Removal of the organic pollution from the dairy wastewater of the milk collection station in the differently constructed sand filters
2011
Askinis, S., Lithuanian Univ. of Agriculture, Vilainiai, Kedainiai (Lithuania). Faculty of Water and Land Management. Water Research Inst.
In 2003 an experimental model of the dairy waste water cleaning facility was equipped for cleaning the wastewater of the milk collection station. We examined the possibilities to destruct the organic pollutants present in the dairy wastewater in the sand filters of vertical and horizontal filtration. The pollution level of the dairy wastewater is from 2 to 4 times higher than that of the domestic wastewater. The dairy wastewater was cleaned following the procedure: cleaning in the aeration-flocculation system-cesspool-two stage sand-reed filter. The pollution of the wastewater leaving the cleaning facility never exceeded the allowable norms. The average BOD5 was 4 mg O2 LE-1 and the maximal value was 9.6 mg O2 LE-1. The investigation revealed that the horizontal sand-reed filter with the filtration path of 7 meters ensured cleaning of the dairy wastewater up to the allowable norms. The organic pollutants were cleaned with the efficiency of 97.2% after filtration through such a sand layer. In order to find out the possibilities of vertical filtration filters use for cleaning the dairy wastewater leaving the milk collection stations, we performed a modelled investigation. The wastewater cleaning efficiency in respect to BOD5 reaches 99.3% in these filters. The calculation according to the regression equation received showed that filtration through 0.6 m sand layer ensured successful cleaning of the wastewater up to the allowable norms. In such a vertical filtration filter the average BOD5 cleaning level was 20 mg O2 LE-1.
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