ELETROOXIDAÇÃO NO TRATAMENTO DE EFLUENTES DE LAVANDERIA HOSPITALAR

No presente estudo foram realizados ensaios de tratamento utilizando os processos oxidativos avançados (POA’s) visando a mineralização e a detoxificação dos efluentes gerados em uma lavanderia hospitalar. Os ensaios envolveram a utilização do processo de eletrooxidação. Foram realizadas análises dos parâmetros globais e análises toxicológicas, antes e após cada ensaio. Desta forma buscou-se avaliar a eficiência dos métodos empregados na redução dos parâmetros globais, e na detoxificação dos efluentes da lavanderia hospitalar em questão. Os ensaios envolvendo o processo de eletrooxidação com condutividade induzida através da adição de NaCl realizados durante 60 minutos obtiveram os melhores desempenhos. O efluente gerado no enxágüe inicial das compressas passou da condição de extremamente tóxico (12,58%) para moderadamente tóxico (61,59%), enquanto que as reduções de DBO5 e DQO foram de respectivamente, 32% e 9%. Com relação ao efluente oriundo da etapa da lavagem, a DQO apresentou uma redução de 41%, enquanto que a toxicidade foi reduzida consideravelmente, passando da condição de extremamente tóxico (6,89%) para pouco tóxico (76,65%

REATOR ANAERÓBIO/BIOFILTRO ANAERÓBIO (RA/BFA) + WETLAND CONSTRUÍDO DE FLUXO VERTICAL DE SUPORTE SATURADO (WCFV-SS) NO TRATAMENTO DE EFLUENTE URBANO

The integrated RA/BFA + WCFV-FS system is one of the proposals that integrate the so-called nature-based solutions (SBN) for basic sanitation. In this work, this system was monitored for 5 months, considering the first half of 2022, with the wetland constructed from vertical flow with saturated bottom (WCFV-FS) with the macrophytes Hymenachne grumosa (Nees) Zuloaga, Canna indica and Helicônia velloziana, useful volume from approx. 450 L, pulse feeding of 70 L for 5 min, adding 4 pulses a day at 6-hour intervals. The system support was 70 cm high of gravel 1 (30 cm) and 2 (30 cm) and 10 cm of pebbles.The loading factors were a maximum of 18.66 g of BOD5 m-2 day-1 and 2.7 g of N-NH4+ m-2 day-1. The samples had weekly characterization of the parameters dissolved oxygen, total dissolved solids (TDS), conductivity, turbidity, N-NH4+, pH, BOD5 and apparent color at 420 nm. The reductions were between 50-75% of the eutrophicant and dissolved oxygen depressant parameters, with the treatment system having an operating time of 5 years.O sistema integrado RA/BFA + WCFV-SS se configura como uma das propostas que integram as chamadas soluções baseadas na natureza (SBN) para o saneamento básico. Neste trabalho a unidade estudada foi monitorada durante 5 meses, considerando o primeiro semestre de 2022, tendo o wetland construído de fluxo vertical com fundo saturado (WCFV-FS) com as macrófitas Hymenachne grumosa (Nees) Zuloaga, Canna índica e Helicônia velloziana, volume útil de aprox. 450 L, alimentação por pulsos de 70 L durante 5 min, somando 4 pulsos ao dia em intervalos de 6h.  O suporte do sistema foi com 70 cm de altura de britas 1 (30 cm) e 2 (30 cm) e 10 cm de seixos. Os fatores de carga foram no máximo de 18,66 g de DBO5 m-2 dia-1 e de 2,7 g de N-NH4+ m-2 dia-1. As amostras tiveram caracterização semanal dos parâmetros oxigênio dissolvido, sólidos totais dissolvidos (STD), condutividade, turbidez, N-NH4+, pH, DBO5 e Cor aparente em 420 nm. As reduções foram entre 50-75 % dos parâmetros eutrofizante e depressor de oxigênio dissolvido, tendo o sistema de tratamento tempo de operação de 5 anos

Floating treatment wetlands in domestic wastewater treatment as a decentralized sanitation alternative

Floating treatment wetlands (FTW) are technologies that have stood out for their efficiency, ease of installation and maintenance. They consist of macrophytes emerging in a floating structure that keep the plant roots in direct contact with the effluent regardless of the water flow variation over time, allowing the removal of pollutants by various processes. The application of FTWs for the treatment of domestic wastewater has the advantage of low costs in terms of removing nutrients and at the same time reducing the cost of maintenance and energy consumption when compared to the conventional centralized treatment of effluent. The lack of wastewater treatment in areas distant from urban centers is even more limited, mainly due to the high cost of tubing and pumps for the effluent to reach the treatment plants. Therefore, the objective of this study was to research FTW systems applied to the decentralized treatment of domestic wastewater. First, a bibliometric analysis was conducted comparing the main issues involving FTW, and the challenges regarding the integration of FTW and domestic wastewater treatment systems. The feasibility of the floating system as a decentralized treatment approach were discussed, as well as the removal of nutrients in domestic wastewater, which was the most covered topic by researchers who developed studies in the area. In addition, other technologies are being integrated into the phytoremediation systems seeking to improve the quality of the treated effluent and assessing the potential reuse in the homes where they are generated and treated, determining the costs and space requirements for the entire process. There is a large research gap regarding the treatment of domestic wastewater by FTW in decentralized systems, mainly in terms of operation, cost assessment and reuse Therefore, further investigations in order to better understand the performance of the process and the reactions that occur with physical, chemical and microbiological removal mechanisms are still necessary

Hybrid constructed wetlands integrated with microbial fuel cells and reactive bed filter for wastewater treatment and bioelectricity generation

The present study aimed to develop a pilot-scale integrated system composed of anaerobic biofilter (AF), a floating treatment wetland (FTW) unit, and a vertical flow constructed wetland coupled with a microbial fuel cell (CW-MFC) and a reactive bed filter (RBF) for simultaneously decentralized urban wastewater treatment and bioelectricity generation. The first treatment stage (AF) had 1450 L and two compartments: a settler and a second one filled with plastic conduits. The two CWs (1000 L each) were vegetated with mixed plant species, the first supported in a buoyant expanded polyethylene foam and the second (CW-MFC) filled with pebbles and gravel, whereas the RBF unit was filled with P adsorbent material (light expanded clay aggregate, or LECA) and sand. In the CW-MFC units, 4 pairs of electrode chambers were placed in different spacing. First, both cathode and anode electrodes were composed of graphite sticks and monitored as open circuit. Later, the cathode electrodes were replaced by granular activated carbon (GAC) and monitored as open and closed circuits. The combined system efficiently reduced COD (> 64.65%), BOD₅(81.95%), N-NH₃(93.17%), TP (86.93%), turbidity (94.3%), and total coliforms (removal of three log units). Concerning bioenergy, highest voltage values were obtained with GAC electrodes, reaching up to 557 mV (open circuit) and considerably lower voltage outputs with closed circuit (23.1 mV). Maximum power densities were obtained with 20 cm (0.325 mW/m²) and 30 cm (0.251 mW/m2). Besides the electrode superficial areas, the HRT and the water level may have influenced the voltage values, impacting DO and COD concentrations in the wastewater