Managing liquid waste in the food manufacturing industry, specifically to meet trade effluent discharge consents and other obligations, is a huge issue. The bakery industry alone, which produces millions of products each day to satisfy consumer demand, is one of the largest water consumers, by far the biggest proportion of which is used for wash down and cleaning purposes. Loaded with fats, flour, sugars and yeast, treating this prior to discharge as wastewater is essential to meet increasingly stringent environmental pressures. Richard Goff, Chief Operating Officer of the Advetec Group explains how new innovative technology is making a difference.
The largest producers, who bake breads and other products on a truly industrial scale, will already have technologies in place to reduce the biological load in wastewater. Conventional solutions include screening and flow equalisation to accommodate production peaks, with FOG separation and Dissolved Air Flotation (DAF) systems to remove most suspended solids (SS) with Activated Sludge Processes to digest the organic content down to acceptable levels.
These are tried and tested systems and they work well. However they are resource intensive and come with high capital and operational overheads. Moreover they tend to be slow, requiring large effluent treatment compounds with storage and settlement tanks to manage wastewater volumes. For smaller bakery and food manufacturers, or where space is an issue, they may not be practical, affordable or desirable. It is here that smaller, discreet, in-vessel solutions will increasingly have the answer.
One UK bakery business for example, which supplies baked goods to food service wholesalers, contract catering and major supermarket customers, has replaced its onsite effluent treatment facility with the latest generation of bio-reactor from environmental technology specialist Advetec.
This is a purpose built self-contained reactor which is plumbed in to the company’s existing effluent treatment system. With a small footprint the unit is designed to handle a production capacity of up to 140m3 of wastewater per day, but without the peripheral storage and balancing tanks that traditional systems require.
Performance optimisation is achieved in part by ensuring a waste flow through the Bio-reactor that constantly mixes and aerates the effluent, preventing suspended solids from settling out and maintaining dissolved oxygen levels.
But it is Advetec’s use of specially developed bio-stimulants to invigorate the bacteria within the reactor, with automated dosing systems and monitoring to ensure optimal performance, which makes the difference. These bio-stimulants, which are matched to individual effluent streams following laboratory testing, both accelerate the process and ensure consistently reliable reductions in organic concentrations to maximise the digestive effectiveness of the system.
The plant produces between 10 and 140m3 of wastewater per day, depending on production volumes, passing from the factory through a filter screen to remove plastic film and other contaminants before entering the Bio-reactor. The main tank and mechanical components are constructed with 316 grade stainless steel to provide the necessary corrosive resistance to varying pH levels typical of bakery industry wastewater, and system monitoring with automatic dosing ensures an optimal internal environment for the process.
As well as a small foot print, the Bio-reactor also requires minimal maintenance, providing the composition of the effluent flow leaving the factory remains consistent and within design parameters. This is important and one of the reasons waste stream sampling and testing is crucial. Other than that a monthly check that dosing pumps and air compressors are working satisfactorily, and to monitor the level of micro-biological media in the dosing system, little intervention is required.
Installed in July 2017, the Advetec Bio-reactor has consistently ensured that the bakery meets its trade effluent discharge consents. Both dissolved and particulate biodegradable components are removed during the process, reducing Biological and Chemical Oxygen Demand (BOD and COD) as well as total suspended solids (TSS). In addition fat and oil content is significantly reduced and odours are also suppressed during the process.
The Advetec Bio-Reactor is a bespoke solution designed and optimised for each site based on the composition and volume of the liquid effluent stream. The solution is also completely scalable.
In future solutions like the bioreactor will be increasingly relevant to small and medium food and drink manufacturers who need to take control of their wastewater stream, treating it at source.
The technology will also appeal as a replacement or supplementary solution for existing effluent treatment plants where capacity deficits are experienced either because production volumes have grown beyond original design parameters or where old technology is increasingly ineffective with repeated consent infringements.
Chief Operating Officer