China - Yunnan Environmental Project : environmental assessment report (Vol. 3 of 3)

YEP COORDINATIVE LEADING GROUP YUNNAN ENVIRONMENTAL PROJECT OFFICE Yunnan Environmental Project ADDENDUM TO ENVIRONMENTAL ASSESSMENT REPORT March 1996 Yunnan Institute of Environmental Sciences in assodation with Montgomery Watson GHK/MRM International IFI Hunting Technical Services FILE C_ _i Severn Trent Water International under assignment from Overseas Development Administration  CONTENTS page no. I.:troduction I Issue No. I Kuumning and Qujing Solid WVaste Landfills I Issue No. 2 Selection of Wastewater Treatmnent Processes for Kumning 2 Issue No.3 Water Demand Management 5 Issue No. 4 Review of Alternatives 5 Issue No. 5 Water Quality Data for Lake Dianchi I I Issue No. 6 Ecology of Lake Dianchi 11 Issue No. 7 The Fisheries of Lakie Dianchi 15 Issue No. 8 Industrial Pollution Control Investments 18 Issue No.9 Water Quality Model 21 Issue No. 10 Beneficiaries of YEP 24 Issue No. I I Implementation of YEP 28 Appendix I Preliminary List of Key Variables to Lake Dianchi Ecosystem Recovery Appendix 2 Data on Lakle Dianchi Fish Fauna and Catches  ADDENDUM EA REPORT Introduction The Environmental Assessment (EA) Report for the Yunnan Environment Project (YEP) was submitted to the World Bank in February 1996. Following its review by the World Bank. a number of issues requiring clarifiration were identified. Furthermore, as a result of ongoing development of the sub-components of the YEP, other aspects of the project were also finalised. This Addendum to the EA Report therefore addresses the issues raised by the World Bank and provides further information on other aspects of the YEP which have now been agreed. Issule No I - Kunmwr' and QXfin, Solid Waste Landfls The EA Report provides few details on the environmendal mitigation measures to be employed at the three landfil sites. tw in Kzmming. one in Qaiing. More detailed information is required on the linersystem, leachate control and teatment and offsite water management. Reference should be made to Sections 3.4.3 and 3.5.4 of the EA Report. Containment The landfill designs for both the Kunming and Qujing Solid Waste projects have progressed to the detail design stage and the preliminary proposals have been reviewed. Containment and removal of leachate are ack-nowledged as the most important objectives of a landfill site. At all three landfills, containment will be achieved by an appropriate combination of impermeable membrane and clay from the site. Further geotechnical tests are to be carried out over the site areas to confirm the precise extent and nature of the clay available on each site. This in turn will permit determination of the areas of impermeable membrane which are required. This will be placed where the clay layer is too thin or where voids are to be filled with a soil-cement mixture. Only clay with a field impermeability of 10'7 cm/s will be used without a liner. Where the clay is not suitable, a single or double impermeable membrane will be used as appropriate, each membrane being placed over 600mm of clay. The membrane will be of HDPE to an appropriate international standard like ASTM. Leacrate Generation and Treatment To minimise the generation of leachate, surface water will be diverted around the landfill sites by temporary and permanent peripheral drains, one of which has already been installed at Hongshuitang to keep water from entering the landfill as run-off from adjacent areas. As far as possible, the sites will be filled from the top down so as to minimise the entry of stormwater into the leachate collection system and into the landfill. Average annual rainfall in Kunming is 1,W07mm, 85% of which falls in the period May to October. Annual average evaporation is 2,120mm. Leachate will be collected in perforated pipe drains with access for internal cleaning byjetting.. A 300mm continuous gravel drainage blanket will be provided to carry the leachate to the drains. The leachate will be collected in a leachate pond with a volume of 24,000 m3 and treated by recirculation through the landfill. Disposal of leachate will be by way of irrigation on the site and later also on completed landfill. Typical leachate production at all sites is about 10% of rainfall, and annual leachate on an area of 30 pageI of 28  Addendum mu (2 ha) would therefore be 20,000 mi. This will increase as morm of the site is filled. The design of the drainage system will ensure that leachate short-circuiting does not occur. Recirculation also has the advantage that it helps speed up refuse degradation. There will be no net outflow of leachate from the site. In the early years, the leachate quantity will be small and easily manageable. Leachate quantity and quality will be monitored and additional treatment and disposal capacity provided when needed. Should further treatment be required, it is likely to be by aeration of the leachate pond. However, recirculation may well be sufficient to ensure satisfactory disposal. After final capping, the annual quantity of leachate will reduce. The leachate quality will also slowly improve when the process of waste stabilisation is well advanced. Average annual rainfall in Qujing is 950mm, 85% of which falls in the period May to October. Annual average evaporation is 2,130mm. Leachate will be collected in perforated pipe drains with access for internal cleaning byjetting. A 300mm continuous gravel drainage blank-et will be provided to canry the leachate to the drains. Initially, the leachate will be collected in a leachate pond with a volume of 24,000 m' and treated by recirculation through the landfill. In due course, the leachate pond is expected to be connected to the city's sewage treatment works, where its impact on the design loads will be minimal. |i is not clear why the specfic approachesfor wastewater treatment were selected as they were. It is clear, however, that phosphoas removal is a primary objecrive Col this not be accomplished in the primary stage using chemical treatment? What other methods are under consideration for reducing the inflows ofphosphorus to Lake DianchZ in particular from non- point sources? What about the use ofphosphate-free detergnts? Reference should be made to Section 3.4.1 of the EA ReporL Wastewater Discharge Standards The philosophy for the design of the sewage treatment works in Kunming is based on the discharge effluent into the Waihai and Caohai via a number of watercourses. The Waihai is one of the city's primary water resources and is suffering from increasing pollution and eutrophication (excessive nutrients and most probably phosphorus). The watercourses draining to the Waihai and Caohai have little base flow (hence there is no dilution of treated effluents) and are used all year round as sources of irrigation water and also for a variety of industrial uses. The relevant Enviromnental Quality Standards (which define Class II IV and V surface waters) and Effluent Discharge Standards (for a Grade I discharge to a Class III surface water) defined in the Integrated Wastewater Discharge Standards are summarised in Table No I on the following page. The criteria defined in the Integrated Wastewater Discharge Standard document are maximum allowabie concentrations (MACs). With the very limited (frequently zero) dilution available within the local watercoumses, the required effluent discharge standards can be considered to be equal to the EQSs. From a design point of view, the average effluent quality should be about 25% of the MAC (and the 95 percentile about half of the MAC) although from a technological standpoint the current state of the art does not provide means to achieve the EQS-based standards for BOD, COD and TP page 2 of 28  EA Report without excessive cost, i.e. microfiltration plus chemical tratnent Thus, a set of standards has been adopted (which are to be complied with on a 95 percentile basis). These are considered to be appropriate, technically achievable without excessive cost and relate to the National Standards. Table No 1 Water and Effluent Quality Standards Maimum Allowable Concentration (mg/1) Effluent Standard for Kunming STWs (mg/l) GB8978-8 GB3838-88 GB383888 GB3838-88 Compliance on a Grade I EQS Class EQS Class EQS Class 95%ile basis discharge to mI IV V Class M BOD 30 4 6 10 15 COD 100 15 20 25 n/s SS 70 n/s n/s nIs 15 TN n/s 21 22 22 - 12 TKN 15 as NH3N 1 2 2 n/s but expect 2 NO3N n/s 20 20 25 n/sbuteexpect 0 |P2asP | 05 0.1* 02 0.2 1.0 Q.05 for lake or reservoir n/s not stacd CLbs;m Il- Domestic Potable Watcr Source Cbss IV - Industrial & Recreafion: Clss V - Agriocltmial and General Amenity TretmentReqairemeas and Options Both oxidation of ammonia and removal of nitate by denitrification will be required to ensure compliance with EQS for Class IV and V waters. The incorporation of denitrification into the treatnent process provides benefits in terms of process economics and process stability, i.e. reduced air requiremnents, reduced alkalinity loss and a selector gradient which will tend to reduce potential sludge bulking problems. Phosphorus remnoval is required to protect the lake. Wastewater characteristics as calculated in the "Design Parameters Reporft indicate that low levels of phosphate (less dhan I mg/l as P) can be easily achieved through the provision of biological phosphorus removal at a very low incremental cost The design proposed for STW Nos. 4B and No. S has been based on the Modified UCT (University of Cape Town) process which provides measures to reduce the potential interference of recycling nitrate associated with the Returned Activated Sludge (RAS) through denitrification. Alternative methods of removal of phosphorus from wastewaters which are not considered appropriate to the local situation in Kunming include: * chenical dosing with iron salts either prior to settlement of crude sewage or into the works final effluent prior to the-renoval of precipitated/flocculated solids by sedimentation or filtration. Aluminium salts are not recommended as any soluble residual is toxic to aquatic life and the use of lime has potential disadvantages as a result of high sludge yields relative to aluminium or ferric addition, potential scaling problems and increased recarbonation requirements (dependent upon the operating pH). page 3of 28  Addendum Chemnical dosing at the primary stage cannot be recommended (these conclusions are supported by USEPA) prior a denitrif;ying activated sludge plant as there would be some loss of soluble carbon which may necessitate an cxternal carbon source such as methanol to ensure denitrification (such practises are of particular concern in this instance due to the toxicity of methanol with respect to water supply); and potential bulking problems may arise by the loss of trace organics from the system. Chemical addition to the works' eMfluent will re-'aire significant additional plant in the form of sedimentation tanks or filtration equipment and facilities for storage, dosing and mixing of chemnieals Further reservations regarding the removal of phosphorus by chemical treatment relate to the high consumption of a number of chemicals (including ferric chloride, lime, polyclectrolyte and possibly methanol) and the associated problems of availability, quality, reliability of supply and cost * more recent innovative designs which include fluidised or fixed upflow beds (such as Crystalactor type process) and ion exchange technology (using cliptilonite and anionic resins) are complex, have high regenerant requirements and are unlikely to be cost effective for large municipal sewage tratnent works. Plhospzarte-hosed Detergeels Consideration was given to the possible banning of the use of phosphate-based detergents in Kunming to reduce phosphorus levels in the raw sewage. The impact of such a policy on the design and operation of a conventional biological sewage treaument works is considered to be negligible, as increased biological phosphorus removal can easily be achieved at a nominal incremental cost For phosphorus removal systems based on the use of chemicals, the impact would be more significant, as operational costs are directly proportional to the reduction in phosphorus levels achieved. However, policies banning phosphate-based detergents are not considered to be practical. Enforcement within the PRC is likely to be difficult to achieve. Furthermore, switching to alternative non-phosphate based detergents such as zeolites has potential secondary impacts on the design of the STWs with respect to sludge production and Ulodegradability. Fortunately, since the STWs for Kunming are based on biological treatment processes, there arc no cost implications related to the level of phosphorus in the raw sewage, so control of detergents is unnecessary. Sluade Treatmen and Disposal For the sewage tratment works in Kumning, the sludge treatment schemes have based on gravity thick-ening followed uy dewatering using conventional belt presses. This option provides a low cost, robust and reliable solution using technologies familiar to local operators. Provision has been included in designs to eliminate phosphorus which may return in the sludge liquors, by precipitation with ferric salts. The slu'dges produced in the wastewater treatment process are considered to be stable, as a result of the long sludge age required to ensure full nitrification hence further stabilisation processes such as aerobic or anaerobic digestion are not considered to be necessary. Dewatered sludge cake will be disposed of to the sanitary landfill sites. page 4 of 28  EA Report Issue Ne 3 - Waer Demand Manngemen: It -would seem that, in a situation where water quantity will be an issue within a few years. more effort shoud be put water conservation and re-use approackes. The EA Report provides litte information on the potential of this. The water losses quoted in the EA (8 to I01%) are those officially reported by the Kunming Water Supply Company (KWSC). However, as all the final flow meters at the water treatment works (WTWs) are either stopped or faulty, the water loss figures are calculated using estimated flows from the WTWs. The State Planning Council has instructed water agencies and companies throughout the country to aim for a target water loss of IO%/o. Preliminary evidence suggests that the actual water losses in Kunming may be in excess of ;0% in some areas. The Kunming People's Government and senior managers of KWSC acknowledge that water losses must be reduced. To this end, KWSC has established a Water Loss Reduction Leading Group which is responsible for developing an integrated company-wide loss reduction strategy for the company. The duties and responsibilities of the group, which have been agreed by management, are to develop loss control strategies, set targets for reducing losses, implement control meares and monitor achievement of the targets. The Water Saving Office of the Kunming Municipality is responsible for setting consumers maximum water consumption targets linked to tariffs. It also has a responsibility for public education about water. | Issue No 4- Review QfAlternC al In the EA Report, one finds lale discussion of aiternatrues or how speciftc technologies and approaches were selected fiom a host of possibilities This pertains in particular to the selection of the wastewater treatment processes. Th also appeors to be little environmental just ftcaftonfor the selection ofapartiwdar alternative aside from simple least cost Reference should be made to Sections 3 and 6 ofthe EA ReporL I KZunmuag Wastewater Project Kunming discharges all its wastewater either directly or through sewers to the rivers and canals which flow into Lake Dianchi. These rivers and canals are therefore grossly polluted. Domestic and industrial pollution, land abuse, erosion and land reclamation have resulted in the lake ecosystem changing to a turbid water body, the Caohai being worse affected than the Waihai. The water quality in the lake has deteriorated to worse than Class V, well below the level at which it should be used as a drinking water source. Nevertheless, the Waihai supplies up to half Kunming's water in dry years and there are therefore very strong environmental reasons why Kunming's wastewater should be treatet. The overall objective of the Kumning wastewater project is therefore to ensure the capture of all wastwater being generated in the urban area (both industrial and non-industrial) and prevent it entering watercourses and the lake untrated. This will be achieved through four integrated strategies: page S of 28  Addendum * constructing trunk sewers; * reticulating currently unsewered areas; * constructing sewage treatmnent works (STWs); * maximising connections to the system. The decision concerning which basic wastewater treatment technologies to adopt for sewage treatment, e.g. chemical treatment, oxidation ponds or conventional, intensive treatment systems, was made first in favour of biological systems (see Issue No 2) and then in favour of intensive treatment on the basis of the excessive land requirements and costs associated with ponds designed for the climatic conditions in Yunnan. The two key factors compared were the number and location of STWs and the detailed selection of processes. The location of the STWs had already been approximately fied by the existing Sewerage Master Plan. However, other potential locations were also identified and comparison analyses carried out. To a large extent, network layout has been determined by the topography, trunk sewer minimisation, location of STWs, and existing and proposed urban development. Thus comparison of network layouts was based more on utilising existing sewers and in ensuring the most economical pipe size was used. Within the city centre, the key issue lay not so much with the network arrangement, but whether to convert the existing combined sewers into a separate system. The latter will ultimately reduce treatment costs as STW capacities can be limited as they will only treat sewage flows and not stormwater flows as they do at present The construction of a separate sewer system also has advantages in that it reduces large sewer size and should minimise pumping, especially in a region with large seasonal rainfall variations. The key selection factor was to achieve the most cost effective method for phosphorus removal, the pollutant of prime concem in the Dianchi Basin. Secondary factors include nitrogen, BODICOD and suspended solids removal. The processes adopted are those believed to be the most suitable to achieve the phosphorus objective without compromising the secondary objectives. In addition, the selected processes have the advantage of being technologies already operating in China. Dewvatered sludge will be disposed of to one of the landfill sites being developed under YEP. The altemative for agricultural use has not been pursued due to the lackl of mark-et potential and ptential difficulties with contamination. 2 Qutjng WastewaterProjed Qujing discharges its wastewater to the Nanpanjiang River (headwater of the Pearl River) whick' plays a decisive role in providing industrial and agricultural water supply to Qujing. Historically, the water was of sufficient quality to pernit its use as a source of potable water, but continued failure to capture and treat the city's wastewater has resulted in serious deterioration. The increasing pollution has reduced the water quality to worse han Class V which now limits its use even to industry and agriculture. To achieve the stated water quality objective of Class IV for the Nanpanjiang River, full sewage treatment would be required, so a least-cost analysis of treatment options was carried out. Four main treatment options were considerecL - oxidation ponds, * primary settlement followed by activated sludge, * extended aeration activated sludge, and * two-stage activated sludge. Despite the low operating costs, the large land requirements of oxidation ponds, together with the lack of suitable waste land or wetlands and the costs and environmental impact of using agricultural land led to this option being rejected. Of the other three, variations on the activated sludge process, the least cost option was identified as the extended aeration activated sludge at a cost (mcluding the vage 6pof028  EA Report sewerage system) of some *l 85 million. An evaluation was also made of an altenative site for the STW, 5 km further away from the city. This would have incurred additional cost for the longer inlet sewer and for upgrading the access road (a total additional cost of some *23 million on an overall sewerage cost of *38 million) without any significant benefits except a lower land cost for the STW site. It was agreed that the Qujing Master Plan should be revised to avoid further development immediately adjacent to the selected STW site. The option of providing two STWs, the second to serve the new Western Development Area after about the year 2010, was also considered. The additional costs of the sewerage and pumping required to carry the flows to-one site were shown to be outweighed by the economies of scale from a single STW, as has also been demonstrated for Kunming. The re-use of the effluent for agriculture also favoured the location of a single STW in the agricultural area However, the autthorities judged the overall cost of the project to be still too high. To reduce the cost of this phase, the decision was taken to provide as extensive a sewerage system as possible at the outset to intercept all the sewage flows reaching the rivers running through the city but initially to lower the discharge standard (with only removal of gross solids and some BOD) in the first phase. This could be achieved by providing a reduced level of treatment. Although this treatment will not meet the long temc requirements, it will nevertheless result in significant environmental quality improvements. Two options to achieve this were considered: * the first stage of the two-stage activated sludge process; * chemically enhanced primary sedimentation. Chemically-enhanced primary sedimentation was found to offer the lowest initial cost but, due to the cost of chemicals, operating costs would be higher. Tests on the actual sewage treated would be required to establish the optimum dose rate. However, lime was expected to offer the lowest chemical cost which was estimated be in the order of 0.01 to 0.02 W/m3 of sewage treated. Investment would be required in chemical storAge, dosing, mixing and flocculating equipment which would become redundant as soon as full sewage treatment is provided. Therefore, alternatives were considered which, although requiring higher initial expenditure, would lead to savings in initial operating costs and less redundant facilities when full treatment is eventually provided. The first stage of the two-stage activated sludge process is a high rate process which produces unstable sludge. It is necessary to stabilise the sludge prior to dewatering. There are several methods of achieving this but, in order for the initial investment in sludge stabilisation to remain useful in the eventual two stage activated sludge process, the most appropriate method is aerobic stabilisation. This can take two forms: * aerobic digestion of surplus sludge; * aerobic stabilisation of return sludge. The volume of the aemted tank required for both alternaives is similar, the former providing a relatively long retention of a smnaller amount of sludge and the latter providing a shorter retention time for the larger volume of return sludge. If the returned sludge is stabilised, the process becomes the contact stabilisation process which provides the additional advantage of reducing the amount of ammonia in the treated sewage. Since only minor modifications are required, both sludge stabilisation options can be provided for little additional cost, giving the flexibility to use the mode of operation which is found by experience to provide the most cost effective treatment. Enhanced primary teatment will be provided using high rate contact oxidation and aerobic stabilisation of either return or surplus activated sludge. Land is being set aside for the provision of full biological treatment using the two-stage activated sludge process as soon as that is affordable. page 7 of 28  Adde-diam 3 Gejia WYastewater Project Gejiu discharges its domestic sewvage .o Lake Gejiu, which receives wastewater from tin mining and processing and other industrial activities and is also used as a balancing reservoir for industrial water supply . As a result, the water quality of the Lake has deteriorated to worse than Class V. Excess water from the lake (particularly in times of wet weather) is pumped out of the closed valley in which the city is located into the Zhadian River to the north. Flooding of Gejiu City occurs when the capacity of the existing pumping station is exceeded. To achieve the stated water quality objective of Class IV, the sewage and industrial wastewater must be prcvented from entering the lake. The considerable benefits to both lake and downstream river of completely separating these from the flood water were identified during project development. Principal options considered were based on the location of the STW, since there are effectively no significant alternatives to the two interceptor sewers which will pick up sewage flows around Lake Gejiu. Four possible STW sites were considered, two by the lake and two beside the road north out of the city. The lakeside sites were rejected on the grounds that the high value of land within the city would not make these the least cost solutions. (Environmental impact on the surrounding urban areas is a further reason for rejecting these, as was the higher cost of treatnent required to achieve the higher effluent standard for discharge to the lake.) Of the two sites north of the city, Site 1 was preferred o-ver Site 2 because of its closer proximity to the city, requiring a shorter inlet sewer. The additional cost of the inlet sewer to Site 2 would be 12 million for the extra I km required. The capital cost of the sewerage and pumping stations for Gejiu is Y40 million. The arguments on the treatment process to be adopted are the similar to those for Qujing, with full treatment options being initially considered. As with Qujing, the overall project was deerned unaffordable by the authorities. The desired reduction in project cost was achieved by reducing the level of treatment provided in the first phase whilst maintaining the extent of the sewerage system (thus ensuring that all wastewater currently reaching Lake Gejiu will be collected and treated). Enhanced primary treatment will therefore be provided using high rate contact oxidation and aerobic stabilisation of either return or surplus activated sludge. Land is being set aside for the provision of full biological treatment using the two-stage activated sludge process as soon as that is affordable. Despite the lower treatment level, Lakle Gejiu water quality will be greatly improved by discharging the treated effluent to the Zhadian River and replacing the lost water in the dry season (if required) with high quality surface water from controlled discharges from local reservoirs. The risk of flooding in the city will be greatly reduced. 4 Kanmdg Water SArply The Kunming Water Supply component was evaluated on a least cost basis. Initially, three options were considered: 1. the extension of two existing WTWs; 2. construction of a new WTW; 3. the extension of existing WTW No I plus construction of a new WTW. Option 3 was selected on least-cost grounds and because it was considered to be the most practical. Sensitivity analysis based on varying the capacities in each of the options found this selection to be robusL A set of long run sraegies are -being evaluated on a least cost basis as part of the Water Resources Master Plan development and the preliminary results of this analysis infonned project identification. All of them include the eventual importation of water, the key being that the page 8 of 28  EA Report combination of effective water demand management and the proposed projects, together with other interventions, should defer importation as long as possible. Provided all potential water resources within the catchment are developed, the indications are that there could be sufficient resources to meet the vater demand up to the year 2020 at 95% reliability. This involves continuing use of Lake Dianchi for municipal water supply, albeit using advanced treatment processes, and therefore justifies the investment to limit damage to the lake. It also clearly stresses the importance of protecting the lake as a local source for future use for drinking, water supply and in so doing defer more costly interventions as long as possible. The raw water source of Songhuaba was _z.lected because it is at present the least cost source and although the primary role of Songhuaba is for irrigation and flood control, small increases in municipal supplies can be obtained at the lowest average incremental cost. The Songhuaba augmentation project will involve a modest increase in the yield of the reservoir initially through the construction of a tail end dam. This was in turn selected as the least cost way of increasing yields as the alternative of resettlement to allow the level of the entire reservoir to be raised would have been much more excpensive. A further increase in yield could also be obtained by the construction of the Huang Shi Yen Reservoir within the Songhuaba catchment. S Qujing Water Project The Qujing Water Supply Project is required primarily because the lackl of available water is severely constramining industrial development in the city and therefore inhibiting its ability to act as a valuable counter-magnet to Kunming despite its abundant coal and other mineral resources. Qujing has made commendable efforts to conserve water and the price of water is presently significantly higher than in Kunming and other towns in the area. The situation does not lend itself to full economic analysis. It is not possible to identify with any accuracy the amount of industry that has been lost due to water shortage and whether this industry had to locate or relocate in areas which result in real economic losses. Nevertheless, the view in the Province and particularly in the Municipality is that the shortage of water is significandy limiting present and future economic welfare. All low cost sources of water for Qujing have been fully developed and the future options will require a significant increase in water costs. Initially, four options were considered, based on the exploitation of two existing reservoirs, Huashan 30km north of Qujing and Du Mu, 40km southeasL For each reservoir, two locations for the WTW were evaluated and costed. Identification of the potential additional yield of Huashan Reservoir rcvealed that, because of existing commitments, it would be insufficient to justify the large expendi:ure. Consideration of Du Mu options revealed that the least cost solution involved location of a new WTW to the south of the city, but that this solution, at Zf440 million, was still considered as too expensive for the city. Following a detailed review and redesign of the project in which the route of the aqueduct was optimised and the pipe material and diameter rationalised, the least cost solution was reduced to *300 million, and the project included in the YEP. 6 Soid Wase - Kwzg and Qjing Initial choices for the solid waste management projects-in both Kunming and Qujing were based on an evaluation aimed at defining the most appropriate technologies. A least cost analysis of options was developed for the optimisation of the key components. Tse initial evaluation considered potential solid waste treatment and disposal strategies including recycling, composting, incineration and gasification, and landfilling. Recycling already plays an active role in each of the cities, capturing most of the five percent of the municipal waste stream that can be profitably recycled, mainly glass, plastics and metals. The industry is highly competitive, with a combination of state- page 9 of 28  Addendum owned and private firms providing services and little scope for additional municipal intervention. It also provides employment for the lower end of the social economic ladder. Composting, to recycle organic materials, has been tested in both Kunming and Qujing, but there have been serious operational and environmental problems. costs have been high and markets have not supported sales. Both incineration and gasification have been shown in other cities with similar waste streams to be substantially more costly than landfill. The current continuing significant us-e of coal in Kunming also gives the waste a low combustion *alue, over half the waste stream being inorganic. This represents a major problem for both composting and incineration/gasification from which the residues still require landfilling. Landfill was therefore chosen in both cities for the disposal of municipal solid wastes. An evaluation of the collection system in Kunming showed the advantage of developing two landfill sites to serve opposite sides of the city and significantly reduce the haul distances and environmental impact. The identification and assessment of sanitary landfill sites took into account factors including haul distance, life expectancy, cost, access, land use, land acquisition and resettlement, cover material, ecology, hydrogeology and potential re-use. Five potential sites were identified for Kunming. Acknowledging the difficulty in a geologically active area lik-e Yunnan of fnding a landfill site which can meet all the impermeability requirements naturally, it was accepted that artificial linings would have to be provided for at least some part of any landfill site chosen for the two cities. However, the risk of earthquake damage to the liner and the potential for groundwater contamination is only smalL there having been only fourteen earthquak-es in the region of not more than 7 (on the Richter scale) over the last 500 years. The preferred sanitaly landfill sites for Kunming were identified as Hongshuitang and Baishuitang with a total cost of W45.8 million and a life expectancy of 21 years. In a similar exercise for Qujing, in which four sites were subject to a similar assessment, a single size, with a total cost of *1 1.8 million in the first phase and a life expectancy of 19 years and located between the city's two main urban centres (Qujing and Zhanyi), was chosen at Back Valley of Tail: Mountain. In both cases, the least cost site had, as one of the main decision criteria, minimization of the joint cost of transport and land- acquisition. Since land acquisition cost correlates very strongly with resettlement impact, this criteria also tends to minimize resettlement Sanitary landfills must also comply with national standards, which require leachate and gas collection. No attempt was made, therefore, to compare the cost of including these with the damage which would ensue from their absence. Given the long run risks inherent in unprotected landfilk, the need to provide leachate and gas collection was accepted and additional impact evaluation was not carried out. Although solid waste collection and transfer vehicles and equipment have a relatively short life, the transfer stations which form an integral part of the systern have much longer lives, and therefore need to be designed for flexibility to adjust to changing situations. The analysis of the waste collection system therefore addressed both the cost of collection and transfer equipment and the optimisation of size, location and c sign of small, medium and large transfer stations (STSs, MTSs and LTSs) within the city. Costs of collection and transfer were analysed and optimised using the UNCHS WAGS Compactor Program for equipment ranging from tricycles to container trucks. Optimisation of the numbers of collection vehicles showed that for Kunming the ideal system should be one with a large numberof STSs. Waste is carried direct from them to the landfill sites in 8 tonne containers. However, an evaluation of the land acquisition and environmental impact aspects of the thirty-five STSs originally proposed demonstrated the considerable problems of trying to locate a large number of transfer stations of any size within the city. Particular environmental problems related to noise disturbance in residential areaS and to increased traffic movements during the nighL page 10 of 28  EA Report On these grounds, the decision was taken to limit the number of transfer stations in Kunming and thus build only thirteen STSs and, instead, to locate four MTSs in the areas of greatest environmental impact. Sites for a further two MTSs were identified for future expansion. The evaluation showed that there was no need at all for LTSs, because the time saving achieved would not justify the additional capital and opeating costs of the LTS and related vehicles. A similar exercise in Qujing showed that the least-cost system would be one with five STSs in Qujing City and one in Zhanyi in the long-term. No MTSs are required because of the short haul distance to the landfill site. Issue No 5 - Water Q&fffli Data for Lk Dianchi Ambient water quality datafor Lake Dianchi appear to have some problems. For exanple, the quaity of the inflows from rzvers is higher than the receiving body There are several values quoted in the data which are contrary to conzmon sense. such as 12 mg/Ifor a dissolved oxygen concentration. cdearly in the supersaturated range- Reference should be made to Section 4.1.7 of the EA Report. Water quality data for Lake Dianchi and its influent rivers have been collected by a number of different agencies during both regular sampling programmes and special surveys over a period of many years. Many of the data available are dated and there are clearly some compatibility problems, which probably derive from different sampling and analysis techniques and different personnel. However, it was not possible within the scope of the project to mount a new comprehensive water quality study, especially as the principal problems with water quality are well-known. The data clearly demonstrate a significant deteriororation since 1988. Issue No 6 - Eology oLak Dianchi We understand there have been sigl4ficant changes in Lake Dianchi's ecology over the past severalyears What are some of these changes and what do theyforetell asfar aspossibilities for restoration? How has hiodiversity been reduced over the years? Few data are available on the ecology of Lake Dianchi. Most are biological data fron the 1950s and 1988-1989, on macrophyts, plankton, fish and benthos, contained in an English translation of a compendium "The Ecosystem in Lake Dianchi Catchment". The spatial and temporal variation of the data is unknown, because most have been sunmarised and/or are only qualitative. Only some structural page 11 of28  Addendum analysis of the ecosystem is possible. A functional analysis would require more data. Table No 2 offers a comparison of the characteristics of the lake between the 1950s and today. Table No. 2 Comparison of both Biotic and Abiotic Characteristics of Lake Dianchi between the 1950s and the 1988-1989/current situation In some cass a disincon was made betwhe Caohai or ,ier lake (1) and dte Waihai or outer lake (0) Variable lunit 1950s current transparency m (bottom) 0A (1) 0.7 (0) max-min watei level m unknown 1.90 total-P mg/l unknown 0.57 (1) 0.14 (0) total-N mgil unknown 3-7 (1) 1-2 (0) N:Y unknown 6 (1) 12 (0) shoreline sloping/gradient steep (1) sediment probably thin thick, polluted macrophyte species n 41 20 macrophyte lake coverage % >80 <3 dominant group Charophyres Eikhomia (1) Myriophyllum (0) phytoplankton species n 186 126 dominant group _ unknown Cyanobacteria * numberof algae n*lO3/l 1 3(1)37(0) 19,000 (1) 11,000 (0) zooplankton species _ unknown 61 dominant group _ Rotifers i abundancy _ _ nll 1200-1,400 14.000 (1) 14,000 (0) dominant fish species endogenous >60% exotic * dominance of Cyamobactria. at kast in biomass. is deduced from the oca rence of alga blooms dmt were reported: ChIoroavaea and BacillariophIcae (sti) domine nnuericaly. Thc species prost have cnged from mesotrophic to etrophic indicato Soume: DRA CotamWs sumway of papcrs by Yutmna organisations ainmges to Lake Ecoloy In the early fifties, Lake Dianchi was an oligo- to mesotrophic clear water lake. Sediments were largely covered by macrophytes, Charophytes being dominant nhe fish community consisted largely of indigenous species, while phytoplankton was dominated by Chlorophymaea (green algae) and Bacillkio- plycaea (diatoms). Some Cyanobacteria (bluegreens) were also present Under these conditions of low to moderate productivity, zooplankton numbers of about 1,20QII apparently succeeded in suppressing algal grwth. Shores were sloping, resulting in different zones of littoral macrophyte communities, contributing to a large biodiversity. In the sixties and seventies, apparently important changes took place in the ecology of the lake. in- creased human activity led to domestic and industrial pollution, land abuse, erosion processes, land reclamation at the shores, overcatching of fish and introduction of exotic edible fish species. As a result, the lake ecosystem changed into a turbid waterbody, the fish community probably being dominated by caps, and the algae by blue-greens, (periodically) including harmful taxa such as AMsrocyutis, Oscglioria and Aphaomenon. Average chlorophyll-a values incrased to 120-150 pg/I for the Caohai and 20-50 WpI in the Waihai. Zoopbnkton numbers increased more than 10-fold over the years and now mainly consists (60%) of page 12 of 28