9-3 The amount and the standard of heavy metal in sludge gm/kg dry sludge Item class Cu Zn Pb Cd Hg As Ni Cr Amount of 609.9 2360 382 18.32 1.82 78.6 59.0 753 sludge Standard amount 500 1000 1000 20 15 75 200 1000 permitted I According to the above table, the amount of Zn in sludge has gone beyond the standard, and the amount of Cd and Cr has been close to the standard. So Digesting sludge of sewage in the program isn't suitable for the usage in the farmland. 9.2.4 The feasibility of Digesting sludge in holt Although Digesting sludge of Shuanglin Sewage Disposal Factory in the 9-5  program can't be used in the farmland, it can be used in holt and lawn. Table 9-4 calculates the fixed number of years of the sludge used in holt of the program. The largest usage amount referring to the limitation of sludge control p standard in agriculture is 2000kg/mu, suppo ng that the amount of metal in holt is soil background value, the weight of surface soil is 150t/mu, the soil remains are 100% temporarily according to conservative calculation. Table 9-4 The effect of applyin sludge in woodland Cu Zn Pb Cd Hg As Ni Cr sludge content 609.9 2360 382 18.32 1.82 78.6 59.0 753 (mg/kg) Quantity per year 1219.8 3326 645.2 26.0 15.221 34.4 282.8 1894 (g/mu.a) l l Convert into topsoil 8.13 31.47 5.09 0.24 0. 024 1.05 0.79 10.04 Amount per year Soil background 27.50 63.90 20.50 0.086 0.0440 10.850 30.15 98.20 content (mg/kg) 1 * 35.63 95.37 25.59 0.326 0.068 11.90 30.94 108.24 2 years 43.76 126.84 30.68 0.566 0.092 12.59 31.73 118.28 2. _ _ _ o 3yer D 3 years 51.89 158.31 35.77 0.806 0.116 14.00 32.52 128.32 C o 5 years 68.15 221.25 45.95 1.286 0.164 16.10 34.10 148.40 1 0 years 108.80 378.60 71.40 2.486 0.284 21.35 38.05 198.60 - 15 years 149.45 535.95 96.85 3.686 0.404 26.60 42.00 248.80 20 years 190.10 693.30 122.30 4.886 0.524 31.85 45.95 299.00 Quality standard of third class soil 400 500 500 1.0 1.5 40 200 300 surroundings (mg/kg) From the result , when the sludge is used in the green field of gardens, though the velocity is not more than 2000kg/mu.a, after continuous 5 years, Cd in the soil will over run the third class of the standard of soil surroundings. After continuous 15 years, Zn will exceed the standard. That is to say,, for protecting the woodland from pollution, the number of using year of this project should not more than 5 years. The sludge product of this project is 11680tVa dry solid, calculated by annual sludge exclusion 2000kg/mu, and the area of the woodland used for the sludge from the project should be 5840 mu. At present, the total garden green field of our city is 82970 mu,. The area needed, which is only 7% of the whole, is sufficient to deal with the sludge from the project. By the analyses above, the final way to deal with the sludge in the near future (3-5years) is the woodland, and for the far future use needs some other ways. 9-6  9.2.5 The feasibility analyses to digesting sludge bury To bury the sludge is a kind of more perfect practice to solve the second pollution of the sludge, and its main advantages are the credibility of technique and the high security, which can avoid from the second pollution effectively. The expenses of building and running are low, and the low technology is required to the operators. The occupied field resource has the repeat-use value. According to the analogized inTableation (The World Bank loan to Liaoning Province Liao River drainage areas sewage project [the first term] the whole report of the environment effect), the lixiviated experiment of the sludge and the garbage of the city sewage disposal factory shows, under the same condition, the content of the heavy metal from the sludge is lower than the common garbage. The project of disposing sludge is anti-oxygen digest though the dehydration and dryness. The containing water rate will be 20%, at last, the buried way is effective to prevent from the second pollution. 9.3 The evaluation of the sludge disposition and environment effects during the period of construction 9.3.1 The sludge disposing project in the period of construction The main sludge of this project comes from the bottom sludge in the riverway of Dagu Sewage River and Fengchan river desilting project. From the evaluation above, the bottom sludge of Dagu Sewage River and Fengchan river has a high content of TN, TP and organic substance, and it has better fertility, especially the silt in the surface layer, which fertility condition exceed over the guideline of the loam of Huabei plain. So, from the condition of the heavy metal pollution in the bottom sludge, some disposing projects as should be used separately: (1 ) Used as farm fertilizer: if the content of heavy metal and mineral oil tally with GB4284-84 ((the standard of control contamination in the farming sludge ) ,and fertility is high, slight salinization, the bottom sludge is used as farming fertilizer firstly. Not only the sludge buries and the capital can be reduced effectively, but also the garbage can be changed into useful, the nature resource can be made the best use of. (2) Piled up at the wilderness of the banks or building dike and planting : if the content of metal and mineral oil tally with GB4284-84 ((the standard of control contamination in the farming sludge)) , but the fertility is worse, and heavy saltinization, the bottom sludge can be directly piled up at the wilderness, or building dike and planting, so as to reduce the sludge buries and the capital. (3) Bury: if the content of the heavy metal and the mineral oil is over GB4284-84(the standard of control contamination in the farming sludge)), the content of heavy metal in the lixivium tally with GB18597-2001 (the standard of control the pollution of dangerous garbage buries)), the bottom sludge should be carried to sludge burying field to bury, so as to prevent the environment from 9-7  the obvious disadvantage effect. From the different character of the sludge, the different deal projects of sludge quantity are as followed, as table9-5. Table 9-5 The sludge quantity of different projects (m3) Deal project Farming Greening Building Dike and Burying Sum up fertilizer Piling sludge quantity 542270 695352 266040 874993 2378655 Ratio (%) 22.8 29.2 11.2 36.8 100 9.3.2 The analyses of the ecology effect on the sludge used in farming fields The content of N, P and organic substance in the farming sludge, as table9-6. Table 9-6 The content of N. P and organic substance in the farming sludge (t) Equal to Polluton Dry Quantit Quantit Quantity of nitrogenous Equal to phosphor recourse sludge y of N y of P organic fertilizer fertilizer (calculate as (t) element element substance (calculate as Ca(H2PO4)2) urea) 1# 32.0 57.8 1117.3 surface 32670 53 206 bo3tl#om 1 0605 4.9 8.9 193.0 bottom 10605 ___ ____ 8 32 256.8 140.3 3821.0 bottom 156600 428 499 8A table 10.8 351.3 17329.1 366366 18 1250 9# 2.1 57.9 2178.0 table 74844 3 206 Sum up 306.6 616.2 24638.4 . 641085 510 2193 From table 9-6, if the sludge from this project is used in farming, the farming soil can be added to 306.6t N, 616.2t P, 24638.4t organic substance, which is equal to add 51 Ot N fertilizer (calculate as urea) and 21 93tP fertilizer (calculate as superphosphate) to the farming soil, it is very advantageous to the grow of crop and development of the product of crop. According to national "LiuWu" science and technology tackle key problem project (The Rational Utilization of Water Resource in Tianjin and the Research of Comprehensive Treatment on Water Pollution)) , by using the city waste water as irrigation area at Dagu Sewage River, the ripe and Chinese cabbage get obvious increase production, this proves that the waste water in Dagu Sewage River is good for increasing the production of crops, and the silt with N, P. organic substance in the Dagu Sewage River used in farming can get the 9-8  similar result. According to some provisions of GB4284-84 ( the standard of control contamination in the farming sludge)) ,when the sludge above used as farming, the quantity should be controlled under 2000kg/mu/year. This evaluation calculated by 2000kg sludge every Mu forecast the content of heavy metal affect on the farming soil after using the sludge. methods as followed: C" C:'o xP, x666.7xh+C,, x2000 P. x666.7xh+ 2000 in the Tableula: C.'-consistence of i gene in the farming soil after using the sludge, mg/Kg -i: C*-in the bottom sludge ,the consistence of I gene, mg/Kg +; P a T 8t of farming soil (Kg/rm3), P =1.5x 103 Kg/m3; h-the average thickness of cultivation layer of farming soil (im), take 0.25m. C,O -consistence of i gene in the farming soil, mg/Kg F; Using the sludge should follow the principle of near to reduce the transportation quantity. So, the background value of the content of the heavy metal in the farming soil can be confirmed according to the actuality measure value. For background value of the farm land of 1#and 3', 8A supervised point has not been supervised, the heavy metal content should be ascertained according to the average value of 7#, 8#, 9#. 10#, 11#, 12#, 13# supervised points. The results show up in the Table 9-7. From the result of Table 9-7,with the premise of sludge implement volume controlled under 2000kg/Mu, the sludge in this project is implemented nearby, the heavy metal content in the earth still complies with the second-class standard limits in GB151618-1995<Quality Standard for the earth environment>, and before and after the sludge implementation, the changeability rate of the heavy metal content is little with the biggest value of 12.45%. Therefore, sludge used in agriculture in this project will not do obvious harm to the farmland earth environment on the banks. In order to further evaluate the effect of sludge implementation on the growth of crops, this evaluation chooses sludge samples of 7# and 9# spot to take the experiment of early growth of seeds, in which each share of sample is made according to 4 proportions (rate of sludge weight to earth weight): control experiment (0%), 5%, 20%, 80%. There are 5 crops available to the experiment: two kinds of monocotyledon (wheat and com) and three kinds of dicotyledonous (white radish, kidney bean and yellow bean), and the experiment period is 15 days. After 15 days, separate menstruation is made about the root length, seedling height, Dry Weight on the ground and Dry Weight of the root part( see attach table and attach picture for the experiment data ). Based on the experiment result, among the samples with sludge density of 5% and 20%, the above data of 9-9  the five crops has not big difference with that of blank sample, that means no big negative effect is made on the growth of crops. Therefore, the utilization of sludge in the agriculture in this project will not made bad effect on the farmland zoology under such proportion. Table 9-7 The influence of the soil condition quantity of sludge usage in farm Station place Total Total Total Ni Total Total Zn Total Pb Total Hg arsenic Cd chrome (pprn) 0.187 11.53 29.1 0.108 97.44 29.17 64.16 1# Forecast value 0.210 11.58 29.8 0.120 102.76 29.42 65.30 (ppm ) _ _ _ _ _ _ _ _ __ _ _ _ _ _ Changeability rate 12.45 0.42 2.56 10.96 5.46 0.87 1.78 Background value 0.187 11.53 29.1 0.108 97.44 29.17 64.16 (ppm) 3# Forecast value 0.193 11.6 29.2 0.112 98.76 29.52 64.71 (ppm) Changeability rate 3.14 0.59 0.35 3. 50 1.33 1.18 0.86 Background value 0.257 10.7 33.4 0.093 94.5 28.8 71.5 (ppm) 7# Forecast value 0.258 10.74 33.37 0.099 98.56 29.31 71.79 (ppm)__ _ _ Changeability rate 0.49 0.34 -0.08 5.69 4.12 1.74 0.40 Background value 0.187 11.53 29.1 0.108 97.44 29.17 64.16 (ppm) ____ 8A Forecast value 0.188 11.57 29.1 0.112 102.02 29.45 64.37 (ppm ) _ _ _ __ _ _ _ Changeability rate 0.21 0.36 0.01 4.13 4.70 0.96 0.32 (% ) I__ _ _ _ Background 0.226 6.56 23.6 0.067 86.5 21.9 55.0 value (ppm) 9# Forecast value 0.227 6.636 23.68 0.07 89.77 22.19 55.56 (ppm) __ _ __ _ _ Changeability rate 0:64 1.14 0.35 4.34 3.64 1.30 1.01 ( % ) I___ _ _ _ _ I_ _ _ _ The second class 0.5 25 50 0.3 250 300 200 standard__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ __ _ _ _ To sum up, the farmland using of sludge in this project can add 306.6t nitrogen, 616.2t phosphor, and 24638.4t organic substance into the farming-earth, equal to implementing 510t nitrogenous fertilizer (calculated as car amide) and 2193t phosphorus fertilizer (calculated as superphosphate), which is very favorable for the growth of crops and the increase of crops production. Under the premise of well controlled sludge implementation according to GB4284-84< Standard for the control of the infect ant in the farmland pollution>, the farmland using of sludge has little effect on the heavy metal content in agricultural earth, and therefore little bad effect on the growth of crops and farmland zoology. Because piled and green sludge, which is relatively thick and is likely to be washed by rain, directly covered on the earth's surface, and the noxious 9-10  components are soaked out, moving into the surrounding soil and channels with pathway current, the evaluation by the experiment forecast makes the eluviations pile and green possible. In this project, the surface sludge samples from the bottom supervised points 2#, 5#, 7#, 9#, and 10* have been taken in the lixiviate experiments. The experiment methods are taking the People's Republic of China ((the methods standard of dangerous waste lixiviate toxicity)) as reference. The forecast subject: COD, Hg, Cd, Cr, As. Pb. Zn. Ni. For the heavy metal and COD content of the piled and green sludge soak liquid in this project, analogy calculated according to the experiment result above and the heavy metal content in the sludge, and compare the result separately with GB8978-1996 ( The Comprehensive Drainage Standard of Sewage)) the second class and GB5084-92 ((the water quality standard of farmland irrigation )) . The lixiviate experiment result, as table9-80 Table 9-8 sludge lixiviate experiment result (mg/I) Sample COD Hg As Cr Pb Cd Zn Ni 2# 317 0.00014 0.00314 0.007 - - 0.032 0.147 5# 475 0.0022 0.00599 0.061 - - 0.051 0.283 7# 158 0.00137 0.0247 0.004 - - 0.043 0.041 9# 142 0.00039 0.0137 0.004 - - 0.015 0.039 10# 738 0.00017 0.0047 0.013 _ _ 0.438 0.102 Note: "-" means 'not detect. The limit amount of Pb is 0.02mgA: and Cd, is 0.005mgA. According to the sludge lixiviate experiment result of the supervised point above, analogy calculate the content of kinds of contamination in the piled and green sludge lixivium, as table 9-9. From table 9-9, the heavy metal content of the piled and planting and the sludge lixivium in this project is far lower than the limited value of GB8978- 1996 ((The Comprehensive Drainage Standard of Sewage)) in second degree and GB5084-92 ((the water quality standard of farmland irrigafion )) , and it proves that rain water in rainy season which soak and flush the sludge piled fields and the green fields can't have an obvious and unfavorable effect on the environment soil quality and the heavy content of the water quality in the river way. 9-11  Table 9-9 the contamination content in the piled and green sludge lixivium Disposal Lixivium concentration (mg/l) way COD Hg As Cr Pb Cd Zn Ni 2# bottom Pile up 81 0.00C N ) 0.0010 0.001 - - 0.002 0.032 5# bottom Pile up 51 0.0001 0.0036 0.007 - - 0.045 0.036 6# bottom Pile up 67 0.00004 0.0028 0.009 - 0.074 0.043 8A bottom Pile up 96 0.00003 0.0019 0.003 - - 0.075 0.061 9# bottom Pile up 550 0.0015 0.0051 0.048 - - 0.028 0.253 9A bottom Pile up. 59 0.0008 0.0052 0.049 0.015 0.248 12# bottom Pile up 300 0.00004 0.0020 0.004 - _ 0.018 0.078 13# bottom Pile up 284 0.00004 0.0014 0.003 - 0.144 0.072 4# bottom Virescence 234 0.00024 0.0060 0.014 = 0.148 0.056 7# surface Virescence 158 0.00137 0.0247 0.004 0.043 0.041 11# surface Virescence 269 0.00017 0.0067 0.003 0.011 0.069 12# surface Virescence 397 0.00009 0.0016 0.003 0.045 0.077 13# surface Virescence 400 0.00004 0.0019 0.004 0.035 0.220 GB8978-1996the second class 150 0.05 0.5 1.5 1.0 0.1 5.0 1.0 G85084-92 300 0.001 0.1 | 0.1 0.005 2.0 note: COD analogy with the amount of organic carbon in sludge (TOC). Because the COD content in hard sludge No.9 and No.12 and soft sludge No.13 exceeds GB5084-92 <<Standard for the quality of water for farmland and irrigating>>,if no measure is carried out, the farmland around will be badly affected. Therefore, the constructing organization should take the following measures when piling up sludge and afforesting. * The ground for piling up sludge should be better located on the saline or grass waste land along the banks of the Dagu Sewage River in order to reduce the sludge-taken cultivated land and prevent the farmland from being rinsed by rain in rainy season. * Cofferdam is set up around the sludge piling ground with Stop-leaking channel and diversion channel in the outer circle. The rain is subsided through Stop-leaking channel, then drained into the drainage waste river so that the earth quality around can be kept from being badly affected. * Cleaning the silt in the river channel and afforesting should be implemented at the same pace at intervals. Afforesting on the banks should be carried out in the same year when cleaning silt is completed 9-12  to reduce rain's rinsing silt in the green band. Meanwhile, Stop-leaking channel should be dug at the external side of the green band, then rain can be drained into the drainage waste river through Stop-leaking channel. * The piling ground should be afforested in the same year when it is built. Planting trees, flowers and grass can not only increase areas of green land and reduce the waste in the silt, but also reduce the rinse to the exposed surface of the piling ground by rain and lessen the bad effect on the earth quality around. After the measures are taken, the rain from the sludge piling ground and green band will not seep into the farmland, therefore, not do noticeable harm to the biological environment. On the other hand, since volume of the drainage waste river is comparatively large in rainy season which contributes to the comparatively slight harm to the water quality of river channel, in addition, with gradual greening of the sludge piling ground and green band, the earth's surface will be covered, and then the negative effect will be lessened annually. 9.3.4 Analysis of the environmental effect by filling and burying sludge 9.3.4.1 Analysis of the feasibility of the selected location of the filling and burying ground According to the result from comparing the above programs, the sludge filling and burying ground in this project is located in the rejected pit in the brick factory of Juge-Dahan village in the southern district of Tianjin. From the view of environmental protection, this selection has following advantages: 1) This site is a rejected pit now which solves the problem of occupying farmland and therefore saves valuable cultivated land resource. 2) This site is far from residential areas and villages, the closest villages even 1km away. There is no surface water body such as natural river channel and reservoir in the range of 150km, hence no environment-sensitive objects exist. So the protective distance complies with the requests of the safe distance by GB18957-2001 <<Standard for controlling the pollution by filling and burying dangerous waste>>. 3) This site is low due to the long time taking earth and now becomes a rejected pit, which is convenient for construction for it reduces the required earth volume in constructing the ground, and therefore, lessens the negative influence on the surrounding in construction. 4) This filling and burying ground is located in the middle of the river channel which needs sludge to fill and bury, so it is easy for sludge transportation and lessens the sludge volume to be carried, therefore, lessens the air pollution in sludge transportation. So, from the view of environmental protection, this site selection is reasonable and feasible. 9.3.4.2 Percolating liquid quality forecast and corresponding treatment 9-13  program (1)production of percolating liquid Percolating liquid is the foul liquid percolating from the bottom of the sludge filling and burying ground. When sludge is rolled over, its innate moisture is squeezed out and the produced liquid is called percolating liquid. But in this project, sludge has been dehydrated in dehydration ground before sludge enters filling and burying ground and the moisture content is reduced from 95%to 75% after dehydration. When this dehydrated sludge is fixedly filled and buried with caustic lime, its inherent moisture will mostly absorbed and fixed by caustic lime, therefore little percolating liquid will be produced. The percolating liquid in sludge filling and burying ground is mainly from the percolating liquid Tableed by the rainfall permeating into the coverage earth layer and sludge layer. So, the volume of percolating liquid can be calculated in the Tableula: Q = C.l.A.10-3 In which, Q---- average volume of percolating liquid, m3/d; I- average rainfall intensity, mm/d; A---- area of cross section of rainfall ( area of filling and burying ground ), m2; C-- percolating coefficient. The parameter can be determined according to concrete climate phenomena of Tianjin and site condition of the filling and burying ground , with concerned data analysis of some domestic garbage filling and burying grounds for reference. Rainfall intensity l: According to Tianjin atmosphere data over the years, the average rainfall volume is 600mm and most of the rainfall is focused between June and September when the rainfall takes the 70% of that of the whole year; the peak rainfall appears in July with average of 190mm in this month. Based on the above data, the rainfall intensity can be worked out separately: According to the average rainfall volume: I = 1.64mm/d According to the rainfall volume of rainy season of four months: I = 3.93mm/d According to the rainfall volume in peak month: I = 6.13mm/d Percolating coefficient C: it refers to the rate of rainfall which changes to percolating liquid in the filling and burying ground. C may be changing due to different qualities and slopes of coverage earth, rainfall time and inherent moisture content. Generally, it can be calculated in the Tableula: C = 10-2 ( 0.002.12 + 0.161 +21) Area of cross section of rainfall A: based on the above analysis and demonstration on the sludge treatment program, this project requires sludge for filling and burying of 799993m2. But after dehydrating treatment (moisture content reduced from 95% to 75% ), the present sludge volume turns 71502m3, and the average filling-and-burying height is designed to be 8m, then the required area of the filling and burying ground is 89400m2, that is, the area of 9-14  cross section of rainfall A = 89400m2. Under different rainfall intensity, percolating coefficient and volume of percolating liquid can be calculated different ( see Table 9-10 ) Table 9-10 Values of C and A under different rainfall intensity Number Value of I (mm/h) Value of C Value of Q Condition ______ ______ (m 3Id) A rainfall volume of 0.2101 31 Annually average 1.64mm/d (0.07) 3 rainfall volume B Rainfall volume of 0.2`103 7Avorume inrainfsason B 3.93mm/d (0.16) 74 volume in rain season _ Rainfall volume of 0.2104 115 Rainfall volume in C 6.13mm/d (0.26) peak month (2) Percolating liquid quality forecast and analysis Based on the above analysis of the sludge treatment program, the required sludge in this project is from the surface soft sludge of the river section of 2#,3#, 4#,5#, 6#, 8#, 9A and 10#, and hard sludge in the bottom of 10# . This evaluation does permeating implement to the surface soft sludge samples from 2#, 5# and 10#. See the above Table 5.4-5 for the result. Since sludge for filling and burying has comparatively high content of organic substance's, TP and TOC (similar to urban daily garbage), and under degradation by microbe in earth, the organic substance will make high content of COD, BOD, ammonia, nitrogen and germs in the percolating liquid. So, this evaluation integrates the permeating experiment and compares with the determined data from the model experiment of permeating components of water in urban daily garbage according to the Environmental Effect Report of Tianjin Shuangkou Hygienic Garbage Filling and Burying Ground, then forecasts percolating liquid quality conditions of the sludge filling and burying ground in this project. See Table 9- 11 for the result. From the data in Table 9-11, in the percolating liquid of sludge filling and burying ground, heavy metal contend is relatively low, far less than the limit values of second-class in GB8978-1996<<Comprehensive standard for sewage discharging>>, which may affect the surrounding little. But its BOD,COD, TP and coliTable bacteria density is high,much higher than the limit values of second-class in GB8978-1996<<Comprehensive standard for sewage discharging>> and V standards in GHZB1-1999<< Standard for the quality of surface water enviroment>>. So,if percolating liquid is discharged without treatment,it will take negative effect on the surrounding surface water quality and biological system of farmland. It must be discharged after administration to standard. 9-15  Table 9-11 Analysis of the components of percolating liquid in the filling and buryi g ground Soaking test Documentary data Forecast Standard Item Soaking Shower value value Range average method method pH _ _ 7.6 7.6 7.6 6-9 SS _ _ 2460 80 1270 150 BOD5 - - 43920 246 246 30 CODCr 317-994 551 10526.5 442.08 551 150 NH3-N _ 94.79 2.32 48.6 25 N03-N _ _ 8.61 0.25 4.43 25 N02-N _ _ 0.183 0.033 0.108 1.0 TP _ 29.614 2.605 16.11 0.12 Hg 0.0001-0.0045 0.002 0.0008 <0.0001 0.002 0.05 Cd Unchecked <0.005 0.168 0.0048 <0.005 0.1 Cr 0.007-0.04 0.014 - - 0.014 1.5 As 0.002-0.006 0.004 0.004 0.001 0.004 0.5 Zn 0.02-0.44 0.186 1.08 - 0.186 5.0 Pb Unchecked <0.02 0.1842 0.0174 <0.02 1.0 Ni 0.10-2.10 0.498 - - 0.498 1.0 Total germs - 3.3 x 109 510X 1.9 x 109 - (CFUIml) _ _ _ __ 108 _ _ _ _ coliTable 1.1 x 106 2-4 x bacteria(MP - 1110 24 6.7 X105 10000 NIl) 105 I Note: (1) "-" refers to unchecked; (2) The standard values in the Table takes the second-class standard in GB8978-1996-Comprehensive standard for sewage discharging