Evaluation of Lemna minor and Chlamydomonas to treat palm oil mill effluent and fertilizer production

Abstract

Malaysia is considered as one of the major palm oil producers in the world. Therefore, it is important to develop an environmentally friendly and economic method to treat palm oil mill effluent (POME). The main aim of this study was to investigate the potential of Lemna minor (L. minor) and Chlamydomonas incerta (C. incerta) with catalog number (KR349061) for the bioremediation of POME in order to achieve higher water quality standard and further produce organic fertilizer. In this study, three different experiments were conducted by using L. minor, followed by addition of C. incerta, and further combination of L. minor and C. incerta. The concentration of nitrate (NO3 −), ammoniacal nitrogen (NH3-N), phosphate (PO4-P), Electrical Conductivity (EC) and salinity in produced fertilizer were measured, and then they were compared with two current commercial fertilizers. Growth factors such as growth rates, average number of leaf and height of root of L. minor of plants were also determined. The results showed that the microalgae and macrophytes were capable of removing only 4.4% of chemical organic demand (COD) whereas the respective maximum removal rates for NO3 −, NH3-N, and PO4-P were 12.5%, 11.3%, and 70.47%. Also, the average differences of NO3 −, NH3-N, and PO4-P concentrations in produced fertilizer in comparison with two current commercial fertilizers were 95, 39.5, and 62.5 mg/g, respectively. The results of this study revealed that only L. minor was converted into fertilizer. This study elaborated that both L. minor and C. incerta are able to remove a part of organic pollutants and nutrients from POME.