Gaseous Waste 1o2w1u

Gaseous waste Gaseous waste which emits from absorber mainly consists of nitrogen, carbon dioxide, carbon monoxide and other traces of material. These pollutants can be removed from airstreams either through absorption, adsorption, condensation or incineration. Each specific instance is carefully analyzed before commitment is made to any type of approach. This is to ensure that the technique is economically feasible under certain condition. Table 4.1 summarizes the limitation for each treatment method. Table 4.1: Summary of limitations for each treatment method Treatment method Condensation

Limitation  Condensation method is generally not utilized as method for removing a solvent vapor from air unless the concentration of solvent in gas is high and the solvent is worth recovery.  Condensation cannot remove all the solvent but it can only be used to reduce the solvent concentration in the carrier gas

Absorption

 Require good liquid-gas and proper equipment selection  Optimization of absorber is important  The power consumption of a modern, high-energy scrubber can be significant because of the high pressure drop involved

Adsorption

 Dry absorbents such as activated carbon and molecular sieves can be used to remove final traces of gaseous pollutants  Generally carried out in large, horizontal fixed bed and often equipped with blower, condenser, separator and control  Typically, installation consists of two bed; one is on stream while the other is being generated.

Incineration

 Two methods in common use : direct flame and catalytic oxidation  Direct flame has lower capital cost requirement but higher operating cost particularly if auxiliary fuel is required  Provides clean, odorless effluent if the exit-gas temperature is sufficiently high

Considering all the options, incineration method has been chosen for treating the gaseous waste. As according to Environment Quality Act (clean air) regulation 1978, the result of all tests conducted on incinerator shall be expressed on the basis of flue gas containing 12% by volume of carbon dioxide.

Direct flame thermal incinerator

steam

Flare stack Waste gas

Solid Waste Handling There are several means of disposal available for solid wastes handling since these wastes will remain at the point of origin until decision is made to dispose them. The method includes recycling, chemical conversion, incineration, pyrolysis and landfill (Peter, Timmerhaus and West, 2003). Environmental regulations, overall economics and local condition are generally are taken in in order to select the most acceptable one. Solid wastes for this process mainly consist of spent catalyst and sludge from wastewater treatment plant. These wastes require different method of disposal. Spent catalyst: Spent catalyst is categorized under scheduled waste. Therefore, proper handling need to be implemented is this waste is hazardous to public health and environment. Spent catalyst is stored in drum and sent to Kualiti Alam for disposal.

Sludge: Sludge is generated from the wastewater treatment plant. The sludge will be de-watered using belt pressing to turn it into dry, lighter sludge cake before disposal.