TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Composition: The consortium further comprises Methanomicrobia, where the consortium comprises at least one of Methanosarcina or Methanosaeta. The consortium comprises Dehalococcoides. A microbial composition for concurrent dechlorination of a mixture of chlorinated ethanes and chlorinated ethenes, comprises a non-naturally occurring consortium of dechlorinatingly effective microbial species, where the consortium of dechlorinatingly effective microbial species comprises at least one 16S rDNA nucleic acid sequence that has more than 95% identity to a defined nucleic acid sequence of 425, 430, or 478 bp (SEQ ID NO: 1-3), given in the specification. The consortium further comprises at least one 16S rDNA a nucleic acid sequence that has more than 95% identity to a defined nucleic acid sequence of 447 or 454 bp (SEQ ID NO: 4 or 5), given in the specification. The consortium further comprises at least one 16S rDNA a nucleic acid sequence that has more than 95% identity to a defined nucleic acid sequence of 464 or 446 bp (SEQ ID NO: 6 or 7), given in the specification. The consortium further comprises at least one methyl coenzyme-M reductase nucleic acid sequence that has more than 95% identity to any of the 13 defined nucleic acid sequences of 367-437 bp (SEQ ID NO: 8-20), given in the specification. Preferred Method: In the method for dechlorinating a mixture of chlorinated ethanes and chlorinated ethenes, the chlorinated ethanes comprise at least one of 1,1,2,2-tetrachloroethane; 1,1,2-trichloroethane; 1,2-dichloroethane, or chloroethane. The chlorinated ethenes comprise at least one of cis 1,2-dichloroethene; trans 1,2-dichloroethene; vinyl chloride; or tetrachloroethene. The mixture further comprises chlorinated methane, where the chlorinated methane comprises carbon tetrachloride or chloroform. In the method for dechlorinating chlorinated waste, the chlorinated waste comprises contaminated soil or contaminated water. In the method of producing a microbial consortium, the electron donor is lactate, succinate, pyruvate, benzoate, propionate, or formate. The electron donor comprises lactate. EXAMPLE - No suitable example given.