INCINERATION AND AIR POLLUTION MANAGEMENT IN NIGERIA
Various incineration technologies are available for handling different types of hazardous wastes, such as rotary kiln, fixed hearth, and fluidized bed incinerators. The rotary kiln incineration system is regarded to be the most versatile for its ability to handle liquid, sludge and solid wastes at a high temperature and throughput.
The newly installed incinerator by The Initiates Plc (TIP) is a rotary kiln incinerator capable of reducing wastes satisfactorily while producing emissions that are compliant with regulatory requirements. This is a bi-chamber incinerator which operates at 1000OC and 1500OC temperature in the primary and secondary chambers respectively. The incinerator has good turbulence (11.6m/sec air flow), and secondary chamber residence time of about 2.1seconds.
Incinerator Air Pollution Management
Historically, incinerator was designed to remove two classes of pollutants which are particulate matters and acid gases. More recently, some methods for improving the removal of dioxins and/or heavy metals (including mecury) are considered necessary. A number of new design features and operating techniques have been adopted to increase temperature, extend residence time, and increase turbulence in waste incinerators in order to improve combustion efficiency and provide other benefits like improved ash quality. They include high-efficiency burner systems, waste-pretreatment practices such as shredding, blending, and oxygen enrichment.
The Initiates Plc puts all these factors into consideration in the design and construction of her 3ton/hr Incinerator which is currently ready for commissioning as at the time of this writing and considerable attention was given to measurement and control of key process operating conditions to allow for better control of the whole combustion process in order to manage air pollution.
Part of the measures put in place to manage air pollution includes;
- Lime Scrubbing for the removal of acid gases
- Activated Carbon injection for the removal of heavy metals
- Venturi for the removal of particulate matters
- Flue gas monitoring system (RAS 1700 supplied by Euroton Instruments UK).
Nigeria Regulatory Requirements for Incineration
Environmental Guidelines and Standards in Nigeria are mainly regulated by Federal Ministry of Environment (FEMEnv), Department of Petroleum Resources (DPR), and National Environmental Standard Regulation and Enforcement Agency (NESREA).
Some of the guidelines for regulating Incineration activities in Nigeria set by the regulatory agencies are:
- Incineration shall be carried out for either total destruction and/or recycling (resources recovery) of the hazardous materials,
- All incinerator shall be designed, constructed, and operated to meet performance standards as follows:
- An incinerator burning dangerous waste shall be designed, constructed, and maintained so as to provide for fugitive emission control
- Incinerator shall achieve a Destruction and Removal Efficiency (DRE) of 99.9% of Principal Organic Hazardous Constituents (POHCs) and Dangerous Combustion by-products (DCBP).
The incinerator shall destroy dangerous combustion by-product and limit emission of HCI particulate matters and ash etc.
Other regulatory requirements specified; waste analysis performance standard, operating requirements, monitoring and inspection as contained in the regulatory documents of DPR, FEMEnv and NESREA respectively.