Phytoremediation of Industrial Waste Leachates by Planted Filters Composed of Phragmites australis (Cav) Trin ex Steud, Typha latifolia L. and Cyperus papyrus L.

The aim of this study is to evaluate the purifying ability of 3 parallel planted filters (PF1, PF2 and PF3) composed of three plants (Phragmites australis (Cav) Trin ex Steud, Typha latifolia L., Cyperus papyrus L.) on leachates from a landfill of industrial waste in Pointe-Noire (Republic of Congo). This landfill site includes a technical landfill for ordinary industrial waste (OIW) and a technical landfill for hazardous and soiled industrial waste (SIW). In order to assess purifying ability, we sampled 14 samples over 8 weeks, with 7 samples of the raw leachates from the technical landfill center, and 7 samples of leachates cleaned after passing through the tryptic vegetable filter. The physico-chemical analyzes made it possible to determine the following parameters: TOC, COD, NO3-,PO42-, Ni, Cd, CrVI, Zn, Cu and Pb. The results showed a significant decrease in organic pollution with abatement rates in TOC and COD greater than 90%. The average removal efficiency is respectively 45.97% for nitrates and 40.2% for phosphates. The abatement rates for heavy metals range from 41.2% to 60.9% for nickel, from 52.2% to 68.5 % for cadmium, from 49% to 71.7% for chromium VI, from 59% to 74.6% for zinc, from 50.9 % to 65 % for copper and from 61.4% to 75.1% for lead. However, additional analyzes are needed to confirm the hypperaccumulator nature of these plant filters in particular absorption isotherms and kinetics of extraction of heavy metals of Phragmites australis (Cav) Trin ex Steud, Typha latifolia L., Cyperus papyrus L.)

Avaliação do desempenho de sistemas alagados construídos de escoamento horizontal subsuperficial tratando efluente de reator UASB, com base em quatro anos de monitoramento / Performance evaluation of horizontal subsurface flow constructed wetlands in the treatment of UASB reactor effluent, based on four years of monitoring

RESUMO Um sistema composto por um reator anaeróbio tipo upflow anaerobic sludge blanket (UASB), seguido de um sistema de alagados construídos (SAC) de escoamento horizontal subsuperficial compreendendo duas unidades em paralelo (50 habitantes cada), foi avaliado para o tratamento de águas residuárias geradas na cidade de Belo Horizonte, Minas Gerais, Brasil. Uma unidade foi plantada com Typha latifolia e a outra não foi vegetada. Amostras semanais do efluente do reator UASB e do efluente das unidades do SAC foram avaliadas por um período de quatro anos de operação do sistema. Nas taxas de aplicação praticadas (média de 0,11 m3.m-2.d-1), o efluente final apresentou excelente qualidade em termos de matéria orgânica e sólidos suspensos, mas baixa capacidade de remoção de nitrogênio. Os valores médios de concentração no efluente das unidades plantadas e não plantadas foram, respectivamente, demanda bioquímica de oxigênio: 25 e 23 mg.L-1; demanda química de oxigênio: 50 e 55 mg.L-1; sólidos suspensos totais: 10 e 8 mg.L-1; nitrogênio Kjeldahl total: 30 e 31 mg.L-1; e nitrogênio amoniacal: 27 e 28 mg.L-1. Não se observou diferença significativa entre as concentrações efluentes das unidades plantada e não plantada para a maioria dos constituintes investigados.

ABSTRACT A system composed of an upflow anaerobic sludge blanket (UASB) reactor followed by two horizontal subsurface flow wetlands (50 inhabitants each) constructed in parallel was evaluated for the treatment of municipal wastewater generated in the city of Belo Horizonte, Minas Gerais, Brazil. One unit was planted with Typha latifolia, and the other one was not planted. Weekly samples of the effluent from the UASB reactor and the effluent from both wetland units were evaluated for a period of four years of the system's operation. With the applied loads (average of 0.11 m3.m-2.d-1), the final effluent showed excellent quality in terms of organic matter and suspended solids, but it showed low capacity for nitrogen removal. Mean concentration values in the effluent from the planted and unplanted units were, respectively, biochemical oxygen demand: 25 and 23 mg.L-1; chemical oxygen demand: 50 and 55 mg.L-1; total suspended solids: 10 and 8 mg.L-1; total Kjeldahl nitrogen: 30 and 31 mg.L-1; and N-ammonia: 27 and 28 mg.L-1. There was no significant difference between the effluent concentrations from the planted and unplanted units for most of the evaluated constituents.

Induced phytoremediation of metals from fly ash mediated by plant growth promoting rhizobacteria.

A study was carried out to observe the impact of a consortium of bacteria isolated from the fly ash on the metal accumulation by T. latifolia. When a consortium of bacteria Bacillus endophyticus NBRFT4 (MTCC 9021), Paenibacillus macerans NBRFT5 (MTCC 8912) and Bacillus pumilus NBRFT9 (MTCC 8913) was bioaugmented into the rhizosphere of T. latifolia, it enhanced the metal concentration in root, stem and leaves of the plants through increased bioavailability of metals Fe, Cd, Pb, Cr, Ni, Cu and Zn in the fly ash. Besides, these bacteria also promoted the plant growth perhaps due to utilization of ACC, synthesis of phytoharmones and solubilisation of essential metals found in fly ash. As compared to fly ash alone, the accumulation of Fe was maximally enhanced by 164%, 196%, and 251%, followed by Ni by 92%, 44% and 56%, Zn by 82%, 57% and 91%, Cu by 71%, 53% and 60%, Cr by 96%, 80% and 105 %, Pb by 119%, 87% and 140%, Cd by 80%, 109% and 115% in root, stem and leaves, respectively in fly ash with bacteria. Thus, an increased solubilisation of metals coupled with enhanced plant growth stimulated the phytoextraction of metals by T. latifolia from fly ash.