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1. Project Summary and Relationship to China's Agenda 21 Coke oven gas is desulphurised and deammonianised in an ammonia-sulphur recycling scrubbing process that will be introduced from international market, and wastewater is treated with an A/O process, all of these will reduce air and water pollution in the area and will be beneficial to local residents. The project is based on priority areas 18A and 10C, and is related to the priority areas 12B, 13A, and 14C of China's Agenda 21.

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2. Background

The Shougang coking plant, which belongs to the Shougang Corporation, located in the west suburbs of Beijing, stands on land higher than the Beijing downtown area. The city centre is directly downwind. The Shougang coking plant is charged with the important task of supplying gas to residents in the west part of Beijing and enterprises of Shougang Corporation itself, produces coke oven gas 766.50 million cubic meters and coke 1.9 million tons per year. At present, the coking plant supplies 474.5 million cubic meters of undesulphurised gas to the enterprises of Shougang corporation. The hydrogen sulphide content of this gas is as high as 6000-7000 mg/m3. About 9000 tons of SO2 are released into the air per year by combustion of this gas. This constitutes 42.2% of the total SO2 discharge generated by the Shougang corporation. This discharge heavily pollutes air in Shijingshan area. Data Monitored in 1994 showed that the annual average value of sulphurisation rate in Shijingshan area was 1.81 mg(SO3)/dm3/ day which is 6.7 times that of clean air. It is time to take measures to control the SO2 pollution in this area. Because of the adoption of simple and easy dry-box desulphurised processing, the hydrogen sulphide content in civil gas is as high as 500-1000 mg/m3, this is also unacceptable. There is a treatment station for coking wastewater, which was built in 1971, and has been operated for 25 years. It adopts activated sludge process. The design parameters are as follows: treatment capacity is 200 tons per hour, hydraulic retention time (HRT) four hours, the concentration of phenol and cyanogen is less than 200 mg/l and 15 mg/l respectively. However, due to new construction and reformation of coke ovens in recent years, both the quantity of wastewater and the concentration of pollutants have increased, which makes the effluent quality can not meet the state standard for wastewater discharge. At a result, the concentration of phenol, cyanide, COD and NH4+-N in this effluent are as high as 0.5-40 mg/l(annual average value 3 mg/l), 0.4-10.25 mg/l (annual average value 4 mg/l), 500-600 mg/l, 280-320 mg/l respectively. The amount of phenol, cyanogen and COD from it constitutes 85%, 76% and 40% of the total discharge of Shougang corporation. The effluent must be diluted 10 times in order to make the concentration of phenol and cyanogen in the discharge outlet of Shougang corporation meet the state standard for wastewater discharge. The phenol and cyanogen have polluted the water system of Liangma river seriously. Both environmental protection departments of the municipality and district and local residents show great concern for the pollution of the coking plant, and have strongly called for resolution to the pollution problem. As a major pollution source of Shougang corporation, the implementation of this project is of vital importance to the improvement on the air quality of Shijingshan district and the water quality of the Liangma river water system. The local government and communities have paid close attention to and given much support to the project concerning gas purification and reformation of existing wastewater treatment system. This project has already been listed in the ninth five-year environmental protection plan of the Shougang corporation. The pre-feasibility study, proposal design and project establishing work have been completed by the corporation. The Shougang corporation is one of five hundred Chinese enterprises with powerful economic strength, and strong capabilities for organising, designing, machining and construction. The company has provided all kinds of technical personnel to this project.

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3. Objectives

3.1 Long-term Objective To improve air and surface water quality of the municipality and Shijingshan district and the living environment of local residents.

3.2 Immediate Objectives * To reduce the SO2 contained in industrial and civil gas to reach the required standards; to reduce SO2 emission per year in local areas by 8600 tons; * To treat wastewater from coking effectively in order to alleviate pollution of surface and ground water in local areas; * To produce sulphur of 99.8% purity.

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4. Outputs and Activities

4.1 To remove H2S, NH4+-N, benzene from coke oven gas and produce high purity sulphur * To confirm ammonia-sulphur recycling process flow and equipment, make international market investigations , and make technical and economic assessments; * To make feasibility study design, concept design, basic design and detailed design; * To Sign a contract, carry out civil construction, purchase and install equipment; * To carry out trial production and evaluation of the project before acceptance . Monitoring Indicators: reduction of H2S content in the coke oven gas from 6-7g/m3 to 0.2g/m3, ammonia from 7.5g/m3 to 0.03g/m3, benzene from 30-45 g/m3 to 2-4g/m3; to produce high purity sulphur 6000 tons per year. Implementing Agencies: Shougang corporation and its subsidiary Time Schedule: July 1997 - June 1999 4.2 Adoption of SRT-controlled A/O bio-chemical treatment system to guarantee an efficient and stable treatment of the wastewater generated in the process of coke oven gas cleaning and recycling * To design the software of automation control system, investigation of the instruments and control equipment to be imported; * To make feasibility study, conceptual design, basic design and detailed design; * To sign contract, carry out civil construction, ship and install equipment; * To debug Process and evaluate project before acceptance. Monitoring Indicators: wastewater handling capacity 298t/h, phenol content in the effluent less than 0.5 mg/l, cyanide less than 0.4 mg/l; COD less than 200 mg/l. Implementing Agencies: Shougang corporation and its subsidiary

Time Schedule: July 1997 - June 1999

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5. Inputs

5.1 Chinese Inputs Shougang corporation has various resources ( wind, water, power, vapour) needed for the implementation of this project, and can bear construction, design, installation and equipment debug, production supervision and manufacture of domestically supplied equipment. US$ 9.68 million funded domestically will be available at the same time with the foreign credit.

5.2 International Inputs To facilitate this project, A- S desulphurising technology, instruments and control system for water treatment and some key equipment which is not available in China will be introduced from abroad. We also welcome technological co-operation with the supplier. 5.3 Budget The total capital needed for this projects is US$ 21.68 million. The Chinese participants will raise US$ 9.68 million from domestic sources, while foreign aid and investment will cover the other US$ 12 million.

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Table 1. Budget by Item (in million US dollars)

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Table 2. Budget by Output (in million US dollars)

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6. Benefits This project will help to improve air and surface water quality in Shijingshan district and in the Beijing municipality. After the completion of this project, SO2[a2] emitted into the air will be reduced by 8600t per year. The discharge of phenol, cyanide, COD and ammonia will be reduced by 84%,90%,46% and 68% respectively. At the same time, this project has good economic benefits with production of 6000 tons of high grade sulphur per year.

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7. Risks Total capital needed for this project is as high as US$ 21.68 million, and some key technology and equipment are not available in China, all of these have hindered the implementation of the project. However, because the project is aimed to deal with the air and water pollution of Shijingshan district and the Beijing Municipality, it has drawn great attention and supports from the local government and the public. After the arrival of the foreign credit of US$ 12 million and with the domestic funds, this project will be able to be implemented.

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