EFFECTS OF STRONG ACID AND IONIC MATERIALS ON MICROWAVE-ASSISTED THERMO-CHEMICAL HYDROLYSIS OF CATTLE MANURE

Jeongmin Lee, Jaeho Lee, Hyanggi Kim, Sanghoon Lee, Youngwoo Kim, Imgyu Byun and Taejoo Park

Department of Civil and Environmental Engineering, Pusan National University, 63beon-gil, Geumjeong-gu, Busan, Korea

Abstract

Microwave (MW) uses electrical energy. A catalytic material added MW hydrolysis is an effective way of reducing electricity consumption and enhancing the hydrolysis of cattle manure. In this study, catalytic materials, such as H2SO4 as the strong acid and NaCl as the ionic material, were applied to enhance the hydrolysis of cattle manure. Food wastewater (FWW) was also applied as the ionic material because of its high contents of NaCl and other ions such as K⁺, NH₄ ⁺, NO₃ ^-. After catalysts added MW-assisted thermo-chemical hydrolysis, the maximum increases of SCOD_release/TCOD_initial ratio were 0.064 for H₂SO₄, 0.050 for NaCl and 0.068 for FWW. And the SCOD_release/TCOD_initial ratio of FWW addition was 1.4 times higher than that with NaCl addition at a MW power of 800 W and target temperature of 40°C. The specific SCOD increase per energy consumption (mgSCOD/kJ) was 169.6 for H2SO4, 132.5 for NaCl and 180.2 for FWW. In biochemical methane potential tests, methane productions of H₂SO₄ and FWW addition were 1.25 times and 1.30 times higher than that with MW only assisted hydrolysis. Therefore, FWW was found to be good agent for enhancing the MW efficiency.

Keywords: Cattle manure, Microwave, Hydrolysis, Pretreatment, Chemical agent.