Construction And Application Of The Evaluation Model For The Treatment And Disposal Of Black And Smelly Water Sediment Based On Fuzzy Comprehensive Evaluation

The treatment and disposal of sediment is one of the difficult problems in the treatment on black and odorous water.The key is to choose an optimal treatment and disposal plan from process,cost and socio-economic factors according to the characteristics of sediment.At present,there is no evaluation and auxiliary decision system with strong operability to support the actual management work.Based on the fuzzy comprehensive evaluation method,a comprehensive evaluation system for the treatment and disposal plan of black and odorous water sediment is established in this paper.The multi-objective such as cost,quality,construction period,environmental impact,social impact and sustainable development are considered comprehensively.The combined weight method of analytic hierarchy process and accelerating genetic algorithm is used to determine the weight of evaluation index and optimize the best Sediment treatment and disposal plan,and carry out assessment of sediment treatment and disposal plan based on actual cases.The main results are as follows:(1)The analysis of the test data of the black and odorous water sediment shows that: most of the black and odorous water sediment can not meet the requirements of the utilization of sediment for agriculture,landscaping,land improvement,etc;the most suitable disposal methods are making bricks,making ceramsite,making cement and landfill;about 1/3 of the sediment pollutants in the detection points meet the requirements of backfilling soil and can be backfilled nearby;the heat value of sediment is generally low,the incineration value is low,and the cost is high.The incineration method can be used to dispose the sediment with excessive pollutants.(2)The cost and benefit of each sediment treatment and disposal method are obtained by collecting and finishing: among the commonly used harmless and stable treatment methods,leaching is the most expensive,followed by stable solidification;among the sediment disposal methods,the comprehensive benefit of land use is the largest,the cost of building materials is high,but it can produce certain economic benefits,and the cost of landfill disposal is low,but it does not produce benefits(3)According to the calculation of the weight,the weight of the first grade indexes decreases in order of function and quality,cost and benefit,environmental impact,social public satisfaction and sustainable development,and project duration,in the second grade indexes,the top five are respectively pollutant stabilization effect,resource utilization effect,mineral resource utilization,pollutant reduction effect and regional macro policy support.(4)The evaluation system was used to evaluate the sediment treatment and disposal plan of 16 black and odorous rivers in Guangzhou: making sediment into ceramsite as building material is the best way to dispose sediment;secondly,it is suggested to use the backfill for the bottom mud with low pollution and meeting the requirements of backfill soil;the third is backfilling after the stabilization and solidification of the sediment;the fourth is sediment incineration;finally is mixing sediment and garbage for landfill.The results match with the characteristics of sediment,regional economic development,environmental protection requirements and supporting infrastructure in the Pearl River Delta.To sum up,the assessment system and model for the treatment and disposal of black odorous water sediment constructed in this paper are highly operable,can meet multiple objectives at the same time,take into account the needs of economy,society and environment,meet the needs of practical management work,and can provide technical support for the management departments at all levels to make scientific decisions on the technical scheme for the treatment and disposal of black odorous water sediment.