Civil Engineerz: WASTE TREATMENT METHODS

WASTE TREATMENT METHODS

INCINERATION

Incineration is the controlled combustion of waste originating form Municipal Commercial and industrial sources in order to destroy it or transform it in to less hazardous materials. Organic constituents break down to give CO₂, steam and other gases such as Sulphur dioxide and Nitrogen Oxide. While inorganic constituents are dehydrated and calcite.

In incineration of Municipal and commercial waste the main objective is to reduce volume and so to save the transportation cost associated with landfill and extending the life of the landfill. In incineration of industrial and hospital waste the objectives are to destroy any hazardous or infectious or organic material present and also to reduce volume. There are incinerators which are used to destroy different waste that is waste which contains hazardous material and these incinerators are used in hospital for destroying clinical waste. Properly managed incineration will reduce the volume of the initial waste but there will be gaseous emission and inorganic residues left at the end of the process. The hazardous organic materials are destroyed in the process. The Municipal and commercial waste is incinerated at a temperature up to 850 °C in the presence of air but for hazardous waste higher temperature of about 1200- 1250^oC is required. The residual ash so collected should be carried and disposed off on the landfill site.

The incinerator used for hospital infectious waste should consist of two chambers i.e. primary and secondary chamber. The primary chamber is operated under reduced mode. Under theses conditions the controlled air is supplied in the primary chamber which is less than the required quantity of complete combustion. The combustion gases produced form the primary chamber is used as fuel in the secondary chamber. Sufficient quantity of air is supplied in the secondary chamber along with auxiliary fuel for complete combustion. Most commonly used auxiliary fuel is diesel oil or natural gas

Depending on fuel case. The natural gas is more economic for incineration and is used for incineration in H.M.C

Following are the figures of different waste treatment processes.