Combined treatment of waste and wastewater for a chocolate factory
Water is a critical resource in the food and beverage industry where increasingly demanding environmental requirements have given rise to new technologies and working practises to create a more sustainable way of treating and recycling wastewater.
Typical (waste)water solutions for these industries consist of multiple treatment steps in order to handle both soluble and solid waste streams. In contrast to the conventional method utilising EGSB and UASB/IC processes in combination with a pre-treatment system, the AECOMIXTM-DGF provides a simple one step solution – treating wastewater and organic waste streams in one reactor.
A typical example of an operating AECOMIXTM-DGF system is a chocolate factory in the Middle East where wastewater and organic waste streams are treated together. The plant treats a volume of approximately 100 m3/day. The wastewater originates from the CIP (cleaning in place) of the chocolate machines. The customer’s intention was to minimize and save water for cleaning the machines on site, resulting in a lower quantity of wastewater and a higher pollution load. To treat the highly polluted wastewater a pre-treatment system was installed which feeds the water into the AECOMIXTM-DGF producing biogas and reducing COD. Additionally a polishing step with a Nijhuis Biotreater, Sandfilter and Carbo-Pure ensures the expected effluent requirements are met.
The liquid volume of the AECOMIXTM-DGF reactor is 1400 m3. The COD reduction as a result of the AECOMIXTM-DGF is 96-98 % and the methane content of the biogas is 63-68%. The results are above expectation (in design stage) resulting in considerable over-capacity during the post- treatment phase.
Operational costs and profits comparison
In comparison to traditional solutions (chemical treatment, UASB or digester), the savings on power and chemicals are more than 20%. Operator attendance is reduced by at least 50% and since significantly less equipment is installed, annual maintenance costs are substantially lowered as well (> 50%). The AECOMIXTM-DGF concept installed at this chocolate factory in the Middle East proved to be a revolutionary and highly innovative solution, especially tailored for food & beverage plants treating wastewasters with high TSS and/or FOG. Additional benefits can be realized when the plant is designed to treat factory waste as well. The concept provides a single step process solution for different substrates with a high removal efficiency (of organic matter) of more than 95% on COD. Since the majority of removed organics is transferred into biogas, a much higher biogas volume is achieved in comparison to traditional routes.
In the event post-treatment is required, this step will be less intensive in comparison to the traditional method because more organics will already have been removed in the AECOMIXTM-DGF process. This results in a smaller footprint and less OPEX for polishing.