WASTEWATER LAGOONS POPLAR IRRIGATION EXPERIENCIES FROM HUNGARY Osztoics András, Szabó Anita, Szilágyi Ferenc
Water supply is over 98 % Sewerage is only 45 % No sewerage system in almost 3000 settlements Consequences: Deterioration of surface waters and shallow ground waters SANITARY CONDITIONS IN HUNGARY
ECONOMIC SITUATION Lack of capital Reorganization of the economy Privatization is almost complete Launching to EU Environmental protection is more important Consequence: There is a need for cheap and effective sewage treatment
category component I.II.III.IV.V.VI. COD Cr TSS NH 4 -N TP Emission standards in Hungary [mg/l]
General data Treatment data Examples Pictures STRUCTURE of the system description Ponds Poplar irrigation
STABILIZATION PONDS Existing ponds or constructed for treatment 2-7 ponds (typical 2-3) Capacity: 80 – m 3 /d (typical: ) Area: 1 – 10 ha Depth: 0.8 – 2.1 m Retention time: 26 – 130 d (typical 50-65) Number: some 10s Treated ww.: both communal and industrial
Rawmg/LTreatedmg/L Removal rate % COD Cr [454]40-280[111]25-88[55] NH 4 -N [49]0-60[13]46-100[83] Treatment data
Special type: BMKO Bio-mechanical combined oxidation system 5 or 9 subsequent stabilization ponds in a circular arrangement
3 m deep inner pond alternatively aerated depth decreases outwards inner circle – organic material 2 nd circle – org. mat and nutrients outer circle – nutrients Capacity: 600 – m 3 /d Area: less than in other stabilization ponds Hydraulic load: 1.5 cm/d
Rawmg/LTreatedmg/L Removal rate % COD Cr [468]38-274[91]38-93[77] TSS42-809[271] [23]63-99[89] NH 4 -N [35]0-66[35]-24-94[39] TN41-88[63]3.5-60[31]16-83[49] TP [10.3] [8.4]-37-70[13] Treatment data
Long term efficiency COD Cr slight decrease TSS NH 4 -N 40% decrease TN 80 30% TPdecrease: negative values only recently
POPLAR IRRIGATION Rows of poplar trees along ditches Capacity: 40 – m 3 /d Area: 6.4 – Hydraulic load: 0.14 – 1.6 cm/d Number: more than 40 Treated ww.: both communal and industrial Drainage !!!
Furrow width: 2.20 m depth: 0.50 m distance: 1.80 m Slope: 1:2 Water depth: 30 cm Dist. of trees: 6.00 m Usual arrangement
Case study: Gyula poplar plantation capacity: m 3 /d irrigation area: ha total area: 145 ha mechanical, biological pretreatment aerobic and facultative ponds
Case study: Zalakaros poplar plantation capacity: m 3 /d irrigation area: 9 ha total area: 12 ha pretreatment: settler terraced
Effective organic material removal, however problems with nutrient removal Large land requirements – we usually have it Low investment and operation costs – because of low land and labour cost Little maintainance work – not always done CONCLUSIONS OF NATURAL TREATMENT SYSTEMS IN HUNGARY
Special Hungarian system – BMKO Special Hungarian system – poplar irrigation Better distribution would be good, but: – Limit values are strict sometimes – Economic supporting system is not appropriate Little operational and design experience CONCLUSION continued