Sewage — a Future Waste Problem?
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Indicator Fact Sheet Signals 2001– Chapter Waste Sewage sludge - a future waste problem? (W5.1) Sludge from waste water treatment, 1992-1998 and expectations for 2000 and 2005 45,0 40,0 35,0 30,0 25,0 20,0 Kg perKg capita 15,0 10,0 5,0 0,0 l in e tria ds c ay land uga land us ran in Spa ort Ire F Sweden A F Greece Norw Denmark Germany P Belgium Luxembourg Netherlan United Kingdom 1992 1995 1998 2000 2005 (W5.1) Sludge from waste water treatment 1992 to 1998 and forecast for 2000 and 2005. Member States sorted by the level of generation in 1995. Sources: Report from the Commission: Implementation of Council Directive 91/271/EEC of 21 May 1991 concerning urban waste water treatment, as amended by Commission Directive 98/15/EC of 27 February 1998. 15 January 1999. Information from ETC/W survey May 2000 1 (W5.2) Treatment of sewage sludge, selected EEA member countries, 1998 45,0 40,0 35,0 30,0 25,0 Kg per20,0 capita 15,0 10,0 5,0 0,0 Denmark Germany : Ã7UHDWPHQWÃRIÃVHZDJHÃVOXGJHÃVHOHFWHGÃ(($ÃPHPEHUÃFRXQWULHVÃÃLuxembourg à 6RXUFHÃ(7&:ÃVXUYH\Ã0D\ÃÃDQGÃLQIRUPDWLRQÃIURPà November 1998, following directive 86/278/EEC on sewage sludgeFinland à (W5.3) Contamination of sewage sludge, selected EEA member countries 1995 to 1997 Portugal Mercury Austria Total landfilling 2,5 Netherlands 2,0 1,5 1,0 Norway 0,5 Total recycling Mg 0,0per kg Phosfor United Kingdom report from Member States to the Commission concerning sewage sludge treatment, Germany Total incineration Spain Denmark France France Ireland Finland Belgium Greece Greece 1995 Ireland 1996 Luxembourg 1997 Norway Sweden UK 2 Cadmium 3,0 2,5 2,0 1,5 1,0 0,5 0,0 Mg per kg phosfor kg per Mg y e n c d d n n n UK la la ourg den rma ra n re b e F Fi Greece I Norway we G Denmark S Luxem 1995 1996 1997 Lead 200 150 100 50 0 Mg per kg phosfor nd UK la way reland r France Fin Greece I Germany Denmark embourg No Sweden ux L 1995 1996 1997 NOTE: VERTICAL AXIS TITLES – milligrams per kg dry matter Note: Average content reported by member countries. Commission in Council Directive 86/278/EEC of 12 June 1986 on use of sludge in agriculture maximum content: Cadmium 20 mg/kg and Mercury 16mg/kg dry matter. à 6RXUFHÃreport from Member States to the Commission concerning sewage sludge treatment, November 1998, following directive 86/278/EEC on sewage sludge and ETC-W survey May 2000. à K The increase in the total generation of sewadge sludge is the side effect of an environmentally positive development in treating waste water. Despite the expected increase in recycling, the total amount of sludge for disposal is expected to increase. à à à Results and assessment Relevance of the indicator for describing developments in the environment Sludge can be a valuable fertiliser for agriculture. It is a good source of phosphorus and its nitrogen content can also be valuable, especially for crops with a long growing season (ISWA 1998). The organic content of the sludge can help improve the soil structure. In general, sludge stimulates beneficial biological activity in the soil (DEPA, 1997). The percentage of nutrients in sludge will 3 increase with more effective cleaning of waste water. Phosphorus being a limited resource makes recycling of sludge for agricultural purposes an appealing solution for sustainable management of sludge. However, sludge is also contaminated with heavy metals, bacteria and viruses and a number of organic substances, and both EU and national regulations set limits for contaminant concentrations in order to protect the soil and humans from pollution. Landfilling of sludge has hitherto been an inexpensive means of disposal, but both national restrictions and the proposed Landfill Directive will make landfilling more expensive. Several countries have introduced general restrictions on the landfilling of organic waste. Incineration reduces the sludge to ash, which can then be landfilled. In most cases supplementary fuel is needed in order to burn the sludge and there is usually no net gain of energy (Johnke, 1998). à Policy relevance and policy references Many new treatment plants are due for completion by 2005 and the amount of sewage sludge is expected to increase by 50 % as a result of more stringent demands for water treatment in the Council Directive concerning urban waste water treatment (91/171/EEC). However the European Commission is considering more rigid limit values for heavy metals and possibly limit values for some organic compounds, and this will limit the potential for recycling. This could be through an amendment to Directive 86/278/EEC on sewage sludge. Several Member countries have already established more stringent limit values for heavy metals and some have also introduced limit values for a number of organic pollutants. The economic consequences of a restricted agricultural application of sewage sludge are considerable. Depending on the alternative chosen, the cost may rise from 75 EURO per tonne for agricultural use to 400 EURO for incineration in some countries (ISWA, 1998). One German source even indicates prices up to 600 EURO per tonne for thermal treatment (Johnke, 1998). Thus, phasing out the use of the problematic compounds may be an economically sound solution. Assessment The total amount of sludge produced in the 15 EU Member States is predicted to increase from 6.6 million tonnes of dry matter in 1992 to least 9.4 million tonnes in 2005. Differences in generation of sludge per capita between Member countries are due to different degrees of waste water cleaning. The difference between the highest and the lowest is 30 kg per capita. Assuming that the content of dry matter is approximately the same in all Member countries, there is a need for further waste water treatment in some countries. Even if this is done, this will not raise the EU average to that of the most active countries within the next five years. This means that there will still be a need for further investment in the waste water treatment and the problems of proper treatment of sewage sludge will still be increasing after 2005. The Commission expects the proportion of sludge used for agriculture and soil conditioning to have increased by 73 % by 2005, to 53 % of the total produced. The proportion incinerated is predicted to increase to 25 % of the total produced and the amount sent to landfill to decease by 33 % from 1992 to 2005. 4 Due to more stringent demands for water treatment in the Council Directive concerning urban waste water treatment (91/171/EEC), many new treatment plants are due for completion by 2005 and the amount of sewage sludge is expected to increase by 50 %. For some countries, the quantity will increase by nearly 300 %. The expected increase is itself a challenge for waste management and the choices of treatment and disposal methods will have large economic and environmental implications. Landfill is expected to fall by 24 % while incineration will increase by about 300 %. Incineration reduces the sludge to ash that requires less landfill capacity. However, an increase in recycling of 75 % will secure that the overall recycling percentage for sludge will increase to more than 50 %. Recycling of sewage sludge mainly means spreading on soil as fertiliser for agriculture or forestry. Growing attention to producing clean and non-contaminated food for human consumption will probably raise debate on this treatment of sludge. On the one hand recycling programmes are encouraged by public opinion; on the other hand the demand for clean and healthy food is growing. The results of surveys in Member countries on contamination of sewage sludge show a development in the right direction: less use of heavy metals lead to less contaminated sludge and thereby to more recycling. However, the increased use of sewage sludge as fertiliser needs to be balanced so that the contamination of agricultural land will neither affect the quality of food nor lead to damage of the environment. A recent positive sign is the fall in the content of heavy metals combined with a higher content of nitrogen and phosphorus due to more efficient waste water cleaning, which has been observed in Denmark, Germany, France and Finland. 5 Data Destination of sludge from treatment plants and forecasts of the destination (in thousands of 1 tonnes of dry matter per year) Disposal B DK D GR E F IRL L NL A P FIN S UK Total Surface Water - - - - 38 - 14 - - - - - : 282 334 1992 Recycling. 17 110 1.018 1 275 402 4 5 134 63 38 87 : 472 2.626 Landfill 34 25 846 65 180 131 16 4 177 58 75 63 : 130 1.804 Incineration – 40 274 - 35 110 – - 12 66 – - : 90 627 Not Specified 8 - 70 - - - 3 - 1 3 13 - : 24 122 Total 59 175 2.208 66 528 643 37 9 324 190 126 150 243 998 5.756 Surface Water - - - - 54 - 15 - - - - - - 267 336 1995 Recycling. 22 120 1.151 1 390 489 7 7 95 63 44 86 120 648 3.243 Landfill 39 25 857 65 257 114 14 3 192 58 88 72 106 114 2004 Incineration – 40 411 - 50 161 – - 56 66 – - - 110 894 Not Specified 17 - 93 - - - 4 - 23 3 15 - 11 19 185 Total 78 185 2.512 66 751 764 40 10 366 190 147 158 236 1.158 6.661 Surface Water - - - - 57 - - - - - - - : 240 297 1998 Recycling. 33 125 1.270 4 410 572 25 9 100 68 74 85 : 672 3.447 Landfill 37 25 744 82 268 92 17 1 108 58 147 65 : 118 1.762 Incineration 11 50 558 - 52 214 – 3 150 66 – - : 144 1.248 Not Specified 32 - 89 - - – 1 - 23 4 25 - : 19 193 Total 113 200 2.661 86 787 878 43 13 381 196 246 150 : 1.193 6.947 Surface Water - - - - 57 - - - - - - - : - 57 2000 Recycling.