By: Akrom Muflih
“Utilization of resources in coastal areas with shrimp aquaculture is now more emphasis on a high level of productivity of the land. Land productivity very closely with the carrying capacity of the pond and aquatic environment.”
Carrying capacity is the ability of the land to collect waste water from aquaculture activity without causing damage to the environment so that the land can continue to function as water resistance and resilience.
Traditional shrimp farms with very low stocking density (20-60 shrimps/ m2) and rely on natural food available in nature are very rare and almost never experienced the problems of water quality and the environment. But should still pay attention to the condition of the aquatic environment for pond water source.
When aquaculture started with the shrimp density systems with a high number (>100 shrimps/m2), the value of the carrying capacity of the pond water is very limited. Limitations of oxygen due to enter the water load coming from feed and waste organisms create the environmental conditions exceed the carrying capacity of natural waters. Therefore, it is necessary enter the appropriate technology to be able to keep the pond water environment parameters to remain stable so that the pond water environment can still support the growth of the shrimp well. In general, the quality of water which makes it a mandatory parameter to be considered by farmers when the cultivation is done by a semi-intensive, intensive and super-intensive in other words, because of the high stocking density.
High productivity with high stocking density implementation of the investment objective to obtain huge profits can be easily achieved. However, the productivity orientation will cause problem if the principles of sustainable aquaculture is not applied properly.
Some principle is to prevent intrusion of pests and diseases through bio-security and responsible process waste generated. Waste treatment in one hand was the expense of land, labor, and financial, but if done properly it will reduce the risk of some infectious disease in shrimp which ultimately could reduce the risk of losses on the farm owner and make sustainable shrimp farming business.
Waste treatment shrimp culture is indispensable to assure the sustainability of the ecosystem around it, especially for large-scale cultivation of intensive and super-intensive. Waste treatment should begin construction planning and applied continuously. The characteristics of the waste from shrimp aquaculture is a micro-sized, dynamic, wide-spread impact, as well as the long-term effects. In addition, the effluent quality is very dependent on several factors : the volume of waste, the content of pollutants, and the frequency of waste disposal.
The main problems in the waste water pond is the high particles of organic materials, as well as the high content of N (nitrogen) and P (phosphate), which can increase the fertility waters. Increased solid waste in the culture system which can result in decreased dissolved oxygen and increase the levels of ammonia due to decomposition of organic materials that are toxic. Therefore, the waste water ponds must be managed either by applying the waste water treatment plant (WWTP).
Wastewater management technology has been widely applied in Indonesia such as recirculation systems, ozonation, ultraviolet, construction of wetlands, and biological systems (activated sludge). The waste water treatment must be in accordance with the quality standards of aquaculture waste effluent according to the environment ministry. Some of the main parameters are TSS (total suspended solid), TOM (total organic matter), total N, phosphate and BOD5 (biochemical oxygen demand).
At present, it has developed a super-intensive application of technology WWTP. Efforts made in the application of wastewater to make waste water treatment pond that consists of the settling ponds, oxygenation, bio-conversion, and shelter. Settling ponds as waste water reservoirs were first to reduce levels of TSS and the stench of H2S. Then an oxygenation to increase dissolved oxygen and lower levels of BOD. Furthermore, bio-conversion of waste into the pond to transform nutrients that can be caused eutrophication be useful for other organisms. Last treatment waste water into the ponds for subsequent disposal into the sea.