Effect of a combined filtration system and drip irrigation laterals on quality of rainbow trout farm effluent

Abstract

The main aim of this study was to investigate the qualitative changes of the rainbow trout effluent as water supply in a drip irrigation system. Two drip irrigation systems with a hydrocyclone filter, sand filter and screen filter for using freshwater (control treatment) and fish farm effluent were tested in Kurdistan province (northwest of Iran) in 2017. In addition, the effect of lateral drainage at the end of each irrigation event was also studied. Two emitter types with different discharge flows were used for each treatment. In the 16 irrigation events carried out, samples were collected from the different water sources (dam, well, and river), filter outlets and lateral locations for measuring total suspended solids (TSS), particle size, pH, electrical conductivity, different compounds (Fe, Na, K, Ca, Mg, NO3, PO4, HCO3) and the number of coliform bacteria. The results showed changes in the TSS and the number of coliform bacteria, but the remaining parameters had slight changes. In both control and effluent treatments, the filtration system significantly reduced TSS, having the screen filters the greatest effect on this decrease and hydro-cyclone and sand filter the least. In order to achieve higher removals, finer grains in sand filters. The filtration of both control and effluent treatments increased the number of bacteria. The highest number of bacteria in the control treatment was measured after the sand filter and in the effluent treatments after the screen filter

Performance of sand filter with disc and screen filters in irrigation with rainbow trout fish effluent

“…This operation time can be acceptable for T1 and T2 treatments but is too short for T3 treatment. Manbari et al (2020) reported a minimal head loss in a sand filter (with 3–5 mm and 5–8 mm grain sizes) in the treatment of rainbow trout effluent. In the present study, however, the sand sizes were smaller (0.8–1.2 mm and 2–3.5 mm), and consequently pressure loss and solids removal were higher, as has been previously reported (Duran‐Ros et al, 2009).…”

“…In the present experiment, solids removal efficiencies with the sand and disc filter (65%–68%) and trout fish effluent were between those values previously observed with urban effluents. Manbari et al (2020) observed suspended solids removal efficiencies for a screen filter placed after a sand filter of 23% and 43% with fresh water and trout fish farm effluent, respectively. In the present work, with a smaller grain size, the efficiencies increased considerably.…”

“…Drip irrigation is the most suitable irrigation system for the reuse of effluents in agriculture (Li et al, 2015; Pandey et al, 2010), but its main drawback is emitter clogging, which is exacerbated when effluents are used (Capra & Scicolone, 2007; Maroufpoor et al, 2021; Pandey et al, 2010). Therefore, using a filtration system to remove suspended solids (Nieto et al, 2016; Wen‐Yong et al, 2015) and thus preventing emitter clogging is required (Manbari et al, 2020; Nieto et al, 2016).…”

“…In Iran, multilayer sand filters filled with silica sand are widely used for freshwater filtration for irrigation of fields since farmers are satisfied with their performance (Daee et al, 2019; Dashti et al, 2021). Manbari et al (2020), using a common sand filter in Iran for irrigation with rainbow trout effluent, found that its performance was very poor, which was attributed to the sand particle size and the type of suspended solids in the fish effluent. With this in mind, Wen‐Yong et al (2015) achieved increased removal efficiencies when a disc filter was placed after a sand filter.…”

Performance of Disc, Conventional and Automatic Screen Filters Under Rainbow Trout Fish Farm Effluent for Drip Irrigation System

“…These varied performances may be attributed to differences in the type of wastewater or the level of treatment. It was shown that in using the e uent of multi-stage farms of rainbow trout, the screen lter (125-149 µm) performed better than the sand lter (grain size 3-5 and 5-8 mm) (Manbari et al, 2020).…”