Page 18

Filtration of colloidal matter in Recirculating Aquaculture Systems (RAS)

More information: Julian A. Mamo Water Engineering, monitoring and control systems AquaBioTech Group Central Complex Naggar Street Targa Gap, Mosta MST 1761 Malta G.C. SKYPE: jam-abtg Main Office: +356 2258 4100 Mobile: +356 9996 7550 Direct Line: +356 2258 4114 Rob J. Davies Senior Aquaculture Consultant AquaBioTech Group Central Complex Naggar Street Targa Gap Mosta MST 1761 Malta G.C. SKYPE: rjd-abtg Main Office: +356 2258 4100 Mobile: +356 9910 2565 Direct Line: +356 2258 4119

Land-based recirculation systems are a

tive methods that are developed and tested

organic matter. The organic matter in

modern alternative to traditional net-pen

at our R&D facility in Malta and applied in

aquaculture water varies with the quality of

and flow through culture systems. They

the construction of our commercial scale

the incoming water, the production on the

offer a strict control and monitoring of the

RAS farms.

farm (species, feed, growth rate, etc.) and

environment that the organisms are grown

whether seawater or freshwater is used.

in, which is bio-secure and non-detrimental

A key component in operating intensive RAS

Colloidal organic compounds, to be

to the surrounding environment. Due to the

is controlling the accumulation of fine

removed, typically include microorganisms

extremely fast growth rates and efficient

particulate matter known as colloids. There

(bacteria, viruses, fungi and algae), faeces

utilization of precious water supplies,

is no strict range of particles that are

and waste feed, while dissolved organic

investment and development of RAS

defined as colloidal matter, but colloids are

material in the RAS water column would be

technology has flourished.

typically particles smaller than one (1)

made up of proteins, amino acids,

this, the Department for Environment, Food

In addition to

micrometre that do not settle and for which

phosphates, urea, humic acids and fatty

& Rural Affairs (DEFRA), Food and Agricul-

mechanical filtration is ineffective. A focus

acids.

ture Organization (FAO) and European

on the control of nitrogenous compounds

Commission have identified that political,

and suspended particulate matter without

Apart from the consumption of dissolved

social and environmental drivers favor

taking a closer look at colloidal matter will

oxygen during the biological degradation of

development of RAS as a sustainable source

have a number of detrimental effects on fish

organic matter, the breakdown of organic

of aquaculture for the future. However,

health and the biological and chemical

wastes by sheer forces and microbial

there are many challenges in a technological

processes controlling the removal of

degradation into other products could both

solution to filtering the metabolites of the

nutrients and particulate wastes from the

increase the total ammonia nitrogen as well

organisms cultured, beyond the removal of

system.

as support the growth of heterotrophic

macro- particulate matter. At AquaBioTech

bacteria affecting nitrification. The concen-

Group, these challenges are being met and

Typically, more than half of the dry weight

tration of both dissolved and colloidal

overcome using new, efficient and innova-

of the total solids in a RAS water column is

organic material also affects the prolifera-

Aquaculture Scoop / March Issue 2016

Page 16

Aquaculture Scoop - March 2016  

In this issue we take a look at Extrusion advances with insight from Andritz, Gordon Young and Dennis Forte. We learn about Processing Techn...

Aquaculture Scoop - March 2016  

In this issue we take a look at Extrusion advances with insight from Andritz, Gordon Young and Dennis Forte. We learn about Processing Techn...

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