Study On Weathered Pisha Sandstone Improved By Sludge And Its Effect On Plant Growth

With the acceleration of urbanization,the requirements for urban sewage treatment rates have increased,and the number and scale of urban sewage treatment facilities are increasing.As a by-product in the sewage treatment process,the treatment and disposal issues of sewage sludge have also received much attention.Sludge can be used in land utilization to improve soil fertility as it has high content of organic matter,N,P and K.Therefore,sludge land utilization has been a trending way to achieve the goals of sludge reduction,harmlessness,and stabilization.Pisha sandstone is a kind of special sandstone,which is suffered severe erosion and has insufficient nutrient,leading to scarce vegetation in this area.A lot of methods have been used to control the soil erosion and land degradation.Pisha sandstone combined with sand can become a compound soil that is suitable for vegetation to grow.Therefore,the utilization of weathered Pisha sandstone has received much attention and become a research hotspot.According to the different composition in sludge and weathered Pisha sandstone,they can form complementarity and improve the structure and the fertility of weathered Pisha sandstone.Therefore,the sludge and weathered Pisha sandstone can be reused for land utilization.In this study,the different ratios of sludge were added into the weathered Pisha sandstone,and then the physical and chemical and fertility of the improved Pisha sandstone were tested.According to the results,the appropriate sludge addition was determined.Additionally,the planting test and the scouring test on the simulated slope were conducted.The main results were as follows:(1)Some soil properties of improved Pisha sandstone was selected for evaluation,such as bulk density,porosity,water-holding capacity,organic matter,alkali-hydrolyzable nitrogen,available phosphorus,available potassium,p H,conductivity,etc.The result showed that the addition of sludge to weathered Pisha sandstone can effectively improve the physical and chemical properties and significantly increase the fertility.Moreover,10% addition of sludge is optimal.(2)The plants on the improved Pisha sandstone grown better than on the weathered Pisha sandstone.The fresh weight,dry weight and plant height of the plants growing on improved Pisha sandstone were all ameliorated comparing with the plants on the weathered Pisha sandstone.Meanwhile,the improving effect of 10%addition was the best.Some physical and chemical properties of improved Pisha sandstone became better after planting.(3)The improved Pisha sandstone(10% addition)has no significant difference in corrosion resistance compared to weathered Pisha sandstone,but the corrosion resistance is significantly improved after adding W-OH material,indicating that the improved Pisha sandstone adding W-OH material is feasible to be applied in the erosion control and vegetation restoration on Pisha sandstone slope.