Goat manure formula in sludge cake wastewater treatment plant as organic fertilizer

Department of Food Science and Biotechnology, Faculty of Agriculture Technology, Brawijaya University, 65145 Malang, Indonesia

^* Corresponding author: nurkusmiyati@ub.ac.id

Abstract

The use of activated sludge in wastewater treatment plants (WWTP) in industry gives a by- product in the form of sludge cake. Sludge cake presents a new problem for the environment because its accumulation causes the land to become unproductive, disrupts aesthetics, increases microbial activity, and pollutes water and soil, which can be harmful to humans and the environment. PT X is one of the industries that produces 80 kg/day of sludge cake. Based on laboratory results, X WWTP sludge cake has the potential to be used as an organic fertilizer. However, the use of sludge cake as organic fertilizer does not meet fertilizer quality standards and does not provide optimal results for plants. Goat manure is known to increase the organic fertilizer content of sludge cake in accordance with fertilizer quality standards. This research aims to find the best formula for adding goat manure to WWTP sludge cake which is carried out using four treatments, namely sludge cake without treatment, and the addition of goat manure 1.4 kg, 2.1 kg, and 2.8 kg. The stages of the research include the preparation of raw materials, the manufacture of organic fertilizers, and testing the content of organic fertilizers. The results showed that there was an increase in physical and chemical parameters on organic fertilizers, namely pH (6.6), C (22.14%), N (3.55%), P (4.65%), K (0.45%), Ca (0.52%), and Mg (0.26)), as well as a decrease in water content (15.40%) at the end of composting. The addition of goat manure with a combination of other additives to X TWP sludge cake can meet organic fertilizer quality standards. The addition of 2.1 kg of goat manure is the best formula to increase organic fertilizer.