Abstract (Introduction): The search for techniques and methods for managing sludge generated during wastewater treatment is necessary to ensure sustainable sanitation in the medium term in Latin America. An interesting approach involves converting sludge into a biosolid usable in agriculture through alkaline sanitization. (Objective): We evaluated this technique’s efficacy and economic and environmental viability for obtaining an agriculturally usable type A biosolid from municipal wastewater treatment plant (WWTP) sludge. (Methodology): To this end, the efficacy in reducing microbiological parameters was experimentally tested at the laboratory scale using quicklime, for anaerobic and aerobic WWTP sludge. The experimental results fed a benefit/cost analysis model and a life cycle assessment. (Results): It was confirmed that applying a 40 % lime dose allowed the obtention of a type A biosolid with non-detectable concentrations of pathogenic microorganisms, which remained in that condition for more than 30 days. Additionally, the benefit/cost and life cycle analyses concluded that this option would be more attractive than sludge disposal in a landfill, due to the corresponding savings in chemical compounds (fertilizers, agricultural lime). (Conclusions): Therefore, alkaline sanitization can be considered suitable for WWTP sludge management. Its application on a larger scale should be further investigated in the country and the Latin-American region, considering the risk associated to the presence of heavy metals too.

Resumen (Introducción): La búsqueda de técnicas y modelos de gestión del lodo generado durante el tratamiento de las aguas residuales es necesaria para garantizar un saneamiento sostenible a mediano plazo en América Latina. Una vía interesante consiste en convertir el lodo en un biosólido aprovechable en la agricultura por medio de la higienización alcalina. (Objetivo): Se evaluó la eficacia y la viabilidad económica y ambiental de esta técnica para la obtención de un biosólido tipo A aprovechable en la agricultura a partir de lodo de planta de tratamiento de aguas residuales (PTAR) ordinaria. (Metodología): Para ello se probó experimentalmente en escala de laboratorio la eficacia en el decaimiento de parámetros microbiológicos higienizados con cal viva, usando lodo anaeróbico y aeróbico de PTAR. Los resultados experimentales alimentaron un modelo de análisis de beneficio/costo y de ciclo de vida. (Resultados): Pudo corroborarse que la aplicación de dosis de cal de 40 % permitió obtener un biosólido tipo A con concentraciones de microorganismos patógenos no detectables, lo cual se mantuvo en esa condición por más de 30 días. Además, el análisis de beneficio/costo y de ciclo de vida permitieron concluir que esta opción sería más atractiva que la disposición del lodo en un relleno sanitario, debido al ahorro correspondiente en compuestos químicos (fertilizantes o cal agrícola) derivado de su aprovechamiento. (Conclusiones): Por lo tanto, la técnica de higienización alcalina puede considerarse como adecuada para la gestión del lodo de PTAR y su aplicación a mayor escala debe investigarse en mayor detalle en el país y la región latinoamericana, considerando también el riesgo de presencia de metales pesados en este subproducto.

EFFECT OF LIQUID SWINE WASTEWATER DOSES ON PHYSICAL, CHEMICAL AND ELECTROCHEMICAL ATTRIBUTES IN A CERRADO OXISOL. The addition of organic residues enhances soil and plant organic matter and nutrient content. To gauge the impact of varying liquid swine waste (LSW) levels on soil, we studied changes in a clayey Oxisol’s physical, chemical, and electrochemical traits from the Cerrado. LSW doses (0, 50, 150, 450, 600 m3 ha−1) were applied to the 0-0.20 m layer in a randomized design with three replicates. Post a 30-day incubation at 60% field capacity, the soil underwent mineralogical, physical (clay dispersed in water - CDW), chemical (sodium adsorption ratio - SAR, cation exchange capacity - CEC, base saturation - V%), and electrochemical (pH in H2O and KCl, ApH, point of zero charge - PZC, point of zero salt effect - PZSE, surface electric potential - iµo, and electrical conductivity - EC) analyses. The levels of exchangeable Ca, K, Mg, Na, and available P increased with increasing LSW doses. Increasing LSW doses in the soil led to an increase in EC, but soil salinization was not observed at the highest dose. With the application of LSW doses, there was a decrease in pH, ApH, PZSE, and an increase in CEC, PZC and ψo. Despite the increase in ψo, low clay dispersibility was observed. PHYSICAL OXISOL content (LSW Oxisols Oxisol s Cerrado 0, 0 (0 50 150 450 60 ha−1 ha1 ha 1 00.20 0020 0.20 20 0-0.2 replicates 30day day 30 mineralogical CDW, CDW , CDW) sodium SAR CEC V%, V V% V%) pH HO H O KCl ApH PZSE iµo EC analyses Ca K Mg Na dose ψo ( 5 15 45 6 ha− 00 00.2 002 020 0.2 2 0-0. 3 4 00. 02 0. 0-0 0-

Bisphenol A (BPA), an endocrine disruptor used in different commercial polymers, is a persistent pollutant commonly found in effluents. Conventional wastewater treatment processes have low chemical removal efficiency and are expensive. This work evaluated BPA removal using laccase enzyme produced from white rot fungus Pleurotus ostreatus. For the enzymatic production, residues of acai berry and pineapple were used as laccase inducers. The use of natural inducers led to a high enzyme production (1139 and 1031 U mL−1 to acai and pineapple, respectively). Bisphenol A was removed to a concentration lower than LOD (limit of detection) after 4 h. The degradation mechanism of BPA occurred by oxidation of methyl to hydroxymethyl group in a propane portion, with breakdown of the aromatic ring. The developed technology brought to the scene a new green, viable methodology, using vegetable waste, adding value to these residues and bringing an alternative to the BPA treatment. BPA, , (BPA) polymers effluents expensive ostreatus 1139 (113 103 mL1 mL 1 mL− respectively. respectively . respectively) limit detection h portion ring green methodology waste (BPA 113 (11 10 11 (1 (

RESUMO A estruvita (NH4MgPO4∙6H2O) é um fertilizante de liberação lenta obtido através da recuperação de fósforo e/ou nitrogênio de águas residuais geralmente pela adição de sais de magnésio. Neste sentido, objetivou-se avaliar a viabilidade da substituição de fontes comerciais de magnésio por fontes alternativas no processo de precipitação de estruvita, em termos de remoção de amônio e fosfato, e quantificação e caracterização do cristal precipitado. Os experimentos foram conduzidos em escala de bancada sob delineamento inteiramente casualizado a pH 9,5 através da precipitação de uma solução de efluente sintético com quatro diferentes fontes de magnésio: MgCl2∙6H2O, MgSO4∙7H2O, MgO e magnesita (MgCO3). Após pré-acidificação, soluções derivadas de fontes alternativas de baixo custo de magnésio removeram acima de 55 e 90% de nitrogênio amoniacal e fosfato em solução, respectivamente, e alcançaram por volta de 10 g L-1 de cristais precipitados. A proximidade dos resultados obtidos com soluções derivadas de fontes comerciais de magnésio (46ꟷ56% de remoção de nitrogênio amoniacal, 97% de remoção de fosfato, e mais de 6 g L-1 de precipitado formado) indicou que reagentes alternativos puderam facilmente substituir os comerciais se submetidos ao prévio processo de digestão, a fim de tornar o magnésio disponível em solução. A análise qualitativa por difratometria de raios-X confirmou a presença de estruvita e newberyita na maioria dos precipitados. NH4MgPO4∙6H2O NH4MgPO46H2O NHMgPOHO NH4MgPO4 6H2O NH MgPO H O (NH4MgPO4∙6H2O eou ou sentido objetivouse objetivou 95 9 5 9, MgCl26H2O MgClHO MgCl2 MgCl MgCl2∙6H2O MgSO47H2O MgSOHO MgSO4 7H2O MgSO MgSO4∙7H2O MgCO3. MgCO3 MgCO . (MgCO3) préacidificação, préacidificação pré acidificação, acidificação pré-acidificação 90 respectivamente 1 L1 L L- precipitados 46ꟷ56% 46ꟷ56 ꟷ (46ꟷ56 97 formado digestão raiosX raios X NHMgPO NH4MgPO HO (MgCO3 46ꟷ5 (46ꟷ5 (MgCO 46ꟷ (46ꟷ

ABSTRACT Struvite (NH4MgPO4∙6H2O) is a slow-release fertilizer obtained through phosphorus and/or nitrogen recovery from wastewaters, usually by adding magnesium salts. In this sense, the aim was to evaluate the viability of replacing commercial magnesium sources with alternative ones in the struvite precipitation process regarding ammonium and phosphate removal and precipitated crystal quantification and characterization. Experiments were conducted on a bench scale in a completely randomized design at pH 9.5 by precipitation of synthetic wastewater solution with four magnesium sources: MgCl2∙6H2O, MgSO4∙7H2O, MgO, and magnesite (MgCO3). After pre-acidification, derived solutions from low-cost alternative sources of magnesium removed above 55 and 90% of ammonium nitrogen and phosphate in solution, respectively, and reached around 10 g L-1 of precipitated crystals. Results proximity obtained with solutions derived from commercial sources of magnesium (46ꟷ56% of ammonium nitrogen removal, 97% of phosphate removal, and more than 6 g L-1 of precipitate formed) indicated that alternative reagents could easily substitute commercial ones if submitted to the previous digestion process, making magnesium available in solution. Qualitative analysis by X-ray diffraction confirmed the presence of both struvite and newberyite in most precipitates. NH4MgPO4∙6H2O NH4MgPO46H2O NHMgPOHO NH4MgPO4 6H2O NH MgPO H O (NH4MgPO4∙6H2O slowrelease slow release andor or wastewaters salts sense characterization 95 9 5 9. MgCl26H2O MgClHO MgCl2 MgCl MgCl2∙6H2O MgSO47H2O MgSOHO MgSO4 7H2O MgSO MgSO4∙7H2O MgO MgCO3. MgCO3 MgCO . (MgCO3) preacidification, preacidification pre acidification, acidification pre-acidification lowcost low cost 90 respectively 1 L1 L L- crystals 46ꟷ56% 46ꟷ56 ꟷ (46ꟷ56 97 formed Xray X ray precipitates NHMgPO NH4MgPO HO (MgCO3 46ꟷ5 (46ꟷ5 (MgCO 46ꟷ (46ꟷ

Groundwater is considered an important source of water aid for human consumption. However, this water can be contaminated by impurities, such contamination spots that might reach the water tables. The aim of this study was to investigate the quality of shallow groundwater in Flores neighborhood, located in the municipality of Benevides, within Belém metropolitan region, State of Pará, Brazil. Recommendations described in Standard Methods for Examination of Water and Wastewater were followed at the time to determine physical-chemical parameters such as potential hydrogen (pH), electrical conductivity (EC), total dissolved solids (TDS), apparent color, turbidity, total hardness (TH), ions and trace elements. Multivariate statistical analysis has shown that most predictive water-quality parameters set for human consumption are associated with natural events involving weathering and leaching processes. Nevertheless, parameters of nitrate, phosphate, EC, TDS and pH are also influenced by anthropic conditions in the surroundings, mainly phosphate and nitrate ions. Therefore, it can be concluded that shallow groundwaters in Flores neighborhood are unsuitable for human consumption, making it necessary for municipal public authorities to take action to solve the problem of water shortage in the borough, thus preventing the population from use those shallow groundwaters, as their consumption can bring health problems. However impurities tables Benevides region Pará Brazil physicalchemical physical chemical pH, , (pH) EC (EC) TDS, (TDS) color turbidity TH, TH (TH) elements waterquality processes Nevertheless surroundings Therefore borough problems (pH (EC (TDS (TH

ABSTRACT The proper disposal of fruit and vegetable waste is essential to promote environmental sustainability, reduce the carbon footprint, improve soil quality, and contribute to the transition to a circular economy. This study examined the impact of incorporating dairy cattle wastewater (DCWW) into anaerobic co-digestion with fruit and vegetable residues and utilization of the resulting biofertilizer as a diluent in the anaerobic mono-digestion of fruit and vegetable residues (recycle). The specific biogas and methane production and the agronomic quality of the biofertilizer were evaluated in a semi-continuous trial. Two startup strategies were employed: initially, the reactors were entirely fed with inoculum (biofertilizer derived from DCWW), and fruit and vegetable residue feedstock was gradually introduced. Anaerobic co-digestion of fruit and vegetable residues with DCWW yielded the highest specific production of biogas and methane at 720 and 436 L kg-1 of volatile solids (VS), respectively. The addition of DCWW increases fruit and vegetable residue alkalinity by 249% and reduces the volatile acidity by 83.4%. Anaerobic mono-digestion of fruit and vegetable residues enhances macronutrient recovery in the biofertilizer through recycle. Logistically, directing fruit and vegetable residues to rural areas for anaerobic co-digestion with DCWW promotes agricultural biofertilizer use. sustainability footprint economy (DCWW codigestion co digestion monodigestion mono recycle . (recycle) semicontinuous semi continuous trial employed initially DCWW, , DCWW) introduced 72 43 kg1 kg 1 kg- VS, VS (VS) respectively 249 834 83 4 83.4% Logistically use (recycle 7 (VS 24 8 83.4 2 83.

RESUMO A destinação adequada dos resíduos de frutas e vegetais é fundamental para promover a sustentabilidade ambiental, reduzir a pegada de carbono, melhorar a qualidade do solo e contribuir para a transição para uma economia circular. Neste estudo, foram avaliados os efeitos da adição de água residuária da bovinocultura de leite em codigestão anaeróbia com resíduos de frutas e vegetais e o uso do biofertilizante como diluente na monodigestão anaeróbia dos resíduos de frutas e vegetais (reciclo). A produção específica de biogás e metano, bem como a qualidade agronômica do biofertilizante em um estudo semicontínuo, foram avaliados. Foram utilizadas duas estratégias para partida dos reatores: o abastecimento inicial dos reatores totalmente com inóculo (biofertilizante proveniente da digestão anaeróbia da água residuária da bovinocultura de leite) e a progressão de carga para os resíduos de frutas e vegetais. A maior produção específica de biogás e metano foi atingida pela codigestão anaeróbia de resíduos de frutas e vegetais com água residuária da bovinocultura de leite, 720 e 436 L kg-1 de sólidos voláteis (SV), respectivamente. A adição da água residuária da bovinocultura de leite aumentou em 249% a alcalinidade dos resíduos de frutas e vegetais e diminuiu em 83,4% sua acidez volátil. A recuperação de macronutrientes no biofertilizante é favorecida pela monodigestão anaeróbia dos resíduos de frutas e vegetais em função do uso do reciclo. Entretanto, visando a destinação destes ao meio rural, a codigestão anaeróbia com água residuária da bovinocultura de leite favorece o uso agrícola do biofertilizante. ambiental carbono circular reciclo . (reciclo) semicontínuo 72 43 kg1 kg 1 kg- SV, SV , (SV) respectivamente 249 834 83 4 83,4 volátil Entretanto rural (reciclo 7 (SV 24 8 83, 2

ABSTRACT Custard apple (Annona squamosa L.) is a sensitive fruit crop to salinity. One of the alternatives to minimize the deleterious effects of salt stress is adopting mineral fertilization management practices, promoting increased crop tolerance to salts. Therefore, the objective of the present study was to evaluate NPK doses to mitigate salt stress in custard apple seedlings irrigated with saline wastewater. The experiment was performed in a greenhouse, adopting a randomized block design in a 3 × 5 factorial scheme, corresponding to three irrigation waters (local-supply water of 0.53 dS m-1 electrical conductivity (control); desalination reject of 3.5 dS m-1; fish farming effluent of 3.5 dS m-1) and five proportions of the NPK recommendation (25, 50, 75, 100, and 125% of the fertilization recommendation), with four replicates. The growth, biomass accumulation, and nutrients were evaluated. Irrigation with desalination reject, and fish farming effluent restricted the growth of custard apple seedlings, regardless of the NPK dose used. The ionic homeostasis of seedlings irrigated with desalination reject and fish farming effluent is optimized by fertilization with 50% of the NPK recommendation corresponding to 50, 150, and 75 mg of N, P2O5, and K2O dm-3, respectively. For the production of seedlings irrigated with local-supply water, the dose of 75% NPK, corresponding to 75, 225, and 112.5 mg of N, P2O5, and K2O dm-3, respectively, is recommended. Annona L. L salinity practices salts Therefore wastewater greenhouse scheme localsupply local supply 053 0 53 0.5 m1 m 1 m- control (control) 35 3. 25, 25 (25 50 100 125 recommendation, , recommendation) replicates accumulation evaluated used 150 7 N P2O5 PO P O KO K dm3, dm3 dm 3, dm-3 respectively 225 1125 112 112. recommended 05 0. (control 2 (2 10 12 15 P2O dm- 22 11 (

RESUMO A pinheira (Annona squamosa L.) é uma frutífera sensível à salinidade. Uma das alternativas para minimizar os efeitos deletérios do estresse salino é a adoção de práticas de manejo da fertilização mineral, promovendo o aumento da tolerância da cultura aos sais. Portanto, o objetivo foi avaliar as doses de NPK para mitigar o estresse salino em mudas de pinheira irrigadas com água residual salina. O experimento foi realizado em casa de vegetação, em delineamento de blocos casualizados, em esquema fatorial 3 × 5, correspondendo a três águas de irrigação (água de abastecimento local de 0,53 dS m-1 de condutividade elétrica (controle); rejeito salino da dessalinização de 3,50 dS m-1; efluente de piscicultura de 3,50 dS m-1) e cinco proporções da recomendação de NPK (25, 50, 75, 100 e 125% da recomendação de fertilização), com quatro repetições. O crescimento, acúmulo de biomassa e nutrientes foram avaliados. A irrigação com rejeito salino e efluente de piscicultura restringe o crescimento das mudas de pinha, independentemente da dose de NPK utilizada. A homeostase iônica das mudas irrigadas com rejeito salino e efluente de piscicultura é otimizada pela fertilização com 50% da recomendação de NPK correspondente a 50, 150 e 75 mg de N, P2O5 e K2O dm-3, respectivamente. Para a produção de mudas irrigadas com água de abastecimento local, recomenda-se a dose de 75% de NPK, correspondente a 75, 225 e 112,5 mg de N, P2O5 e K2O dm-3, respectivamente. Annona L. L salinidade mineral sais Portanto salina vegetação casualizados 5 053 0 53 0,5 m1 m 1 m- controle (controle) 350 50 3,5 25, 25 (25 10 125 fertilização, , fertilização) repetições avaliados pinha utilizada 15 7 N PO P P2O KO K dm3, dm3 dm 3, dm-3 respectivamente recomendase recomenda se 22 1125 112 112, 05 0, (controle 35 2 (2 12 dm- 11 (

Microbial fuel cells (MFCs) represent a promising technology to generate bio-electricity and synchronously reduce wastewater pollutants. The presence of exoelectrogens in wastewater is critical for bio-electricity and pollutant reduction, but the performance of exoelectrogens at different pH levels remains unknown. This study aims to bridge this gap by offering an integrated approach to understanding the performance of exoelectrogens under varying substrate pH, particularly in bio-electricity generation and pollutant reduction in sugarbeet processing wastewater (SBWW). Three pH levels (ranging from acidic to alkaline) were studied and MFC's electricity output was measured. Later, current density, power density, and coulombic efficiency (CE) were calculated. Both pre- and post-experiment substrate samples were analysed with inductively coupled plasma (ICP). Furthermore, 16S rRNA gene analysis, DNA amplification, sequencing library preparation, and bioinformatics workflows on post-experiment samples of the substrate and anode samples were conducted. A diverse community of microorganisms was identified, especially Alphaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria (Geobacter). Bacteroidetes and Desulfovibrio were the major exoelectrogens responsible for electricity generation. Among the three pH levels tested, the most alkaline pH level (9.5±0.1) outperformed the others, achieving a 54% higher power density, 21% greater current density, and a 40% higher CE compared to the acidic pH level (6.5±0.1). Around 50-99% of pollutants were removed from the SBWW. The study revealed that Gammaproteobacteria thrive and perform better in alkaline environment.

In this study, the analysis of metals in tap, river, wastewater, and sludge samples was conducted using ICP-OES after hotplate- or microwave-assisted digestion. Both digestion methods produced a good degree of accuracy, indicating their suitability for the analysis of the studied metals in water samples. From method development studies, 100 mL of HNO3 was found to be the optimum sample volume and acid type for digestion. The average concentrations obtained ranged from 4.9-410.8 μg/L, 5.9-465.0 μg/L, 3.6-425.4 μg/L, 16.1-647 μg/L and 9.7-784 μg/L in tap water, river, influent, effluent, and sludge samples, respectively. All metals were below their maximum permissible limits, with the exception of Mn in all sludge samples and Pb in all tap water, Umhlathuzana River, and Northern Works influent samples. Comparable recoveries and metal concentrations were obtained by microwave and hotplate methods, suggesting that the cheaper hotplate method can be used as an effective digestion method for daily analysis. Common anion concentrations obtained ranged from 0.03-23.5 mg/L, 0.02-3 064.67 mg/L, and 0.32-175.67 mg/L for tap, river, and wastewater samples, respectively. The anion concentrations were found to be below the maximum acceptable limits indicating no negative health effect on human and aquatic life, with the exception of Cl- and SO4(2-) in Amanzimtoti and Northern River water, respectively.

ABSTRACT Cassava wastewater (CWW) is a natural biofertilizer successfully tested as a source of K in long-cycle crops; however, it still needs to be better evaluated in short-cycle crops. This study aimed to evaluate the use of CWW as a source of K in the growth, yield, and physicochemical quality of curly lettuce. The study was conducted in a greenhouse, in a randomized block design arranged in a 5 × 2 + 1 factorial scheme, with four replicates. Five CWW doses were evaluated as an exclusive source of K: 0, 60, 120, 180, and 240 kg ha-1 of K2O; two forms of application: 1-total dose at planting: 2-application of 50% of the dose at planting + 50% of the dose in topdressing, and an additional treatment: 100% mineral fertilization at 120 kg ha-1 of K2O dose, using KCl as the source. The number of leaves (NL), plant height (PH), fresh mass (FM), dry mass (DM), moisture (MO), ashes (ASH), fibers (FB), lipids (LIP), proteins (PTN), and carbohydrates (CHO) contents were evaluated. All agronomic attributes of lettuce showed lower values when fertilized only with CWW than mineral fertilization. Lettuce fertilized only with CWW, depending on total or split application and dose, showed higher ASH, FB, LIP, PTN, and CHO contents reaching 4.05, 3.97, 1.75, 7.11, and 3.63%, respectively, compared to mineral fertilization. The CWW can potentially be used as a complementary K source in lettuce cultivation, as its exclusive use does not replace traditional mineral fertilization. (CWW longcycle long cycle crops however shortcycle short growth yield greenhouse scheme replicates 0 60 180 24 ha1 ha ha- KO O 1total 2application 50 topdressing treatment 100 12 NL, NL , (NL) PH, PH (PH) FM, FM (FM) DM, DM (DM) MO, MO (MO) ASH (ASH) FB (FB) LIP (LIP) PTN (PTN) (CHO 405 4 05 4.05 397 3 97 3.97 175 75 1.75 711 7 11 7.11 363 63 3.63% respectively cultivation 6 18 10 (NL (PH (FM (DM (MO (ASH (FB (LIP (PTN 40 4.0 39 9 3.9 17 1.7 71 7.1 36 3.63 4. 3. 1. 7. 3.6

RESUMO Água residuária de mandioca (ARM) é um biofertilizante natural que foi testado com sucesso como fonte de K para culturas de ciclo longo; entretanto, ainda precisa ser melhor avaliado em culturas de ciclo curto. Este estudo teve como objetivo avaliar a utilização do ARM como fonte de K no crescimento, produção e qualidade físico-química da alface crespa. O estudo foi realizado em casa de vegetação, em delineamento de blocos casualizados, em esquema fatorial 5 × 2 + 1, com quatro replicações. Foram avaliadas cinco doses de ARM como fonte exclusiva de K: 0, 60, 120, 180 e 240 kg ha-1 de K2O; duas formas de aplicação: 1-dose total no plantio: 2-aplicação de 50% da dose no plantio + 50% em cobertura, e um tratamento adicional: adubação 100% mineral com dose de 120 kg ha-1 de K2O, utilizando KCl como fonte. O número de folhas (NF), altura da planta (AP), massa fresca (MF), massa seca (MS), umidade (UM), conteúdos de cinzas (CZ), fibras (FB), lipídios (LIP), proteínas (PTN) e carboidratos (CHO) foram avaliados. Todos os atributos agronômicos da alface avaliados apresentaram valores inferiores quando adubada apenas com ARM comparado à adubação mineral. A alface adubada apenas com ARM, dependendo da aplicação total ou parcelamento e da dose, apresentou maiores teores de CZ, FB, LIP, PTN e CHO atingindo 4,05, 3,97, 1,75, 7,11 e 3,63%, respectivamente, em comparação à adubação mineral. A água residuária de mandioca pode potencialmente ser utilizado como fonte complementar de K na produção de alface, pois seu uso único não substitui a adubação mineral. (ARM longo entretanto curto crescimento físicoquímica físico química crespa vegetação casualizados 1 replicações 0 60 18 24 ha1 ha ha- K2O KO 1dose 2aplicação 50 cobertura adicional 100 12 NF, NF , (NF) AP, AP (AP) MF, MF (MF) MS, MS (MS) UM, UM (UM) CZ (CZ) FB (FB) LIP (LIP) (PTN (CHO 405 4 05 4,05 397 3 97 3,97 175 75 1,75 711 7 11 7,1 363 63 3,63% respectivamente 6 10 (NF (AP (MF (MS (UM (CZ (FB (LIP 40 4,0 39 9 3,9 17 1,7 71 7, 36 3,63 4, 3, 3,6

Abstract In Costa Rica, there are significant challenges regarding wastewater treatment. This study evaluated the management of municipal wastewater in Costa Rica, with emphasis on the technological profile, the use of anaerobic systems, and the recovery of generated by-products. A mixed approach was used, combining secondary information from databases, expert consultations, and participatory workshops. It was found that most existing systems work with activated sludge and direct discharge to receiving bodies. Additionally, significant gaps were identified for the implementation of anaerobic systems for wastewater treatment. From a technical standpoint, the lack of training and confidence in designing and operating these systems was noted, along with the relevance of controlling the treatment of emerging contaminants. From an economic standpoint, the lack of financial sustainability of projects, low capacity for user payment, and lack of incentives or tiered tariff systems were identified. Within institutional gaps, the main issue was the need for clearer sectoral leadership and avoiding duplication of functions. All the above requires robust and clear regulations that allow for innovation in the systems to be implemented. Finally, it was found that, for the circular economy principle to become a reality, cultural change is required, and the paradigm that wastewater is only meant for disposal must be changed.

Resumen En Costa Rica, existen grandes desafíos en materia de tratamiento de aguas residuales. Este trabajo evaluó la gestión de aguas residuales ordinarias en Costa Rica, dando énfasis al perfil tecnológico, al uso de sistemas anaeróbicos y a la recuperación de los subproductos generados. Se consideró un abordaje mixto, combinando información secundaria de bases de datos, consultas a expertos y talleres participativos. Se logró evidenciar que la mayoría de los sistemas que existen trabaja con lodos activados y con vertido directo a cuerpo receptor. Además, se evidenciaron brechas importantes para la implementación de los sistemas de tratamiento de aguas residuales, en especial para los sistemas anaeróbicos. Desde el punto de vista técnico, se identificó la falta de capacitación y de confianza en diseñarlos y operarlos, aunado a la relevancia de controlar el tratamiento de contaminantes emergentes; desde el punto de vista económico, se apunta hacia la falta de sostenibilidad financiera de los proyectos y poca capacidad de pago de los usuarios, falta de incentivos o de sistemas tarifarios escalonados; dentro de las brechas institucionales, la principal es la necesidad de tener una rectoría más clara del sector y evitar la duplicidad de funciones. Se demostró que lo anterior requiere ir ligado de una normativa robusta y clara, que permita la innovación en los sistemas a implementar. Finalmente, se pudo detectar que, para que el principio de economía circular sea una realidad, se requiere trabajar en un cambio cultural y en romper el paradigma de que las aguas residuales solo sirven para desecharlas.

ABSTRACT Introduction: In the treatment of waste water at the “Desembarco del Granma” textile factory there is a neutralization tank, which resembles a continuous reactor with agitation. This equipment uses H2SO4, which must be replaced by a chemical agent with a lower impact on the environment. Objective: To determine the viability of using the existing reactor at the “Desembarco del Granma” textile factory for the neutralization of residual water when using CO2. Materials and Methods: Continuous stirred reactors were compared at laboratory and industrial levels, where the criterion of geometric similarity was considered. The Aspen Plus program was used to simulate the industrial reactor, considering the kinetics obtained at the laboratory level. The fluid package selected was the UNIQUAC. Results and Discussion: The speed at the tip of the impeller is the same for both reactors and the relationship between the diameter of the impeller and that of the tank remains practically constant, so there is geometric similarity between the reactors. The pH of the residual water neutralized with CO2 was 7.2, showing adequate neutralization. Conclusions: Geometric similarity was evidenced between continuous stirred reactors at laboratory and industrial levels. The pH of the neutralized wastewater in the industrial reactor, determined by simulation, was 7.2. It was proven, with the use of Aspen Plus, that the textile company's industrial reactor can be used for the wastewater neutralization process when CO2 is used instead of H2SO4.

RESUMEN Introducción: En el tratamiento del agua residual en la textilera “Desembarco del Granma” existe una cisterna de neutralización, que se asemeja a un reactor continuo con agitación. En dicho equipo se emplea H2SO4, el cual debe ser sustituido por un agente químico con un impacto menor sobre el medio ambiente. Objetivo: Determinar la viabilidad de la utilización de reactor existente en la textilera “Desembarco del Granma” para la neutralización del agua residual al emplear CO2. Materiales y Métodos: Se compararon los reactores continuos con agitación a nivel de laboratorio e industrial, donde se consideró el criterio de similitud geométrica. Se utilizó el programa Aspen Plus para simular el reactor industrial, considerando la cinética obtenida a nivel de laboratorio. El paquete de fluidos seleccionado fue el UNIQUAC. Resultados y Discusión: La velocidad en la punta del impulsor es igual para ambos reactores y la relación entre el diámetro del impelente y el del tanque se mantiene prácticamente constante, hay similitud geométrica entre los reactores. El pH del agua residual neutralizada con CO2 fue 7,2, manifestando una adecuada neutralización. Conclusiones: Se evidenció similitud geométrica entre los reactores continuos con agitación a nivel de laboratorio e industrial. El pH del agua residual neutralizada en el reactor industrial, determinado por simulación fue de 7,2. Se comprobó, con el empleo del Aspen Plus, que el reactor industrial de la textilera se puede usar para el proceso de neutralización del agua residual cuando se emplee CO2 en lugar de H2SO4.

ABSTRACT Introduction: Nowadays the pollutants produced in water exceed the capabilities of its decontamination mechanisms. It is necessary to evaluate the wastewater belonging to the Central Refinería Ecuador (Sugar Refinery Ecuador). Objective: To evaluate the quality of the wastewater from the Central Refinería Ecuador (Sugar Refinery Ecuador) for its possible use in agricultural irrigation. Materials and Methods: The quality of the wastewater was evaluated through physical, chemical and microbiological tests. Results and Discussion: The main physical, chemical and microbiological results evaluated at two points in time were: temperature 46.6 and 43.6 ºC, electrical conductivity 2 359 and 1 366 µS cm-1, sedimentable solids 8 and 3.50 mL L-1. pH 5.8 and 6.3 pH units, total phosphorus 5 and 3.75 mg L-1, total nitrogen 4.20 and 6.45 mg L-1, chemical oxygen demand 1 832 and 1 742 mg L-1, biochemical oxygen demand 1 671 and 1 451 mg L-1, fats and oils 296.90 and 30.90 mg L-1; cadmium 0.06 and 0.16 mg L-1, total chromium 0.10 and 0.20 mg L-1, copper 1.19 and 1.80 mg L-1, lead 0.43 and 0.55 mg L-1, zinc 1.37 and 2.33 mg L-1, total coliforms 8 800 000 and 160 000 mg L-1 and fecal coliforms 8 800 000 and 1 070 000 mg L-1. Conclusions: The effluent does not comply with the discharge requirements of NC 27, (2012) and is classified of poor quality to be used for sugarcane irrigation according to NC 855, (2011).

RESUMEN Introducción: Hoy en día los contaminantes producidos en el agua superan las capacidades de sus mecanismos de descontaminación. Siendo necesario evaluar las aguas residuales pertenecientes al Central Refinería Ecuador. Objetivo: Evaluar la calidad del agua residual del Central Refinería Ecuador, para su posible aprovechamiento en riego agrícola. Materiales y Métodos: La calidad del agua residual se evaluó mediante ensayos físicos, químicos y microbiológicos. Resultados y Discusión: Los principales resultados físico, químicos y microbiológicos evaluados en dos momentos fueron: temperatura 46,6 y 43,6 ºC, conductividad eléctrica 2 359 y 1 366 µS cm-1, sólidos sedimentables 8 y 3,50 mL L-1. pH 5,80 y 6,30 unidades de pH, fósforo total 5 y 3,75 mg L-1, nitrógeno total 4,20 y 6,45 mg L-1, demanda química de oxígeno 1 832 y 1 742 mg L-1, demanda bioquímica de oxígeno 1 671 y 1 451 mg L-1, grasas y aceites 296,9 y 30,9 mg L-1; cadmio 0,06 y 0,16 mg L-1, cromo total 0,10 y 0,20 mg L-1, cobre 1,19 y 1,80 mg L-1, plomo 0,43 y 0,55 mg L-1, zinc 1,37 y 2,33 mg L-1, coliformes totales 8 800 000 y 1 60 000 mg L-1 y coliformes fecales 8 800 000 y 1 070 000 mg L-1. Conclusiones: El efluente no cumple con los requisitos de vertimiento de la NC 27, (2012)y es clasificada de mala calidad para ser aprovechada en el riego de la caña de azúcar según NC 855, (2011).

ABSTRACT Introduction: The discharge of hospital wastewater leads to the establishment of microorganisms from human biota in aquatic ecosystems. This is risky, as there is the possibility of horizontal gene transfer of antibiotic resistance genes from bacteria to other bacterial strains in the aquatic ecosystem and the environment in general, contributing to the expansion of bacterial resistance to antibiotics and the therapeutic ineffectiveness of these medicines. Objective: To demonstrate the environmental risk due to discharge of wastewater from a hospital into an urban river in Santa Clara, Cuba. Materials and Methods: Bacteria were isolated from sediment and soil from the banks of the Bélico river and their resistance to parenteral antibiotics for intra-hospital use employed between 2015 and 2019 was determined. If positive, the environmental risk of these medicines in terrestrial surface waters was estimated, and the resistance of in-hospital strains was assessed. Results and Discussion: All isolated bacterial strains were resistant to at least one of the parenteral antibiotics for intra-hospital use employed in the period under study. All antibiotics were environmentally risky in terrestrial surface waters. There was a high antibiotic resistance of the strains isolated from hospitalized patients. Conclusions: The discharge of untreated wastewater into the Bélico river led to the establishment of bacterial strains which can have a negative impact on the environment, including human health.

RESUMEN Introducción: El vertimiento de aguas residuales hospitalarias conduce al establecimiento de microorganismos de la biota humana en ecosistemas acuáticos. Lo anterior es riesgoso, al existir la posibilidad de transferencia génica horizontal de genes de resistencia de antibióticos de las bacterias a otras cepas bacterianas del ecosistema acuático y del ambiente en general; contribuyendo a la expansión de la resistencia bacteriana a antibióticos y la inefectividad terapéutica de estos medicamentos. Objetivo: Demostrar el riesgo ambiental por vertimiento de aguas residuales de un hospital a un río urbano en Santa Clara, Cuba. Materiales y Métodos: Se aislaron bacterias del sedimento y suelo de la ribera del río Bélico y se determinó su resistencia a los antibióticos parenterales de uso intrahospitalario empleados entre 2015 y 2019. De ser esta positiva, se estimó el riesgo ambiental de estos medicamentos en aguas superficiales terrestres y se valoró la resistencia de cepas intrahospitalarias. Resultados y Discusión: Todas las cepas bacterianas aisladas fueron resistentes al menos a uno de los antibióticos parenterales de uso intrahospitalario empleados en el período objeto de estudio. Todos los antibióticos resultaron ambientalmente riesgosos en aguas superficiales terrestres. Existió una elevada resistencia microbiana a antibióticos en las cepas aisladas de pacientes hospitalizados. Conclusiones: El vertimiento de las aguas residuales sin tratar al río Bélico, condujo al establecimiento de cepas bacterianas que pueden tener un impacto negativo en el ambiente, incluyendo la salud humana.

RESUMEN El constante desarrollo de las industrias, ha incrementado el uso del cromo ocasionando descargas en aguas residuales. Se ha planteado la implementación de biorremediación microbiana como alternativa ecológica, eficiente y económica de utilización de microorganismos para reducir el cromo a una forma menos tóxica. En este sentido, el objetivo de este trabajo fue evaluar la capacidad de remoción de Cr (VI) de consorcios microbianos en distintas concentraciones. Para ello, se realizó una activación e identificación de microorganismos provenientes de aguas residuales con cromo, se establecieron siete consorcios microbianos evaluando su sinergia, curvas de crecimiento individuales y en consorcio. Posteriormente, se realizó una adaptación escalonada de los consorcios con ocho concentraciones de Cr (VI), efectuando modelos de regresión recíproca, curvas de crecimiento e identificando el consorcio con mayor remoción. Se encontró sinergia en los consorcios evaluados, evidenciándose curvas de crecimiento con mayor absorbancia en éstos que de forma individual, con mayor absorción en el consorcio Candida famata-Serratia sp. Sin embargo, en la adaptación escalonada, se demostró mayor capacidad de reducción de Cr (VI) en Candida tropicalis-Serratia sp. con 79,20% en la concentración de 100 ppm y una reducción del cromo total del 31,12%. A su vez, se identificó mayor adaptación de los consorcios en altas concentraciones de Cr (VI). En este estudio, se reporta por primera vez, al consorcio C. tropicalis-Serratia sp. con una interacción positiva y mayor capacidad metabólica de reducción, lo cual tendrá un impacto positivo en biorremediación de aguas residuales con cromo.

ABSTRACT Constant industrial development has increased chromium use, resulting in chromium discharge into wastewater. The implementation of microbial bioremediation has been proposed as an ecological, efficient and economical alternative for the use of microorganisms to reduce chromium to a less toxic form. Our objective was to evaluate the Cr (VI) removal capacity of microbial consortia at different concentrations. Accordingly, an activation and identification of microorganisms from chromium-containing wastewater was carried out. Seven microbial consortia were established and their synergy, individual and consortium growth curves were evaluated. Subsequently, a scaled adaptation of the consortia was carried out with eight concentrations of Cr (VI). Reciprocal regression models and growth curves were used to identify the consortium with the highest removal. Synergy was found in the consortia evaluated; growth curves of consortia showed higher absorbance than individually, with higher absorption in the Candida famata-Serratia sp. consortium. However, in the scaled adaptation, greater Cr (VI) reduction capacity was demonstrated in Candida tropicalis-Serratia sp. with 79.20% at a concentration of 100 ppm with a total chromium reduction of 31.12%. At the same time, a greater adaptation of the consortia to high concentrations of Cr (VI) was identified. This is the first research to report C. tropicalis-Serratia sp. microbial consortium with a positive interaction and higher metabolic reduction capacity, which will have a positive impact on bioremediation of chromium-containing wastewater.