Regulatory approaches to application of biosolids to agricultural - PowerPoint PPT Presentation

Regulatory approaches to application of biosolids to agricultural land in Australia and New Zealand Professor Michael Warne 1,2,3 1 Centre for Agroecology, Water and Resilience, Coventry University 2 School of Earth and Environmental Sciences, University of Queensland 3 Queensland Department of Environment and Science

Australia NZ Australia & NZ only only These symbols, in the top left corner, indicate which countries I am talking about

Biosolids are the treated and/or stabilised Australia organic solids produced by wastewater & NZ treatment processes Type of Australia treatment Any Agricultural land treatment Sludge Biosolids Other uses New Zealand Sufficient treatment Sludge Biosolids Agricultural land Sludge Other uses No or insufficient treatment

Potential uses of biosolids Australia & NZ Waste Wealth from Waste Incorporation & Energy Land applications Waste disposal production Agriculture Cement Waste dumps Compost/soil Incineration additive Waterbodies Oxidation Roadbase Hydrolysis Landscaping Methane Mine rehabilitation production

Use of biosolids Australia & NZ Australia New Zealand (~ 300 000 dry tonnes/yr) (~ 70 000 dry tonnes/yr) 9% 0% 1% 3% 9 75 agriculture 4% 4 0 18% forestry 11% 59 2 landfill 5% 8% 5% 2% 8 5 landscaping 5 11 land rehabilitation 75% 59% ocean discharge 18 1 stockpile 0 3 Beneficial use - 23% Beneficial use - 94% 3 states 100% beneficial use A goal of 75% beneficial use 1 state 99% beneficial use

Australia Trends in biosolids use over last 5 years & NZ New Zealand Australia 23% 10% Land rehabilitation Stockpiling 5% 3% Landfill, agricultural land 75% Agricultural land Minor increases for other uses 55% Essentially no change

Biosolids guidelines Australia & NZ Australia New Zealand National 2004 2003 Being revised QLD, NSW, VIC, TAS, NT Apply NZ guidelines State Territory SA, WA, ACT have Region own guidelines

Why are there state guidelines? Australia only • Australia is a federation • Australia was created by the joining together the colonies of New South Wales, Queensland, South Australia, Victoria, Tasmania, Western Australia • Powers were split between the Australian and the State and Territory governments. • The states control chemical management, environmental and The colonies that formed Australia human health

What do the guidelines do? Australia & NZ Determine • how the biosolids can be used If they can be applied to agricultural land • how much can be applied • where they can be applied

How can biosolids be used? Australia & NZ • The decision is based on Stabilisation grade Contamination grade Pathogen concentration Contaminants present Treatment type, duration & temp Contaminant concentration Pb DDT Zn Lindane

Stabilisation grades Australia & NZ State/Country Stabilisation grade NZ A B Australia, NT, WA P1 P2 P3 P4 VIC T1 T2 T3 SA A B TAS A B >B NSW, QLD A B C

Contaminant grades Australia & NZ State/Country Contaminant grade NZ a b Australia, NT C1 C2 >C2 VIC, WA C1 C2 C3 SA A B C WA, TAS A B >B NSW, QLD A B C D

Contaminants assessed Australia & NZ

Maximum concentration in biosolids Australia & NZ Country Cadmium (mg/Kg) Zinc (mg/Kg) /State Grade Grade Grade Grade Grade A Grade Grade Grade A B C D B C D Aus 1 20 200 – 250 2500 NZ 3 10 600 1500 NSW 3 5 20 32 200 700 2500 3500 WA 1 20 >20 200 2500 >2500 SA 1 11 20 200 1400 2500 Vic 1 10 200 2500 Tas 3 20 200 2500 >2500

How do you calculate the Australia & NZ contaminant grade? • BCC – biosolids contaminant concentration Infrequent sampling BCC = mean conc + SD Frequent sampling BCC = mean conc + 2SD i.e. 95%ile of concentrations

Maximum concentration in biosolids Australia & NZ Country Cadmium (mg/Kg) Zinc (mg/Kg) /State Grade Grade Grade Grade Grade A Grade Grade Grade A B C D B C D Aus 1 20 200 – 250 2500 NZ 3 10 600 1500 NSW 3 5 20 32 200 700 2500 3500 WA 1 20 >20 200 2500 >2500 SA 1 11 20 200 1400 2500 Vic 1 10 200 2500 Tas 3 20 200 2500 >2500

Contaminant grade Australia & NZ Determine the contaminant grade for all contaminants in the guidelines The lowest grade for all contaminants in a biosolid becomes the biosolids contaminant grade Biosolid Grade for each contaminant Biosolids contam grade Cd Cr Zn Lindane C Bios 1 A A C B C Bios 2 B C B B A Bios 3 A A A A

Biosolids grades & potential uses Australia only Contam Stab Permissible biosolids use grade grade C1 P1 Unrestricted except sensitive sites C2 P2 Agric for salad plants & root crops C2 P3 Agric for crops that are cooked or processed, grazing, dairy. C2 P1 Institutional (recreational) & landscaping C2 P3 Institutional (non-recreational), landscaping, forestry, land rehabilitation, landfill, sub-surface application. >C2 P4 Landfill or secure landfill.

Permitted land uses NZ only Stabilisation Contaminant Biosolids Permitted uses grade grade classification A a Aa unrestricted use biosolids* – permitted activity rule (e.g. fertilisers) A b Ab Restricted use biosolids - regional council assess B a Ba and give a “resource B b Bb consent” *sufficiently high quality that they can be safely handled by the public and applied to land without risk of significant adverse effects

How much biosolids can be applied? Australia & NZ • The amount depends on • Concentration of nitrogen in biosolids • Concentration of phosphorus in biosolids • Concentration of contaminants in biosolids

N and P limits Australia only • Are called the nitrogen limiting biosolids application rate (NLBAR) and phosphorus limiting biosolids application rate (PLBAR) • 1 NLBAR or 1 PLBAR is the largest amount of biosolids that can be applied so that the nutrient levels do not exceed the annual nutrient requirements of the crops (i.e. there should be no net increase in nutrient concentrations after one year) • NLBARs and PLBARs are plant and site specific

Calculating the Nitrogen Limiting Australia only Biosolids Application Rate (NLBAR) NLBAR (tonne/ha) = crop nutrient requirement (kg/ha) available bios nitrogen (kg/tonne) Some Australian crop nutrient requirements: Crop N requirement P requirement (kg/ha/yr) (kg/ha/yr) Clover 180 20 220 – 540 20 – 30 Lucerne Oranges 40 - Sorghum 90 15

Available Biosolids Nitrogen (ABN) Australia only ABN = [Ammonium N] + [Oxidised N] + ([Organic N] x MR x 1000) Organic N = TKN – (Ammonium N + Oxidised N) Oxidised N = Nitrite and nitrate TKN = Total Kjeldahl N MR is mineralisation rate: Anaerobic digestion - 15% Aerobic digestion - 25% Composted - 10%

Contaminant Limiting Application Australia only Rate (CLAR) For all contaminants except Cadmium CLAR = (MPCC – MSCC) x ρ /d x M BCC MPCC = maximum permissible contaminant concentration (mg/kg) MSCC = measured soil contaminant concentration (mg/kg) ρ = soil bulk density 1.333 dry tonnes/ha d = incorporation depth (cm) M = incorporate soil mass of 1 ha of soil (dry tonnes) BCC = biosolids contaminant concentration (mg/kg)

Calculating the MPCC for Cu and Australia only Zn MPCC = MPACB + BC MPACB = maximum permitted added biosolids concentration (mg/kg) BC = background concentration (mg/kg)

MPABC for Copper (mg/kg) Australia only pH OC (%) 0.5 1 2 3 4 5 6 4.0 4.1 8.5 17.7 27.1 36.7 46.4 56.2 5.0 8.4 17.4 36.0 55.2 74.7 94.5 114.5 6.0 17.0 35.3 73.3 112.4 152.2 192.5 233.2 7.0 34.7 72.0 149.9 228.9 309.9 392.0 475.0 8.0 70.7 146.7 304.3 466.4 631.4 798.6 967.6

How to determine background Australia only concentrations 1. If there is no history of metal additions (e.g. no intensive fertiliser, biosolid or pesticide use or not located close to urban/industrial centres) – measure soil concentrations and use as the background. 2. If there has been a history of metal additions or the history is unknown, use the models of Hamon et al . (2004) to estimate the background concentration.

Background conc of Cu & Zn Australia only Based on Hamon et al ., Global Geochem Cycles, V18, 2004.

Contaminant Limiting Australia only Application Rate (CLAR) for Cd Annual addition of Cd in biosolids can not exceed 0.03 kg/ha/year or 0.15kg/ha/5 years and must not exceed the Cd maximum permissible concentration (MPC)

Maximum permissible Cd soil Australia only concentration (Cd MPC) Soil pH Clay content (%) 5 25 50 4.5 0.54 1.17 1.96 6.5 0.82 1.45 2.24 8.5 1.10 1.73 2.52

CLAR calculations Australia only CLAR calculations should be done for all contaminants listed in the biosolids guidelines

How much biosolids can be Australia only applied? Cd Cu Other Zn NLBAR PLBAR CLAR CLAR CLARs CLAR The lowest application rate (above) determines how much biosolids can be applied