High-Strength Domestic Wastewater Treatment and Reuse with Onsite Passive Methods

Abstract

This paper describes the preliminary monitoring results of an onsite pilot wastewater treatment plant consisting of a septic tank, an anaerobic up-flow filter, and a horizontal subsurface flow wetland system planted with Agapanthus africanus. The system was designed to treat heavily polluted domestic wastewater produced in a research and development (R&D) center, reaching additional goals of zero energy consumption and eliminating the use of chemical additives. First water quality data shows that organic load in the treated sewage were removed achieving more than 95% efficiency. Nutrients were removed by almost 50%, and fecal and total coliform counts decreased by 99.96%. The results were compared to official Mexican regulations for wastewater discharged into lakes and reservoirs complied with all of them except for nutrients. In this pilot project, the resulting treated wastewater was directly reused for watering the green areas of the R&D center. The result was that the excess of nutrients improved the quality of the grass, avoiding the use of synthetic fertilizers, and created a wetland habitat for small wildlife species living in the area.

Characterization of the Spatial Variation of Microbial Communities in a Decentralized Subtropical Wastewater Treatment Plant Using Passive Methods

“…The WWTP receives a wastewater load of approximately 7.5 m 3 /day. Untreated wastewater is received in the pump sump, where it is pumped to the ST. At this stage most particulate solids are removed by sedimentation, and anaerobic conditions promote the anaerobic digestion of organic matter [3,4]. The second treatment stage is the UAF, a tank filled with a porous volcanic rock called tezontle.…”

“…Centralized wastewater treatment plants (WWTPs) involve higher maintenance and operational costs than decentralized WWTPs, which are also easier to operate [2]. Anaerobic bioreactors (ARs) and constructed wetlands (CWs) are treatment stages that are commonly used in decentralized systems [3]; these units are classified as passive technologies, since they require low energy consumption and maintenance and operational costs [3,4]. Up-flow anaerobic filters (UAFs) and a septic tank (ST) are examples of ARs that can efficiently remove organic matter and suspended solids.…”

“…However, CWs may also have limitations, such as the possibility of clogging caused by the load of suspended solids in wastewater [11]. Systems consisting of ARs followed by CWs are known to be an efficient combination for wastewater treatment [3,12]. These configurations present advantages such as low energy requirements, low operational costs, and low sludge generation [13].…”

“…These configurations present advantages such as low energy requirements, low operational costs, and low sludge generation [13]. Furthermore, by incorporating an AR, such as a ST and UAF, as a pretreatment stage before wastewater is fed into a CW can significantly reduce the solid particles and organic matter levels [3,4], while the CW is useful in reducing nutrient loads in wastewater after anaerobic pre-treatment [14].…”

Low pH treatment of starch industry effluent with bacteria from leaf debris for methane production

“…Biological treatment of biodegradable waste is preferred globally due to its low operation cost and low maintenance and use of minimal hazardous chemicals (de Anda, López‐López, Villegas‐García, & Valdivia‐Aviña, ; Casiano Flores, Bressers, Gutierrez, & de Boer, ). Methanogenesis is a prominent popular technology worldwide, which involves degradation of biological waste through undefined microflora to produce methane and carbon dioxide (Angenent, Karim, Al‐Dahhan, Wrenn, & Domíguez‐Espinosa, ; Dilkes‐Hoffman et al., ).…”