Anaerobic co-digestion using processed food and distillery wastewater

Abstract

Due to urbanization and industrialization, food wastes has increased in Korea. About 90 % of the F.W is recycled to be used as animal feed or composting. Removing salt from F.W is needed to make F.W animal feed or composting. Generally removing salt is needed to make F.W animal feed or composting. Food wastewater (F.W.) occurs consistently by washing water and water in content of F.W during the process (Ministry of Environment, 2008-2012). In Korea alone produces more than 9000tons F.W. /d (MOE, 2012). F.W.W is the high-concent ration organic wastewater which has 150,000mg/L of the COD (chemical oxygen demand). If F.W. neglect, it can cause the serious environmental problems. Before 2013, most F.W. was discarded by ocean dumping, but this practice was prohibited by the London Convention 97 protocol of 2013 in Korea. Thus treatment of F.W. is important for environmental protection (hyun-min Jang etc al., 2014). Therefore, it is urgent for us to make good use of F.W. and land disposal.

Anaerobic digestion (A.D) process among various land disposals processes is getting the spotlight. A.D is a multi-stage process that complex organic components of the waste are hydrolyzed. Into intermediated products and finally methane and carbon dioxide. In addition A.D was used to treat high concentration of organic waste in warming area (Kelleher, 2000). Generally the advantages of A.D was that it causes less secondary pollution, kills pathogenic bacteria and coverts organic matter into methane gas (John et al., 2011). A.D has high stability process and low cost technology because they do not require specialized operating skills. However, when operating single-stage A.D at F.W., it can reduce biogas yield and removal efficiency of organic matter by high concentration of salt and organic matter in F.W.W and it can be extinction anaerobic microorganisms by low pH (El-Mashad et al., 2008).

Thus, we considered anaerobic co-digestion treatment of distillery wastewater (D.W.) to supplement aforementioned weakness. D.W. has treated by the anaerobic treatment (Yong-Chul, Kim, 1991). But as the use of rice and barley has increased according to national agricultural policy, the efficiency of A.D efficiency has declined sharply and methane gas yield has reduced (Jong-Hun, Won 2007). Also, lack of trace element can impede activity of anaerobic microorganisms.

Therefore, in this study mixed F.W and D.W. So, we make supposition about supplement point operating anaerobic co-digestion. We decided that toxic materials (Cl⁻, Na⁺ etc) of F.W. can be diluted through D.W. Also we assumed that low organic matter and trace elements of D.W. can be supplemented by injecting F.W. Until recently most of the studies on merging A.D of F.W. have been combined connect with sewage sludge. Studies on anaerobic co-digestion have been insufficient about treatment of D.W. and F.W. (Xiaofeng Liano et al., 2014; M. Barrantes Leiva et al., 2014; Lei Zhang et al., 2011; C.Ratanatamskul,G 2014; Yun-gi, Hong 2011; Won-geun, Lee 2011). This purpose of this study is to explore the possibility of anaerobic co-digestion of processed food wastewater and distillery wastewater. And provide basic information for anaerobic co-digestion.