Microbial Metabolic Potential Affected by Surplus Wastewater Irrigation in Tropical Soil Cultivated with Tifton 85 Bermuda Grass (Cynodon dactylon Pers. X C. niemfuensis Vanderyst)

Agricultural reuse of treated sewage effluent (TSE) is an environmental and economic practice; however, little is known about its effects on the characteristics and microbial function in tropical soils. The effect of surplus irrigation of a pasture with TSE, in a period of 18 months, was investigated, considering the effect of 0% surplus irrigation with TSE as a control. In addition, the experiment consisted of three surplus treatments (25%, 50%, and 100% excess) and a nonirrigated pasture area (SE) to compare the soil microbial community level physiological profiles, using the Biolog method. The TSE application increased the average substrate consumption of the soil microbial community, based on the kinetic parameters of the average well color development curve fitting. There were no significant differences between the levels of surplus irrigation treatments. Surplus TSE pasture irrigation caused minor increases in the physiological status of the soil microbial community but no detectable damage to the pasture or soil.

Nutrients and Nonessential Elements in Soil after 11 Years of Wastewater Irrigation

Irrigation of citrus (Citrus aurantium L. x Citrus paradise Macf.) with urban reclaimed wastewater (RWW) can be economical and conserve fresh water. However, concerns remain regarding its deleterious effects on soil quality. We investigated the ionic speciation (ISP) of RWW and potential impacts of 11 yr of irrigation with RWW on soil quality, compared with well-water (WW) irrigation. Most of nutrients (similar to 53-99%) in RWW are free ionic species and readily available for plant uptake, such as: NH4+, NO3-, K+, Ca2+, Mg2+, SO42-, H3BO3, Cl-, Fe2+, Mn2+, Zn2+, Co2+, and Ni2+, whereas more than about 80% of Cu, Cr, Pb, and Al are complexed with CO3-, OH-, and/or organic matter. The RWW irrigation increased the availability and total concentrations of nutrients and nonessential elements, and soil salinity and sodicity by two to three times compared with WW-irrigated soils. Although RWW irrigation changed many soil parameters, no difference in citrus yield was observed. The risk of negative impacts from RWW irrigation on soil quality appears to be minimal because of: (i) adequate quality of RWW, according to USEPA limits; (ii) low concentrations of metals in soil after 11 yr of irrigation with RWW; and (iii) rapid leaching of salts in RWW-irrigated soil during the rainy season.

Wastewater irrigation at Tallahassee, Florida /

Aug. 1979.

Carbon and nitrogen cycling in a tropical Brazilian soil cropped with sugarcane and irrigated with wastewater

Carbon (C) and nitrogen (N) dynamics in agro-systems can be altered as a consequence of treated sewage effluent (TSE) irrigation. The present study evaluated the effects of TSE irrigation over 16 months on N concentrations in sugarcane (leaves, stalks and juice), total soil carbon (TC), total soil nitrogen (TN), NO(3)(-)-N in soil and nitrate (NO(3)(-)) and dissolved organic carbon (DOC) in soil solution. The soil was classified as an Oxisol and samplings were carried out during the first productive crop cycle, from February 2005 (before planting) to September 2006 (after sugarcane harvest and 16 months of TSE irrigation). The experiment was arranged in a complete block design with five treatments and four replicates. Irrigated plots received 50% of the recommended mineral N fertilization and 100% (T100), 125% (T125), 150% (T150) and 200% (T200) of crop water demand. No mineral N and irrigation were applied to the control plots. TSE irrigation enhanced sugarcane yield but resulted in total-N inputs(804-1622 kg N ha(-1)) greater than exported N (463-597 kg N ha(-1)). Hence, throughout the irrigation period, high NO(3)(-) concentrations (up to 388 mg L(-1) at T200) and DOC (up to 142 mg L(-1) at T100) were measured in soil solution below the root zone, indicating the potential of groundwater contamination. TSE irrigation did not change soil TC and TN. (C) 2009 Elsevier B.V. All rights reserved.

Reclaimed wastewater: Effects on citrus nutrition

The effects of irrigation with reclaimed wastewater (RWW) were compared with well water (WW) on citrus (Citrus paradisi Macfad. X Citrus aurantium L) nutrition. The deviation from the optimum percentage (DOP) index of macro- and micro-nutrients were used to evaluate the nutritional status: optimal (DOP = 0), deficiency (DOP < 0) or excess (DOP > 0). After 11 years of RWW irrigation the influence on nutrient concentration in plants decreased in the order: B > Zn > Mn = Ca > Cu > Mg > P > K. Reclaimed wastewater irritation positively affected citrus nutrition as it rendered the concentration of macronutrients, i.e. P, Ca, and K. closer to their optimum levels (Sigma DOP(macro) = 7). However micro-nutrients tended to be excessive in plants (EDOP(micro) = 753) due to imbalanced supply of these elements in the RWW, particularly, for B and Cu. Citrus groves with long-term RWW irrigation may exercised caution in monitoring concentrations of B and Cu to avoid plant toxicity and soil quality degradation. (C) 2011 Elsevier B.V. All rights reserved.

Wastewater usage in urban and peri-urban agricultural production systems: scenarios from India

The role urban and peri-urban agriculture (UPA) plays in reducing urban poverty and ensuring environmental sustainability was recognized by the Millennium Development Goals (MGDs). India is the world’s largest democratic nation with a population of 1.2 billion. The rapid urbanization and high proportion of people below the poverty line along with higher migration to urban areas make India vulnerable to food crisis and urbanization of poverty. Ensuring jobs and food security among urban poor is a major challenge in India. The role of UPA can be well explained and understood in this context. This paper focuses on the current situation of UPA production in India with special attention to wastewater irrigation. This question is being posed about the various human health risks from wastewater irrigation which are faced by farmers and labourers, and, secondly by consumers. The possible health hazards involve microbial pathogens as well as helminth (intestinal parasites). Based on primary and secondary data, this paper attempts to confirm that UPA is one of the best options to address increasing urban food demand and can serve to complement rural supply chains and reduce ecological food prints in India. “Good practice urban and peri-urban agriculture” necessitates an integrated approach with suitable risk reduction mechanisms to improve the efficiency and safety of UPA production.

Parasitological risk assessment from wastewater reuse for disposal in soil in developing countries

The purpose of this work is to analyze the parasitological risks of treated wastewater reuse from a stabilization pond in the city of Piracicaba, in the State of Sao Paulo (Brazil), and the level of treatment required to protect public health. Samples were taken from raw and treated wastewater in stabilization ponds and submitted to a parasitological, microbiological and physicochemical analysis. The study revealed on treated wastewater the presence of Ascaris sp. and Entamoeba coli with an average density of 1 cysts L-1 and 6 eggs L-1, respectively. For Ascaris, the annual risks of infection due to the accidental ingestion of wastewater irrigation were 7.5 x 10(-2) in 208 days and 8.7 x 10(-2) in 240 days. For Total Coliforms and Escherichia coli in treated wastewater, the average density was 1.0 x 10(5) MPN/100 ml and 2.7 x 10(4) MPN/100 ml respectively, representing 99% and 94% removal efficiency, respectively. For BOD, COD, TS and TSS removal efficiency was 69, 80, 50 and 71%, respectively. The removal efficiency for nitrogen; ammonia nitrogen and total phosphate was 24, 19 and 68%, respectively. The average density of helminths eggs in treated wastewater is higher compared to the density of the limit value of <= 1 egg L-1 and tolerable risk is above the level recommended by the World Health Organization. Multiple barriers are necessary for the reduction of organic matter, chemical contaminants and parasites from treated wastewater. Standards for the sanitary control of treated wastewater to be reused in agricultural irrigation areas should be compiled for developing countries in order to minimize public health risks.

Effet de l’irrigation par l’eau usée sur la biomasse aérienne et souterraine d’une culture intensive de saules en courtes rotations

Le but de cette étude est de comprendre l’effet d’une irrigation par les eaux usées et /ou de la fertilisation par les engrais chimiques sur la productivité aérienne et souterraine d’une plantation de saule Salix miyabeana SX67 en CICR dans un contexte de filtre végétal. Nous avons d’une part évalué l’impact de diverses doses d’eau usées et/ou de la fertilisation minérale sur les rendements en biomasse ligneuse d’une culture de saules au cours d’un cycle de croissance de deux ans. D’autre part et pour la même période nous avons comparé le développement racinaire (biomasse, morphologie et distribution dans le sol) suite aux divers traitements. Les résultats ont montré qu’au terme de deux ans de croissance, les traitements par les eaux usées aussi bien que celle par les engrais a permis l’augmentation des rendements de la biomasse aérienne de notre culture de saules avec un effet plus prononcé suite au traitements des eaux usées qu’à celui du fertilisant chimique. Nous avons mesuré des productivités en biomasse aussi élevées que 39,4 Mg ha-1 et 54,7 Mg ha-1 et ce pour les parcelles qui ont reçu la plus grande quantité d'eaux usées, respectivement pour les saules non fertilisé et fertilisé (D3-NF et D3-F). La majeure partie du système racinaire était en superficie avec 92-96% des racines (racine fine et racine grosse) concentrées dans les premiers 40 cm de sol et nous avons trouvé que la biomasse des racines fines était comprise entre 1,01 et 1,99 Mg ha-1. Généralement la fertilisation chimique n’a pas eu d’effet sur les rendements en biomasse des racines totales et/ou fines. Bien que l’irrigation par les eaux usées ait entraîné une réduction statistiquement significative de la biomasse racinaire, néanmoins cette réduction n'était pas linéaire (avec une réduction de la biomasse de D0 à D1, une augmentation de D1 à D2 pour réduire de nouveau de D2 à D3). Cette tendance porte à penser qu'au-delà d'une certaine quantité d'eau et de nutriments (suite à l’irrigation par les eaux usées), le développement du système racinaire des saules est affecté négativement, et bien que la biomasse aérienne soit restée élevée sous le traitement D3, nous pensons que le développement de la plante a été quelque peu déséquilibré. Aucun changement significatif n'a été constaté dans les traits morphologiques liés à l'irrigation par les eaux usées.

Socio-economic characterization of integrated cropping systems in urban and peri-urban agriculture of Faisalabad, Pakistan

Faisalabad city is surrounded by agricultural lands, where farmers are growing vegetables, grain crops, and fodder for auto-consumption and local marketing. To study the socioeconomic impact and resource use in these urban and peri-urban agricultural production (UPA) systems, a baseline survey was conducted during 2009–2010. A total of 140 households were selected using a stratified sampling method and interviewed with a structured questionnaire. The results revealed that 96 % of the households rely on agriculture as their main occupation. Thirty percent of the households were owners of the land and the rest cultivated either rented or sharecropped land. Most of the families (70 %) were headed by a member with primary education, and only 10 % of the household head had a secondary school certificate. Irrigationwater was obtained from waste water (37 %), canals (27 %), and mixed alternative sources (36 %). A total of 35 species were cultivated in the UPA systems of which were 65% vegetables, 15% grain and fodder crops, and 5% medicinal plants. Fifty-nine percent of the households cultivated wheat, mostly for auto-consumption. The 51 % of the respondents grew cauliflower (Brassica oleracea L.) and gourds (Cucurbitaceae) in the winter and summer seasons, respectively. Group marketing was uncommon and most of the farmers sold their produce at the farm gate (45 %) and on local markets (43 %). Seeds and fertilizers were available from commission agents and dealers on a credit basis with the obligation to pay by harvested produce. A major problem reported by the UPA farmers of Faisalabad was the scarcity of high quality irrigation water, especially during the hot dry summer months, in addition to lacking adequate quantities of mineral fertilizers and other inputs during sowing time. Half of the respondents estimated their daily income to be less than 1.25 US$ and spent almost half of it on food. Monthly average household income and expenses were 334 and 237 US$, respectively.

Connecting the Water and Carbon Cycles for the Generation of Food Security and Ecosystem Services

Water scarcity and food insecurity are pervasive issues in the developing world and are also intrinsically linked to one another. Through the connection of the water cycle and the carbon cycle this study illustrates that synergistic benefits can be realized by small scale farmers through the implementation of waste water irrigated agroforestry. The WaNuLCAS model is employed using La Huerta agroforestry site in Texcoco, South Central Mexico, as the basis for parameterization. The results of model simulations depicting scenarios of water scarcity and waste water irrigation clearly show that the addition of waste water greatly increases the agroforestry system’s generation of crop yields, above- and below-ground biomass, soil organic matter and carbon storage potential. This increase in carbon sequestration by the system translates into better local food security, diversified household income through payments for ecosystem services and contributes to the mitigation of global climate change.

Ensaios de tratamento de efluentes de indústria de chapa dura de fibra de madeira

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da qualidade microbiológica e produção de alface americana (Lactuca sativa L.) sob diferentes sistemas de irrigação, utilizando águas residuárias

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aplicação de água residuária de suinocultura tratada em sistema de alagados construídos, via irrigação por gotejamento nas culturas de milho e de sorgo

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Impactos en el agua subterránea de un sistema de efluentes para riego : el Sistema Paramillos (Lavalle, Mendoza, Argentina)

En este trabajo se evalúa el impacto de un sistema de aprovechamiento de efluentes domésticos para riego en la calidad del agua subterránea. Los puntos de muestreo seleccionados son parte de un monitoreo a mayor escala del cual sólo se incluyeron aquellos relacionados con el sistema de la planta depuradora Paramillos, ubicada al Norte del aglomerado Mendoza. Esta planta consiste en una laguna de estabilización facultativa. Los resultados, presentados en gráficos, mapas y tablas, se discuten a partir del comportamiento de tres componentes del sistema hídrico: agua superficial (efluente), agua subterránea del nivel superior del acuífero (freática) y agua subterránea del acuífero profundo (confinado/ semiconfinado) y su interacción con el perfil del suelo. Se concluye que el acuífero profundo no es alcanzado por nitratos ni nitritos productos de la degradación biológica de la materia orgánica del efluente, lo que se atribuye a la capa impermeable subyacente. En el nivel superior o freático, el perfil del suelo remueve parte del N total y P total ingresado, entre el 39 y 90%. La remoción de DBO varía entre 30 y 90% y la remoción de E. coli remanente en efluente es total.

Effect of phytoremediation with Atriplex nummularia in irrigated soils with saline waste..

In the semi-arid region of northeastern Brazil, the Atriplex plant genus has been efficient in removing salts from soils irrigated with saline wastewater. However, this removal might not be significant compared with the amount of salts added to the soil by the wastewater irrigation. Considering this aspect, the aim of this work was to evaluate the effectiveness of Atriplex nummularia Lindl plants in the remediation of a soil submitted to saline wastewater irrigation. Despite the known inhibition effect of saline wastewater on soil enzyme activity, the cultivation of Atriplex nummularia Lindl maintained the treated soil enzyme activity levels similar to the ones found in natural soils.