Utilization of domestic wastewaters for freshwater flea (Moina macrocopa) culture

Domestic wastewater used in this experiment is the raw sewage obtained from a treatment plan at Huay Kwang National Housing Development. Individual rearing of Moina in this wastewater for five successive generations is found to be successful. Moina has the average life span of 8, 13 days and reproducess parthenogenetically at the average of 7.6 times. The latter generations have the tendency to be short lived with rapid growth development, reaching maturity faster than the first generation. Duration of brooding and the number of youngs of the five generation have the same trend. The first brood occurs at the average of 41.2 hours and the number of young averages at 8.1 individuals. The subsequent broods occur at the average of 20.8 hours, with an average number of 14.9 young individuals per brooding Experiment of Moina culture in wastewater at various BOD values showed that the suitable range of BOD5 for was 320.5 mg./1. Wastewater with BOD5 at 603.0 mg./1 did significantly decrease the Moina population. BOD5 at 822.8 and 932.7 mg./1 had detrimental effect on Moina in a few days. The continous mass culture of Moina was started with 400 individuals per 30 liters of wastewater in plastic containers. There was a semi-continuous transfer of wastewater at 15 liters every fourth day and the removal of half Moina population during the first ten days, with subsequent removal of 1-3 when densities were reached at 200 and 100 individuals/100 ml. consecutively. Moina culture with this procedure was able to maintained for the whole two months period. Moina production was obtained almost everyday, averaging at 10.5x103 individuals/day This cultivation was able to improve water quality in the following. Total Bacteria, Escherichia coli and BOD were reduced at 91.2 %, 98.2 % and 83.7 % accordingly. In addition, pH and DO values were elevated but NO3-N and Total PO4-P fluctuated sporadically. These four parameters were not directly related to Moina activities.