Research Article
Duygu Karaalp, Nurdan Doruk
Abstract
Chicken manure has high solid and high ammonia content which dictates the dilution of feed material with huge amount of freshwater in order to minimize ammonia toxicity, if it is to be digested alone. In this study, a novel approach is presented to significantly minimize fresh water need for biogas application and to eliminate the construction of costly digestate storage tanks. For this purpose, membrane process which allows recycling of digestate after ammonia removal was integrated to the conventional biogas system. Therefore, the selection of proper membranes for the removal of ammonia from digestate was carried out by testing six different types of Nano Filtration (NF) membranes (NF270, NF245, NF200, NF90, NF-NF, NP010) and three different types of Reverse Osmosis (RO) membranes (BW30, SW30, X20) in cross flow microfiltration experiments. The performance of the membranes was tested by monitoring parameters such as pH, conductivity, COD, TN, NO2-N, NO3-N, TP in the permeate under various operating conditions. NF90 (83%) and X20 (92%) type membranes were found to be most effective for the removal of TN from the digestate. Moreover, COD (Chemical Oxygen Demand) removal efficiency reached up to 99% for both NF90 and X20 membrane.