Reduction in effluent nutrient loads from flow-through facilities for trout production: a review

Abstract

The environmental legislation on waste loadings and the public discussion on environmental issues concerning inland aquaculture facilities have become stronger in recent years. An end of the discussion cannot be foreseen. At the same time, the pollution emitted per ton of ¢sh produced has decreased successively over the last 20 years. In this con£ict, this paper provides an overview on: (1) pollutants typical for £ow-through trout aquaculture, (2) their source and potential environmental impacts and (3) strategies to reduce the e¥uent pollution from £owthrough trout farms, a brief description of their function principles and application and, if possible, their economical feasibility. This study aims to identify the actual e¥uent problems of £ow-through trout aquaculture and to o¡er possible solutions by either pollution avoidance or e¥uent treatment. Future trends and research needs on e¥uent treatment are outlined. As the amount of nutrients discharged is typically site and operation speci¢c, farm management is most important for avoidance of e¥uent pollution. Nevertheless, for further production expansion, 'end of pipe' technologies are needed to reach adequate e¥uent qualities. Partial water reuse can improve ef-£uent discharge. Physical, chemical and biological technologies can be used to treat trout farm e¥uents. Today, the commonly used physical (mechanical) treatments in trout aquaculture like screening and sedimentation only remove suspended solids, containing up to 7^32% of total nitrogen and 30^84% of total phosphorus. The remaining soluble nutrients can only be removed by either the application of che-micals or biological e¥uent treatments. The possible applications of biological technologies are manifold, but practical and upscale experience is lacking.

Waste loading into a regulated stream from land-based trout farms

“…Determined ranges and mean nutrient increases in effluents in our study are broadly consistent with the summarized data for several rainbow trout Oncorhynchus mykiss farms (Stewart et al 2006, Sindilariu 2007, Aubin et al 2009, Sindilariu et al 2009, Tello et al 2010. Effluent characteristics are also in concordance with the results of previous research on flowthrough rainbow trout farms in the same region as our study (Tekinay et al 2009, Bilgin Yıldırım & Pulatsü 2011.…”

Water Quality Index as a Tool for Assessment of Status of an Urban Lake of Mumbai

“…3), in catchments under the effect of diffuse discharges from industrial as well as treated and untreated sewage wastes of urban community (Neal and Jarvie, 2005;Jarvie et al, 2008). For a well thrive aquaculture, DO and BOD are critical to a certain degree (Sindilariu, 2007;Shamir et al, 2015), are dominated by COD as well as A/T and W/T, (Fig. 4 and 5) respectively (Foy and Rosell, 1991;Roque d'Orbcastel et al, 2008;Mehet and Huseyin, 2014).…”

“…4 and 5) respectively (Foy and Rosell, 1991;Roque d'Orbcastel et al, 2008;Mehet and Huseyin, 2014). Chloride can be removed up to 90-95% via aeration and distillation, but the removal of hardness is highly difficult (Sindilariu, 2007;Sindilariu et al, 2009b); thereby the ratio of alkalinity may increase (Dalsgaard and Pedersen, 2011).…”

The potential of a salt-tolerant plant (Distichlis spicata cv. NyPa Forage) to treat effluent from inland saline aquaculture and provide livestock feed on salt-affected farmland

“…These effects are due partly to the toxicity of substances such as ammonia and nitrite, but mostly to the promotion of eutrophication (Sindilariu, 2007;Simōes et al, 2008). Eutrophication of freshwater ecosystems is increasingly being recognised as a major environmental problem in Australia (Davis and Koop, 2006).…”

“…Aquaculture effluent contains nutrients in both particulate and dissolved forms (Sindilariu, 2007). Technologies for treating aquaculture effluent have been mainly based on the mechanical separation of solids to purify drained water using static and rotating screens, or in the case of flow through systems, effluent sedimentation in tanks or ponds (Van Rijn, 1996).…”