Zero Effluent Systems

Some packaging paper mills in central Europe today run with zero effluent systems (Fig. 5.6 ) using a combination of anaerobic/aerobic biological treatment (see Section 10.1) as kidney technology for COD reduction [5]. 

The driving forces for reducing the effluent to 01 (kg paper) for these mills were unique to each miU. In one case there was high cost-saving potential by completely avoiding effluent fees for disposal into a public effluent treatment plant. In another the reason for complete water circuit system closure was the lack of available fresh water due to the local conditions when installing additional production capacity [7]. 

The other mentioned kidney technologies, i.e. membrane filtration and evaporation, are mainly known as pilot scale appHcations as they are quite cost-intensive and still not proven state-of-the-art 7]. 

Zippel, Water Management in Paper Mills, Deutscher Fachverlag, Frankfurt, 2001, Preface by L. Gottsching. 

AnionicTrash Controlling Detrimental Substances, Tappi 1987, 10, 79. 

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A skilful arrangement may produce waste water qualities that meet even stringent requirements, for instance as boiler feed water, and it is theoretically possible to realize a zero effluent system which produces only very small quantities of regenerates. 

Do not let out the processed liquor go directly to ground. Emphasize on zero discharge system of effluent treatment. 

The effluent concentration history is the breakthrough curve, also shown in Fig. 16-3. The effluent concentration stays at or near zero or a low residual concentration until the transition reaches the column outlet. The effluent concentration then rises until it becomes unacceptable, this time being called the breakthrough time. The feed step must stop and, for a regenerative system, the regeneration step begins. 

Membrane systems followed by an evaporator (for low-volume highly concentrated effluent) can enable industries to achieve zero liquid discharge goals. 

Not all power plant designs fit into an upstream or downstream category. Integrated systems let carbon move through the entire process, but they prevent normal dilution of the output flue gas, so that the effluent is concentrated CO2. While most of the plants in this category are still in an early development phase, they promise to combine high efficiency, virtually zero atmospheric pollution, and complete capture of all CO2. All avoid the intake of air. 

Adoption of new technologies producing zero waste material will no doubt be the best alternative but may not be always easily possible. Therefore minimization or if possible, total elimination of solid waste material from the liquid effluents and recycle of water to the plant will benefit the manufacturers and the eco-system in more ways than one. 

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