ABSTRACT Constructed wetland systems have been used to treat different wastewater; among their essential components are the cultivated plant species and type of substrate used to fill them. The choice of plant species and type of substrate are important for the good system performance in wastewater treatment. This study aimed to evaluate the extraction capacity of Napier and Tifton 85 grasses when cultivated at different positions in horizontal subsurface flow constructed wetlands (HSSF-CWs) filled with different substrates in wastewater treatment from a bulk milk-cooling tank (MTWW). The experimental unit consisted of four HSSF-CWs, in which an average surface organic loading rate of 318 kg ha−1 d−1 of BOD5,20 was imposed and a hydraulic holding time of 1.8 and 3.0 d, respectively, in units filled with gravel or crushed PET bottles. Tifton 85 grass presented the highest Na extraction capacity, with better results obtained in HSSF-CWs filled with crushed PET bottles, while Napier grass was more effective in extracting N, K, and P from MTWW. When cultivated in the second half of gravel-filled HSSF-CWs, both grasses provided higher average N extractions when compared to those filled with crushed PET bottles, which had higher extractions in the first half of HSSF-CWs.

ABSTRACT We aimed to evaluate the efficiency of six different horizontal subsurface flow constructed wetlands (HSSF-CWs), with different substrates (gravel and crushed PET bottles), which also varied in relation to the presence and arrangement of plant species (elephant grass and Tifton 85 bermudagrass) in the removal of pollutants from a bulk milk cooling tank (MTWW). Each bed was fed at a flow rate of 0.18 m3 d-1 and average organic load rate (OLR) of 318 kg ha-1 d-1 of BOD5, with hydraulic detention time (HRT) of 1.84 days in the gravel-filled HSSF-CWs (CWS-G) and 2.97 days in the PET-filled HSSF-CWs (CWs-P). The CWs-P were as efficient as the CWs-G in the removal of BOD5, COD, Total-P, and K-Total, being in some cases even more effective (turbidity, TS, TSS and Na). The gravel, on the other hand, provided greater removals of Total-N from the MTWW. In the non-cultivated CWs and those cultivated with elephant grass, in its first half and Tifton 85 grass in its second half, there were higher average efficiencies in COD and TSS removal sand, in the latter, the highest average removal of Total-N.

ABSTRACT This study aimed to characterize the material composition responsible for clogging the porous medium of horizontal subsurface flow constructed wetland (HSSF–CW) systems, which is detrimental to a proper system operation. Six completely clogged HSSF–CWs were used after treatment of swine wastewater. Operating conditions of these systems were named CW–C (HSSF– CW 1 and HSSF–CW 4, non-cultivated, i.e. controls), CW–T (HSSF–CW 2 and HSSF–CW 5, cultivated with Tifton 85 (Cynodon spp.)), and CW–A (HSSF–CW 3 and HSSF–CW 6, cultivated with alligator weed (Alternanthera philoxeroides)). The results showed that most of the clogging material was composed of total fixed solids (95, 84, and 82% in CW–C, CW–T, and CW–A, respectively). However, total volatile solids (TVS) mostly affected pore clogging. The larger accumulations and productions of TVS in CWs might have originated from dead plants.

ABSTRACT Many modifications in hydrodynamic conditions occur inside the bed of a horizontal subsurface flow constructed wetland (HSSF–CW) in operation. Studies on hydraulic conductivity measurement techniques in HSSF–CW are imperative since the monitoring of flow conditions is essential for understanding and controlling its clogging. This study aimed to assess the hydrodynamic behavior in HSSF–CW by means of saturated hydraulic conductivity (Ks) analysis. For this, six HSSF–CW were used: two non-cultivated (control), two cultivated with Tifton 85 (Cynodon spp.), and two cultivated with alligator weed (Alternanthera philoxeroides). Application of swine wastewater (SW) in HSSF–CW started on June 15, 2011, with Ks measurement period between September 9 and November 11, 2011, in which five measurements were performed in different positions along the system length and over experimental period in order to assess the effects of vegetation, position, and time factors on this variable. Ks values ranged from 1,392 to 2,834 m d−1. Plant presence led to Ks decreasing in the systems, but cultivated species had no influence on this variable. Monitoring time of HSSF–CW was no longer enough to provide a reduction in Ks, at 10% probability level.

ABSTRACT This study aimed to monitor degradation of compost from undigested sewage sludge disposed on soil surface or incorporated it. The sewage sludge was blended with wood sawdust during a 90-day composting to achieve a C/N ratio of 9. Each waste was dosed based on its total content of nitrogen and on an annual dose of 500 kg ha-1, which is broadly recommended for forage fertilization. After incorporation and surface applied (five replicates each), waste mineralization was monitored for 131 days by samplings taken from both conditions for further analyses. The samples were measured for total organic carbon (TOC); easily oxidizable carbon (OOC); total nitrogen (TN); ammonia and nitric nitrogen, and from them the total organic nitrogen (ON); volatile solids; and water content. The findings pointed to a decrease in TOC, OOC and ON contents throughout monitoring, regardless of disposal method, however, most remarkable whether incorporated to the soil, computing mineralization rates above 87%.

RESUMO A colmatação é um fenômeno intrínseco aos sistemas alagados construídos (SACs) utilizados no tratamento de esgotos, sendo decorrente dos mecanismos de remoção de poluentes. Dentre os métodos disponíveis para a avaliação da colmatação, destaca-se o uso de traçadores para a obtenção das condições hidrodinâmicas dos SACs. No entanto, não há um traçador ideal; os salinos, por exemplo, são passíveis de absorção, mecanismo influenciado pelo estádio no qual a planta se apresenta. Assim, objetivou-se, com a realização do trabalho, avaliar a utilização do NaCl para caracterização do grau de colmatação e das condições hidrodinâmicas de SACs de escoamento horizontal subsuperficial, plantado e não plantado, verificar a confiabilidade do uso desse traçador em testes executados durante o estádio de crescimento (após o corte da parte aérea) e o florescimento da taboa (Typha latifolia), além da suscetibilidade de causar danos às plantas. Os resultados indicaram que o NaCl pode ser utilizado para estudos de comparação do grau de colmatação de SACs, inclusive não apresentando danos à taboa. Verificou-se que, após sete anos de operação, a unidade plantada encontra-se mais colmatada e com regime de escoamento mais turbulento. Também foi possível inferir que o corte das plantas propiciou aumento na dispersão no sistema.

ABSTRACT Clogging is an intrinsic phenomenon of constructed wetland systems (CWs) used in sewage treatment, and resulting from pollutant removal mechanisms. Among clogging evaluation methods, tracers may be highlighted since they can used to determine CW hydrodynamic conditions. However, there is no ideal tracer; saline ones, for example, are able to be absorbed, which is influenced by plant stage. Thus, this study aimed to assess the use of NaCl to characterize the clogging degree and hydrodynamic conditions in subsurface horizontal flow constructed wetland, with or without cropping, as well as check this tracer reliability under tests during southern cattail (Typha latifolia) growth stage (after shoot cutting) and flourishing, as well as its ability to damage the plants. The results showed that NaCl could be used for studies comparing the degree of clogging of CWs, aside from presenting no damage to cattail. It was found that after seven years operating, cropped area is further clogged and has more turbulent flow. It was also possible to infer that plant cuttings led to increased dispersion within the system.

RESUMO Objetivou-se, com a realização deste trabalho, determinar a eficiência de aeração e a capacidade do sistema de aeração em cascata em remover matéria orgânica da água residuária do processamento dos frutos do cafeeiro (ARC). O sistema de aeração foi constituído por cascata com 4,14 m de altura, distribuída em 23 degraus (altura, largura e comprimento de 0,18; 0,32 e 0,60 m, respectivamente), reservatório para a recepção/detenção da ARC escoada, por três horas, e reservatório de distribuição, de onde era recirculada no sistema. Durante a fase experimental, o sistema de tratamento ficou em operação por trinta dias, sendo a ARC recirculada três vezes por dia, numa vazão constante de 1 L s-1, e substituída a cada dez dias. A cada recirculação, amostras do afluente e efluente foram coletadas e analisadas. Com a utilização do sistema de aeração em cascatas, foi possível incorporar, em média, 0,2 mg L-1 de oxigênio a cada lance de 1 m de degraus na cascata. A eficiência de aeração na cascata foi de 0,128 ou 0,141, dependendo se foi considerado ou não o efeito salino na ARC. A alta concentração de material orgânico não permitiu que se detectassem grandes alterações na concentração de oxigênio dissolvido na ARC. O tempo de detenção ideal da ARC no tanque de recepção/detenção foi de 26 min.

ABSTRACT This study aimed at assessing the efficiency of aeration and organic matter removal of a cascade aeration system treating wastewater derived from coffee fruit processing (CW). The system consisted of one 4.14-m cascade with 23 steps (height, width and length of 0.18, 0.32 and 0.60 m, respectively), one receiving tank to store CW for three hours and one distribution tank, from which it was recirculated through the system. The system remained operating for thirty days during which CW recirculated three times a day under a constant flow rate of 1 L s-1 and being replaced every ten days. In each recirculation cycle, samples of effluent and affluent were collected and analyzed. The cascade aeration system incorporated an average of 0.2 mg L-1 of oxygen every one meter of cascade steps. The aeration efficiency was 0.128 or 0.141 depending whether or not salt effect on CW was considered. The high concentration of organic material in CW hampered the detection of major changes in dissolved oxygen contents. We also found that 26 minutes was the ideal time to maintain CW in the receiving tank.

Propôs-se, neste trabalho, avaliar a influência de características físicas, químicas e mineralógicas de três solos oxídicos no potencial de sua sodificação. Nesta avaliação foram utilizadas amostras coletadas no horizonte B, de um Latossolo Vermelho-Amarelo, Latossolo Vermelho e um Argissolo Vermelho, que apresentavam, respectivamente, presença marcante dos minerais caulinita, hematita e gibbsita. As amostras foram caracterizadas em termos físicos, químicos e mineralógicos e, após seu acondicionamento em colunas de solo, submetidas à percolação de soluções com condutividade elétrica (CE) de 8,0 dS m-1 e relação de adsorção do sódio (RAS) de 0, 10, 20, 30, 40 e 50 (mmol c L-1)0,5, em três repetições. A porcentagem de sódio trocável (PST) e a relação de sódio trocável (RST) foram obtidas por cálculo a partir dos valores de concentração trocável de sódio nos solos. O aumento na RAS da solução de percolação proporcionou aumento nas RST e PST em todos os solos e foi influenciado pela mineralogia, grau de intemperismo e conteúdo de argila. Os solos analisados podem receber águas com RAS e CE altas sem sofrer sodificação expressiva.

This study investigated the influence of physical, chemical and mineralogical properties of three oxidic soils in their potential sodification. In this evaluation, samples collected in the B horizon of two Oxisol and a Ultisol were used, which presented, respectively, high presence of the mineral kaolinite, hematite and gibbsite. Samples were subjected to physical, chemical and mineralogical analysis and filled soil columns were submitted to leaching with solutions of electrical conductivity (CE) of 8.0 dS m-1 and sodium adsorption ratio (SAR) 0, 10, 20, 30, 40 and 50 (mmol L-1)0.5, in three replications. The exchangeable sodium percentage (ESP) and exchangeable sodium adsorption ratio (ESR) were obtained by calculation from the values of exchangeable sodium in the soil. The increase in the SAR of percolation solution provided an increase in the ESR and ESP of all soils and was influenced by the mineralogy, weathering degree and clay content of soil. The analysed soils can receive waters with high SAR and EC without suffering significant sodification.

Pesquisas sobre o efeito da temperatura e do tempo de incubação de amostras de águas residuárias, para estimativa da matéria orgânica biodegradável, por meio da demanda bioquímica de oxigênio (DBO), atualmente são raras, tendo em vista que têm sido aceitos, como padrão, os resultados obtidos no trabalho clássico de STREETER & PHELPS (1925). Entretanto, ainda permanecem questionamentos, como se seria possível reduzir o tempo de incubação; se o valor do coeficiente de temperatura (θ) varia com a temperatura e com o tipo de água residuária e se aproxima de 1,047. Com o objetivo de elucidar tais questões, foram incubadas amostras de águas residuárias de laticínios, suinocultura e esgotos sanitários tratados em fossa séptica, sob as temperaturas de 20; 30 e 35 ºC, respectivamente, por 5; 3,16 e 2,5 dias. A partir do parâmetro coeficiente de desoxigenação a 20 ºC (k20), foram calculados θ30 e θ35. Os resultados indicaram que o valor de θ muda com o tipo de água residuária, embora não varie na faixa de temperatura entre 30 e 35 ºC, e que o emprego do valor de 1,047 não implicou diferenças significativas na obtenção de k para uma determinada temperatura T. Assim, observa-se que esse valor de θ pode ser empregado caso se queira estimar o tempo necessário de incubação das amostras em diferentes temperaturas.

Studies on the effects of temperature and time of incubation of wastewater samples for the estimation of biodegradable organic matter through the biochemical oxygen demand (BOD), that nowadays are rare, considering that the results of the classic study of STREETER & PHELPS(1925) have been accepted as standard. However, there are still questions how could be possible to reduce the incubation time; whether the coefficient of temperature (θ) varies with the temperature and with the type of wastewater and if it approaches 1.047. Aiming the elucidation of these questions, wastewater samples of dairy, swine and sewage treated in septic tanks were incubated at temperatures of 20, 30 and 35 °C, respectively for 5, 3.16 and 2.5 days. From the parameter of deoxygenation coefficient at 20 °C (k20), θ30 and θ35 were calculated. The results indicated that θ values changes with the type of wastewater, however does not vary in the temperature range between 30 and 35 °C, and that the use of 1.047 value did not implied significant differences in obtaining k in a determined T temperature. Thus, it is observed that the value of θ can be used to estimate the required incubation time of the samples at different temperatures.

Objetivou-se, neste trabalho, avaliar a capacidade extratora de duas espécies vegetais quando cultivadas em sistemas alagados construídos (SAC) utilizados no tratamento de águas residuárias de laticínios (ARL). As unidades experimentais foram constituídas por cinco SAC cultivados com capim elefante (Pennisetum purpureum schum) e cinco SAC cultivados com capim tifton 85 (Cynodon spp.), com escoamento subsuperficial horizontal. A ARL foi aplicada numa vazão média de 60 L d-1 e tempo de residência hidráulica de 4,8 dias, sendo os SAC submetidos a Taxas de Carregamento Orgânico (TCO) de 66, 130, 190, 320 e 570 kg ha-1 d-1 de DBO. O capim tifton 85 extraiu mais nitrogênio e sódio enquanto o capim elefante extraiu maior quantidade de potássio da ARL, quando cultivado sob as taxas de carregamento orgânico (TCO) avaliadas. A concentração de fósforo na parte aérea e a capacidade extratora foram semelhantes nos dois capins; entretanto, existem evidências de aumento na capacidade de extração desse nutriente pelo capim tifton 85, com o aumento da TCO aplicada nos SAC.

The objective of this research was to evaluate the extraction capacity of two plant species when grown in constructed wetland systems (CWS) used for dairy wastewater (DW) treatment. The experimental units were formed by five CWS grown with Pennisetum purpureum schum grass and five CWS cultivated with grass tifton 85 (Cynodon spp.), with horizontal subsurface flow. The DW was applied at an average flow of 60 L d-1 and hydraulic residence time of 4.8 days, and subjected to organic loading rates (ORL) of 66, 130, 190, 320 and 570 kg ha-1 d-1 of BOD. The grass tifton 85 extracted more nitrogen and sodium, while the elephant grass extracted a larger amount of potassium from the DW, when grown under the evaluated organic loading rates (ORL). The concentration of phosphorus in aerial parts of plants and extraction capacity were similar in the two grasses, however, there is evidence of an increase in the extraction this nutrient, by the grass tifton 85, with the increase of the ORL applied in the CWS.

Seis sistemas de tratamento, compostos por três filtros anaeróbios com escoamento descendente, seguidos por seis Sistemas Alagados Construídos (SACs), tiveram suas condições operacionais avaliadas quando utilizados no tratamento da água residuária do processamento dos frutos do cafeeiro (ARC). Os filtros foram confeccionados em PVC (1,5 m de altura e 0,35 m de diâmetro) e preenchidos com brita nº 2. Os SACs foram constituídos por caixas de madeira (1,5 m de comprimento, 0,4 m de altura e 0,5 m de largura), sendo impermeabilizados e preenchidos com brita "zero". A ARC teve o pH corrigido com cal até valores próximos a 7,0, e a concentração de nutrientes alterada, de forma a se obter uma relação DBO/N/P de 100/5/1. Em metade dos SACs foi plantado o azevém (Lolium multiflorum Lam.), e na outra metade, aveia-preta (Avena strigosa Schreb). Como resultado, observou-se que as espécies vegetais cultivadas nos SACs não influenciaram nas eficiências globais de remoção de poluentes pelos sistemas. Os sistemas que receberam as menores cargas orgânicas apresentaram as maiores eficiências de remoção de matéria orgânica, alcançando 78% para DQO e 70% para DBO. A remoção de SST foi superior a 70% em todos os sistemas avaliados, indicando a viabilidade da aplicação de filtro anaeróbio seguido por SACs no tratamento da ARC.

Six treatment systems, composed of three downflow anaerobic filters followed by six Constructed Wetlands (SACs), had their operating conditions evaluated when used in the treatment of wastewater from coffee fruit processing (ARC). The filters were made of PVC (1.5 m high and 0.35 m in diameter) and filled with n. 2 crushed stone. SACs were constructed of wood boxes (1.5 m long, 0.4 m high and 0.5 m wide) being sealed with an HDPE geomembrane and filled with "zero" crushed stone. The pH of the ARC was corrected with lime to values near 7.0 and nutrient concentration altered in order to obtain a BOD/N/P ratio equal to 500/5/1. In half of the SACs was planted ryegrass (Lolium multiflorum Lam.) and in the other half oat (Avena strigosa Schreb). As a result, it was observed that the plant species grown in the SACs didn't affect the overall efficiencies of pollutant removal by the systems. The systems that received the lowest organic loading showed the highest efficiencies of removal of organic matter, reaching 78% for COD and 70% for BOD and the removal of TSS was higher than 70% in all systems studied, indicating the feasibility of applying anaerobic filter system followed by constructed wetland system in ARC treatment.

Seis sistemas de tratamento foram compostos por três filtros anaeróbios com escoamento descendente, seguidos por seis sistemas alagados construídos (SACs), sendo avaliados, sob o ponto de vista operacional, no tratamento da água residuária do processamento dos frutos do cafeeiro (ARC). Os filtros foram confeccionados em PVC (1,5 m de altura e 0,35 m de diâmetro) e preenchidos com brita nº 2 e os SACs foram constituídos por caixas de madeira (1,5 m de comprimento, 0,4 m de altura e 0,5 m de largura), sendo impermeabilizados e preenchidos com brita "zero". A ARC teve o pH corrigido com cal até valores próximos a 7,0, e a concentração de nutrientes alterada, com a adição de fertilizantes, de forma a se obter uma relação DBO/N/P igual a 100/5/1. Em metade dos SACs, foi plantado o azevém (Lolium multiflorum Lam.), e na outra metade, aveia-preta (Avena strigosa Schreb). Como resultado, observou-se que as espécies vegetais cultivadas nos SACs influenciaram nas eficiências de remoção de fósforo pelos sistemas (SAC3 e SAC4; SAC5 e SAC6). Os sistemas que receberam as menores cargas de nutrientes e compostos fenólicos, via ARC, apresentaram as maiores eficiências de remoção destas variáveis, tendo sido alcançadas remoções de 40% do N T e 50% do P T. A remoção de compostos fenólicos totais foi superior a 65% na maior parte dos sistemas. Desta forma, considera-se ser viável a aplicação de filtros anaeróbios seguidos por sistemas alagados construídos no tratamento da ARC.

Six treatment systems composed of three anaerobic filters with downflow followed by six constructed wetlands (SACs) have been operationally evaluated in the treatment of wastewater from coffee fruit processing (ARC). The filters were made of PVC (1.5 m high and 0.35 m in diameter) and filled with n. 2 crushed stone. SACs were constructed of wood boxes (1.5 m long, 0.4 m high and 0.5 m wide) being sealed with an HDPE geomembrane and filled with "zero" crushed stone. The ARC had the pH adjusted with lime to values close to 7.0 and concentration of nutrients modified to have a relationship BOD/N/P equal to 100/5/1. In half of the SACs was planted ryegrass (Lolium multiflorum Lam.) and in the other half oat (Avena strigosa Schreb). As a result, it was observed that the plant species grown in the SACs have influenced the removal efficiencies of phosphorus by the systems (SAC3 e SAC4; SAC5 e SAC6). The systems that received the lowest loads of nutrients and phenolic compounds showed the highest removal efficiencies, reaching 40% for N T and 50% for P T. The removal of total phenolic compounds was higher than 65% in most systems. Thus, it is considered to be feasible the application of anaerobic filter system followed by constructed wetland system for the treatment of ARC.

Duas gramíneas forrageiras de inverno, azevém (Lolium multiflorum) e aveia preta (Avena strigosa Schreb), foram cultivadas em sistemas alagados construídos (SACs) utilizados no tratamento das águas residuárias do processamento dos frutos do cafeeiro (ARC) com o objetivo de se avaliar seu desempenho agronômico. Essas forrageiras foram submetidas a diferentes cargas orgânicas (650 a 1.500 kg ha-1 d-1 de DQO), proporcionadas pela aplicação dos efluentes de filtros anaeróbios, utilizados no tratamento da ARC. Como tratamento testemunha, as mesmas espécies vegetais foram cultivadas em solução de Hoagland. A matéria seca produzida pelas forrageiras ao longo dos 53 dias de monitoramento dos SACs variou de 7,4 a 14,0 e 0,5 a 2,7 t ha-1, e os rendimentos acumulados de proteína bruta variaram de 1.017 a 2.187 e 66,6 a 316,8 kg ha-1 para o azevém e a aveia, respectivamente. Os resultados permitiram concluir que, dentre as forrageiras estudadas, o azevém se mostrou mais adequado para ser cultivado em SACs utilizados no pós-tratamento da ARC efluente de filtros anaeróbios, já que apresentou maior rendimento de matéria seca e proteína bruta e, portanto, melhor adaptação ao sistema.

Two winter grasses, ryegrass (Lolium multiflorum) and oats (Avena strigosa Schreb), were grown in constructed wetlands (SACs) used in the treatment of wastewater of coffee processing (ARC) with the aim to evaluate their agronomic performance. These forage crops were submitted to different organic loads (650 to 1500 kg ha-1 d-1 of COD), offered by the application of anaerobic effluent filters, used in the treatment of ARC. As a control treatment, the same plant species were grown in a Hoagland solution. The forage dry matter produced by over 53 days of monitoring SACs ranged from 7.4 to 14.0 and from 0.5 to 2.7 t ha-1, and the crude protein yield ranged from 1017 to 2187 and 66.6 to 316.8 kg ha-1 for ryegrass and oats, respectively. The results showed that, among the forages studied, the ryegrass was more suitable to be grown in SACs used in the post-treatment of ARC anaerobic effluent filters, presenting higher dry matter yield and crude protein, and therefore better adaptation to the system.