## 2 Centralized Treatment Plants
### Industrial Wastewater Remediation
#### 2.3.4 Food and Beverage Industry  
The production of packaged foods or drinks requires important amounts of primary water to clean the original natural matters and containers or to perform other steps of the productive process. The wastewater can be more or less contaminated according to its use and can be remediated and recycled; even its reuse at the food production line can encounter various difficulties [94; 95]  
An interesting example of easy water reuse is the recovery of the high-quality wastewater from the bottle washing step and its reuse in the cooling process. The hydrogen peroxide, a by-product of the peracetic acid employed as disinfectant, can be removed by acid-washed activate carbon treatment to avoid oxidation of the refrigeration circuit. Laboratory-scale experiments demonstrated the total absence of hydrogen peroxide in the regenerated water and gave the starting signal for a one-year application at an industrial scale, resulting in 5 m\({}^{3}\)/h of water savings and 100% replacement of the water employed in the cooling towers. After one year of reclaimed water use in the presence of isothialone, no reduction in the effectiveness of this biocide was detected. Furthermore, the authors developed and proposed a control plan to monitor the presence of _Legionella_ and possible corrosion effects [96]. In other cases, produced wastewaters can contain high concentrations of organic compounds, like in the fish canning industry, requiring the application of biodegradation treatments. A pilot-scale anaerobic MBBR (AnMBBR) was set up with six separated zones and immobilizing bacteria, mainly _Metunosaeta_ spp., on polyvinyl alcohol gel beads. It was installed at the WWTP of a fish canning factory, connected to an inlet tank receiving raw wastewater after primary treatment (organic loading rates in the range 3.0-8.7 kg COD/m\({}^{3}\) day) and to an outlet tank, pumps and pipes. The system was operated for a total period of 6 months and its COD removal efficiency was 81.0% at a flow rate of 350 L/D, reduced to 70.6% at 1000 L/D FR.81. The mean COD removal efficiency was above 60% [97]. For the in situ treatment of such heavily contaminated WW, an integrated process was developed into a flexible, easy-to-transport modular system. WW from a fish processing plant was treated in a dissolved air flotation (DAF) unit built in a sea container (20 m\({}^{3}\) volume) to remove oil, grease and other suspended solids, separated from the water using microbubbles. An iron-based coagulant and a polyacrylamide flocculant were added. The hydraulic residence time was 4 h, and the unit was monitored for 54 days. The treatment removed about 70% of the turbidity, 83% of COD, 93% of phosphorus and 99% of oil and grease. The residual nutrients were adsorbed onto a mixture of hemp and spruce biochar in a pilot-scale column filtration system, which removed 60% of residual turbidity and to some extent residual COD, nitrogen and phosphorous. At the end of the cycle, biochar can be used as a soil conditioner and slow-release fertilizer in fields. When the treated water was used for washing the production lines, a disinfection treatment was necessary. DAF and biochar-filtered effluents cannot be released into the environment because of the still high content of nitrogen and organics, but the treatment greatly reduced the organic load reaching the WWTP [98]. For reclaimed water reuse at a brewery production plant, two different advanced tertiary treatments were applied to the brewery WWTP secondary effluent as a pilot-scale plant. One system consisted of UF + RO membranes, and the second one included ozonation, coagulation, microfiltration with ceramic membranes (MF) and RO. The UF pilot plant was operated for 4 months at increasing fluxes. Chemically Enhanced Backwash (CEB) was employed after each filtration cycle. The RO unit was fed with UF permeate on a semi-continuous basis for 2 months, and the MF membrane with enhanced ozonation and coagulation was operated for the same time period.