The banana tree circle (BTC) is a low-cost system for local greywater management, using a natural treatment and disposal process, providing additional resource recovery benefits. However, there are ...no standard design criteria for BTC that would allow for quality control of its efficiency and sustainability, and little is currently known about the full-scale performance of BTC. Based on the scoping literature review of 31 documents in the scientific database and eight documents from grey literature, a standard design model was proposed for the BTC technology based on the concept of water balance, greywater flows, rain, infiltration, and evapotranspiration. The first two steps of the BTC design were determining the areas required for infiltration and evapotranspiration. A cylindrical form trench, the soil percolation rate, and the hydraulic loading rate were considered for the infiltration area. The banana trees' evapotranspiration rate was taken into consideration for the evapotranspiration area. The proposed model was applied in a case study where we used a trench with 0.8 m depth and 1.5 m diameter. This study proposes a standard design criterion for the BTC based on environmental factors, and the scoping of the literature provides the basis for future studies to evaluate its environmental sustainability.
The use of greywater for agricultural purposes can contribute to water conservation, the resilience of family farming food systems, and food security, especially in regions with higher water ...deficits. However, the social acceptance of this practice has been poorly evaluated systematically and hinders the implementation due to the resulting uncertainty among decision-makers and other stakeholders in the management of alternative sources of water in agriculture. This study was designed in the concept of the Attitude and the Perceived Behavioral Control to investigate the acceptance and perception of risks and benefits of the use of greywater as an alternative water resource in agriculture and the personal environmental values and beliefs (New Ecological Paradigm scale) by 300 professionals of agricultural technicians from 12 meso-regions in Minas Gerais State, Brazil. In general, the technicians showed a positive attitude toward reusing greywater in agriculture. The willingness to consume food grown with greywater was the least positive aspect (59.3%) compared to the willingness to perform the practice (87.7%) and the belief in reusing greywater as an alternative water resource (81.7%). The result indicates a great potential for using greywater as an alternative water resource for irrigating non-food crops. The environmental position of the studied public was not a decisive guarantee for a final attitude towards the use of greywater in agriculture. The study identified a clear relationship between a positive acceptance to support the development of public policies for water reuse (81.7%) and the interviewee's local contexts of water scarcity, lack of sanitation, and socioeconomic conditions. This study contributes to the discussions about water reuse in agriculture and developing public wastewater reuse policies.
•Agricultural technicians were interviewed to assess their acceptance and perception of greywater use in agriculture.•Interviewers show a positive attitude toward the use of greywater in agriculture.•Most respondents believe treatment and irrigation techniques can minimize eventual risks to human health from greywater reuse.•The interest in greywater reuse is more effective in water scarcity regions and more precarious socioeconomic situations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Os sistemas alagados construídos (SACs) têm sido utilizados para tratamentos de efluentes, principalmente como unidades terciárias. Apresentam moderado custo de instalação e considerável remoção de ...nutrientes e a vegetação que o compõem pode ser aproveitada para fins de alimentação animal. Neste trabalho, avaliou-se o desempenho do capim-tifton 85 (Cynodon spp.) no tratamento de água residuária de suinocultura. O experimento foi conduzido durante 131 dias, em três fases. As taxas de aplicação chegaram a 6.335, 464, e 240 kg ha-1 d-1 de DQO, NTK e PT, respectivamente. A cada corte, foram quantificadas massas verde e seca, os teores de nitrogênio, fósforo e proteína bruta. Conclui-se que houve aumento nas concentrações de proteína bruta, NTK e PT no tecido do capim-tifton 85 com o aumento da taxa de aplicação superficial de nutrientes, mas a produtividade de matéria seca reduziu na terceira fase, provavelmente, por fatores como diminuição da temperatura ambiente e excesso de sólidos retidos no SAC. Elevadas taxas orgânicas de aplicação limitaram o desenvolvimento do capim-tifton 85 em termos de matéria seca.
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