Some exceptional features of the dynamically changing environment require the additional means for qualitative knowledge representation, data verification and ensurance of operativity of decision making processes. The article considers the possibilities of integration the safequard methods for impartial multicriteria: decision making with the three levels of knowledge representation distinguished in the decision support system (DSS). The approach is to represent static and dynamic aspects of the target system and to reflect them in deep knowledge representation level. The means to formalize multiple objective decision making mechanisms is proposed. The examples developed during the designing stages of the ecological evaluation system for different enterprises demonstrate the results of using extended E-nets for modeling cognitive processes leading to decisions.