CEM India CEM India

CEM India - Abstract

CEM India

CEM India

Session Choice: Monitoring Techniques: Trace species
Presenter Name: Mr Ajay S V
Co-authors:Dr Prathish K P
Dr Ajit Haridas
Company/Organisation: CSIR-National Institute for Interdisciplinary Science and Technology
Country: India

Abstract Information :

Unenclosed burning of MSW in open premises is a common practice in the state and inadvertently it acts as a major source of PCDD/Fs into atmosphere. Polychlorinated dibenzo-dioxins and furans (PCDD/Fs) are highly toxic contaminants and its exposure can cause immunotoxicity, carcinogenicity and reproductive ailments. This study is focused to develop an inventory of dioxin emission from open burning of MSWs in Kerala by carrying out simulated waste combustion experiments in a custom made ‘Burn Hut’ facility. Burn Hut is equipped with real time monitoring systems for weight and temperature changes and air flow controllers to simulate open air conditions. Combustion experiments with waste prepared by collecting different types of waste and manually mixing it to desired compositions as well as composite waste collected from waste dumpyards were conducted. The effect of typical waste composition and combustion conditions on the emission factor of PCDD/Fs were investigated during the study. The moisture percentage and the composition of the waste were determined prior to each combustion experiment. The air sampling from the burn hut was carried out using iso-kinetic sampler as per USEPA method 23 and residual ash samples were collected after the completion of combustion by coning and quartering method. The samples were processed as per USEPA – 8290 method and quantified using GC-MS/MS. The emission factors of dioxins during combustion of wastes with different moisture levels (pre-dried; moisture % - 10-20%, wet; moisture % - 50-78%) were determined. The air emission factor (EFair) and the ash emission factor (EFash) during pre-dried waste combustion was found to be 2.89 ug TEQ/ton and 2.95 ug TEQ/ton respectively. EFair and EFash obtained for wet waste combustion studies were 5.94 ug TEQ/ton and 61.65 ug TEQ/ton respectively. For experiments conducted with waste collected from dumpyards, 90.6 ug TEQ/ton was observed as EFair and 5.16 ug TEQ/ton as EFash. The typical moisture content of Kerala’ MSW composite is in the range of 60 – 70% and hence the total emission factor of PCDD/F from open burning of MSW was decided by considering the concentrations obtained from the experiments done on wet waste (original) basis. The total emission factor was taken as the geometric mean of the values obtained from experiments. 17.7 ug TEQ/ton is the EFair and 27.0 ug TEQ/ton is the EFash observed and the total emission factor (EFtotal) comes to be 44.7 ug TEQ/ton. The studies gives a hint that the moisture content in the waste has a critical role in dioxin formation as it can lead to poor combustion conditions and prolonged smoldering period. The congener profiling of PCDD/F showed predominance of higher chlorinated dioxins and the presence of highest toxic tetra and penta congeners. Further studies on deeper understanding of the influence of moisture content as well as waste composition on dioxin emission and congener concentrations are ongoing.