Greenhouse gas inventory for an industrial wastewater treatment plant

Industrial wastewater treatment plant from a food factory is taken as case study for preparing greenhouse gas inventory in Kemalpasa, Izmir. The scope of the inventory is limited to identifying sources and calculating of the gases emissions. At the conclusion part, activities beneficial that reduce emissions are explained for this wastewater treatment plant. Community-level/ industrial inventory is prepared that includes emissions from activities in the plant of the company such as energy consumption and transportation. As a first step of this study, boundaries and activity categories of the organization are determined and activity data are collected according to "top-down" approach. In the calculation part of the study, a methodology is chosen for calculation of emissions which is called "greenhouse gas data is multiplied by the factors of greenhouse gas emissions." According to this method, greenhouse gas emissions are calculated by collected data entering into a calculation program. The programs are defined "stationary combustion tool", "purchased electricity tool" and "transportation tool" by Greenhouse Gas Protocol. Stationary combustion tool is used for calculating direct emissions from fossil fuel consumption. Purchased electricity tool is related to indirect emissions as electricity consumption of the equipment and transportation tool is related to other indirect emissions related to the transfer of wastewater chemical needs. In this study, direct and indirect greenhouse gas emissions is calculated as of 2178.35 tons/year (due to the fossil fuels) and 903.37 tons/year (due to the electrical consumptions) respectively. After carbon dioxide emissions are determined for the wastewater treatment system, carbon management methods are discussed for reducing the carbon dioxide emissions. Finally tree planting method is preferred to carbon offsetting as it is the cheapest and easiest method that can be applied for the company. As a result, the company can be neutral by planting 5173 number of tree with 25865 TL cost in each year. In addition, reducing the sludge quantities that is processing in the rendering unit will be resulted in drastic decrease in fossil fuel consumption, and thus in extreme decrease in direct greenhouse gas emissions. Theoretic studies shown that transporting of the sludge to the landfill site results with 931.27 tons carbon dioxide emissions to atmosphere; the company can plant only 1552 tree and pay 7760 TL to become carbon neutral in each year. Keywords: Greenhouse gas inventory, GHG Protocol, carbon offsetting, calculation