Skip to main content

Energy-Use Minimization in Residuals Management in the Personal Care Product Industry

Final Report Summary - ENERMIN (Energy-use minimization in residuals management in the personal care product industry)

The development of safe, long-term solutions to the current global energy crisis and problems of global warming demand the combined efforts of academia, government and industry to create more sustainable modes of operation. Although many activities are needed, one of the most immediate issues requiring action is the development and implementation of new methods for reducing energy consumption and minimising waste generation in all sectors of society. This is especially true in large industries, which frequently consider waste handling and management with disinterest, tending to neglect innovation in this side of their operations. In fact, this is very much against their best interest because industries often use vast amounts of energy in waste handling and treatment during normal operations and often underestimate energy savings that are possible if their wastes are viewed as useful resources rather than things to be discarded.

The 'Energy minimisation in residuals management' (ENERMIN) project was initiated to examine how wastes are handled and treated in the personal care product industry (PCP) with the goal of developing new technologies that reduce energy use in waste management, sustain waste treatment efficiency and show other industries that wastes can be resources, not liabilities. This project combined the skills and experience of Newcastle University, United Kingdom (UK), L'Oreal Industries (France) and ACS-Umwelttechnik (Germany) to study and develop alternative waste management approaches for the PCP industry. The PCP industry is of particular interest because it historically has used high levels of energy in waste management and urgently needs new approaches. However, the PCP industry also is typical of any industry that produces concentrated carbon wastes. As such, L'Oreal and the PCP industry is a valuable test-bed for new approaches that might be applicable across all industrial applications.

As background, waste treatment from PCP operations traditionally uses high levels of air to stimulate aerobic biological activity to biodegrade the wastes prior to release to the environment. However, aeration also uses vast amounts of electricity, making aerated treatment methods very energy intensive. Further, aerobic biological processes also produce large amounts of extraneous biosolids (sludge), which creates a biosolids handling problem that also is energy intensive. As such, the focus in ENERMIN was to examine the suitability of anaerobic and other low-air technologies in PCP waste management and also to examine how previous aerobic technologies might be retrofit to use less air.

Anaerobic technologies often are favoured for waste treatment because they can produce methane (combustible biogas), which in turn, can be used to produce energy production via combustion. Unfortunately, not all wastes can be effectively treated by anaerobic processes because of the occasional presence of inhibiting compounds in the waste; therefore is sometimes necessary to source-separate waste streams to optimise biogas production. However, if the waste is innately amenable to biogas production or can be made amenable by separation, consequent reduced aeration also can reduce energy needs. Therefore, combining source separation and anaerobic-aerobic treatment processes within the same system can produce potential energy and also reduce energy consumption, doubly reducing net energy demand. This provides an ideal system for industrial waste treatment, which might even make some industries into net energy producers.

Examples of specific technologies assessed in ENERMIN included:

1. source separation and parallel treatment of different carbon-rich waste streams to remove potentially inhibitory sub-streams that negatively affect methane-producing treatment technologies (i.e. to increase biogas yields);
2. combining anaerobic and aerobic biological processes to sustain treatment efficiency, generate potential energy as combustible biogas and reduce energy use in aeration;
3. development of alternate biological media designs that allow aerobic treatment, but do not need substantial air addition (e.g. sponge reactors), which is the most costly element of aerobic processes.

The project was very successful and all three approaches proved to have significant merit. Various pre- and post-treatment approaches were tested at the laboratory and at the pilot scale and results generally showed that low-air systems, source separation and anaerobic-aerobic reactor systems were viable options for reducing energy consumption and solids production. Specifically, ENERMIN laboratory work indicated that a 68 % reduction in net energy use was possible using approaches developed in the project. In fact, a PCP factory located in Suzhou, China recently built a new treatment facility based on treatment strategies developed by ENERMIN. Similar anaerobic-aerobic and low-air aerobic processes now are being considered elsewhere for reducing net energy consumption in industrial waste management. Follow-on work is on-going, especially the application of ENERMIN technologies to other types of wastes, including domestic wastes in developed, emerging and developing countries. Further details about the project can be found at http://www.ceg.ncl.ac.uk/enermin.