Abstract:

According to engineering geologic investigation and sample test analysis, reclaimed water of Chaobai River in Shunyi, Beijing was selected to take three kinds of typical representative soil medium (sandy gravel, fine sand, silty clay) to install the soil column, and was used to carry on the leaching simulation test. The column test results show that the cation exchange adsorption mainly manifests the K⁺and Ca²⁺ exchange in three kinds of typical soil medium, and the cation exchange function compares the sandy gravel column and the fine sand column is more remarkable  in the silty clay column. Moreover, the column test results also indicated that, with increasing of clay content, total organic compounds (TOC)cation exchange capacity (CEC) and total amount of clay minerals, in the typical medium leaching simulation column experiment, the cation exchange functions equilibrium time is also longer, and is 72 days for the sandy gravel,80 days for the fine sand and 86 days for the silty clay, respectively. The quantificational results computation has also proven the above conclusion: the background value of various anions and cations concentration of the silty clay medium is highest; the contribution quantity of the hardness of the unit mass silty clay medium and the total dissolved solids (TDS) is biggest, and is 5,767 mg/g and 6,952 mg/g, respectively.

Key words:  reclaimed water, cation exchange, hardness of groundwater, total dissolved solid, Chaobai River, Shunyi, Beijing