【摘要】 为解决我国污染源在线监控数据缺乏深层次利用、监测数据对污染源不能有效预警的状况,对企业日常污水排放的污染物进行监控预警,综合运用层次分析法和频次分析法,分别确立了在线监控预警的指标体系和污水排放不同警情的阈值范围,并以某化工厂12个月的在线监测数据为案例对方法进行了验证.分析结果表明,某化工厂污染源废水中ρ（氰化物）在0～0. 50mgL之间,其中88. 54%的监控数据分布范围为0～0. 20 mgL,均未超过GB 8978—1996《污水综合排放标准》Ⅱ级标准限值;ρ（CODCr）在3. 51～499. 17 mgL之间,其中51. 74%的数据分布在>300～400 mgL之间,接近GB 8978—1996Ⅲ级标准限值,出水ρ（CODCr）偏高;ρ（NH₄+-N）在0～45 mgL之间,均未超过GB 8978—1996Ⅱ级标准限值,其中91. 13%的数据低于30 mgL,出水ρ（NH₄+-N）较低.对确定的预警阈值方法验证结果表明:①依据权重值的大小最终筛选出氰化物、CODCr及NH₄+-N为预警指标.②某化工厂氰化物在排放正常、一般、不正常及极不正常状态对应的阈值范围分别可设为40%频次、30%频次、5%频次及超过5%频次所对应的浓度范围; CODCr和NH₄+-N各状态对应阈值浓度范围一致,均为50%频次、40%频次、5%频次及超过5%频次对应的数值.研究显示,基于在线监测数据并结合相关标准、化工企业排污风险特征和化工厂的生产特征及工艺等基本条件,提出利用频次分析法确定化工厂各采样时刻不同警情阈值的方法较为科学合理.更多还原

【Abstract】 In view of the inadequate use of the monitoring data of pollution sources and the failure to early warn pollution accidents in China,monitoring and early warning of pollutants discharged from wastewater of enterprises were carried out. Using analytic hierarchy process and frequency analysis,the index system of online monitoring and early warning and the threshold range of different warning conditions for wastewater discharge were established respectively. The method was validated by a 12-month online monitoring data of a chemical plant. The data analysis results show that the concentration of cyanide in the wastewater of the chemical plant was between 0 and0. 50 mgL,of which 88. 54% of the data was distributed between 0 and 0. 20 mgL,which didn’t exceed the level Ⅱ standard limit of Integrated Wastewater Discharge Standard（GB 8978-1996）; The CODCrconcentration was between 3. 51 and 499. 17 mgL,of which51. 74% of the data was distributed between 300 and 400 mgL,which was close to the GB 8978-1996 Ⅲ standard limit,and the concentration were high; The ammonia nitrogen concentration was between 0 and 45 mgL,of which 91. 13% were less than 30 mgL,indicating that the ammonia nitrogen concentration in chemical plants was low. The results of validation of early warning threshold determination method show that:（1） The indexes with larger weights（cyanide,CODCrand NH₄-N） were selected to conduct the online monitoring and early warning.（2） The threshold of exceedance frequency for cyanide emissions could be set as 40%,30%,5% and above 5% for the normal,regular,abnormal and extremely abnormal status,and the threshold of exceedance frequency for CODCrand ammonia nitrogen emissions could be set as 50%,40%,5% and above 5% for the normal,regular,abnormal and extremely abnormal status in chemical plants. The research showed that the method for determining different warning thresholds at each sampling time in chemical plants by frequency analysis method,which based on the on-line monitoring data,combined with the relevant standards,the basic conditions of emission risk characteristics,production characteristics and process of chemical plants,made the determination of the threshold more reasonable and scientific,and it had certain reference value for the determination of early warning threshold of different industries in the future.更多还原