Based on the POS expansion and COD expansion,the relation between cj coefficients and gj coefficients is discussed in detail and the method of matric transform is presented.

Based on the CRM expansion and COD expansion, the relation between d_j coefficients and g_j coefficients is discussed, and matric transform method proposed.

Based on the XOS expansion and COD expansion,this paper discusses the relation between e_j coefficients and g_j coefficients,and proposes a matrix transform method.

Detection of CODcr by Microwave Digestion Photometric Method and Its Unified Benefits Analysis;

The correlation of BOD5 and CODcr were analyzed in this paper according to the measured data of water quality of Cihu Lake in Hubei Province and the mathematical statistics, and meanwhile some questions in applying the correlation are also presented.

Properties of modified bentonite were characterized by various analysis techniques and modified bentonites were applied to pretreatment of high strength landfill leachate with CODCr up to 20,000~37,000mg/L.

The experimental results show that the declining rates of chromaticity and chemical oxygen demand(COD) can extend to 84% and 60% respectively.

The main defects of the standard method for the determination of chemical oxygen demand in water by potassium dichromate, such as measurement time consuming, Hg salt polluting, Cl~- disturbance were ameliorated by increasing acidity and adding catalyst silver sulfate.

It is shown that colority and chemical oxygen demand of the wastewater can be decreased to thirty times and less than 300 mg/L respectively by 10% iron(Ⅲ) chloride liquor and powdered carbon.