Preliminary Analysis of Sewage Management in Sokólski District

K e y w o r d s : Cesspit; concentration ratio of sewage system; household sewage treatment plant; sewage system. 4/2018 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 179 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T The Si les ian Univers i ty of Technology No. 4/2018 d o i : 1 0 . 2 1 3 0 7 / A C E E 2 0 1 8 0 6 4 I . S k o c z k o , K . O s z c z a p i ń s k a 180 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 4/2018 Planning wastewater systems need to be based on the principles of sustainable development, and therefore consider political, economic and social aspects in accordance with environment balance and sustainability of fundamental natural processes [20]. However, rural areas, similar to the produced sewage amount to the urban areas, are very rarely part of the agglomerations. The wastewater management regulation in rural areas is, therefore, a big challenge. As can be seen in Fig. 1, rural areas produce almost half of the sewage in Poland. The septic tanks, often old and in poor technical condition, are still predominant there [9]. Planning sewage systems in rural areas is complex, mainly due to the dispersed development, varied land falls and sewage receiver location. To the difficulties we can also include demographic development, often observed abandonment of the countryside, which can increase sewage systems operating costs [12]. The average population per one kilometre for the Podlaskie Voivodship reached 175 in 2016, while in 2008 there were 245 people per one kilometre of the sewage system. A similar tendency in decreasing concentration ratio is observed in particular districts and communes of Podlaskie Voivodeship. In 2008-2016, the average population per one kilometre in Sokólski district declined from 200 to 151 people per one kilometre [1]. 2. DESCRIPTION OF THE RESEARCH AREA Water and wastewater management in Sokólski Disctict in Poland was analysed (Fig. 2). There were chosen two communes vary in area and population. The study was based on the Central Statistical Office’s Local Data Bank and information from communes’ bureaus. 2.1. Nowy Dwór Commune The Nowy Dwór Commune is in the eastern, borderland part of the Podlasie Voivodeship, in the Sokólski District. It is a typical rural commune in which only four out of 19 village councils have a population of over 200. At 2875 inhabitants, only 23.1% of them had access to the sewage system (data for 2015). Most of the sewage is discharged into cesspits, the number of which is amounted to 171 in 2016 [11]. The commune is not an agglomeration as defined in the Water Law [19]. 2.2. Dąbrowa Białostocka Commune The Dąbrowa Białostocka Commune, with an area of 264 km2, is in the central-eastern part of the Podlasie Voivodeship, in the northern part of the Sokólski District. The administrative and economic centre is the city of Dąbrowa Białostocka. In 2015, the sewage system was 86.6% (urban area), 4.7% (rural area) and 44.1% in total [10]. Dąbrowa Białostocka Commune is an agglomeration according to the Water Law, with an equivalent of 10 502 inhabitants. [18, 19]. Figure 1. Sewage annual output in the division into urban and agricultural lands (own study based on [1]) Figure 2. Location of Nowy Dwór and Dąbrowa Białostocka communes in Sokólski District [3] P R E L I M I N A R Y A N A L Y S I S O F S E W A G E M A N A G E M E N T I N S O K Ó L S K I D I S T R I C T E N V I R O N M E N T 4 /2018 A R C H I T E C T U R E C I V I L E N G I N E E R I N G E N V I R O N M E N T 181 3. WATER AND WASTEWATER MANAGEMENT IN 2008–2016