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O aporte de nutrientes das águas residuárias doméstica estimula a prática do reuso na produção agrícola, porém a presença de metais pesados, mesmo que em baixas concentrações, pode acarretar problemas ambientais no longo prazo. O presente trabalho objetivou analisar os efeitos da aplicação da água residuária doméstica e água de poço na alteração dos teores de metais pesados em um cambissolo cultivado com pimenta malagueta. Para isso, uma área experimental de 744 m² foi montada no assentamento Milagres em Apodi-RN. Essa área é composta de estação de tratamento de esgoto e de sistema de irrigação por gotejamento. Os tratamentos utilizados foram T1 - 100% de aplicação água residuária doméstica tratada (ART) e 0% de água de poço (AP), T2 - 75% de ART e 25% de AP, T3 - 50% de ART e 50% de AP, T4 - 25% de ART e 75% de AP e T5 - 0% de ART e 100% de AP. No período experimental foram realizadas análises químicas da ART e AP, enquanto do solo foram coletadas amostras nas camadas de 0 a 0,20 m, 0,20 a 0,40 m e 0,40 a 0,60 m para determinação dos valores de pH e do conteúdo de cobre, zinco, ferro e manganês. Os resultados indicaram que os teores de cobre, zinco, ferro e manganês do cambissolo não foram influenciados pelas proporções de água residuária doméstica tratada e de água de poço. Os valores de pH do solo apresentaram tendência de redução nas proporções com mais água residuária doméstica tratada em relação a água de poço.

A aplicação de esgoto doméstico tratado é uma forma efetiva de controle da poluição ambiental, sendo uma alternativa viável para aumentar a disponibilidade hídrica nas regiões áridas e semiáridas. O presente estudo objetivou analisar a produção de milho (Zea mays L) fertirrigado com esgoto doméstico primário do Assentamento Rural Milagres em Apodi-RN. No período experimental as características avaliadas na cultura do milho foram: altura de planta (AP), diâmetro do caule (DC), número de folhas (NF), peso médio de espiga com e sem palha (PMECP), (PMESP), peso úmido e seco de grãos (PUG), (PSG). Os resultados do estudo indicaram que a fertirrigação com esgoto doméstico primário proporcionou maiores valores de altura de planta (AP), diâmetro do caule (DC), número de folhas (NF), peso de espiga com palha (PMECP), peso de espiga sem palha (PMESP), peso úmido dos grãos (PUG), peso seco dos grãos (PSG) e produtividade de grãos em relação às mesmas características obtidas com água do poço artesiano. O uso de esgoto doméstico consiste em uma fonte de nutriente para produção agrícola.

The objective of this study was to analyze the use of hog production wastewater in the production of seedlings of Eucalyptus urophylla, using a compound of municipal solid waste (SRSU) as substrate, and evaluating the effect of different proportions of ARS and of seedling ages in their morphological and nutritional quality. The experiment was conducted in a greenhouse at the Experimental Hydraulics, Irrigation and Drainage, Department of Agricultural Engineering. The statistical design was randomized blocks with different numbers of repetitions, consisting of 10 treatments in a 5 x 2 factorial design (5 proportions of ARS supplemented with nitrogen fertilization and 2 seedling ages). The variables measured were shoot height (H), stem diameter (SD), shoot dry matter (SDM), root dry mass (RDM), total dry matter (TDM), ratio of seedling height / diameter of the girth (H / SD), ratio of dry weight of shoot / root dry mass (SDM / RDM), Dickson quality index (DQI) and concentrations of nutrients in the plants leaf, stem and root. These characteristics were evaluated at 75 and 90 days after seeding (DAS). It was concluded that the proportion of 50% ARS improved the nutritional and morphological characteristics of eucalyptus. The seedlings achieved morphological characteristics suitable for planting in the field 90 days after sowing and showed appropriate levels for most nutrients at both ages.

This study aimed to analyze the performance of digester decant system with biological filter followed by constructed wetland and solar reactor in the treatment of domestic sewage from Milagres rural community in Apodi-RN. The treatment system was monitored for the period of October and November 2010, 48 days after planting Pennisetum purpureum Schumach. Samples of domestic sewage were collected at different stages of treatment, in four replications on time, to determine physicochemical and microbiological characteristics about the system performance. The results indicated significant removal of turbidity, biochemical oxygen demand, chemical oxygen demand, total solids, suspended solids, phosphorus and oil and grease using the set digester decant with biological filter, followed by constructed wetland and solar reactor; the association of average solar radiation of 28.73 MJ m-2 d-1, effluent depth of 0.10 m on reactor and time of sun exposure of 12 hours provided removal of fecal coliform up to 99.99% of domestic sewage in Apodi, RN, the treated effluent met microbiological standard of the Brazilian guidelines for agricultural use with restrictions.

The present study aimed to analyze the removal of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) in biofilters operating with domestic sewage. Experimental tests were conducted at the Universidade Federal de Viçosa (UFV), Viçosa-MG. The experiment was a split split plot scheme, and in the plots different rates of sewage (0.5, 1.0 and 1.5 m3 m2 d-1) were applied, in the subplot, types of organic material (waste compost, sugar cane bagasse and sawdust) were tested and in the subsubplots, five dates of measurements (August, September, October, November and December 2009) were evaluated, in a randomized block with three replications. Samples of domestic sewage were collected upstream and downstream of 27 biofilters for determination of BOD and COD, monthly for five months. The results showed that the effluent from biofilters meets the national standard for release in water streams, with regard to the BOD, after stabilization of the filter elements, and the use of biofilters for the treatment of domestic sewage is a viable technology for small scale because it has low cost, easy operation and good ability to remove biochemical pollutants.

Fertigation with wastewaters is a great option for reuse of effluents in agriculture. Domestic effluent can be reused after primary treatment, reducing treatment costs and pollution, also providing water and nutrients to crops. This work aimed to quantify the nutrients income in coffee crop fertigated with domestic sewage. Five treatments were used. T1 received only clean water, and treatments T2, T3, T4 e T5 received 180, 350, 480 and 638 mm of sewage, respectively, during four months. Monthly soil analyses allowed to quantify nutrient inputs of 67.45 kg ha-1 of N, 81.89 kg ha-1 of P, 33.34 kg ha-1 of K+, 173.24 kg ha-1 of Ca2+, 49.18 kg ha-1 of Mg2+, 161.56 kg ha-1 of Na+ and 116.19 kg ha-1 of S. Even though the treatments promoted reductions in fertilization and liming, it was still necessary to complement fertilization of coffee crop fertigated with domestic sewage.