China - Guangxi Urban Environment Project : environmental impact assessment (Vol. 2 of 3)

E-/tt - Loan from the wxorld Bankn Guangxi Environmental V* S Protection Project Statement on Environmental Impact Assessment of Chaoyangxi Comprehensive Treatment Project in Nanning City Guangxi Zhuang Autonomous Region Compiler: Chirncsc Research Academy of Environmental Scicnces Ccrtificatc Grade: A Ccrtificate Numbcr: NEPA Ap 0901 Compiililg Time: April. 1995  a 4 1 I'V II I 4. i ~~~~~~~~~~~~~~~~I'c'  Contents Executive summary L. PREFACE ....................................................... 1I I. I PURPOSE OF ASSESSMENT . 1.2 BASIS FOR THE COMPILING OF EIA . 1.3 SCOPE AND STANDARD OF EIA .2 1.4 GOALS OF ENVIRONMENTAL .3 1.5 CONTENTS AND KEY OF ASSESSMENT ......................................................., 3 1.6 MAIN TECHNIQUES AND MEASURES ADOPTED [N THE ASSESSMENT. 3 1.7 BRIEF INTRODUCTION OF ASSESSMENT INSTITUTIONS AND PERSONNEL 5 2. GENERAL INTRODUCTION TO PROJECT CONSTRUCTED WITH LOANS. 6 2.1 BASIC SITUATION OF THE PROJECT .6 2.2 PRODUCTION TECHNOLOGY .1 7 2.3 MAJOR POLLUTION SOURCES AND THEIR DISCIiARGING OF POLLUTANTS .20 3. GENERAL SITUATION OF THE ENVIRONMENT OF THE AREA OF THE PROPOSED PROJECT .23 3.1 NATURAL [ENVIRONMENT .23 3.2 GENERAL. SIT1UATION OF ITS ECOLOGICAL ENVIRONMENT .26 3.3 SOCIAL. IENVIRONMEN .26 3.4 PEOPLE'S I.!FE QUALITY .28 3.5 ENVIRONMENTAL QUALIT,Y .29 4. PREDICTED ENVIRONMENTAL IMPACT AND CONTROLLING MEASURES .42 4.1 RECOGNITION OF ENVIRONMENTAL AFFECTING FACTORS AND SCREENING OF FACTORS TO BE ASSESSED ........ 42 4.2 ANALIYSIS ON TI IE CH IARACT1ERIS-I ICS OF ENVIRONMENTAL IMPACT ................................. 42 4.3 PREDICTION ON TI IE PROJIEC'S ENVIRONMENTAL EFFECT DURING ITS CONSTRUCTION ... 48 4.4 PREDICTION ON TIHE ENVIRONMENTAI. IMPACT DURING TiE II OPERATION OF TIIE P'ROJECT ............................................................................................ 68 4.5 RISK ANALYSIS .................................................................. 135 1  4.6 COUNTERMEASURES TO ELIMINATE OR EASE UP THE LNFAVORABLE IMPACT ................ 136 5. ALTERNATE PLANS ......................................................... 140 5.1 ALTERNATE PLAN FOR THE WASTE WATER INTERCEPTING SYSTEM ON THE CHAOYANG STREAM ................................... 141 5.2 ALTERNATE PLANS FOR THE TREATING OF THE WATER WAY OF THE CHAOYANG STREAM ................................ 147 6. ANALYSIS ON THE BENEFIT OF THE CHAOYANG STREAM COMPREHENSIVE TREATING PROJECT ................................... 149 6.1 ANALYSIS ON ITS SOCIAL BENEFIT ................................... 149 6.2 ANALYSIS ON THE ECONOMIC BENEFIT OF THE PROJECT ................................15......... 151 6.3 ANALYSIS ON ITS ENVIRONMENTAL BENEFIT ......................................... 158 7. PLAN FOR ENVIRONMENTAL ADMINISTRATION AND ENVIRONMENTAL MONITORING ......................................... 160 7.1 SETTING UP OF ENVIRONMENTAL PROTECTION BODIES ......................................... 160 7.2 MEASURES FOR ENVIRONMENTAL ADMINISTRATION ......................................... 161 7.3 ENVIRONMENTAL MONITORING PLAN ....................................: 162 8. P'UBLIC PARTICIPATION ...................................1 64 S. I A.I AND PURPOSI ..6.................................... 164 8.2 M ETI IODSOF INVESTIGATION ................................... 164 8.3 ScoPE OF INVESTIGATION ................................... 164 8.4 SUBJECT OF INVESTIGATION ................................... . 164 8.5 METI-IOD OF INVESTIGATION ................................... 165 8.6 ANALYSIS ON THIE RESUITS OF INVESTIGATION ................................... 165 9. CONCLUSION ............ .170 Attachment 2  Statement on Environmental Impact-Assessment of Chaoyangxi Comprehensive Treatment Project in Nanning City Compiler of the assessment: Chinese Research Academy of Environmental Sciences President: Chen Fu(Professor) Persons in charge of the item: Jin Xiangcan (director, professor) Cao Hongfa (director, professor) Main Participants and their qualification: Name Subject Division Qualification Specialth Jin Xiangcani Engineering analysis recognition of Professor Water environment environmuent factors Cao Hongla Management and monilonng plan Professor Enmironunental ecologe Bon2 Denitin2 Analysis on the environmiental impact Professor En virounmental Clhenstrit during construction Li Junqi Measures on the envirounmenital impact Senior professor Environmental Chemistry during construction Xu Nani il Alternative plants anid Nattire Senior engineer Water environein enivironment l:u Guo Water environmental impact assessme:nt Engineer Environmental hv-draulics .JI1 Daaniue Environmental cost-Beniefit analysis Engineer management Wan2 Yu Existing enviroiunental qutalitx Seiior en2iiieer Env-ironmziental monitonn2 flan l.ng Pliblic participationi and demolishing and Seiiior eingineer lnVironmnental plan reimioval work [I lan Xilig!t Measures on noise durinig coistnictnoni Senior engineer lEnvironimenial engineer Ciao l:tlmllia Investigation and assessment of existing Senior engineelr Environmental monitonng Environimental quality Kwinge Jieren Investigationi and assessmelint ol exisitilg Seniior enginieer Environmiental tionitonng E'nvironmnental quality Z;hou Yunxin Investigationi and assessmenit ot existing Senior cilgineer Evinironmnental nionitonn2 Environmental qtualitv l,glio iiu Investigation and assessmlent of exi sting Scnior engin.eer l nvironmental monittonng Envirolunental quality I htnig Chao Investigation and assessment of existing Senior enngineer Environmental mnonitoniioJ Enivironientai quality Nlionitorinig participation ClienJiabao Xie Ytt Xie I lonigbit l.tang .lttiuinig( femiale) Lang Zlitting(tniale) Z.atiag lhiulting L.it Yon-iguing Shii Niaiqimig I ltianig M;toc;ai .ain Jil'eieing Yuin Weilianto Xti Xaohta Zhanig Qtioguitl 1'eii WVeiutgli, imuang l)ong Wei L.iqutn ktu Yuuileti P'an Yiliing Fei Xuioqi 1.m iie Suill (itit luang llaibao Clen Situang /.iul )anitang Wei Cuitinim Wui Xtaovin L.an I uatllao f fuzing Sitlitia Xi Ytuqlimg Zhitt Wenjiutn Li WVeikang Li Fang I [itnilng Zilenilhenig  a, I5  ~~~~~ir~~~~~~~J l s"ec;oec4n0e ~~~~~.~ \;. A4I E t R f }, ;tzn 4-~ ~ ~~k- 14- g 1io 9 ot g~~~~~~~~~~~~~~~~~~~~~T- llt INT, 9ifIATf  t I so U  EXECUTI E SUMMARY Nanning is the capital of Guangxi Zhuang Autonomous Region, serving as its political, economic, financial, cultural center, as well as the region's center of science, technology and information. It is also the hub of transportation, which links the sea with southwest China. The State Council decided in 1992 to open the city of Nanning and turn it into an international garden city facing Southeast Asia with unique ethnic and local characteristics. The city has a total area of 10 029km2, with a population of 1.07 million (1994), of which 0.76 million living in the urban area. The city govemment of Nanning is planning to renovate the Chaoyang Stream, better the city's waste water and rain collecting system and built waste water treatment plants with loans from the World Bank so as to bring the pollution into control, improve its water quality and the life quality inhabitants, as well as to make the city more adapted to further opening up. 1. Main content and investment of the proposed project See table I for the main content and investment of the Chaovang Stream treatment project is as follow table: Table I Main content and investment for the comprehensive environmental treatment project of the Chaoyang Stream in Nanning City No. Procic Mam Coniteit investment I *nic Chaovang Strcam Treatmlient Project id) Inginieerini of renovationl of the river Renovation of'thle nver course. 1 004( l0' vuanl course | zatr supplciemet_ _ (2) Interceptioni Svsteni of vwaste water d'IF0-d-2000inin, L=6Skni I__'__ _ _ _) X 2000f)-C 80oo 2400mi i_iii (3) pipeline of passing river 1= l kl;t (4) liangbei main sewer r 1S0 X 2400mm [.=1.2kmri (5) Waster wvater raising ptunp station 2 -:f Is (one) (6) waste water treating plant 2 > *10 mId subtotal 25046( 104 yuan) 2 Drainage system prolect in Nanning I ) Rain trunk i: -ani main trnks, d600-d200tu),im 1 2806( 104 yuan) L I tox I1000-C 2800 x 18 )00niui (2) Sewer pipeline 2' <e.-r pipelines d600 X 900nnuit S27(l0' yuan) (3) renovationi of pipeliie in Old citv *" rnlpsine d8()-d 1800mliim one puimp station 2597(104 uall) (4) cquipmiicnts for maintaining the pipeline nt=iwbr of vehiicle 12 1 164(1 y- uan) (5) mnaintenanice ofi'hc pipchlnie le.th 28.3kn I .00( l0 0uan) 6O) subtotal v 18694(1 % yuan) _ other I a remitovazl and inhabitant resetticleient 1 35858(1 i unl) 4 total 57304(1 10 ytian!)  2. Major pollution sources and their discharging of polluttants for the proposed project a 2. 1 The Chaoyang Stream treatmenit project I Major pollution sources during the construction of the project (I). Sediment of the Chaoyang Stream, cast away soil during the construction, and garbage The renovation of the river course shall clean away a total of 0.2 million m:' of sludee. The construction of the waste water interception system will produce a cernain amount of soil to be cast away. Construction garbage mainly consists of broken bricks, broken pieces of asphalt road surface, concrete blocks, and waste wood bits, and so on. (2) Construction noise The engineering of the renovation of the river course and the laying of w'aste water pipe lines are all to be carried out in the central part of the city. As the construction takes a fairly long time, noise of construction machines is also a sensitive problem. See Table 2 for the intensity of construction machines. Table 2 Intensity of noise of different sources during construction Noise source Noise intensitv dB(A) Noise source Noise intensitv dB(A, Air dnil 10( Soil shiited 94 P'uddle uniwr 98 Road scraper 94 Scapcr pan 96 Bullodozer 92 Excavator 95 Air compressor 92 ( ) Raised dust The 0 2 million n' of sludge dug up, the earthwork to be dug and the laying of pipe lines and its transportation will cause raised dust. M Major polluted sources and their discharging of pollutants during operation (I) waste water After the completion of the comprehensive environmental treatment of the Chaoyang Stream project, waste water form an area of 258 OOOm;/d will flow to the Jiangnan waste water treating plant through the trunk pipe line in Jiangnan. then discharged into the Yongjiang River after primary treatment. See Table 3 for the waste water composition of the project. 2  -5 /; J-.'' Table 3 Amount of Waste Water of Areas in the project (1994) Catcluneit PopulatLon Dailv sexvaoe _iLdustrial waste %ater Total * M. '. l o000 I 0000m3/dq % I 0p00UY /d 0 IOpOOm'/d R. Chaovano Stream 271 81.3 69.9 3 5 1 31 116.3 R. Erkeng 147 44.1 49.0 45.9 1I 0 90 Xixianztang 72 26 48.5 22.9 15I 44. 5 (2). Solid wa., Sludge produced in the production of the waste water treating plant, mainly of digested and dehydrated clay cakes and inorganic matters from the detracts chamber. Whether the clay cakes contain harmful substances or pollution shall be determined by the quality of the water drawn in. But daily output clay cakes is fairly small. (3). Waste gas Waste gas mainly consists of the biogas produced in the sludge digestion pool, which is of an unpleasant smell and, as the waste water treating plant is located in the windward direction of the city, it poses as a negative factor. (4). Noise Waste water pumping station produces much noise and it is located in downtown area, thus much impact xvill be caused. 2. 2 Drainage .sysIem in IIJ-htzr areas I Major pollution sources during construction of the project (I). Raised dust The breaking up of the road surface, earthwork to be dug. layingt of pipe lines and the transportation and piling of materials will all produce raised dust It will influence areas along the transpiration route and even the whole of urban areas of the city. (2). Noise The noise produced bv construction machines and transportation vehicles will have much impact. Please refer to Table 2 fourth intensity of noise sources. (3). Sludge and castawav soil The amount of sludge to be dredged amounts to 52 OOOm If not properly handled, secondary pollution will be caused. The soil to be cast away during the earthwork, all will produce some negative inipact on the environment. 2. Major pollution sources during the operation of the project ( 1). Non-point pollution sources Pollutants like surtace silt, nutritious and organic matters %ill enter surface water bodies with surface runofl'through drainage pipe lines and pollute the environment. 3  (2). Industrial waste water The protect plans to lay waster water pipe lines in Tinghong Road and Baisha Avenue so as to collect industrial waste water from the Tingzichong area to be transferred to the planned Jiangnan waste water treating plant, thus restoring the function of the water body of the Tingzichong Stream and improve the water quality of the Yongjiang River. See Table 4 for the amount of waste water from major industrial sources and their quality. Table 4 Main pollutant sources in Tinzichong Industrial Distract waste wvater SS COD BODs Namc of factory 100inm3/d t/d mg/L t/d mg/L t/d mng/L_ Namiing Chemical Group 29 1 18.64 641 7.84 269 Nanuing Sugar Refiner' 299 19.61 *656 39.51 1321 9.85 329 Lvsine Factory 7 8 0.82 105 1.22 156 0.47 60 Nanning Tannerv 6 5 8.14 1252 9.96 1532 3.17 488 Nanning Silk Spinning Factorv 4 5 0.69 153 0.42 9; 0.26 58 Nanning Smelting Plant 04 0.02 50 0.01 25 1 T otal 78 2 47 92 58.96 _ = _ 3. Present statuis of enivironmental quiality J. / I ',v,,ne,zial ,:ialiiv of surfatce wsater Monitoring data show The water bodies of the Chaoyang Stream, the Erkeng Stream, the Zhupaichong Stream, and the Shuitangjiang Stream are all seriously polluted, major pollutants being COD and BODs, followed by NH--N, as a whole no longer meeting the standard for Grade V surface water. The water quality of the Yongiang River is fairly good before it enters Nanning City, within the standard for Grade III of surface water except few items like (SS, oil and NH.-N). After passing through the city, affected by the sewage and industrial waste water discharged into it, its water quality turns remarkably worse, no longer meeting the standard for Grade Ill surface water. And the tendency of deterioration is going on and the major pollutants are organic matters. 3.2 OQuality of atmospheric e'iiirotnment The average daily value of S02 in Nanning City is 0.064mg/m', exceeding the 4  standard for Grade II of national standard of the atmosphere, that of TSP 0.201 mg/m-. within the standard for Grade II atmosphere but exceeding the standard for cities in south China (0.20mg/mrn) as set by the state, that of NOX ranges from 0.008 to 0.0 12mg/m'. So, major pollutants affecting the city atmosphere are TSP and NOX. 3.3 Acoutslic environmental qu/ality As for the acoustic environmental quality of Nanning, the equivalent sound level in functional regions of Nanning City in 1994 averaged 61.70dB(A) during day time and at night, exceeding the standard for Type II areas set in "Urban Area Environmental Noise Standard". The actual monitored average values was 55.4dB(A), exceeding the standard by 5.4dB(A). The noise pollution in the city has a tendency of increasing along with the opening up of the city, the renovation of the old part of the city, and the flourishing of the real estate market. 3.4 Solid l'aste Industrial solid wastes from industry and daily life in Nanning in 1994 amounted to 806 SOOt, of which industrial wastes amounted to 558 500t, accounting for 62%, and daily life garbage 248 OOt, accounting for 37. 1%. The rate of comprehensive utilization of industrial solid waste matters has reached 86%. However, though 100% of the city's domestic garbage was transported away, only 28 OOOt was treated to be harmless, accounting for only 11.3% of the total. So daily life garbage is causing more and more serious pollution. 3. S Botlomz cla (?/f/le (7haoin-wg Streant Assessment of the bottom clay with Hakanson index method showed that the heavy metals contained in it posed as a potential hazard to the ecological system. The RI risk index of the bottom clay of the Chaoyang Stream was 1400, of extreme harmfulness 4 Prediction of thle projects' enzvrioniniental impact and prevention ineasures 4. 1 lredicuotn of Ihe' iml.)aci dIiriffz i/ic conmStrilction oIf ilie project I Prediction of the environmental impact of the renovation of the Chaoyang- Stream during its construction (I) Environmental impact of the bottom clay of the Chaoyang Stream In the project of the renovation of the Chaoyang Stream, a total amount of 0.2 million m' of bottom clay shall be dredged. Testing found it contained 13.70% organic 5  matters, The concentrations of mineral oil, Hg, Cr, Cu, and Zn respectively reached 1196mg/k-g, 2.33mg/kg, 212.4mg/kg, 132 346mgkg, and 1 805mg/k-g, denoting serious pollution. Assessment with Honkanson potential risk index method found its potential ecological risk index (RI) reached 400, being extremely harmful. Secondary pollution may occur during the digging, transpiration, and disposal of the bottom clay. (2). Noise produced by machines used to dredge the bottom clay of the Chaoyang Stream Excavators, bulldozers, and ioading machines used in the dredging will affect sensitive places of living quarters and schools within lOOm of both banks of the Chaoyang Stream. The noise produced exceeds the standard by 2-5dB(A), lasting 20- 30 days. (3). Environmental impact of the bottom clay piled temporarily Under normnal conditions when the wind speed is 2.5m/s, the concentration of the TSP from the piled bottom clay can reach 490mg/m-' at a distance of 150m in its leeward., exceeding the standard for Grade II atmospheric standard set by the state by 1.6 times. The bottom clay piled may leak out 20 OOOm' of percolate, whose BOD5 concentration may reach 20 OOOmg/L, giving out fouls smells of the fourth level, This is serious secondary pollution and will affect the landscape of the city. (4). Impact of house removal and inhabitant resettlement Buildings to be removed involve an area within 30-68m along both banks from the middle of the river. 769 households will be resettled, with a population of 4506. The resettlement of the inhabitants will be arranged by the overall plan of the city. They are to resettle in Luwei quarters of Xinyang Road and Zhong,xiao Road quarters. The life quality and living conditions of the inhabitants resettled will have much improvement. 100% of the people involved in the public participation are in support of the project. The removal of the houses will produce 65 million min of construction garbage, which will be transported to Santang garbage filling ground as part of the citys garbage. With other administrative and controlling measures, this will not cause much negative impact on the area around the construction site of the project 2. Prediction of the environmental impact of the project of the city's sewage system (1). Environmental impact of raised dust during construction Analogical investigation finds out that raised dust during construction may affect the area within 50-lOOm in thc leeward of the construction site, where the concentration of TSP can reach 0.37-8.6mg/mn', 1 5-5 times that in the contrasting point in the windward direction.. 6  Transportation of earth to be flack idled and cast away may affect a distance of IfOm in its leeward. The concentration of TSP at both sides within Sm from the road can reach 8-1 Omg/m', exceeding the standard by 30 times. (2). Environmental impact of construction noise Construction machines are the main noise sources. Without considering the attenuation caused by houses and trees, the range affected may reach l00m during daytime and 300m at night. (3).Impact of the construction on the city's traffic 30-50% of the road surface will be occupied for laying pipelines, which seriously affect traffic, causing traffic jams and affect people's normnal work and life. (4).Environmental impact of pipeline desilting Statistics shows that 22 pipelines with a total length of 28.4km are silted with 52 600m- of sludge, whose foul smells can affect an range of 25m, where the concentration of foul smells may reach 15-30, exceeding the standard by 0.5-2.0 times. 4.2 Predictioni of the impact dutri-ig the operationl of the project 1. Prediction on the environmental impact after the Chaoyang Stream treatment project is put into operation (I). Polluted belts along the banks of the segment of the Yongjiang River at the outlets of the Chaoyang Stream. the Erkeng Stream and the Tingzichong Stream will be relieved, favorable to the protection of the water source of Lintie Water Mill and improvement of the environmental quality of the Yongjiang River. The outlet of waste water discharge is removed dow n to the outlet of the Shuitangjiang Stream, ridding the potential threat to polluted the water environmental quality of the central part of Nanning City by the- Chaoyang Stream and the Erkeng Stream. This will play an unreplaceable role in building Nanning into an international garden city with its unique characteristics. The completion of the project will realize thle long cherished wish of "drawing water from the upper reach and discharge waste water to the lower reach", so that the functions of the cit\ will be in better coordination to produce much environmental economic benefit (2). The completion of the project will radically improve the water environment of the Chaoyang Stream, turning it from a sewage ditch into a clean river for landscape. This is the most direct manifestation of the environnmental benefit of the project. After the project is put into operation. water will be drawn from the Yongjiang River into the Chaoyang Stream, so the lather's water quality will be guaranteed for most years. Changing of water replenishing period can keep the water quality of the Chaoyang Strcam at a fairly high level. As the amount of water changed is comparatively small, and the water quality of the Chaoyang Stream is much better than the original waste 7  water, not much effect will be caused to the water quality of the Yongjiang River. It is suggested that artificial springs and waterfalls be built in the construction of the water supplement system of the Chaoyane Stream in coordination with the renovation of the city, so that the city will be more beautiful and more oxygen can be restored in the water body. As a result, its qualitv can maintain a longer period to lessen the water changing frequency. As the present design contains no water replenishment to the Tingzichong Stream , the project will not have much effect on its water quality. The water surface of the stream shrinks too much in the low water season and there won't be any improvement on the landscape. It is suggested supplemental design be made on the water replenishment to the Tinezichong Stream and carry it out in proper time. (3). According to the plan of the project, waste water will be led to the outlet of the Shuitangiiang Stream throug-h river crossing pipelines. This is much better environmentally than the alternate plans that plan to lead waste water to the waste water treating plant in Langdong. To lead the tail water to be discharged into the Zhupaichong Stream. can prevent the water quality of the Zhupaichong Stream from getting worse than the present condition and make it easy for it to reach the standard for Grade V water in the future. To build the waste water treating plant in Jiangnan instead of in Langdong will save much fund of waste water transportation. (4). After the project is put into operation, the polluted belts along the river banks in the central part of the city will be reduced or totally illuminated, but the polluted belts in the Shuitangjiang Stream "-ill grow longer, increasing local pollution intensity. But as waste water from the citv will be discharged into the Shuitangjiang Stream, shortening the distance to the countv seat of Pumiao, the amount of waste water allowed to be discharged will be reduced. This is the inevitable price for cutting the pollution in the central, part of the citv. The completion of the project will reduce 10% of total BOD, load, this can improve water quality at the down stream area of Pumiao. The completion of Jiangnan waste water treating Plant at the outlet of the Shuitangjiang Stream will reduce 70% of total BOD5 load (at the load level of years of normal water in the plan). It controls pollution effectively to down stream. This can be solved by raising the treating level and amount of the Jiangnan waste water treating plant, so as to achieve coordinated development of the economy and the environment. (5). At the scale of 260 000m'1d as the capacity of the first stage of the Jiangnan waste water treating plant, the rate of BODs cut can reach 35%, equivalent to+edui6iig 91 000m '/d of waste water. The amount of waste water from the city in 1996 was 597 700m'/d, that in 2000 is estimated to be 682 000ni/d. In normal years, the amount of BOD5 entering thc Yongjiang River then will be about the same as present (1996). If the BODs cutting rate can not reach 35%, with the discharging point shifting R  eastward, the DO level of the Pumiao segment will continue to deteriorate To view the issue from the total amount of control, level one treatment of the 200 000m7/d will cut 15% of the total pollution from the city. It can thus be seen, the project will have remarkable effect in controlling the deterioration of the water quality in the lower reaches of the Yongjiang River. It is one of the most important steps to make the segment of the Yongjiang River from the Shuitangjiang Stream to the Pumiao River reach the standard for Grade III water. 2. Prediction of the environmental impact of the drainage system of the city when in operation The completion of the rain water pipeline network will play a decisive role in solving the serious water logging of the city, tallying with the demand set in "Drainage Plan of Nanning City". It also will also have positive effect on the hygiene and landscape of the city. The operation of the rain water pipeline network will not have much impact on the water quality of the Yongjiang River and its tributaries. (I). The three trunk rain water pipelines discharging into the Nanhu Lake are the main non-point input entering the lake, playing a remarkable role in restoring the water quality of the lake After the completion of the waste water interception project around the Nanhu Lake, non-point sources will control the water quality of the lake. This may cause environmental problems like eutrophication of the lake. During low water level period, there may be lack of water. So the Nanhu Lake is facing dual problems of water replenishment and non-point sources pollution. (2). The completion of the waste water trunk pipelines in Tinghonc Road and Baisha Avenue will bring waste water in Jiangnan District into effective control, making full use of the functions of the trunk waste water pipelines in Jiangbei and the Jiangnan waste water treating plant. This will surely diminish the polluted belts along the outlet of the Tingzichong Stream to the Yongjiang River. Plus the function of the Jiangnan waste water treating plant, it will alleviate the deterioration of the water quality in the lower reaches at Pumiao. a. The two waste water trunk pipelines will cut the pollution concentrations, restoring 17% water environmental capacity of that segment of the river. b. The water environment upper the outlet of waste water treating plant at Shuitangjiang can be remarkably improved, reaching the standard for Grade V water in part time of the year. (3). The renovation of sewage pipelines is actually the construction of branch rain water pipelines. Betore thc completion of waste water pipeline network, it will not causc the redistribution of point and non-poinit sources pollution, nor deteriorate the present discharge of waste water This can solve the problem of serious wvater logging 9  because the pipelines in these areas are too narrow. 5 Measures to eliminate negatiove impact 5. 1. Prevenitive measures to be lakeni durinig the cotistrrchiol, of the project (1) Strengthen the administration, planning and management of the construction, and carry it out by stages and sections so as to raise efficiency and shorten construction time. Dug up earth should be bank filled and road restored in time, so as to reduce raised dust, noise, foul smells and impact on the traffic of the city. (2) Optimize the time of working, avoid the use of machines at night that produce strong noise, so as to reduce the impact on people's life. (3).Establish temporary traffic routes in downtown areas and busy traffic routes, and assign people to direct vehicles so as to prevent traffic jams. (4) Carry out the dredging of the Chaoyang Stream in the dry season, and timely transport away bottom clay dug up, so as to prevent it from washed into the river by rain. It is suggested to use encircled bank for the piling and burial of bottom clay so as to dlininish its environmental impact. 5.2. Countermeasures to be takeli during the operationl of thle project (I ).The feasibility report did not study the problem that the three trunk pipelines for rain water to be discharged into the Nanhu Lake will cause difficulties for the treatment of the initial rain which bring heavy pollution into the lake and waste money as the three pipelines are not connected, It is suggested, after the determination of alternate plan, to adjust the design of the depth of the pipelines in Qixin-Jiaoyu Road and Taoyuan Road, so that the problem of initial rain can be solved. (2).lt is suggested to redesign the flow of the waste water pipelines in Tinghong Road and Baisha Avenue as the original design is too small to lead the waste water from major industrial polluters into Jiangnan waste water treating plant. (3).There should be vibration damper in the waste water pumping station at the outlet of the Dakeng Stream, so as to reduce the impact of noise on nearby inhabitants. (4).AII together a total amount of 336 000m'/d (1994 data) of waste water needs to be treated by the Jianginan waste water treating plant after the completion of the renovation of the Chaovang Stream and the sewage system. But the capacity of the plant is only 260 000'/d So it is suggested that the design of the scale of the Jiangnan waste water treating plant be enlarged. 5.3. Capacity of fhe' .hIangnan waste water Ireating p)lant Form the viewpoint of the water environmcnt of the Yongjiang River, it is t0  necessary and urgent to make the plant be capable of level I treatment. Main reasons: (1) Analysis of practicality shows that it is very difficult for the water quality of the Yongjiang River (especially the segment in the lower reach at Pumiao) to meet the standard for Grade III surface water under the designed condition (Qp=90%=t70m7/s). The water quality index are DO and NH;-N. According to the field monitoring carried out in 1991-1994, the flow in low water level period was 1.5 times over the designed flow, when the concentration of DO exceeded the standard for Grade III water. The actual oxygen was about 1.5 times that of usable oxygen. This reveals that Nanning City poses as a serious threat to the water in its lower reaches, especially to the composition of aquatic organisms. (2) According to the result of the "Study on the Plan of the Environmental Capacity and Water Quality of the Yongjiang River" (Nov., 1993), the discharge of BODs allowed from the outlet of the Machao River to the outlet of the Shuitangjiang Stream is 378.7g/s. equivalent to 222 600m-/d of waste water discharged. So the environmental capacity of the Yongjiang River is fully occupied since the beginning of the 90's. The actual amount discharged was twice more than the allowed amount. After the completion of the project, waste water discharging will be shifted eastwards to the Shuitangjiang Stream, the allowed amount of discharge will still cut by about 200 000m /d. Therefore the treating should cut BOD5 by 60% in the year when the project is completed, and S'% in normal year designed (2015) to meet the demand of DO of the water quality. (3) The above analysis states that the design of the Jiangnan waste water treating plant shiould be able of level two treating to meet the demand of the environment. It should be able to carrv out level I treating in the near future to maintain the water quality and prevent it for further deteriorating. If the waste water is treated in the level of pretreatment, the pollution load cut will not be able to catch up with the increase of pollution load, and the pollution will be worse than the present as soon as the project is completed. (4) If the Baise Reservoir is to be built within ten years, the runoff flow during the low water period can reach Qi'.-,=300m3/s, a little larger than the runoff monitored in 1991-94, the discharge allowed can increase to 350 OOOm3/d or so, then the waste water from the citV still needs to be treated. If the waste water increases to 650 000m-ld, the treating rate required will be 46%. So if the Jiangnan waste water treating plant is designed with a capacity of 520 000nm-d and level I treating, there won't be any waste of fund So the project should build a level I waste water treating plant at the outlet of the Shuitangiiang Stream in the near future, which will be enlarged to level 2 treating later. It  Such design tallies with the economical development of Nanning City and at the same time taking into consideration the demand for environmental protection. It is more practical than to build the plant of level I treating in one step. 5.4. Addition7 of invesiment of the Jiangnan wasle wuter treatinig plant The feasibility report only altos 17.44 million yuan as the investment for the Jiangnan waste water treating plant. This is far from enough to make it reach level I treating. It is thus suggested to add its investment according to the level I treating design in the feasibility report of the project. 5..3 Charge on wi'asle iiater discharge The improvement of the water environment of Nanning City and the water quality of the Yongjiang River depend on the rational ratio of economic development and investment for environmental treatment. The investment of environmental treatment needs rolling development. It is thus suggested to charge waste water discharge fee during the operation of the project, so that it will be able to pay the loan and operational expense, and collect find for the further development of the Jiangnan waste water treating plant and waste water collecting system. This will bring a benign cycle of water pollution control and rolling development. 6. Comparison of plalls After analyzing and comparing the recommended plan and alternate plans form the angles of economic benefit, environmental benefit, and social benefit, it is concluded that the recommended plan for the comprehensive treatment of the Chaoyang Stream is the most rational. 7. A nalysis of tlie betiefit of thle project The Chaoyang Stream comprehensive treating project will bring great environmental benefit and social benefit by solving the problems of flood and water logging which have been worrying the city for years and improve the sewage system of the city, thus greatly improving the city's landscape and people's living conditions. The project can collect and treat over 60% of the city's waste water, thus reducing the pressure on the pollution and environmental capacity of the Yongjiang River and protecting its water quality The project is financially practicable as the main fund of the construction is investment from the government during its construction 12  8. Putblic participationz Opinions were solicited from people from 15 neighborhood committees with 174 households and experts of various fields. The results showed that 100%/o of the investigated people supported the construction of the project. 86% of the inhabitants said they could understand the short impact of the construction, only 14% though it unbearable. If the removal of the houses and resettlement of the inhabitants are carried properly with proper policies, their attitude will surely change to support the project for the overall interest. To sum up, the Chaoyang Stream comprehensive treating project is an environmental protection project that will bring remarkable environmental benefit, social benefit and economic benefit. It tallies with the overall plan of Nanning City and is totally practical. 13  'A I  - ! :~~~~~~~> R1 0 0 r / . ~~~~~~~~~~~~LX i ji| 00* i :t r , ' il ,' ''-,' ' '' ,i. it r t. >t '" : sS"i''TiN S '-& :' " <>/& ;; J tig' 1|