COMBINATION OF CHEMICAL BIOLOGICAL FLOCCULATION AND MICROALGAE BIO FILM GROWTH FOR DECENTRALIZED SEWAGE TREATMEN

摘要

The ZeroWasteWater approach was proposed as an alternative to traditional wastewater treatment to maximize energy and valuable materials production from sewage and to minimize waste production (Verstraete et al., 2009; Ver-straete and Vlaeminck, 2011). Overall, domestic wastewater should be up-concentrated producing two sub-products; one with high and one with low levels of suspended and colloidal solids. An up-concentration technique that could be used is the chemical biological adsorption also known as the A-stage (Bohnke, 1977; Versprille et al., 1985). The sub-product with high levels of organic matter can be subjected to anaerobic digestion to recover energy. The sub-products with low suspended solids can follow further treatment for nutrient removal for instance nutrient removal by the OLAND process (Kuai and Verstraete, 1998). Nutrient removal can also be carried out by microalgae. However, the main constraint of using microalgae for nutrient uptake is the fact that the solid liquid separation is highly energy-consuming and the bioreactor technology is expensive (Uduman et al., 2010). Therefore, the development of a microalgae system that is inexpensive and has low energetic requirements is essential. The purpose of this study was to perform a technical evaluation and preliminary cost assessment of a decentralized nutrient immobilization concept for domestic wastewater treatment. The proposed strategy consists of a chemical biological adsorption (A-stage) followed by microalgae biofilm immobilization (referred to here as an I-stage).