Subsurface flow reedbeds using alternative media for the treatment of domestic greywater in Monteverde, Costa Rica, Central America

Abstract

This paper describes the performance of reedbeds using plastic (PET) bottle segments as an alternative low-cost media for the treatment of domestic greywater in Monteverde, Costa Rica, Central America. Twelve reedbeds consisting of four sets of triplicates were monitored through wet and dry seasons in order to determine the effect of media type (PET versus crushed rock) and the effect of plants. In both seasons, performance of the planted reedbeds with PET media, for BOD and fecal coliform removal, was either comparable to, or better than, that of the crushed rock systems. The planted PET reedbeds achieved fecal coliform removal rates > 99.9% in all cases equating to reductions of between 3 and nearly 5 log, with an average BOD outflow of 12.9 mg/L over both seasons. The hydraulic loading rate varied between 1.33 and 2.67 cm/day and hydraulic retention times (HRT) ranged from 3.5 to 7.5 days. The six reedbeds planted with Coix lacryma-jobi proved to be significantly more effective in pathogen removal and BOD reduction than the unplanted reedbeds. The planted PET reedbeds also increased their biomass by twice that of the planted crushed rock reedbeds during the study period. The majority of this increase was shown to be due to root growth. This paper discusses the implications of the above results for developing countries and identifies potential areas for further research.

Greywater Characteristics, Treatment Systems, Reuse Strategies and User Perception—a Review

“…This caused unsightly conditions. After construction of this system, conditions improved.BOD 5 99%NH 4 -N 95%PO 4 -P 84%Dallas and Ho (2005)Tufileh, JordanAutomated greywater systemOptimization and validation of a system for reusing greywater in home gardens in JordanAl-Jayousi (2003)…”

Ultraviolet (Uv) Disinfection of Grey Water: Particle Size Effects

“…Tertiary treatment of the wastewater by sand filtration followed by a UV dose of at least 97mJ·cm -2 consistently met the Title 22 criteria for unrestricted urban reuse, whereas UV doses of up to 239mJ·cm -2 applied to the unfiltered wastewater effluent did not always meet the the Title 22 criteria. Biological treatment systems that incorporate a filtration step, such as membrane bioreactors (MBR) and porous media reed beds, can provide good organics removal [37,38] as well as removal of large particles that shield coliforms from UV light. Treatment of grey water through a horizontal flow reed bed allowed complete inactivation of total coliforms in the effluent at a low UV dose of 11mJ·cm -2 ( Figure 3).…”

Efeito da vegetação em sistemas alagados construídos para tratar águas residuárias da suinocultura

“…No entanto novos trabalhos, notadamente aqueles que consideram as perdas de água por evapotranspiração no sistema, têm evidenciado essa importância (BIAŁOWIEC; JANCZUKOWICZ; RANDUSON, 2011;MESQUITA et al, 2013). Em algumas pesquisas, têm sido descritos melhores desempenhos em SACs cultivados com espécies aquáticas em relação aos não cultivados (DALLAS & HO, 2005). Pelos motivos citados, Brix (1994) sugere o uso de plantas em SACs, embora afirme que a quantidade de nutrientes extraídos é muito pequena quando comparada às cargas aplicadas.…”