Analysis of accidents at municipal wastewater treatment plants in Europe

Abstract The article deals with the still not much described issue of the process safety of municipal wastewater treatment plants. An author's database describing 232 accidents was created. These accidents were firstly classified into categories. Basic statistics, including an analysis of the number of accidents, were subsequently implemented for these categories. The potential consequences of accidents on human lives, the environment, and property have been referred to. An important part of the article is a description of the causes of accidents, which also points out the possibilities of how to prevent the respective accidents. Special attention is paid to the storage and handling of hazardous chemicals. The analysis of the information contained in the database shows that the environment is most often damaged in the event of an accident at WWTP; this occurs in 58% of cases, the most common cause being device or structural failure. It also transpires that a significant number of accidents at WWTPs are caused by extreme weather conditions, such as torrential rains, floods, etc., totalling 13% of all accidents. It can be estimated that, due to the higher frequency of extreme weather conditions, the number of such accidents will increase. WWTP operators should be prepared for this.