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