Effects of fertigation with purified urban wastewater on soil and pepper plant (Capsicum annuum L.) production, fruit quality and pollutant contents

Abstract

The effects, in greenhouse conditions, of Purified Urban Wastewater (PW) from Almería (Spain), in the fertigation of pepper (Capsicum annuum L.) on sandy mulch soil, were evaluated. Primary, secondary (active sludges) and tertiary (Chlorination + ozonation) purification treatments were applied to wastewater. Irrigation treatments applied were PW, natural Ground Water (GW), Fertilizer PW (FPW) and Fertilizer GW (FGW). The vegetal biomass, yield and fruit quality were controlled. Heavy metals (Cr, Cd, Pb, Ni, Mn, Cu and Zn), arsenic (As) and Polycyclic Aromatic Hydrocarbons (PAH) in water, soil, leaf, and fruit were analysed. The PW presented heavy metal, As and PAH contents acceptable for its use in drip irrigation. In the soil, fertigated with PW, the concentration of heavy metals and As did not increase, whilst the PAH concentration decreased. The PW treatment supplied enough nutrients to obtain yield and fruit quality equal to that of GW with fertilization. A significant saving on N, P and K fertilizers (37%, 66% and 12% respectively) was achieved by using PW. The Cd, Pb and As contents of the fruit did not show risk for human consumption. The total PAH concentrations in the fruit were low, the highest of which was phenathrene, with no carcinogenic signification.Additional key words: fertilizer savings; food safety; heavy metals; irrigation; polycyclic aromatic hydrocarbons (PAH); treated wastewater. ResumenEfectos de la fertirrigación con agua urbana regenerada sobre el suelo, la producción y calidad de pimiento (Capsicum annuum L.) y contenidos de contaminantes Se han evaluado los efectos de la utilización de un agua residual urbana purificada (PW) procedente de la ciudad de Almería (España) para la fertirrigación del cultivo de pimiento (Capsicum annuum L.) en invernadero sobre enarenado. Al agua residual se le aplicó tratamiento de depuración primario, secundario (lodos activados) y terciario (cloración + ozonización). Los tratamientos de fertirrigación fueron: PW, agua natural de origen subterráneo (GW), agua residual urbana depurada con fertilización (FPW) y agua natural de origen subterráneo con fertilización (FGW). Se controlaron la biomasa vegetal, la producción y la calidad del fruto. En las aguas, suelos, hojas y frutos, se analizaron metales pesados (Cr, Cd, Pb, Ni, Mn, Cu and Zn), arsenico (As) e hidrocarburos aromáticos policíclicos (PAH). El PW se consideró apta para uso en riego localizado atendiendo a sus niveles de metales pesados, As y PAH. El tratamiento PW suministró nutrientes suficientes para obtener producción y calidad de pimiento iguales al tratamiento FGW. En suelo, no se observó acumulación de metales pesados ni As y disminuyeron las concentraciones de PAH. Se obtuvieron ahorros significativos de fertilizantes nitrogenados, fosfóricos y potasicos (37, 66 y 12% respectivamente) al utilizar PW. Los contenidos de metales pesados, As y PAH en el fruto no representaron riesgo para el consumo humano. En cuanto a PAH, la mayor concentración registrada fue de fenantreno, compuesto n...

Effect of Substrate, Feeding Mode and Number of Stages on the Performance of Hybrid Constructed Wetland Systems

“…Nevertheless, far from being a disadvantage the modest efficiency of CWs in the removal of N and P can be regarded as a way to decrease the demand for expensive inorganic fertilizers in agriculture [39]. For instance, García-Delgado et al [40] saved considerable amounts of fertilizer (37% N, 66% P and 12% K) by applying treated urban wastewater in pepper cultivation. In fact, wastewater effluent reuse has been widely implemented in many countries with Israel and California (USA) leading wastewater reuse with 65-70% of the wastewater reused in agriculture [41].…”

Recycling of domestic wastewater treated by vertical-flow wetlands for irrigating Chillies and Sweet Peppers

“…Unfavourable concentrations of certain nutrients and trace elements are a challenge to the growth of plants fed by recycled pre-treated wastewater. Moreover, traces of hydrocarbons from diesel spills associated with urban runoff or industrial effluent are a more recent challenge (García-Delgado et al, 2012;Scholz, 2010). García-Delgado et al (2012) undertook a greenhouse study in Spain to assess the effect of treated urban waste water on soil and pepper quality.…”

“…Moreover, traces of hydrocarbons from diesel spills associated with urban runoff or industrial effluent are a more recent challenge (García-Delgado et al, 2012;Scholz, 2010). García-Delgado et al (2012) undertook a greenhouse study in Spain to assess the effect of treated urban waste water on soil and pepper quality. The wastewater application saved fertiliser (37% nitrogen, 66% phosphorus and 12% potassium).…”

Microbial contamination of Capsicum annuum irrigated with recycled domestic wastewater treated by vertical-flow wetlands

“…The maximum number of total coliforms is 1000 CFU/100 ml for irrigation of crops that are likely to be eaten uncooked (WHO, 1989;FAO, 2003). García-Delgado et al (2012) undertook a greenhouse study in Spain to assess the effect of treated urban wastewater on soil and pepper quality. They concluded that the wastewater application saved fertilizer (37% nitrogen, 66% phosphorus and 12% potassium) as well as that the total polyaromatic hydrocarbons and heavy metals (cadmium, lead and arsenic) within the pepper fruits were low.…”

“…The highest concentration (lower than the proposed threshold concentration for carcinogenicity) was recorded for phenathrene. Moreover, traces of hydrocarbons from diesel spills associated with urban runoff or industrial effluent are a more recent challenge (Scholz, 2010;García-Delgado et al, 2012). Furthermore, Benedek et al (2013) studied the impact of long-term total petroleum hydrocarbons (TPH), volatile petroleum hydrocarbons, total alkyl benzenes and polycyclic aromatic hydrocarbons on the structure of bacterial communities of four different contaminated soil samples.…”