The Design of Aquaculture Waste Reduce for Water Recycling System by Macroalgae, Gracilaria
Date Issued
2005
Date
2005
Author(s)
Huang, Jei-Ming
DOI
zh-TW
Abstract
Aquaculture wastewater mainly derives from leftover feeds and creatures’ excrements. Differing from the running-flow-type culture which causes significant pollution by directly discharging the waste water into the coast, recirculation culture is one of the most efficient improvements on the aquaculture wastewater treatment in coastal area of Taiwan. In addition to decreasing the expenditure of effort, finance and manpower, it can create high density aquaculture only by regularly adding small amount of water due to evaporation.
This research uses Gracilaria as the target of biological treatment and investigates the reduction power of waste in abalone aquaculture recycling system. Factors that influence the growth of Gracilaria and Abalone (Haliotis diversicolor supertexta) is salinity 35 0/00,pH 7.0 – 8.5, and dissolved oxygen about 5ppm. In addition, the triangle-solid cultivation density of multilayer culture density of Gracilaria is 10.2 g/L. Not only it is able to save space and increase the fresh quality of Abalone food but also improve the absorption rate to Ammonia.
It must consider adding artificial light source such as blue light or red light when cloudy day, insufficient illumination, indoor cultivation or multilayer culture and the water depth is above 90cm. Gracilaria absorbs NH4+ during daytime and soaks up NO3- during night. However, when Gracilaria is stressed by the environment (e.g. the concentration of NH4+ is too high, low temperature, and high salinity), it also absorbs NO3-. When NH4+ concentration is higher than 2 mg/L and Gracilaria is unable to eliminate it stably, it has to add tiny air-bubble device which helps wastewater to lower the concentration of nitrogen compounds. When NH4+ concentration is lower than 2 mg/L, Gracilaria can decrease the concentration NH4+ at below 1mg/L. If setting up a nitrification tank for nurturing nitrifying bacteria, it can aid NO3- in oxidizing NH4+ and increasing the absorption of Gracilaria.
Therefore, Gracilaria not only keeps Abalone food fresh for more than one week, but it also can efficiently utilize redundant organic substance in abalone aquaculture recycling system as nutrition salt for the need of growth. Moreover it provides a best water quality environment to reach the balance of recycling water environment and the design of aquaculture waste reduce for water recycling system.
Subjects
養殖廢污利用
龍鬚菜立體養殖
循環水系統
Aquaculture waste reuse
Gracilaria Multilayer culture
Water recycling system
Type
thesis
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