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Against the growing world demand for food and the possibility of recovering some nutrients, this work focused on the evaluation of the use of Bioclastic Granules (BG) from the algae Lithothamnium calcareum as sorbent material for the removal/recovery of phosphorus from aqueous solutions. The main variables that affect the sorption process, pH, initial concentration of phosphate, and GB, as well as the contact time, were evaluated. The effect of pH was very significant, obtaining the best results of PO43- removal at pH 5. In the coarser granulometric fractions (+ 106 - 150 and + 210 - 300 µm), the best removals were observed (around 75%). Regarding the initial PO43- concentration in the solutions, the highest removal (in the range of 74 to 78%) was observed in the lowest concentrations (5 to 70 mg L-1) and the best uptake (10 to 14 mg g-1) at higher concentrations (200 to 420 mg L-1). The PO43- sorption data fitted the Freundlich model well, with kF of 1.35 L mg-1 and n of 2.43. A qmax of 14.35 mg g-1 was obtained using the Langmuir model. Regarding the sorption data over time, a better fit to the pseudo-first-order kinetic model was observed, obtaining a calculated qeq of 6.56 mg g-1 and a k1 of 0.0073 min-1. The incorporation of PO43- ions in the GB structure was confirmed through the characterization results before and after the sorption experiments using X-ray fluorescence (FRX) and scanning electron microscopy (SEM) techniques.

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The objectives of the present study were to characterize and evaluate a pilot treatment unit (PTU) for dairy cattle wastewater (DCW) in relation to its efficiency in reducing the physicochemical and microbiological parameters and possible application of this fertilizer in organic production. A PTU was set up, composed of the following elements: a dung pit of 7.8 m3, already in place; a septic tank; a set of anaerobic biological filters comprising an upflow filter and a downward-flow filter filled with fragments PVC corrugated conduit; and two constructed wetland systems (CWSs) of horizontal subsurface flow in two parallel routes (Routes 1 and 2), controlled by means of a flow rate divider box. Route 1 passed through CWS 1 cultivated with cattail (Typha domingensis) and Route 2 passed through CWS 2 cultivated with vetiver grass (Chrysopogon zizanioides). To evaluate the treatment stages, biweekly investigations were carried out to collect effluent samples. The results of monitoring, in absolute values, were evaluated by means of the medians and variation coefficients and compared by means of Kruskal-Wallis non-parametric test followed by the Student Newman Keuls test. The treatment efficiencies of Routes 1 and 2 were calculated. The influence of vetiver on the removal of nutrients from the DCW was analyzed and the productivity estimate (t.ha-1) was performed. CWS 1 was not able to reduce the organic load indices, but it was able to retain fatty material and sodium. CWS 2 showed a reduction in nitrogenous forms and also for other nutrients, achieving the greatest removal of sodium and greatest decay of fecal contamination indicators, thermotolerant coliforms (56.13%), and E. coli (46.82%).

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RESUMO Neste trabalho, são apresentados os resultados do desempenho de dois sistemas de tratamento combinado de lixiviado de aterros sanitários e lodos de fossas. Na escala de laboratório, empregou-se um geobag de pequenas dimensões e um filtro biológico de percolação a jusante dele. Na escala real, investigou-se o desempenho de uma unidade de tratamento constituída de geobag seguido de lagoas de estabilização e wetland. Em ambos os estudos, empregou-se relação volumétrica de 4:1 (lodo de fossa:lixiviado) e adicionou-se floculante à mistura antes de sua alimentação no geobag. As remoções obtidas na unidade de campo foram superiores às alcançadas em laboratório para os parâmetros carbono orgânico dissolvido (COD) e sólidos em suspensão totais, cujas remoções foram superiores a 50 e a 95%, respectivamente. A remoção de nitrogênio amoniacal, entretanto, foi maior na instalação de bancada (68%). O desempenho desses sistemas de tratamento com relação à toxicidade para os organismos-teste Aliivibriofischeri, Daphniasimillis e Daniorerio também foi investigado.

ABSTRACT This paper presents the performance results of two combined landfill leachate and sewage sludge treatment systems. In the laboratory scale, a small geobag was followed by a trickling filter. In the real scale, the performance of a geobag treatment unit followed by stabilization and wetland lagoons was investigated. In both studies, a 4:1 volumetric ratio (pit sludge: leachate) was employed and flocculant was added to the mixture prior to feeding in the geobag. The field unit removals were higher than those obtained in the laboratory for the following parameters: dissolved organic carbon and suspended solids, whose removals were greater than 50 and 95%, respectively. Ammonium nitrogen was removed at higher percentages in the lab-scale unit (68%). The performance of both treatment units regarding toxicity to Aliivibriofischeri, Daphnia simillis and Danio rerio organisms was also investigated.

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RESUMO Misturas diferentes de lixiviado de aterro sanitário e esgoto doméstico foram aplicadas em 16 reatores em batelada usando o processo PACT® (lodos ativados com adição de carvão ativado em pó - CAP). O objetivo do trabalho foi representar a remoção de cor utilizando dois ajustes matemáticos: o primeiro combinou as variáveis concentração de CAP (0 a 6 g.L-1) e mistura lixiviado/esgoto (0 a 10%, em volume); e o segundo, a concentração de CAP e a cor da mistura (276 a 1.199 uH). A metodologia de superfície de resposta (MSR) foi escolhida para representar a resposta dos ajustes. Os resultados indicaram que, conforme a concentração de lixiviado aumentou até 5%, a adição de CAP resultou em um maior percentual de remoção de cor. No entanto, para a mistura com 10% de lixiviado, os reatores perderam eficácia, com exceção do reator com 6 g.L-1 de CAP, que apresentou os melhores resultados de remoção de cor.

ABSTRACT Sixteen batch reactors fed with different mixtures of landfill leachate combined with synthetic wastewater were treated using the PACT® process (activated sludge process plus powdered activated carbon addition - PAC). The objective was to measure the color removal using two mathematical adjustments: the first adjustment combined the variables PAC concentration (0 to 6 g.L-1) and landfill leachate concentration in the wastewater (0 to 10%, in volume); and the second model combined PAC concentration and the influent color (276 to 1,199 uH). The response surface methodology was used to describe the response of both adjustments. The results indicated that as the proportion of leachate was increased up to 5%, higher PAC concentrations resulted in a better color removal in the reactors. When the leachate proportion was 10%, the reactors were less efficacious, except for the one with 6 g.L-1, which presented the highest color removal within the experiment.

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The experiments performed in this study consisted of 16 batch reactors fed different mixtures of landfill leachate combined with synthetic wastewater treated using the Powdered Activated Carbon Treatment (PACT) process. The objective was to measure the COD mass removal per liter each day for each reactor using two models: the first model combined the variables PAC concentration (0 g·L(-1), 2 g·L(-1), 4 g·L(-1), and 6 g·L(-1)) and leachate rate in the wastewater (0%, 2%, 5%, and 10%), and the second model combined the PAC concentration and the influent COD. The Response Surface Methodology with Central Composite Design was used to describe the response surface of both models considered in this study. Domestic wastewater was produced under controlled conditions in the laboratory where the experiments were performed. The results indicated that the PAC effect was null when the influent did not contain leachate; however, as the concentration of leachate applied to the mixture was increased, the addition of a higher PAC concentration resulted in a better COD mass removal in the reactors. The adjusted R(2) values of the two models were greater than 0.95, and the predicted R(2) values were greater than 0.93. The models may be useful for wastewater treatment companies to calculate PAC requirements in order to meet COD mass removal objectives in combined treatment.

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Inegavelmente os custos e a complexidade de alguns dos principais processos de tratamento de esgotos sanitários dificultam sua aplicação, de forma mais efetiva, nas diversas localidades do território nacional. A Pesquisa Nacional do Saneamento Básico, publicada em 2002 pelo IBGE – Instituto Brasileiro de Geografia e Estatística, aponta para um percentual ínfimo de distritos que contam com algum tipo de tratamento de seus esgotos. Tem-se, ainda, que 91 por cento dos municípios brasileiros possuem população menor que 50.000 habitantes. Esta condição claramente pressupõe uma maior dificuldade da municipalidade dispor de recursos financeiros e corpo técnico qualificado para instalar e operar estações de tratamento de esgotos. Nesse sentido, este trabalho pretende contribuir para a pesquisa e o desenvolvimento de tecnologias simplificadas e de baixo custo para tratamento de esgotos sanitários. O sistema em estudo é a associação de um Reator Anaeróbio de Manta de Lodo e Fluxo Ascendente a um Filtro Biológico, cujo meio suporte é proveniente do refugo de uma indústria de embalagens plásticas, produto alternativo e de elevada disponibilidade na região do estudo. Para a realização dos estudos foi montado um modelo reduzido do sistema proposto, que foi monitorado para avaliação de sua eficiência, com o objetivo de que o sistema viesse a ser uma alternativa de baixo custo capaz de atender a padrões restritivos de lançamento de efluentes. Foram comparados sistemas com e sem recirculação de lodo, verificando-se a influência dessa recirculação sobre o tratamento. Embora o modelo não tenha, durante a fase experimental, respondido da forma esperada, a literatura técnica mostra que a solução anaeróbia-aeróbia, de modo geral, produz um efluente de qualidade compatível com as normas ambientais, devendo-se realizar novos estudos com vistas ao fortalecimento do sistema estudado como alternativa viável de tratamento de esgotos mesmo para legislações mais exigentes.

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