Elsevier

Aquaculture

Volume 306, Issues 1–4, 15 August 2010, Pages 153-159
Aquaculture

Keeping the water clean — Seaweed biofiltration outperforms traditional bacterial biofilms in recirculating aquaculture

https://doi.org/10.1016/j.aquaculture.2010.05.032Get rights and content

Abstract

In order to compare the efficacy of seaweeds and bacterial biofilm for removing nitrogenous wastes from recirculating marine aquaculture, Ulva lactuca L., Undaria pinnatifida Suringar, and a trickling biofilm filter were introduced to systems housing Haliotis iris Gmelin. Experiments were triplicated and run for 14 days. Although biofilm filtration maintained ammonium at low concentrations (around 0.10 mg l 1), nitrate levels increased linearly over time, reaching 2.30 mg l 1. Seaweeds maintained ammonium at concentrations that were consistently lower (around 0.03 mg l 1) than those observed with biofilm filtration. Moreover, nitrates were undetectable and pH less variable, whilst valuable seaweed biomass, with increases up to 50%, was generated. Seaweed filtration thus has the potential to improve the efficiency and productivity of recirculating aquaculture, via enhanced culture conditions and the production of economically valuable biomass.

Introduction

Reducing the negative environmental impacts associated with aquaculture activities is key to ensuring the long-term sustainability of the industry (Troell et al., 2003). One potential avenue is the increased use of land-based recirculating aquaculture systems. Such systems allow more effective control of culture conditions, and permit many negative impacts on the surrounding environment to be minimised (Piedrahita, 2003). Waste products can be contained within the facility, habitat degradation is decreased or eliminated, and decreased interaction between culture organisms and wild organisms prevents spread of disease or escape of exotic species (Emerson, 1999, Piedrahita, 2003).

However, the accumulation of nitrogenous wastes is a major drawback of recirculating systems; such wastes are typically excreted by the culture species as ammonium (Randall and Wright, 1987, Wood, 1958, Wright, 1995), which is acutely and chronically toxic to aquatic organisms (Randall and Tsui, 2002, Thurston and Russo, 1983). Therefore, some form of filtration is required to keep these wastes below levels that cause biological and economic harm. Traditionally, biofilm filtration has been employed to control ammonium concentrations (Greiner and Timmons, 1998). Such systems exploit the action of Nitrosomonas and Nitrobacter bacteria (van Rijn, 1996, Watten and Sirbrell, 2006), which work in tandem to oxidise highly toxic ammonium to largely inert nitrate in a two part process. However, this system has several disadvantages because i) nitrifying bacteria compete with the culture species for oxygen (Greiner and Timmons, 1998) ii) nitrate can be converted to the highly toxic compound nitrite under anoxic conditions (van Rijn, 1996, Watten and Sirbrell, 2006) and iii) systems using biofilm filtration typically acidify over time due to respiration of both the culture species and the biofilm (van Rijn, 1996). These factors can all contribute to decrease survival, growth and reproduction of the culture organism. An additional issue is that biofilm filtration does not make commercial use of waste nitrogen.

In contrast seaweeds are able to convert nutrient-rich effluents into biomass, which can then be harvested and used to feed the aquaculture species or sold for human consumption, pharmaceuticals, etc. (Chopin et al., 2001, Neori et al., 2004). Thus, the integrated growth of seaweeds can add significant revenue to an aquaculture concern (Chopin et al., 2001, Shpigel and Neori, 1996). Several studies have investigated integrated multi-trophic aquaculture (IMTA), co-culturing Gracilariopsis bialinae Zhang and Zia and Chanos chanos Forsskal (Alcantara et al., 1999), Ulva rigida Agardh and Sparus aurata L. (Ramazanov and Garcia-Reina, 1994), Ulva latuca L. and S. aurata (Ellner et al., 1996), Palmaria mollis Stearn and Haliotis rufescens Swainson (Evans and Langdon, 2000), S. aurata, Haliotis tuberculata L. and U. lactuca (Neori et al., 1996, Neori et al., 1998, Neori et al., 2000, Neori et al., 2003). The success of many of these preliminary studies indicates that the use of seaweeds as biofilters is likely to have significant industrial applications for a range of aquaculture species.

While many studies have proven the feasibility of seaweed biofiltration, none so far have directly compared the efficacy of such systems to biofilm filtration. The aim of the current study, therefore, was to directly compare the efficacy of two seaweed species (U. lactua and Undaria pinnatifida Suringar) in assimilating nitrogenous wastes, produced by blackfoot abalone (Haliotis iris Gmelin), to biofilm filtration.

Section snippets

Experimental systems

All experiments were carried out at Portobello Marine Laboratory, University of Otago, Dunedin, New Zealand. The experimental tanks were situated in a semi-enclosed glass house, which provided protection from the weather while allowing natural light.

The experimental setup consisted of four identical systems, each comprising of an upper filtration tank and a lower culture tank (both 70 l plastic bins), giving a total volume of approximately 80 l. Water was pumped from the lower culture tanks into

Stocking rates and tank effect

There was no significant difference between the biomass of H. iris added to each treatment (DF = 11, F = 0.46, p = 0.716). Similarly, there was no significant difference in the average starting and finishing weight or length distributions of H. iris between the four treatments; in effect, growth (length, weight) was near-zero in all groups (average change in length: 0.05 ± 0.02 mm, average change in weight: − 0.01 ± 0.01 g). The similar stocking rates and size distributions of H. iris added to each

Discussion

The aim of this study was to compare the ability of seaweed and biofilm filtration in controlling ammonium concentrations in a recirculating marine aquaculture system. It was observed that biofiltration is a powerful means to maintain ammonium concentrations within low to undetectable levels, and seaweeds, under the conditions used, are better than biofilm filtration in this capacity. Indeed, seaweeds exhibited an ability to maintain ammonium at a lower concentration than did the biofilm. As

Acknowledgements

A special thanks to Dr. Rodney Roberts from Oceanz Blue NZ Ltd for offering to donate the abalone used in our study, and for the advice offered on various aspects of abalone culture. Staff at Portobello Marine Laboratory (especially Bev Dickson, Rene van Balen and Dave Wilson) are acknowledged for making facilities and human resources available for our experiment. We are also grateful to Mrs Nicky McHugh, Dr. Christoph Mathaei and Mr Ken Miller (all Department of Zoology, University of Otago,

References (44)

  • A. Neori et al.

    Integrated aquaculture: rationale, evolution and state of the art emphasising seaweed biofiltration in modern mariculture

    Aquaculture

    (2004)
  • R.H. Piedrahita

    Reducing the overall impact of tank aquaculture effluents through intensification and recirculation

    Aquaculture

    (2003)
  • S. Porrello et al.

    Reduction of aquaculture wastewater eutrophication by phytotreatment ponds system: II. Nitrogen and phosphorous content in macroalgae and sediment

    Aquaculture

    (2003)
  • S. Porrello et al.

    Reduction of aquaculture wastewater eutrophication by phytotreatment pond systems: I. Dissolved and particulate nitrogen and phosphorous

    Aquaculture

    (2003)
  • H.B.A. Prins et al.

    Bicarbonate utilization: function and mechanisms

    Aqua. Bot.

    (1989)
  • P. Ralph et al.

    Rapid light curves: a powerful tool to asses photosynthetic activity

    Aqua. Bot.

    (2005)
  • D.J. Randall et al.

    Ammonia toxicity in fish

    Mar. Pollut. Bull.

    (2002)
  • M. Shpigel et al.

    The integrated culture of seaweed, abalone, fish and clams in modular intensive land based systems: I. Proportions of size and projected revenues

    Aquac. Eng.

    (1996)
  • M. Troell et al.

    Integrated mariculture: asking the right questions

    Aquaculture

    (2003)
  • J. van Rijn

    The potential for integrated biological treatment systems in recirculating fish culture: a review

    Aquaculture

    (1996)
  • S. Zhu et al.

    An experimental study on nitrification biofilm performance using a series of reactor systems

    Aquac. Eng.

    (1999)
  • L.B. Alcantara et al.

    Comparison of the performance of the agarophyte, Gracilaria bilaine, and the milkfish, Chanos chanos, in mono- and bi-culture

    Hydrobiologia

    (1999)
  • Cited by (44)

    • A dynamic nutrient mass balance model for optimizing waste treatment in RAS and associated IMTA system

      2022, Aquaculture
      Citation Excerpt :

      In RAS, ammonic nitrogen (NH4+) released as dissolved inorganic waste from salmon, undergoes aerobic nitrification in a biological filtration unit, such as a moving bed bioreactor (MBBR) (Emparanza, 2009). This process converts toxic NH4+ into nitrate (NO3−) which can be tolerated at much higher concentrations by salmon (Cahill et al., 2010; Martins et al., 2010; Yogev et al., 2017). The range of particle sizes requires the use of multiple treatment methods in particulate waste removing within RAS (McMillan et al., 2003).

    • Opportunities and challenges in algal biofuel

      2022, Algae and Aquatic Macrophytes in Cities: Bioremediation, Biomass, Biofuels and Bioproducts
    • Insights on broad spectrum applications and pertinence of biofiltration in various fields

      2021, An Innovative Role of Biofiltration in Wastewater Treatment Plants (WWTPs)
    • Oxytetracycline accumulation in the macroalgae Ulva: Potential risks for IMTA systems

      2019, Chemosphere
      Citation Excerpt :

      Such detoxification mechanisms were already described for some macroalgae (Lewis et al., 2001; Mehrtens, 1994) and also for Ulva (Pflugmacher and Sandermann, 1998; Pflugmacher et al., 1999), but to the best of knowledge, no studies on OTC have been addressed concerning potential detoxification mechanisms. It is vastly agreed that macroalgae can have an important bioremediation role, such as in aquaculture sites (e.g. Ben-Ari et al., 2014; Granada et al., 2015), with several works addressing the positive nutrient uptake from such sites (Cahill et al., 2010; Zhou et al., 2006). This capacity will also translate into accumulation of hazardous compounds such as metals (Jarvis and Bielmyer-Fraser, 2015) or antibiotics (Leston et al., 2014, 2011), which may pose a risk to the consumer when macroalgae is cultivated with the purpose of use either in cosmetic or pharmaceutical purposes, or more relevant, as food products (Barrington et al., 2009; FAO, 2014; Neori et al., 2004; Troell et al., 2009).

    • Response and environmental assessment of two Chinese conventional carps to water quality regulation in recirculating aquaculture

      2016, Aquacultural Engineering
      Citation Excerpt :

      The higher quantities of feed intake/total yield in the recirculating ponds might be largely attributed to the replenishment of clean water from the four-stage hybrid CWs. Similarly, there are also some cases supporting that recirculation treatment or filtration has the potential to improve culture efficacy via enhanced culture conditions (Cahill et al., 2010; Lin et al., 2003; Liu et al., 2014). Moreover, the negative correlations between water quality parameters and feed intake/grass carp yield may have been observed because more fish not only ingested more corresponding to higher excretion but also led to stronger feeding and swimming activities that might induce the release of dissolved solids from the sediment.

    View all citing articles on Scopus
    View full text