Poultry litter ash characterisation and recovery

• This paper reports a complete characterisation of poultry litter ash and its potential use as a heavy metal stabiliser. We propose a novel approach, in which the ashes deriving from municipal solid waste incineration (MSWI) are combined with poultry litter ash, rather than with coal combustion flue gas desulfurisation (FGD) residues. Heavy metals stabilisation was demonstrated by comparing the elemental concentrations in the leaching solutions of the starting raw and stabilised materials: leachable Pb and Zn showed a reduced solubility. The characterisation was conducted by total reflection X-ray fluorescence (TXRF), X-ray diffraction (XRD), micro-Raman spectroscopy and scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDX). The results showed that the poultry litter ash was Ca-, P-, K- and S-rich (>29 g/kg). It contained amorphous materials (i.e. fly ash economiser (FAECO) 73% and fly ash cyclone (FACYC) 61%) and soluble phases (e.g. arkanite and sylvite; up to 13% FAECO and 28% FACYC), as well as resilient crystalline (up to 2% of FAECO and FACYC) and amorphous phases (e.g. hydroxyapatite). After two months, the Pb and Zn concentrations in the leachate solutions were below the limit set by the European regulations for waste disposal (<0.2 mg/L and 1.5 mg/L, respectively). We propose a mechanism for the heavy metals stabilisation based on the carbonation process and high amounts of P, Ca and reactive amorphous phases. In conclusion, it is demonstrated that poultry litter ash can be an effective secondary source of heavy metals, allowing their immobilisation through P- and Ca-based reactive amorphous phases.

Nyckelord

Heavy metals

Incineration waste products

Phosphate

Poultry litter ash

Waste management

Amorphous materials

Coal ash

Coal combustion

Fly ash

Hydroxyapatite

Municipal solid waste

Nanocrystalline materials

Scanning electron microscopy

Stabilization

Storms

Waste disposal

Carbonation process

Coal combustion flue gas

Elemental concentrations

Energy dispersive X-ray spectrometry

European regulation

Micro Raman Spectroscopy

Stabilised materials

Total reflection X-ray fluorescence

Waste incineration

calcium

heavy metal

lead

phosphorus

potassium

sulfur

zinc

carbon

ash

concentration (composition)

incineration

leachate

solubility

agricultural waste

Article

concentration (parameter)

immobilization

leaching

priority journal

animal

particulate matter

poultry

solid waste

Animals

Metals

Heavy

Refuse Disposal

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)