State of the Bay Report 2011-Final.pdf - Anchor Environmental

State of Saldanha Bay & Langebaan Lagoon 2011
Activities & discharges
Table 3.8.
Characterisation of effluent from Sea Harvest (data for 2001 and 2011) and Southern Seas
Fishing factories (data for 1996/7) (Data from Entech 1996 In CSIR 2002 and Paul Cloete,
Environmental Office for Sea Harvest 2012). SA WQ guidelines are based on those published in
1998, as the 2009 revised guidelines do not offer recommended physio-chemical targets
except for temperature and pH.
Sea Harvest
(2001)
Sea Harvest
(2011)
Southern Sea Fishing
(1996/1997)
SA WQ
Guidelines
Effluent volume (m 3 /month) 69 595 - 160 674 -
Suspended solids(mg/l) 164 332 652 *
Combustable solids (mg/l) 144 - 522 *
Fat, Oil and grease(mg/l) 212 - 390 *
Ammonia-N (mg/l) 164 147 137 0.020 mg/l
Kjeldahl Nitrogen-N (mg/l) 83 83 317 -
Phosphate-P (mg/l) 34 - 28 -
Faecal coliform (CFU/100 ml) 751 965 - -
E. coli (CFU/100ml) 5 941 - †
* Water should not contain floating particulate matter, debris, oil, grease, wax, scum, foam or any
similar floating materials and residues from land-based sources in concentrations that may cause
nuisance.
Water should not contain materials from non-natural land-based sources which will settle to form
putrescence.
† Max 100 CFU in 80 % of the samples and max 2 000 in 95 % of the samples
Sea Harvest discharge fresh fish processing (FFP) effluent into the sea daily. This includes
seawater that has been used as wash-water as well as freshwater effluent originating from the fish
processing. Monthly volumes of effluent discharged in the sea from 2004 to 2007 by Sea Harvest are
shown in Table 3.8. The volume of effluent disposed by Sea Harvest increased radically from August
2006 to November 2007, and then decreased drastically again. It is not clear why this increase
occurred, as data reporting and environmental monitoring at Sea Harvest have suffered irregularities
due to high staff turnover (F Hickley, pers. Comm.). The volumes of effluent discharge released from
May 2004 to May 2006 resemble those reported by the CSIR for 2001 and 2002, which ranged
between 50 000 to 90 000 m 3 /month. Regular monitoring of effluent quality produced was reinitiated
in 2010. It is estimated that approximately 1 152 m 3 of effluent is released on a daily basis
(35 000 m 3 /month, Paul Cloete, Environmental Officer, Sea Harvest Corporation (Pty) Ltd, pers.
comm.). Variations in the characteristics of this effluent are shown in Figure 3.32. Measured levels
of faecal coliforms in the effluent are relatively high, in the range of 0 to 3 300 CFU/100 ml,
averaging 611 cfu/100 ml (Figure 3.32). The source of this contamination is not clear, as faecal
coliforms are derived from the guts of warm blooded animals such as human and livestock rather
than cold blooded animals such as fish. Levels of suspended solids, ammonia and nitrate/nitrite are
similar to those reported for the earlier period (1996/7, Figure 3.32). It is not clear what permit
conditions are attached to the discharge of effluent from the Sea Harvest factor but these levels are
certainly well in excess of those permissible in terms of a General Authorisation under the National
Water Act (1998).
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