ON December 6, 2014, the major sewage pipe carrying waste from Suva to Kinoya Sewage Treatment Plant collapsed, sending about 200 litres per second into Cunningham Creek, through Samabula River and into Laucala Bay.
The immediate cause of the spill was flash flooding caused by heavy rain. The spill resulted in an immediate stench and a public health risk. The spill continued until December 24 when a temporary bypass was installed, and the sewage was again delivered to Kinoya.
The Water Authority of Fiji notified local residents that the spill caused unsafe conditions, and advised people not to swim or eat fish from the contaminated water.
An Environmental Emergency Declaration was passed by Cabinet on January 3, 2015. It made it illegal to swim or fish in any waters in Laucala Bay and parts of the Suva foreshore.
These are the facts
What has escaped attention during this environmental emergency, is that the creeks and rivers in the local area have always been severely polluted, and the entire shoreline in the Suva area is moderately polluted. Nasinu River, Samabula River, Vatuwaga River, Nubukalou Creek and Lami River are all spectacularly polluted. At least 600 students in a course in marine pollution at the University of the South Pacific know this. I have presented our results to several scientific conferences, but not to a newspaper.
It appears that when an actual emergency occurred, authorities were too busy fixing the immediate problem to worry about the causes or the larger context. We should all be thankful for the Water Authority of Fiji for fixing the problem promptly.
A short history
of sewage in Suva
Sewage from central Suva was delivered to an outfall near the foot of Southern Cross Rd near the present Holiday Inn until 1983 when a tunnel and lift pumps were installed. Thereafter sewage from Suva was diverted to the Kinoya Sewage Treatment Plant.
About 50 per cent of the Suva residences are connected to the sewer. The remainder are on septic tanks. After secondary treatment, sewage goes into Laucala Bay through a submerged outfall about 2km long.
The spill
The break occurred in the main sewage line between Suva and Kinoya at Four Miles, Cunningham Creek.
This creek is quite small. The large volume of sewage completely overwhelmed the capacity of the creek to handle it.
The result was anoxia — no oxygen — because the organic matter in sewage exerts a high oxygen demand. A consequence of anoxia is that sulphur-containing compounds are reduced to hydrogen sulphide, a gas.
In high concentrations, hydrogen sulphide is toxic. In lower concentrations, as in this case, it produces the smell of rotten eggs or sewage. When anoxia persists for a long time, all animal life is excluded. Along with the stink, there is a health risk of bacterial contamination.
Background
The primary indicator of sewage contamination is faecal coliform bacteria, or FC. These bacteria aid the digestive process in the guts of all warm blooded animals, including humans, cattle, pigs, dogs and birds.
They are necessary, not harmful.
FC also indicate the possible presence of serious disease-causing microbes such as those which cause typhoid, cholera and hepatitis, as well as less serious diseases such as diarrhoea and skin infections.
FC cannot grow outside the gut. In our laboratory experiments FC die off to about half their initial concentration within six hours in the dark. Sunlight further reduces their survival. The FC introduced in the sewage spill should have disappeared within one week. The anoxia will take somewhat longer to come back to background levels.
The question is, what are the background levels?
In every year since 1994, my students have conducted monitoring for FC, salinity, temperature and dissolved oxygen in all of the creeks and rivers from Samabula River to Navesi Creek, near Lami as well as the shoreline.
In every case, this was done on a single March day at 17 stations. The results can be compared to standards in the Fiji Environmental Management Act, US Environmental Protection Act and the World Health Organisation. Below 200 colonies per 100ml is considered safe for swimming.
On average, Samabula River is 244 times over the standard, Vatuwaga River is 222 times over the standard and Nubukalou Creek is 657 times over the standard.
Nasinu River and Lami River were not tested in this series but other observations show they are also very polluted.
For the shoreline, there are a few places which approach the standard, but most are above the standard.
We have also conducted a few tests at Nukulau Island, Beqa, and popular swimming beaches in the Pacific Harbour and Deuba areas. All were found acceptable. Figure 1 shows our result.
In short, when the Environmental Emergency Declaration was posted most of the emergency was over. However, “back to normal” in the Suva area is a continuing problem with respect to sewage pollution.
* Ed Andesron is with the School of Marine Studies of the University of the South Pacific. The views expressed are his and not of this newspaper.
