NOVELTY - Raw sewage purification treatment in gas collection, sewage purification treatment in slurry of bored well, biochemical treatment of product water and water quality adjustment, precise filtration discharge of product water, sludge purification and pollutant curing treatment are sequentially carried out to enable treatment of sewage and solid pollutant in natural gas field.    USE - Treatment of sewage and solid pollutant in natural gas field.    ADVANTAGE - The sewage and solid pollutant are effectively and economically treated without affecting the environment.    DETAILED DESCRIPTION - Raw sewage purification treatment in gas collection, sewage purification treatment in slurry of bored well, biochemical treatment of product water and water quality adjustment, precise filtration discharge of product water, sludge purification and pollutant curing treatment are sequentially carried out to enable treatment of sewage and solid pollutant. The raw sewage purification treatment is carried out by sewage gathering and transportation, close sewage adjustment and oil-water separation, precise oil-water separation, air floatation or flocculation treatment. The sewage is collected in a water collection tank produced by metals including steel, aluminum, stainless steel or composite material of steel, aluminum and ceramics, glass, plastic materials including polyvinyl chloride, polyethylene, acrylonitrile butadiene styrene, or composite material of plastic materials and glass fiber. The sewage is transported in water collection tank to sewage treatment plant. The resulting sewage is supplied to close sewage adjustment and oil-water separation device. The pH and temperature of sewage are regulated, and dirty oil is separated. The sewage is fed to water/oil fine separation system to separate oil. The separated sump oil is fed into refining device for stabilizing oil product, and stable oil product is obtained. The resulting sewage is fed to air supporting or flocculating system for complete removal of oil. A portion of organic substance and inorganic substance is removed, and chemical oxygen demand, biological oxygen demand and suspended substance are reduced. The pH value of the gas production sewage is adjusted to 5-7. A flotation agent and flotation assistant agent are added. The gas for air supporting is air, nitrogen, natural gas, carbon dioxide, flue gas or waste gas. The flotation agent is nitride of iron and aluminum, bromide, sulfate, nitrate, chlorate, perchlorate, and complex polymeric aluminum. The flotation assistant agent is polyacrylamide, modified starch, biological yellow collagen, biological protein, cellulose and/or modified cellulose. The effluent of flocculation/air supporting is fed into biochemical treatment water quality regulation unit, and flocculated sludge and mud are fed into the dehydration drying device. The slop sewage purification is carried out by slop pool oxidation gel-out settlement, sewage centralized transportation, secondary oxidation gel-out sewage regulation, mud/water separation of coagulation settlement, and micro-electrolysis. An oxidant and catalyst are placed in well field slop pool and stirred. The pollutant is oxidized and settled. The oxidant is peroxide, chlorate, perchlorate, chlorine dioxide, hypermanganate, ferrate, ozone, pure oxygen or air. The catalyst is oxide of iron, manganese, cobalt and nickel, sulfate, nitrate, acetate, and phosphate. The sewage is collected in slop pool after settlement, and transmitted to water quality regulation pool. The pH is adjusted to 5-7, and catalyst and oxidant are added. Secondary deep oxidation is carried out to remove colloidal substance and pollutant. Air is blown, and oxidation is accelerated for 6 hours. The oxidized sewage is supplied to flocculation, sedimentation and mud-water separation device. A coagulant and coagulant aid are added to sewage, and sedimentation separation is carried out. The coagulant and coagulant aid are added by pipeline mixer or directly added. The coagulant is chloride, bromide, sulfate, nitrate, chlorate, perchlorate, poly-aluminum compound and poly-ferrum compound. The coagulant aid is polyacrylamide, biological xanthan, modified starch, bioprotein, cellulose or modified cellulose. The mud-water separation is carried out by natural sedimentation separation, sloping plate sedimentation pool separation or mechanically forced separation. The sewage is supplied to micro electrolysis pool after pH regulation, and pollutant is degraded. The sewage is supplied to deep oxidation device, and oxidant and positive ion produced by electrolysis form a hydroxyl radical. The organic pollutant is oxidized into carbon dioxide and water. The effluent is supplied to biochemical treatment and water quality regulation unit. The biochemical treatment unit carries out processing of effluent of gas production pollutant sewage purification process unit and drilling mud sewage purification process unit. Biochemical treatment is carried out by anaerobic reaction and aerobic reaction which are performed in two reaction systems in different order. The effluent after biochemical treatment is guided into filtering system, and mud is cleared. A portion of mud is maintained to make pool maintain a certain concentration of active bacterial population, and remaining mud is air-cured. The effluent is precisely filtered using filter material such as quartz sand, anthracite, walnut shell, glass microballoon particles and ceramics. The suspended substance and tiny particle in sewage are removed. The purified water used for recycling is filtered by filter material such as modified fiber. The purified water is recycled as water for operation of oil-gas field, industrial cooling water, industrial water, water for building, boiler water, agricultural and forestry irrigation water and water for gardening. The mud generated in sewage treatment plant is supplied to mud dewatering and drying device, and content of water is reduced. The dewatering and drying device is a seasoning yard or percolating air-curing yard. The dewatering machine is a vertical centrifugal solid-liquid separator, horizontal centrifugal solid-liquid separator, swirl solid-liquid separator, vacuum solid-liquid separator, belt filter press, vacuum belt filter press or sheet filter press. The dewatered dry mud is sintered in a furnace, and mud residue is utilized to build road bed. The residue forms a solid together with concrete, lime, slag and silicate, and is used for paving roads. Thus, sewage and solid pollutant are treated.