CS277555B6 - Process for waste water disposal - Google Patents

Abstract

The invention relates to a process for treating effluents which contain dissolved or dispersed organic or inorganic substances. It is characterised by (A) mixing the effluent with one or more inorganic or organic substances inducing thixotropy, preferably with homogenisation, and (B) sorption of the mixture onto an inorganic or organic natural or synthetic sorbent. During sorption, aeration is advantageously simultaneously carried out. The mass ratio of mixture from step A to sorbent is 2 to 12:1 and advantageously 8 to 10:1. Suitable substances inducing thixotropy are derivatives of polyacrylic acid or polysaccharides and derivatives thereof, in addition in- organic substances such as bentonites, zeolites, clays or power station fly ashes. Expedient sorbents are cereal straw, maize panicles, disintegrated wood mass or municipal wastes or alternatively bentonites, zeolites, clays or power station fly ashes.

Description

Technical field

The invention relates to the disposal of waste water contaminated with dissolved or dispersed organic or inorganic substances.

BACKGROUND OF THE INVENTION

Waste water, contaminated with organic or inorganic substances dissolved or dispersed, arises from various human activities. The main amount of water of this nature is represented by various municipal waste. Other producers are agricultural businesses and the food industry.

The most common group of organic contaminants are proteinaceous substances, carbohydrates and fats. The most common inorganic substances are salts of alkali metals, especially sodium.

The principle applied primarily in the disposal of polluted waste water is its mechanical separation into solid and liquid phase. This separation is effected by high-performance centrifuges. While the solids, if they do not contain toxic substances, are relatively easy to process, for example by composting, the processing of the liquid portion is always associated with technical and economic problems. The liquid fraction is several times greater than the solid fraction. This brings increased investment requirements for cleaning stations. The main purification principle of organic compounds is the use of a microbiological treatment of the liquid fractions, essentially a varied mixture of microorganisms which in an aerobic or anaerobic environment consume organic matter for their multiplication. It should be noted, however, that the biological aerobic treatment of wastewater from organic matter works reliably only at temperatures above 5 to 8 °. This means that in winter, aerobic cleaning is less effective, so environmental accidents can easily occur. Although the anaerobic fermentation of wastewater works equally reliably in winter, the investment costs are considerably higher than those of aerobic systems.

However, biological treatment of wastewater does not remove inorganic substances. Of the most frequently present anions, only sulphates can be removed economically - by precipitation of calcium sulphate, while chlorides and nitrates, as other major representatives of salinity, are practically impossible to remove. They increase the salinity of watercourses and the only penalty for this ecological nuisance is the payment of a penalty.

Thus, it can be stated that the technology of wastewater treatment lags behind the general state of the art.

SUMMARY OF THE INVENTION

The method of disposing of waste water contaminated by dissolved or dispersed organic or inorganic substances consists in homogenizing these waste waters with substances which increase the waste water thixotropy and possibly with a mixed culture

CS 277555 Β6 2 *

microorganisms, such as water-activated activated sludge, whereupon the mixture is sorbed in one or more portions to the sorption material while aerating, preferably between the individual sorption operations. The thixotropy treated waste water is capable of being absorbed to various inorganic or organic sorption materials in a weight ratio of S to 10 parts water per 1 part sorption material.

The organic materials which modify the thixotropic and other physical properties are preferably acrylic acid derivatives or polysaccharides or derivatives thereof, for example sulfite extracts, various cellulose derivatives, starch and its derivatives. Sulphite leaches also carry water-soluble sugars, which are discharged in the sulphite process during cellulose production, and thus increase the amount of nutrients in the waste water, which is advantageous for subsequent biological treatment on a solid substrate. Cellulose derivatives, starch, polyacrylic derivatives, or other polysaccharides then significantly increase thixotropy of treated waste water, thereby achieving several times greater adherence to solid sorbent materials.

Treatment of the physical and thixotropic properties of the wastewater can also be achieved by the addition of inorganic compounds such as bentonite, zeolite, clays, power fly ash. All these substances also increase the adhesion of the waste water to the sorption material.

In the process according to the invention, it is advantageous, especially in the case of severe organic contamination, to add cultures of microorganisms accelerating biological processes to the waste water. In this respect, for example, the addition of sewage treatment plant activated sludge has proven to be very useful.

By adjusting the thixotropic and physical properties, the wastewater is prepared for sorption to solid organic or inorganic sorption materials. Up to 10 times the amount of treated waste water is applied to solid organic or inorganic sorption materials. This amount is preferably applied in several portions, preferably 4 to 5, and between each dosing, the mixture of sorption material and the applied effluent has to be intensively mixed by mechanical means to achieve perfect aeration and to provide an oxygen supply for subsequent fermentation.

The solid sorbent materials may be organic or inorganic in nature. In the group of organic sorbents cereal straw, corn cob, disintegrated wood mass or tree bark are the best.

The waste water can also be applied to inorganic grit materials. Suitable materials are bentonite, zeolite, clays, loess, power ash. However, the sorption capacity of these inorganic materials is in most cases lower than that of organic materials.

Disintegrated solid urban waste, which is a mixture of organic and inorganic compounds, can also be used as sorption materials.

After all the treated waste water has been applied to the sorbent material, the resulting mixture of sorbent material and the adsorbed wastewater is treated by mechanical means into conventional spatial shapes of industrial compost.

The organic sorbent and the products of microbial life, which takes place in the compost pile, are an excellent fertilizer material after fermentation processes have been completed. At the same time, it is an advantage of the process according to the invention that high temperatures of 70 to 75 ° are achieved in the fermentation processes, thereby eliminating all germs and resulting in absolutely harmless compost. High temperature also destroys all weed seeds.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Waste water from porcine farming with a content of 5.3% dry matter was mixed with 5 parts by weight of waste concentrated sulphite liquor. The resulting mixture was mixed and dosed at a ratio of 7: 1 to rapeseed straw. The fermentation process started after 27 hours, after 4 days the temperature inside the compost reached 73 °. After 6 Sundays, the compost was overcoated, after 2 days the temperature inside the overlaid compost rose to 45 ° and then gradually over the course of six weeks it settled to ambient temperature. The resulting compost was fertilized a field prepared for maize sowing. Corn yield in this field was 35% higher than in a field fertilized with the NPK. Example 2

Municipal wastewater with a dry matter content of 1.35% was mixed in a ratio of 0.4 kg of oxidized starch per m ^{3 of} wastewater and the resulting viscous mixture was dosed in a weight ratio of 10: 1 to crushed barley straw. After 3 months of fermentation, the resulting compost was mature and was used to fertilize haylage oats. Compared to the control field, the yield was 52% higher.

Example 3

Waste water from the production of potato chips containing dry matter

1.8% was concentrated by adding 1 kg carboxymethylcellulose per m ^{3 of} waste water and was then dosed to beech sawdust in an amount of 9: 1. After completion of the fermentation processes, the resulting compost was broken and another 5 parts of this waste water were dosed again, but in this case 100 g of polyacrylamide and 5 kg of bentonite were used to modify the thixotropic properties. Compost was formed again, the new fermentation started after 5 days and was completed in another 2 months. During the fermentation processes, sawdust was biodegraded to form a fertilizer substrate, which was applied to the soil for cauliflower production. Cauliflower harvesting was accelerated by 6 days, with head diameters 8 to 10% higher.

Example 4

Waste starch containing protein, entrained grains of starch and cellulose pulp was mixed with livestock manure from -1: 1 ratio and after addition of activated sludge it was applied to disintegrated urban waste in a ratio of 8 parts of waste water mixture to 1 part of disintegrated urban waste. waste. Organic waste predominated in the disintegrated urban waste. After maturing, the compost was used to fertilize the maize, with the yield of maize being 41% higher than the control trials.

Example 5

The tannery waste water (tanning) was mixed

O with zeolite at a rate of 10 kg of zeolite per 1 m of waste water, silage juices thickened with 1/2 kg of oxidized starch per 1 m ^{3 of} silage juices were added to the resulting mixture and after thorough mixing the batch was dosed to a mixture of 85 parts by weight of barley straw; 15 parts by weight of fly ash. After processing the adsorbed material as described above, the resulting compost was left over the winter until spring next year and was then used to fertilize a field ready for harvesting potatoes. The harvest of potatoes was 17% higher, and it was particularly noteworthy that the harvested potatoes did not show scab, while the control field potatoes were heavily affected by this defect.

Example 6

Waste manure containing 7.8% dry matter was mixed with 10 kg of finely dispersed clays per ton of manure and the resulting mixture was applied to a mixture of 65 parts of crushed corn cob, 25 parts of beech sawdust and 10 parts of loess. After the mixture was worked up and the fermentation was completed, the compost was used to fertilize the vine. The yield from grapes was 17% higher than the control vineyards with the same type of vine.

Industrial applicability

The method of disposal of waste water contaminated with dissolved or suspended inorganic or organic substances is applicable in all areas of human activity. It brings completely new solutions to agricultural and food practice. It is absolutely easy to invest and therefore generally applicable.

Claims (1)

PATENT CLAIMS A method of disposing of waste water contaminated with dissolved or dispersed organic or inorganic substances, in particular from the food industry, livestock farming or municipal waste water, characterized in that the waste water is homogenized with substances increasing their thixotropy, for example polysaccharides or derivatives thereof, with polyacrylic acid derivatives or with inorganic substances such as bentonite, zeolite, clays, power plant fly ash and optionally homogenized with a mixed culture of microorganisms such as water-activated activated sludge, whereupon the mixture is sorbed in one or more portions on the sorption material while aerating preferably between 8 to 10 parts by weight of waste water per part of the sorption material, which are organic substances such as cereal straw, corn cob, disintegrated wood or tree bark, possibly disintegrated urban waste, or inorganic materials such as bentonite, zeolite, clay loess.