Water quality in drip/trickle irrigation: A review

Abstract

The intensive treatment of irrigation water required for the proper operation of drip irrigation systems is presently an accepted practice. To control emitter clogging, we need to know the basic causes of clogging. The major clogging factors have been identified and control measures developed to prevent emitter malfunction. All emitter clogging problems, however, have not been solved primarily because of cost. The main approach to control clogging is proper water treatment. The type of treatment is based on the quality of the irrigation water, which can be classified in terms of its physical, chemical and biological composition. The causes of emitter clogging and possible water treatment and preventive measures to maintain reliable operation are reviewed. Water quality and emitter cloggingDrip irrigation in the mid-1960's through mid-1970's was considered an emerging technology with its application limited only to high-priced, specialty crops. Today it is used on a wide variety of crops, even those that were initially considered unprofitable for management under drip irrigation.Through careful nurturing, drip irrigation has grown into a stable and economically significant part of the farming community which has also had great impact on the irrigation and associated industries. In its infancy some difficult and seemingly unsolvable problems were encountered in operating drip/trickle systems particularly those related to the clogging of emitters. Also during this period, numerous inventors and entrepreneurs sold various types of "non-clogging" or "self-cleaning" emitters which were promised to solve the most serious problem of emitter plugging, but unfortunately did not adequately do so. The clogging problem, if not properly solved, would have resulted in the complete rejection or Offprint request to: E S. Nakayama severe restriction of a promising, efficient method of irrigation and water conservation.Work on improving drip system operations went along two different directions, independent, but closely in touch with one another. One group concentrated on improving the hydraulic operation of the emitters; the other focused on studying the clogging process and from such knowledge developing procedures for alleviating the clogging problem. The main conclusion drawn from the latter type of studies is that clogging is closely related to the quality of water used in the drip system, e.g.

Obstrução e uniformidade de aplicação em sistemas de irrigação por gotejamento aplicando-se efluente da suinocultura

“…Os valores de CUD das subunidades submetidas aos manejos 1E3A, 2E2A, 3E1A e 4E apresentaram reduções de 5, 62, 54 e 1%, respectivamente, quando se estabeleceu comparação entre os tempos de funcionamento inicial e 160 h. Os maiores níveis de entupimento ocorreram no gotejador G1 em relação a G2 e G3, devido ao maior comprimento de labirinto (Tabela 1) que favorece o desenvolvimento de biofilme nos trechos de menor velocidade de escoamento do efluente (Dazhuang et al, 2009 Apesar do lançamento dos emissores autocompensantes no mercado, a avaliação dos sistemas de irrigação continua sendo um dos pontos de partida para o sucesso das lavouras. Portanto, sistemas bem dimensionados e uniformes na distribuição de água são fundamentais para a técnica da quimigação, o que resulta em aumento de produtividade (Nakayama & Bucks, 1991).…”

“…Na realização das análises estatísticas utilizou-se o programa computacional SAEG 9.1 (Ribeiro Júnior & Melo, 2008) resultados e dIscussão Na Tabela 2 se encontram as características físico-químicas e microbiológicas da água residuária de suinocultura (ARS) e da água limpa (AL) utilizadas nos ensaios com sistemas de irrigação por gotejamento, além dos riscos de entupimento de emissores. As características SS, Fe e PB da ARS, representam risco severo de entupimento de gotejadores; enquanto para pH, SD, Mn e Mg 2+ tal risco foi moderado e, para Ca 2+ , baixo (Nakayama & Bucks, 1991;Capra & Scicolone, 1998).…”

Chemical treatment to unclogg dripper irrigation systems due to biological problems

“…Among the factors shown in Table 1 and other found in literature as restrictive to the use of water for trickle irrigations systems Bucks, 1991 andRibeiro et al, 2004), it was verified that there was no restriction for the well water. For the reservoir, iron presented a moderate risk and phosphorus a high risk, whereas in the supply lake there was a moderate restriction to pH and iron and a high restriction for phosphorus.…”

“…These included: pH, solids in suspension, turbidity, dissolved solids, electric conductivity, iron, manganese, total hardness, alkalinity, Langelier index and bacteria concentration. The classification of the water for the trickle irrigation system in relation to clogging problems followed the recommendations of Nakayama & Bucks (1991) and Ribeiro et al (2004). The water used for irrigation comes from a 250 m 3 reservoir, comprised of a small dam that is supplied by two sources; the first by pumping water from a dam that receives water contribution from other springs in the surrounding area, and the second from an artesian well, the greatest contribution was comming from the dam.…”

Preliminary surface topographical characteristics of biofilms attached on drip irrigation emitters using reclaimed water

“…However, due to the poor quality of reclaimed water, the clogging mechanisms of the drip irrigation system and clogging control technology are very complex (Rowan 2004;Li et al 2012a, b;Nakayama and Bucks 1991) and have been a major difficulty in the application of reclaimed water drip irrigation technology. Although reclaimed water can reach basic requirements for drainage and irrigation, the microbial communities, nutrients and particles in reclaimed water can still penetrate through the filter to the irrigation system.…”