| Front page | | Contents | | Previous | | Next |

Cleaner Technology Projects in Denmark 1996

Development of Lock Systems for Dry Transportation in the Beluga Processing Industry

Udvikling af slusesystemer til tørtransport i hvidfiskeindustrien
Arbejdsrapport nr. 8, 1996, Miljøstyrelsen

The beluga processing industry contributes considerably to pollution when offal from the fillet lines is washed away. In the present system, which is based on water transportation, the fish offal is washed out during the transportation, which causes organic compounds in the wastewater in the subsequent separation in spiral and rotosieve.

In order to change these conditions in the fish processing industry, further actions for development must be taken. Earlier projects completed in the fish processing industry have shown that the implementation of vacuum transportation systems and suction apparatus at the filet lines results in cleaner technology.

Based on the experience derived from earlier projects, the purpose of this project is to develop a new technique for transportation of offal. The technique intents to let in the offal gradually at the fillet line and to sluice it out from a vacuum transportation system.

The practical part of the project was carried out in the period January 1994 – July 1994.

In order to start the development of locks, the water consumption at the test line has to be reduced to a minimum consumption. The report describes how water savings systematically are gained on all parts of the fillet lines. That is the head cutter, the filleting part and the skinning part. The results are presented schematically.

After the presentation of the water savings, the report describes how the construction of a separation system for the lockage funnel and the vacuum plant is made.

The results of the reductions of different parameters with and without the vacuum system are presented below.

Parameter kg/h

Without vacuum system

With vacuum system

BOD

6,6 +/ - 0,4

2,3 +/- 0,4

COD

12,3 +/- 1,6

4,1 +/- 0,5

Total-N

0,95 +/- 0.14

0,38 +/- 0,06

Total-P

0,189 +/- 0,024

0,062 +/- 0,007

Dry matter

12,0 +/- 0,97

3,6 +/- 0,5

Ashes

3,3 +/- 0,97

0,57 +/- 0,1

Water consumption m³/h

2,2 +/- 0,36

0,73 +/- 0,07


The offal from the two transportation systems – water and vacuum – is evaluated according to its ability to maintain quality. The offal is kept in cold storage for 48 hours, after which the total volume of nitrogen is measured on day 1 and 2. The results of the evaluation, in which offal and drippage are measured after 24 and 48 hours, are illustrated below.

Offal: Coalfish

TVN mg N/100g

g TS/kg

mg N/g TS

Results

24 hours – 48 hours

24 hours – 48 hours

24 hours – 48 hours

 

 

 

 

Drippage from normal

24,0 – 35,3

38,8 – 41,1

6,2 - 8,6

Drippage from vacuum

45,2 – 51,4

62,4 – 66,8

7,2 – 7,7

 

 

 

 

Normal offal

37,3 – 48,6

191 – 200

2,0 – 2,4

Offal with vacuum

37,6 – 48,8

191 – 191

2,0 – 2,6


The energy consumption in the present offal plant is compared to the new vacuum plant. Moreover, for each type of plant the resource consumption in relation to investment in new equipment, savings in water costs and water purification costs and earnings derived from the sale of increased offal volume are estimated.

The project concludes that the implementation of a vacuum system for sluicing of fish offal results in a smaller impact on the environment, and, consequently, green taxes are saved. When employing the vacuum system, the water consumption and the environmental impact are reduced by 65%. This reduction means a cost saving in the wastewater taxes and an additional income because of the increased volume of offal. At the same time the work environment is improved, as humidity and water on the floor areas are reduced. Employment of the vacuum system does not change the energy consumption.

Author/ institution

Højmarkslaboratoriet

This report is subsidised by the National Council for Recycling and Cleaner Technology

ISSN no. 0908-9195
ISBN no. 87-7810-537-4

 

| Front page | | Contents | | Previous | | Next | | Top |