| In order to explore the harmless treatment and resource utilization of laboratory acidic waste liquid,the pollutant and its content of acidic waste liquid were detected,and the harmless treatment was carried out by adsorption method to make it reach the sewage discharge standard.The dissolution test of desulfurized gypsum with hydrochloric acid and acid waste liquid proves that the acid waste liquid can improve the solubility of desulfurized gypsum.The effects of the combined application of acidic waste liquid and desulfurized gypsum on the chemical properties of alkaline soil and the growth of Medicago sativa and Puccinellia distans were studied by greenhouse pot experiment and field experiment respectively.The main conclusions are as follows:（1）The pollutants exceeding the standard in the acidic waste liquid in the laboratory are mainly Cr6+,and the other heavy metals are in line with the national agricultural irrigation water quality standard.In this study,different adsorbents such as activated carbon,biochar,activated carbon+biochar combination and ferrous sulfate were used for adsorption test of Cr6+.The adsorption effect of activated carbon was the best,and the Cr6+content of waste liquid decreased from 6mg/L to 0.09mg/L,which met the discharge standard of agricultural irrigation water and could be used for soil improvement research.（2）Through the dissolution test results of desulfurized gypsum in hydrochloric acid and acid waste liquid,the solubility of desulfurized gypsum in acid waste liquid is better than that in hydrochloric acid.When the optimal concentration is 25%,the solubility of desulfurized gypsum is 2.53g/100m L,so the soil improvement effect of desulfurized gypsum can be improved.（3）The results of pot experiments on improving alkaline soil by applying desulphurized gypsum with acidic waste solution and planting Medicago sativa and Puccinellia distans showed that 30%waste acid+0.6%desulphurized gypsum,30%waste acid+1.3%desulphurized gypsum,and 30%waste acid+2%desulphurized gypsum.The soil p H and alkalinity were decreased and soil nutrients were increased,and the improvement effect of alkaline soil was good.The emergence rate and growth of Medicago sativa and Puccinellia distans were significantly better than those of other treatments.（4）The results of field trials of improving alkaline soil by applying desulphurized gypsum with acidic waste solution and planting Medicago sativa and Puccinellia distans,The two treatments of 30%waste acid+1.3%desulfurized gypsum and 30%waste acid+2%desulfurized gypsum had better improvement effect on soil p H,conductivity and alkalinity,emergence rate,survival rate and growth of Puccinellia distans than other treatments.The Puccinellia distans can be recreated on the salt flats of the dry salt lake basin. |
