Primary treatment of the waste water treatment plant from the point of view of the current legislation

Abstract

SZOSTKOVÁ, M., VÍTĚZ, T.: Primary treatment of the waste water treatment plant from the point of view of the current legislation. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 2, pp. 205-212 This contribution focuses on an analysis of sand from nine diff erent wastewater treatment plants in South Moravian Region. We conducted an analysis and evaluation of microbial properties of sand in accordance to Act No. 185/2001 Coll. on waste as amended, resp. Decree No. 381/2001 Coll. Content of following parameters were monitored, thermotolerant coliform bacteria, coliform bacteria, enterococci, total solid, ash free dry mass. We encountered several interesting fi ndings, which pertained mainly to the content of microorganisms in sand. Knowledge of microorganism content should show, how the primary treatment of the wastewater treatment plant works, and should be very interesting indicator.wastewater treatment, primary treatment, detritus tank, wastewater treatment sand, microbial contamination, mechanical properties Primary treatment of domestic wastewater represents an extensive range of physical and chemical activities which directly or indirectly aff ect fun ctiona li ty of the treatment plant as a whole. The aforementioned eff ect might be rather signifi cant in many respects. The respective matter proves to be highly underestimated (by both operators and designers) at many treatment plants. However, an incorrectly designed or operated primary treatment might result in an unnecessary increase of operating costs and should have a negative impact on the biological level or sludge treatment and disposal. A detritus tank proves to have a key role in the process of primary treatment. The principal task of a detritus tank is to collect the maximum possible amount of mine ral substances from wastewater in a manner ensuring that organic substances will remain present in the upli and they are to fl ow to the subsequent treatment level. The structure of a detritus tank is to ensure that solely sand without any organic substances will be settling down. However, it is highly complicated to achieve these conditions considering the high level of infl ow irregularity, and therefore a high level of concentration of organic solids in the excavated material (Fujioka et al., 2001).Furthermore, a detritus tank performs also a protective function, which means that it protects other equipment complexes against excessive wear and tear. A correctly rated detritus tank is supposed to catch all sand, i.e. mineral particles featuring the grain size above 0.2 mm and specifi c density of 2400 kg/m 3 or more (Claydong et al., 2001). This means that a detritus tanks is to be rated in a manner ensuring that wastewater will fl ow through it at a constant speed in all fl ow conditions. Should a detritus tank fail to function, the mixture of organic material and sand creates a sediment layer that causes major problems in the following stages of wastewater treatment. The scope, however, does not comprise solely damage caused t...