摘要：
为解决生物质灰渣利用和沼液排放引起的污染环境问题,以生物质灰渣为滤料采用自然渗滤对沼液进行了净化处理试验.结果表明:灰渣对沼液具有较好的净化能力,粒径是影响灰渣对沼液净化效果的重要因素,灰渣粒径越小净化效果越明显,相同质量灰渣粒径＞3 mm时,渗滤速率为4.17 mL/s,出水COD为1 880 mg/L,出水TS为1.46 g/L,COD和TS去除率为58.71％和67.69％;而粒径＜0.5 mm时,渗滤速率为0.46 mL/s,出水COD为221 mg/L,出水TS为0.61 g/L,COD和TS去除率达到94.07％和87.16％.净化柱的高径比直接影响沼液流通路径,以COD去除率作为评价指标时,为获得较好的沼液净化效果,不同粒径灰渣(＜0.5、0.5～1、＞1～1.5、＞1.5～2、＞2～3 mm)所采用净化柱的高径比应不小于1.34、2.3、2.68、5.01、10.66,此时对应出水COD值分别为236、276、305、315、342 mg/L,COD去除率分别达到94.82％、93.94％、93.3％、93.08％和92.49％,出水水质接近农田灌溉用水要求.不同粒径(＜0.5、0.5～1.0、＞1.0～1.5、＞1.5～2.0、＞2.0～3.0)灰渣对沼液的最大的过滤能力分别为9～10、10～11、8～9、4～5、3～4 mL/g.%In order to avoid environmental pollution caused by biomass ash piled up on the open air and digested slurry discharged directly,and explore the utilization way,biomass ash was used as filter material to clarify digested slurry in infiltration.The results show that biomass ash can be used as filter material to clarify digested slurry.Particle size is the major influence factor for the cleaning of digested slurry,and the small particles have the better cleaning effect than large particles due to their specific surface area and spatial structure.Under the same experimental conditions,when particle size is large than 3 mm,infiltration rate is 4.17 mL/s,COD (chemical oxygen demand) of clarified digested slurry is 1 880 mg/L,TS (total solid) content of clarified digested slurry is 1.46 g/L,and the removal rates of COD and TS in digested slurry are 58.71％ and 67.69％,respectively.When particle size is less than 0.5 mm,infiltration rate is 0.46 mL/s,COD of clarified digested slurry is 221 mg/L and TS of clarified digested slurry is 0.61 g/L,and the removal rates of COD and TS in digested slurry are 94.07％ and 87.16％,respectively.The ratio of height to diameter of clarification column not only affects the flow path of digested slurry,but also affects its clarifying effect.When COD removal ratio is used as evaluating indicator,in order to get better cleaning effect,the height-diameter ratio of clarification column is more than 1.34 when particle size of biomass ash is less than 0.5 mm,is not less than 2.3 when particle size ofbiomass ash is between 0.5 and 1 mm,is not less than 2.68 when particle size ofbiomass ash is between 1 and 1.5 mm,is not less than 5.01 when particle size of biomass ash is between 1.5 and 2 mm,and is not less than 10.662 when particle size ofbiomass ash is greater than 3 mm,the COD values of clarified digested slurry were 236,276,305,315 and 342 mg/L respectively,and the removal rates of COD were 94.82％,93.94％,93.3％,93.08％ and 92.49％,respectively.The clarified digested slurry quality is close to agricultural irrigation water requirements.The clarifying capacity ofbiomass ash in different particle sizes is 9-10 mL/g when particle size of biomass ash is less than 0.5 mm,10-11 mL/g when particle size of biomass ash is between 0.5 and 1 mm,8-9 mL/g when particle size of biomass ash is between 1 and 1.5 mm,4-5 mL/g when particle size of biomass ash is between 1.5 and 2 mm,and 3-4 mL/g when particle size of biomass ash is greater than 3 mm,respectively.
