Evaluating Optimal Cultivation Sites for Microalgae Based on Dairy Farm Wastewater using Analytical Hierarchy Process and Geographic Information System Techniques

Dairy farm wastewater contains high BOD, COD, and TSS, thus harming the environment if discharged without proper treatment. However, it is rich in nutrients, primarily nitrogen and phosphorus, which are needed by microalgae to grow and synthesis useful and high-value organic compounds. Microalgae biomass can be generated from a cultivation system that is integrated with wastewater sources efficiently. Selecting a suitable location is thereby crucial for the sustainable development of microalgae cultivation. This study aimed to select suitable locations in Cangkringan District, Indonesia for microalgae cultivation sites using the analytical hierarchy process (AHP) method integrated with geographic information system (GIS) and weighted overlay analysis (WOA). AHP helped determine the relative weights of the relevant factors, including dairy farm wastewater, temperature, land use, land elevation, and land slope in the study area. These weights were subsequently applied in WOA to determine locations that were most suitable for microalgae cultivation sites. The results of WOA, presented in the form of a land suitability map, showed that 0.1% (0.04 km2 ) of the studied areas is highly suitable for the development of microalgae cultivation and that a significant portion, approximately 67.2% (29.75 km2 ), is not suitable.