Desenvolvimento da ecotecnologia dos wetlands constru?dos aplicados para o tratamento descentralizado de efluentes nos ?ltimos 30 anos

The different active elements in the process of treatment on wetlands ecotechnology, such as the sizing and operating criteria (organic load, add rate, hydraulic loading rate, among others), the wetland mode, the filter media composition and the macrophytes used, present particular characteristics subject to the location of the project and/or its application. The significant variability in the parameters data mentioned above makes it difficult to compare and standardize. Because of that, in Brazil there are no regulatory standards for construction, operation and maintenance for this technology. This paper compiles the compilation of 274 scientific articles from indexed journals (impact factor > 1.0), in order to map and discuss the advances of this treatment model, with the general aim of evaluating the performance of the application of different constructed wetland types (WC) under the context of decentralized sewage over a period of 30 years (1980 to 2018). Therefore, a systematic review was carried out with stratified analysis of scientific articles in indexed journals, two international platforms: Scopus and Science Direct, because they contain the largest number of studies addressing wetlands. From this, the keyword "wetlands" was determined to select the articles and the downloads of 391 scientific articles (Scopus) and 694 scientific articles (Science Direct) were carried out. After that, a stratified sampling was performed by means of which the analysis of 25 % was determined, resulting in 100 (Scopus) and 174 (Science Direct) articles, totalizing in 274 scientific articles. Subsequently, the topics were established to the systematic review, being these: reference; data base; country; technological arrangement; WC mode; filter material; macrophyte; hydraulic system; volume; treated effluent; applied organic load (in terms of COD and BOD); hydraulic application rate; total nitrogen load; affluent C/N ratio; removal of pollutants; general objective of the research; and analytical technique employed (ATE). From the analysis of these parameters it was possible to explain the main agents in order to evaluate the performance of the different WC modalities in the period from 1980 to 2018 under the context of decentralized sewage. The results showed that during the three decades, the evolution of the application of different modalities of wetlands presented a tendency to decrease the use of WN (natural wetlands) and greater use of WC. From the mid-1990s onwards, a trend towards demand for WC evolution of surface flow (WCFS) and subsurface (WCFSS). There was a gradual increase of studies with the use of horizontal WC (WCH), vertical descendent WC (WCVD), vertical ascendent WC (WCVA), hybrid system (WCVD - WCH) and saturated vertical WC (WCV - FS). The WCH as post-treatment of wastewater was the most used technological arrangement over the evaluated period, making a total of 97 studies, followed by WCFS (70 articles), WCVD (58 articles), WC (42 articles) and WN (36 articles), with respective numbers of scientific articles. The most studied types of effluents addressed in the studies were: household or sanitary effluents (105 articles), effluents from agroindustry activities (61 articles), industrial sewage (59 articles), surface water (41 articles) and synthetic effluent (25 articles). The most used macrophytes in the different WC modalities were those of the genus Phragmites spp. (110 articles), Typha spp. (86 articles), Scirpus spp. (24 articles), Cyperus spp. (22 articles), Juncus spp. (19 articles), Schoenoplectus spp. (15 articles), Carex spp. (13 articles), Pontederia spp. (10 articles), Iris spp. (10 articles) e Canna spp. (10 articles). The types of filtering masses most used were: gravel (130 articles), sand (76 articles), clay (18 articles), soil (14 articles) and organic compounds (11 articles). The pollutants treated in the studies corresponded to nitrogen compounds (136 articles), organic matter (66 articles), phosphorus compounds (62 articles), metals (43 articles), solids series (42 articles) and agrochemicals (26 articles). It was also verified that most of the values adopted in the studies attributed the organic load in terms of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) ranging from 0.05 g BOD m-2 d-1 to 70,200 g BOD m-2 d-1 and from 0.07 g COD D m-2 d-1 to 50,000,000 g COD m-2 d-1. In relation to total nitrogen (TN) applied the values vary from 0.00196 g TN m-2 d-1 to 685,800 g TN m-2 d-1. The values of affluent hydraulic rate ranged from 0.003 mm d-1 to 25,920,000 mm d-1. In the case of the concentration of BOD, COD and TN the values varied from 0.483 mg BOD L-1 to 68,163.00 mg BOD L-1, from 0.0000207 mg COD L-1 to 57,934.80 mg COD L-1 and from 0.01 mg TN L-1 to 116912 mg TT L-1. These constituent elements and operational conditions were considered as promising alternatives for the maximization of performances of the different WC modalities in the treatment of different effluents.Na ecotecnologia de wetlands, os diferentes elementos atuantes no processo de tratamento, como os crit?rios de dimensionamento e opera??o (carga org?nica, regime de alimenta??o, taxa hidr?ulica, e outros), a modalidade de wetland, a composi??o do maci?o filtrante e as macr?fitas utilizadas, apresentam caracter?sticas particulares sujeito ? localiza??o do projeto e/ou sua aplica??o. A variabilidade significativa nos dados dos par?metros citados anteriormente dificulta uma an?lise comparativa e uma tend?ncia de padroniza??o. Em virtude disso, no Brasil n?o h? normas regulamentadoras de constru??o, opera??o e manuten??o para essa tecnologia. O presente trabalho re?ne a compila??o de 274 artigos cient?ficos de revistas indexadas (fator de impacto > 1,0), a fim de mapear e discutir os avan?os desse modelo de tratamento, com o objetivo geral de avaliar o desempenho da aplica??o de diferentes modalidades de wetlands constru?dos (WC) sob o contexto do saneamento descentralizado em um per?odo de 30 anos (1980 a 2018). Para tanto, realizou-se uma revis?o sistem?tica com an?lise estratificada de artigos cient?ficos em revistas indexadas, duas plataformas internacionais: Scopus e Science Direct, devido a estas conterem o maior n?mero de estudos que abordam a tem?tica de wetlands. A partir disto, determinou-se a palavra-chave ?wetlands? para selecionar os artigos e realizou-se os downloads de 391 artigos cient?ficos (Scopus) e 694 artigos cient?ficos (Science Direct). Em sequ?ncia, efetuou-se a amostragem estratificada, por meio da qual se determinou a an?lise de 25 %, resultando em 100 (Scopus) e 174 (Science Direct) artigos, totalizando em 274 artigos cient?ficos. A posteriori, estabeleceu-se os t?picos ? revis?o sistem?tica, sendo estes: refer?ncia; base de dados; pa?s; arranjo tecnol?gico; modalidade de WC; material filtrante; macr?fita; regime hidr?ulico; volume; efluente tratado; carga org?nica aplicada (em termos de DQO e DBO); taxa hidr?ulica; carga de nitrog?nio total; rela??o C/N afluente; remo??es de poluentes; objetivo geral da pesquisa; e t?cnica anal?tica empregada (TAE). A partir das an?lises destes par?metros foi poss?vel explicitar os principais agentes atuantes, a fim de, avaliar o desempenho da aplica??o das distintas modalidades de WC no per?odo de 1980 a 2018 sob o contexto do saneamento descentralizado. Os resultados mostraram que ao longo das tr?s d?cadas, a evolu??o da aplica??o de diferentes modalidades de wetlands apresentou uma tend?ncia de diminui??o da utiliza??o dos WN (wetlands naturais) e maior emprego dos WC. A partir da metade da d?cada de 1990, iniciou-se uma tend?ncia de procura ? evolu??o dos WC de fluxo superficial (WCFS) e subsuperficial (WCFSS). Observou-se um aumento gradativo de estudos com o emprego de WC horizontal (WCH), WC vertical descendente (WCVD), WC vertical ascendente (WCVA), sistema h?brido (WCVD ? WCH) e WC vertical de fundo saturado (WCV-FS). O WCH como p?s-tratamento de ?guas residu?rias foi o arranjo tecnol?gico mais empregado ao longo do per?odo avaliado perfazendo um total de 97 estudos, seguido de WCFS, WCVD, WC e WN, com respectivos n?meros de artigos cient?ficos, 70, 58, 42 e 36. Os tipos de efluentes tratados mais abordado nos estudos, foram: efluentes dom?sticos ou sanit?rios (105 artigos), efluentes de atividades agroindustriais (61 artigos), esgotos industriais (59 artigos), ?guas superficiais (41 artigos) e efluentes sint?ticos (25 artigos). As macr?fitas mais empregadas nas diferentes modalidades de WC foram as dos g?neros Phragmites spp. (110 artigos), Typha spp. (86 artigos), Scirpus spp. (24 artigos), Cyperus spp. (22 artigos), Juncus spp. (19 artigos), Schoenoplectus spp. (15 artigos), Carex spp. (13 artigos), Pontederia spp. (10 artigos), Iris spp. (10 artigos) e Canna spp. (10 artigos). Os tipos de maci?os filtrantes mais empregados foram: cascalho (130 artigos), areia (76 artigos), argila (18 artigos), solo (14 artigos) e compostos org?nicos (11 artigos). Os poluentes tratados nos estudos corresponderam a: compostos nitrogenados (136 artigos), mat?ria org?nica (66 artigos), compostos com f?sforo (62 artigos), metais (43 artigos), s?rie de s?lidos (42 artigos) e agrot?xicos (26 artigos). Verificou-se ainda, que a maioria dos valores adotados nos estudos atribuem o carregamento org?nico em termos de demanda bioqu?mica de oxig?nio (DBO) e demanda qu?mica de oxig?nio (DQO) variando de 0,05 g DBO m-2 d-1 a 70.200 g DBO m-2 d-1 e de 0,07 g DQO m-2 d-1 a 50.000.000 g DQO m-2 d-1. Com rela??o a carga de nitrog?nio total (NT) aplicada os valores variam de 0,00196 g NT m-2 d-1 a 685.800 g NT m-2 d-1. Os valores de taxa hidr?ulica afluente variaram de 0,003 mm d-1 a 25.920.000 mm d-1. No caso da concentra??o de DBO, DQO e NT os valores variaram de 0,483 mg DBO L-1 a 68163,00 mg DBO L-1, de 0,0000207 mg DQO L-1 a 57934,80 mg DQO L-1 e de 0,01 mg NT L-1 a 116912 mg NT L-1. Estes elementos constituintes e as condi??es operacionais foram consideradas como alternativas promissoras para a maximiza??o dos desempenhos das distintas modalidades de WC no tratamento de diferentes efluentes