Socio-environmental externalities of sewage waste management

Conventional sewage management is expensive and inefficient, putting the environment and public health at risk, making access to sewage services difficult for everyone. Reusing sewage waste has agricultural and economic potential, but can contain harmful contaminants if not treated properly. This review is based on the hypothesis that the destination of sewage waste generates environmental and social externalities, which have not yet been widely compared. With the aim of identifying, from the literature, the socio-environmental externalities generated by different sewage waste management approaches, a systematic review of the literature was carried out, including 244 documents, with 50 % of these discussing impacts of conventional treatment and 37 % analyzing the reuse of waste. The main impacts and externalities were evaluated in three situations: untreated sewage, treated sewage, and reused waste. The results indicate that sewage waste has an underutilized economic value and can generate revenue, reduce operational costs and electricity expenses. Six negative externalities generated by conventional sewage treatment were identified: health costs; environmental cleaning; carbon offsetting; damage to tourism; damage to fishing and agriculture; and real estate depreciation. In reuse, there is a risk of two negative externalities: health costs and environmental cleaning, but two positive externalities were also identified: the reduction of phosphate rock mining and the neutralization of carbon credits. The complexity of the transition to sustainable sewage treatment practices is highlighted given the lack of consensus on the safe use of sewage waste, the lack of regulatory standardization, implementation costs and differences in regional parameters, highlighting the need for preliminary experimentation in a multidisciplinary and contextualized approach, considering comparative externalities among the available sewage waste management possibilities. [Display omitted] •The impacts of sewage cause economic losses for public coffers and individuals.•Human health and the ecosystem face externalities in all sewage destinations.•Sewage waste has underutilized economic value.•Sewage waste can replace fossil products and neutralize GHG emissions.•Lack of scientific consensus on safe sewage waste use and legislation.