Anaerobic Processes as the Core Technology for Sustainable Domestic Wastewater Treatment: Consolidated Applications, New Trends, Perspectives, and Challenges

Abstract

Anaerobic digesters have been responsible for the removal of large fraction of organic matter (mineralization of waste sludge) in conventional aerobic sewage treatment plants since the early years of domestic sewage treatment (DST). Attention on the anaerobic technology for improving the sustainability of sewage treatment has been paid mainly after the energy crisis in the 1970s. The successful use of anaerobic reactors (especially up-flow anaerobic sludge blanket (UASB) reactors) for the treatment of raw domestic sewage in tropical and sub-tropical regions (where ambient temperatures are not restrictive for anaerobic digestion) opened the opportunity to substitute the aerobic processes for the anaerobic technology in removal of the influent organic matter. Despite the success, effluents from anaerobic reactors treating domestic sewage require post-treatment in order to achieve the emission standards prevailing in most countries. Initially, the composition of this effluent rich in reduced compounds has required the adoption of post-treatment (mainly aerobic) systems able to remove the undesirable constituents. Currently, however, a wealth of information obtained on biological and physical-chemical processes related to the recovery or removal of nitrogen, phosphorus and sulfur compounds creates the opportunity for new treatment systems. The design of DST plant with the anaerobic reactor as core unit coupled to the pre-and post-treatment systems in order to promote the recovery of resources and the polishing of effluent quality can improve the sustainability of treatment systems. This paper presents a broader view on the possible applications of anaerobic treatment systems not only for organic matter removal but also for resources recovery aiming at the improvement of the sustainability of DST.

Comportamento dinâmico e hidrodinâmico de reator tipo UASB submetido à variação de carga hidráulica

“…Foresti et al (2006) indicam a faixa de temperatura de 25ºC a 35ºC como ótima para a atividade bacteriana no processo de digestão anaeróbia. Neste trabalho, as temperaturas mé-dias resultaram abaixo dessa faixa indicada e podem ter contribuído para a redução da eficiência do reator quanto à remoção da matéria orgânica.…”

“…Esse tipo de reator também é capaz de absorver grandes variações de carga hidráulica e orgânica, porém essas variações causam redução da eficiência de remoção da matéria orgânica do reator (que, em condições normais de operação, ficam na faixa de 60% a 80% em termos de DBO), e por isso devem ser avaliadas para que a estabilidade operacional do sistema seja mantida (CARVALHO et al 2008;FORESTI et al, 2006).…”

Modeling the Two-Stage Anaerobic Digestion of Domestic Wastewater With the Development of a Monitoring Application

“…The use of anaerobic treatment as the main process for domestic wastewater can help to improve sustainability due to low energy consumption, production of methane gas, and the opportunity for recovery of compounds of interest (e.g., nitrogen and phosphorous) during post-treatment (Foresti et al, 2006). For this purpose, a two-stage anaerobic digestion process can be suitable.…”

Produção de biogás a partir de glicerol oriundo de biodiesel

“…A diluição do glicerol residual pode ser uma solução para a inibição microbiana pela elevada salinidade (SUEHARA et al, 2005), embora em escala industrial o uso de água bruta para este fim poderia encarecer o processo. Uma alternativa poderia ser a mistura com outras correntes de efluentes, como a proveniente de processos de lavagem ou esgoto sanitário, o que também pode ser uma fonte de macro e micronutrientes (FORESTI et al, 2006;.…”