Domestic sewage treatment plants

The standard size of tanks we manufacture ranges from 4 PE to 25 PE

*PE – population equivalent. The equivalent, in terms of a fixed population, of a varying or transient population.

A domestic sewage treatment plant is a facility for treatment of sewage and discharging the treated wastewater into the ground. The treated effluent comes only and exclusively from the building for which it was designed. The sewage treatment process takes place as a result of anaerobic digestion (a septic tank – the first stage of sewage treatment) and subsequently the activity of aerobic bacteria (leach drains – the second stage of the treatment process). The facility is intended to be used exclusively for the treatment of domestic sewage coming from households, that is: washing water, food preparation wastes, laundry wastes and body waste (urine and faeces). In most cases treatment plants operate by gravity.

Domestic sewage treatment in Domestic Sewage Treatment Plants is performed in the following stages:

  • pretreatment – the process that takes place in a septic tank. A correctly designed and constructed septic tank digests about 60-75% of solids, about 40-70 % of BOD5. Generally speaking, it can be assumed that the effluent discharged from a septic tank is about 65% pre-treated;

  • further treatment – this stage is performed in the drainage field, that is a network of subsurface pipes. The aim of the drainage field is to aerate the effluent and to spread it evenly into ground for further treatment.

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