The physicochemical characteristics and anaerobic degradability of desiccated coconut industry waste water

Abstract

Desiccated coconut industries (DCI) create various intermediates from fresh coconut kernel for cosmetic, pharmaceutical and food industries. The mechanized and non-mechanized DCI process between 10,000 and 100,000 nuts/day to discharge 6-150 m(3) of malodorous waste water leading to a discharge of 264-6642 kg chemical oxygen demand (COD) daily. In these units, three main types of waste water streams are coconut kernel water, kernel wash water and virgin oil waste water. The effluent streams contain lipids (1-55 g/l), suspended solids (6-80 g/l) and volatile fatty acids (VFA) at concentrations that are inhibitory to anaerobic bacteria. Coconut water contributes to 20-50% of the total volume and 50-60% of the total organic loads and causes higher inhibition of anaerobic bacteria with an initial lag phase of 30 days. The lagooning method of treatment widely adopted failed to appreciably treat the waste water and often led to the accumulation of volatile fatty acids (propionic acid) along with long-chain unsaturated free fatty acids. Biogas generation during biological methane potential (BMP) assay required a 15-day adaptation time, and gas production occurred at low concentrations of coconut water while the other two streams did not appear to be inhibitory. The anaerobic bacteria can mineralize coconut lipids at concentrations of 175 mg/l; however; they are severely inhibited at a lipid level of ≥350 mg/g bacterial inoculum. The modified Gompertz model showed a good fit with the BMP data with a simple sigmoid pattern. However, it failed to fit experimental BMP data either possessing a longer lag phase and/or diauxic biogas production suggesting inhibition of anaerobic bacteria.

Identification of new critical points for logistics model in cumulative methane yield curves after co‐digestion of apple pulp and chicken manure with sulphuric acid pretreatment and a new modelling study

“…MLM is widely used for biogas . MGM showed a good fit to the cumulative methane production data from organic wastes derived from desiccated coconut industries with a sigmoid pattern . In order to achieve a better fit in this study, four models were compared and MHM was successfully introduced as an alternative model.…”

Investigation of different pre-treatments of chromium leather shavings to improve biogas production

“…This is the case when the substrate is difficult to degrade [49]. The modified Gompertz model has been widely used in the simulation of biogas and methane production results [54][55][56][57]. This model can predict the lag-phase of the process, a period associated with the hydrolysis of the substrate in the digester.…”

Food‐Processing Wastes

“…A Seoul, Korea lab-scale study on thermophilic anaerobic digestion of food waste showed that methanogenic activity was impacted at high OLR, which led to accumulation of volatile fatty acids (VFAs) and concomitant decrease in pH . Chanakya et al (2015) reported that coconut processing wastewater from three different industrial processing separate streams: coconut kernel water, kernel wash water, and virgin oil wastewater was treated anaerobically.…”