Biodegradation mechanisms and functional microbiology in conventional septic tanks: a systematic review and meta-analysis

Abstract

Knowledge gaps exist pertaining to the interaction between anaerobic conditions, microbiology and activity that characterize biodegradation mechanisms in septic tanks.

Non-Sewered Sanitation Systems’ Global Greenhouse Gas Emissions: Balancing Sustainable Development Goal Tradeoffs to End Open Defecation

“…for each scenario and decentralized sanitation technology [21,22]. It should be noted that CH 4 and N 2 O were considered the most important GHGs directly produced from excreta in decentralized on-site sanitation systems [19,23] since a large fraction of decentralized sanitation systems are assumed to digest waste anaerobically [13]. and the two gases have a 100-year GWP of 21 and 310, respectively [22].…”

“…The current IPCC GHG estimation methodology has been used as the basis for calculations in this analysis [26]. However, this methodology has significant limitations as GHG emissions vary widely among waste treatment technologies, especially among decentralized sanitation, depending on the biogeochemical conditions, operating conditions and associated collection and discharge systems [2,13,19,27]. As such, this analysis made provisions for refinement and comparison of the current IPCC model with improved and experimentally verified emission factors (EFs).…”

“…Decentralized (on-site) sanitation technologies are the focus of this assessment as they are generally the most scalable, effective and equitable adaptation measure within the sanitation sector and are typically the first accessible improved sanitation option for those that currently have no access to sanitation [2,13]. They have a lower economic burden on the household user [14,15], some forms have been proven to be effective in reducing negative climate impacts [16][17][18][19], and most importantly, they can provide access to improved sanitation for the most vulnerable populations [13,15,17].…”

“…Decentralized (on-site) sanitation technologies are the focus of this assessment as they are generally the most scalable, effective and equitable adaptation measure within the sanitation sector and are typically the first accessible improved sanitation option for those that currently have no access to sanitation [2,13]. They have a lower economic burden on the household user [14,15], some forms have been proven to be effective in reducing negative climate impacts [16][17][18][19], and most importantly, they can provide access to improved sanitation for the most vulnerable populations [13,15,17]. Specifically, this assessment focused on the three different service levels of sanitation (i.e., improved, unimproved and no service), as defined by the Joint Monitoring Programme (JMP) [20], as they pertain to three Shared Socioeconomic Pathways (SSPs), as described in the framework presented by O'Neill et al (2014).…”

“…Discharge of untreated waste into the environment and the use of on-site technologies, such as septic tanks, pit latrines and ecological sanitation (i.e., container-based sanitation, composting toilets, etc.) contribute to greenhouse gas (GHG) emissions but have remained poorly quantified [2,13,15,19]. This analysis explored scenarios for global future GHG emissions from households implementing different forms of decentralized sanitation technologies to end open defecation practices.…”