Case Helsinki: Composting

Transcription

1 Case Helsinki: Composting Helsinki Region Environmental Services Authority Janne Nipuli, Daugavpils HSY/Janne Nipuli 1

2 HSY HSY began its operations on 1 January HSY provides waste and water management services for the more than one million residents of the Helsinki metropolitan area. In addition, it produces information on, for example, air quality, the climate and housing HSY/Janne Nipuli 2

3 HSY HSY's nearly 800 employees work efficiently to make the Helsinki area an environmentally responsible metropolitan area and to ensure that acting in an environmentally friendly fashion is made easy to all residents of the region. HSY was formed by consolidating the waterworks of the Helsinki region as well as the Helsinki Metropolitan Area Council's waste management, and regional and environmental information services HSY/Janne Nipuli 3

4 HSY works in favour of the environment HSY provides high-quality drinking water for the more than one million residents of the Helsinki metropolitan area. HSY efficiently purifies the wastewater produced by the city residents and local industry to protect the Baltic Sea. At HSY's wastewater treatment plants, the organic matter contained by the sludge is digested and the resulting biogas is used to produce electricity and heat for the plants HSY/Janne Nipuli 4

5 HSY works in favour of the environment The bio-sludge generated by the wastewater treatment plants is further treated into soil on specialised composting fields. The waste heat of the treated wastewater is utilised in the production of district heating at the Katri Vala heat pump plant. Landfill gas is collected and utilised to produce electricity and heat HSY/Janne Nipuli 5

6 HSY works in favour of the environment We provide waste management services for residential properties and the public administration in the metropolitan area. We also collect recyclable and hazardous waste. We provide up-to-date information on the sorting, reduction and prevention of waste. We monitor air quality at 11 monitoring stations across the metropolitan area HSY/Janne Nipuli 6

7 Sludge processing operations Viikinmäki WWTP (PE ) and Suomenoja WWTP (PE ) produce approximately tons of sludge with SS concentration of 30 % Both treatment plants have a mesophilic digestion process (ca. 20 days) and a centrifuge sludge dewatering process HSY/Janne Nipuli 7

8 Sludge processing operations Sludge from Suomenoja WWTP (appr tons/a) is processed in Kekkilä Oy s composting site Sludge from Viikinmäki WWTP (appr tons/a) is processed in HSY s own composting site The machine work of Metsäpirtti composting site is outsourced HSY/Janne Nipuli 8

9 Composting site of Metsäpirtti Founded 1994, area is about 17 ha Waterproof rubber-bitumen asphalt surface Runoff water are collected and leaded to Viikinmäki WWTP HSY/Janne Nipuli 9

10 Määrä (m3/a) Composted soil sale rate Metsäpirtin myyntimäärä kompostimulta maanparannuskomposti HSY/Janne Nipuli 10

11 Composting process lawn soil Sludge 1 ton Sedge peat 1,25 m 3 1. Mixing Stack composting mechanical mixing composting period ½ year 2. Mixing 1 ton composted sludge 0,6 ton sand 15 kg biotite Recirculatable screenings Screening screen size 20 mm Screening refuse METSÄPIRTTI LAWN SOIL HSY/Janne Nipuli 11

12 Composting process Soil betterment compost Sludge 1 ton Sedge peat 1,25 m 3 1. Mixing Stack composting mechanical mixing 3 times composting period minimum ½ year METSÄPIRTTI SOIL BETTERMENT COMPOST HSY/Janne Nipuli 12

13 Mixing Station Pre-mixer Input material silos Capacity: about 50 ton sludge per hour Drum-mixer, 14m x 2m HSY/Janne Nipuli 13

14 Compost turning (aeration) ALLU Windrow Turner ALLU screener crusher bucket for a wheel loader HSY/Janne Nipuli 14

15 Soil mixing station Control cabin Input silos Mixer Star screen, 100 m3/h HSY/Janne Nipuli 15

16 Positive/negative about stack composting + Flexible, reliable method + Only simple machines needed - Long composting time (winter time) - Needs much effort for quality monitoring HSY/Janne Nipuli 16

17 Quality All kind of use is allowed High standard raw materials => high quality product High level self-monitoring Production quality is spot checked by EVIRA HSY/Janne Nipuli 17

18 Heavy metals in sludge VIIKINMÄKI WWTP SLUDGE ANALYSES 2011 min. average max. ph 7,8 8,1 8,3 TS % Ignition residue % TS Nitrogen g/kgts Phosphorus g/kgts Potassium g/kgts 1,2 1,5 2,0 Calsium g/kgts Aluminum g/kgts Magnesium g/kgts 2,6 3,1 3,4 Iron g/kgts Mercury mg/kgts 0,4 0,5 0,8 Cadmium mg/kgts 0,6 0,7 1,0 Cobalt mg/kgts Chrome mg/kgts Copper mg/kgts Lead mg/kgts Manganese mg/kgts Nickel mg/kgts Zinc mg/kgts Arsenic mg/kgts 4,0 5,0 7, HSY/Janne Nipuli 18

19 The highest permitted heavy metal concentrations of farming sludge and sludge mixture comparing to the concentrations of Metsäpirtti lawn soil Limit values* mg/kg of solid matter Mean values of analytical data Lawn soil concentration s percentace of the limit value Arsenic ,0% Cadmium 1,5 0,2 13,3% Chrome ,3% Copper ,1% Mercury 1 0,1 10,0% Nickel ,0% Lead ,0% * Regulation of the Council of State (282/94 The use of wastewater treatment plant sludge in farming) HSY/Janne Nipuli 19

20 Expenses and prices 2011 Operation costs 4,3 Milj. Personnel 0,3 M (7 %) Material costs 1,5 M (35 %) Outsourced services 2,5 M (58 %) Other 0,02 M (0,5 %) Income 1,7 Milj. Unit cost ca. 43 /sludge ton Composted soil price /m3 (including VAT and transportation) Price depends on the load size and delivery place HSY/Janne Nipuli 20

21 Conclusion It s about responsible waste recycling Recycling tons phosphorus and nitrogen Carbon back to the ground Continuation: tons per year to recycle High standard products Marketing HSY/Janne Nipuli 21

22 THANK YOU FOR YOUR ATTENTION!