Human and domestic wastes in Fiji cause serious problems to the marine environment. In this paper I will describe the magnitude of the problems. I will explain how the pollutants affect the pH, the salinity of the seawater and marine resources. Also I will discuss some possible solutions to this pollution problem.
Magnitude of the problem in Fiji Islands
The disposal of untreated human and domestic waste is the largest contributor to the pollution of the marine environment in Fiji. There are numerous problems associated with human and domestic waste. The Raiwaqa sewage treatment plant is inadequate. In places where there are septic tanks and latrines they tend to overflow and in many of the coastal villages in rural settings due to lack of proper facilities, human waste gets directly discharged into the sea either directly or through streams, rivers and storm drains.
Effect on pH, salinity and marine resources
Salinity is the total mass of dissolved salt in a kg of seawater. Despite variations in salinity in the oceans of the world, the proportion of the major constituent ions remains constant . The former is the combined effects of diffusion, wave and tidal action and surface and ocean currents. The salinity around the Fiji islands is constant. The effect of untreated sewage on salinity is nill, apart from those places where a lot of fresh water is pumped into the ocean for instance where the Raiwaqa treatment plant discharges into the ocean.
Untreated sewage is slightly acid. One of the acids which causes that is the uric acid (in urine) This means the pH will be lower than normal. If the sewage gets primary treatment onwards the pH will be neutralised in the process and will not have an effect on the ocean.
Untreated sewage contains bacteria, parasites and viruses. The greatest impact is on the fringing reef, which is used for catching small fish and shellfish. Shellfish concentrate bacteria and viruses from sewage. Consuming raw or partially raw shellfish can lead to transmission of viral diseases. Also since shellfish are at the bottom of the food chain it also has many effect on other fish species. Untreated sewage also contains high levels of nutrients, which stimulate massive algae growth. This leads ultimately to a decreased oxygen level. These anoxic conditions can lead to death of fish. Furthermore algae bloom can lead to death of coral which leads to death of reef, which in turn decreases fish stock. Nitrogen is a nutrient that is also poisonous to fish in the form of ammonia gases and may become poisonous in the form of nitrate.
Reef building corals can not survive unless the conditions are just right. Corals flourish in nutrient poor waters and suffer severe impacts if nutrients are high.
In many of the rural areas the well being of the people is directly related to the health of the marine environment.
Possible solutions to the problems
There are several innovative treatment options are available. The common features are that no pollutants are discharged into the surrounding environment. They use a combination of micro-organisms, plants and sometimes animals - like tapia (fish) to process the organic materials and to convert them into a form that has a value, such as food, fuel and fertiliser.
Some examples are
• Waterless Biological Toilets (composting toilets, septic alternative system)
• Constructed Wetlands - very good in combination of primary or secondary treatment plants
• Solar Aquatics Systems - which are more complex constructed ecosystems like Living Machines
Many of the building plans of the above solutions are readily available. The problem in the Fiji is implementing them. Money is needed for the initial set-up and they need continuous maintenance in order to work properly. The best solution for the more rural communities would be zero discharge systems, like the waterless biological toilets. These systems are relatively cheap and no pollution is discharged at all.
For water-based systems several measures can be taken:
• Water conservation. This includes low-flush toilets, low-flow showerheads
• Conservation and use of sludge. The sludge left over from econdary and tertiary sewage treatment palnts can be used as compost.
• Wastewater reuse. It is important to note that UV rays can kill pathogens like bacteria, viruses and protozoa. This is a solution to the chlorine which is used at present in Fiji. Chlorine has a reverse impact on the environment as it kills beneficial and non-beneficial bacteria.
Other solutions are:
• Regulations and implementations (a good start is to start with hotels and resorts). Worth mentioning is Lalita Resort on Beqa Islands. The owners wanted a wastewater system that would not pollute the water. They built a wastewater system with micro-flush toilets. Many resorts should take their example.
• Education and community involvement. Workshops, building of composting toilets and training in rural communities would be essential.
• Economic valuation of the resources. The cost of health care, loss of tourism and loss of marine resources might be much higher than cost of implementing solutions.
My conclusion is that the marine pollution problem in the Fiji Islands is huge and that if the problems are not addresses soon the effect on the local rural communities in relation to food supplies, health and tourism are extremely serious.
Greenpeace. Sewage Pollution in the Pacific and how to prevent it.
South, R., Todd H., Coll R., Taylor N., Yeo G., Veitayaki J. and McDowell, R (1994). Introduction to Marine Sciences for the Pacific Islands. Suva, University of the South Pacific.
South Pacific Applied Geoscience Commission. Report on projest criteria, guidelines and technologies (July 1999)
Websites: http://www.ecological-engineering.com/ and http://www.ltluk.com
Marc Overmars from SOPAC for providing me with information on marine pollution of human and domestic wastes in the Pacific