Study On Ecological Risk Assessment Of Heavy Metals In Textile Printing And Dyeing Sludge And It’s Garden Utilization

The large amount of sludge produced by the textile printing and dyeing industry is rich in organic matter and nutrients such as nitrogen,phosphorus,and potassium,which can promote the growth and development of plants.The utilization of sludge resources has become the main trend today.The use of textile printing and dyeing sludge in gardens is An economically viable and environmentally sustainable method.However,textile printing and dyeing sludge also contains a large amount of heavy metals,which will be added to the garden soil along with the sludge.If the content of heavy metals is too high,it will also harm the soil environment and plant health.Therefore,studying the environmental impact of heavy metals in textile printing and dyeing sludge is of great significance to the rational application of sludge and the growth of plants.In this paper,by measuring the physical and chemical properties and heavy metal content of textile printing and dyeing sludge at different depths,and comparing the control standards of muddy pollutants for landscaping,the feasibility of its garden utilization is judged;according to the form and content of each heavy metal,Cr,Cd,Cu,Pb,The pollution degree and ecological risk of Ni,Zn,As and Hg;the results obtained from the pot experiment,study the influence of textile printing and dyeing sludge garden utilization on plants and soil,and draw the best growth substrate for plants and the most heavy metal absorption effect Good plants.The main conclusions are as follows:(1)The content of various pollutant indicators and heavy metals in the sludge is less than the A-level sludge product limit in the agricultural sludge pollution control standard and the minimum limit of the sewage treatment plant sludge disposal landscaping sludge pollution control standard Value,in line with the standards for garden use.The garden use of textile printing and dyeing sludge can improve the soil environment,adjust the soil p H and electrical conductivity in the range more suitable for plant growth.(2)The pollution degree and ecological risk of heavy metals Cr,Cu,Pb,Ni,Zn,As and Hg are relatively small,ranging from Ⅰ to Ⅱ(low risk to medium risk);the pollution degree and ecological risk of heavy metal Cd are relatively high.It is grade III to IV(medium risk to high risk).The results of Cr,Cd,Cu,Pb,Ni,Zn,As and Hg(including Cd)according to DC and GCF are severe pollution,and the results obtained from RI and GRI are medium to high risk.Heavy metals have a greater degree of comprehensive pollution and ecological risks;while Cr,Cu,Pb,Ni,Zn,As and Hg are light to moderate pollution based on DC and GCF.The results of RI and GRI are low risk,and the comprehensive pollution degree and ecological risk of multiple heavy metals(excluding Cd)are small.(3)The plant with the best absorption of Cu and As in the sludge is marigold,the best absorption of Pb and Hg is zinnia,and the highest absorption of Zn,Cr,Ni and Cd is For ryegrass,calendula officinalis has the best absorption effect on nutrients in the sludge.The most suitable substrate for plant growth is a soil substrate with a 2:1mixing ratio of sludge and garden soil.