Method for biological treatment of water by adding macromolecular carbohydrates

#The invention relates to a method for biological treatment of water, and to a water treatment agent that is applied to biological water treatment systems in small amounts, with the objective of reducing the residue quantities obtained.

#Biological methods are used for treating domestic and industrial waters. In the biological conversion of dissolved and undissolved ingredients, new micro-organisms are formed, with which solids with poor biodegradability properties contained in the waters are separated off and then removed from the treatment systems. These residues are reused in agriculture or in recultivation, depending on the harmful substances contained therein and the concentration thereof. Furthermore, heat treatment and landfill as well as reuse/disposal are performed using special methods. Agricultural reuse can be carried out immediately or after pre-treatment. Most disposal/reuse methods require pre-treatment of the residues. This generally consists of the following procedural steps: rotting, thickening and dehydration with conditioning, whereby a solid concentration of 20% to 40% is attained. Drying methods are used to reduce the water content further. This reduces the storage space requirement and enables the dried residues to be used as fuel in thermal systems. The costs increase significantly the more the water content is reduced. The specific costs for residue disposal/reuse range between DM 400 and DM 1500 per tonne of dry substance (Geiβen, S.-U, A. Vogelpohl, GVC—Symposium Abfall—Wirtscheft Herausforderung und Chancen (The Waste Industry—Challenge and Opportunities) 17-19 Oct. 1994, Würzburg) and will increase further in future. For this reason, it is of particular interest to reduce the generated residue quantity as much as possible.

#EP 0 659 695 describes a process in which the sludge is mixed with biodegradable tensides, which are intended to lead to lysis of the micro-organisms and a 50% dry substance reduction. Up to 200 mg of tenside per kilogram of dry substance must be added. The method has not yet entered into widespread practical use.

#TABLE 1 Active substance Substance group (S) or additive (A) Individual substance Concentration in g/l Electrolyte salts A Sodium chloride (NaCl) 2 Potassium chloride (KCl) 2 Low-molecular A Glycine (C2H5NO2) 5 aminocarbon acid Polyvalent alcohols A Sorbite-mannite mixture 1 (C6H14O6) Salts of organic acids A Trisodium citrate dihydrate 4 (C6H5Na3O72H2O) Macropeptides A Bovine serum albumin 0.01 Aromas A Pineapple aroma 0.25 Vitamins A 1) Biotin (C10H16N2O3S) 1) 0.01 2) Thiamine hydrochloride 2) 0.1 (C12H16Cl2N4OS xH2O) 3) Pyridoxine hydrochloride 3) 0.02 (C8H11NO3—HCl) 4) Aminobenzoic acid 4) 0.1 (C7H7NO2) Macromolecular W Sodium alginate 20 carbohydrates ((C6H7O6Na)n) All substances dissolved in water

#The aqueous mixture stated in table 1 is preferably added to the systems in small amounts, diluted with water (1:2 to 1:10).

#The doses stated in the examples below relate to the mixture stated in the table, unless otherwise described.