Keywords: urban sewage, Daphnia, cladocerans, waste recycling, live fish food, organic carbon, phosphorus, nitrate-nitrogen, ammonia-nitrogen
Recycling of Urban Sewage through cladoceran culture system
The feasibility of using Urban Sewage (US) was tested in static water holdings for the culture of Daphnia, a cladoceran that is used as a live fish food. US was diluted to 60% (D40), 50% (D50), 40% (D60) and 30% (D70) by adding normal freshwater to constitute a total volume of 15 litres. Each culture medium (in triplicate) was inoculated with four units of Daphnia sps. per litre. The population of Daphnia increased significantly (p ? 0.01) in each culture medium, the highest being 4340 no. /l after 20 days in D50. At the end of the experiment, after 30 days, the highest mean population of 3057 no. /l was recorded in D50. The concentration of organic carbon, phosphorus, nitrate-nitrogen and ammonia-nitrogen reduced significantly (p ? 0.05) in each culture medium from the initial levels. The study suggests that US could be used for culture of cladocerans that is also helpful in waste recycling.