CS260625B1 - Method of cleaning and thickening of liquid biological waste - Google Patents

Abstract

The problem being solved is the increase in the dry matter content in liquid waste and sewage sludge. The 80 to 90% water content makes it difficult to process them and effectively use the nutrients they contain. The thickening of waste and sludge is carried out by filtration through power plant or heating plant fly ash, which captures organic substances and biogenic salts. The resulting substrate contains 30 to 60% dry matter, does not flow and can be handled by conventional trucks and transport vehicles. When saturating fly ash with biological waste on large areas (in underground tanks), the areas can be sown with plants whose root system increases the filtration efficiency of the fly ash. The substrate is enriched with organic substances from plant biomass. A mixture of fly ash, organic substances and biogenic salts can be used as an organic fertilizer. The method of use is determined by the content of foreign substances.

Description

The invention solves the cleaning of liquid biological waste generated in the food industry (sewage from dairies, meat industry, breweries, distilleries, starch factories and fat factories), paper industry, municipal hygiene (domestic sewage, sewage sludge, septic tank sludge) , in primary agricultural production (sewage from dairies, seaweed, cattle, pigs and poultry, liquid fraction after separation of slurry and silage juice) and further deals with thickening of liquid sludge from sewage treatment plants and after biogas production. These liquid biological wastes contain biological substances and biogenic elements with a nitrogen content of 0.005% to 1.5%, phosphorus of 0.005% to 1%, a potassium of 0.01%. up to 1.2% and other biogenic elements with a total dry matter content of 0.2% to 20% by weight. The invention belongs to the field of water treatment and environmental protection. Liquid biowaste worsens the environment by polluting groundwater and watercourses. Significant environmental pollution is caused by improper application of cattle, pig, poultry and manure slurry. Throughout the year there are few suitable days for the correct application of bio-waste on agricultural land. If liquid bio-waste is not applied to the farmland in the right amount and incorporated into the soil immediately after application, it degrades the environment by odor, insects, compacting the soil only after degradation of natural soil fertility.

Filtration of sludge (especially in waste water treatment plants) is currently carried out most often using sand or soil filters. The filtration itself is often preceded by sludge activation. This method is widespread in the Czech Republic and abroad. E.g. Neurohr 1984, Wiken 1981, Monograph 1977, Frostell 1977, Strathman 1979, etc. Sludge pressing or vacuum filtration are also used to enhance filtration efficiency (e.g., Kobayaski, Okuyama 1976, Osborne 1975, Sugimoto et al. 1975, Martin, Hayden 1977, Hutton 1981, Gasper 1981, Nelson, Tavery 1978 et al.). Various chemical compounds such as aluminum and iron salts (Arvin et al 1981, etc.), lime additives (eg Borchers et al. 1979) or bioflocculants (Raynal 1980) are used to precipitate the dispersed organic impurities in the sludge with subsequent filtration. chemical compounds with polyelectrolyte characterization (White 1974, Kabata, Uchlda 1977, Kamata, Uchida 1978). Various waste materials of organic origin, such as tree bark (Lightsey et al 1976) or reed material (Neurohr 1984), have also been tried to filter the sludge. Coal materials, either pulverized coal (Hathaway, Olexsey 1977) or coal pulp (Pitzer et al 1978), have also been tested for their large active surface. In both cases, co-pressing was used simultaneously for filtration through coal.

It is an object of the present invention to purify and densify liquid biowaste and digested sewage sludge having a dry matter content of 0.2% to 20%, which are allowed to flow through the power or heat fly ash once or repeatedly. The dry matter content of biowaste or sewage sludge is increased by the outflow of water. The flow of liquid bio-waste and fly ash treatment sludge results in a mixture of fly ash and entrapped organic matter. Dissolved biogenic salts in bio-waste and sewage sludge are bound in entrapped organic matter and a large specific fly ash surface. A substrate with a dry matter content of 30% to 60% is formed. At this dry matter content, heterotrophic bacteria develop best and rapid decomposition and milling of organic substances and pathogenic microflora occur. The resulting substrate can advantageously be used as an organic fertilizer. When cleaning and densifying liquid biowaste on large areas of fly ash, eg ground tanks, the area saturated with liquid biowaste is sown by plants. The plants use part of the water and biogenic salts from the liquid biological waste to produce their own biomass, and the resulting substrate enriched in plant biomass is preferably used as an organic fertilizer.

Compared to the most used sand filters, fly ash has a higher efficiency due to its specific properties. They are characterized by a specific weight of 2,400 kg. m ^-3 , bulk density 798 kg. . m ^-3 , specific surface 20 820 m ⁺² . kg ^-1 , not radioactive, average chemical composition of SiO2 45.9%, Al2O3 20.6 ° / o, Fe2O3 14.3 ° / o, CaO 2.9%, T1O2 1.4%, ž. of. 11%. Foreign substances, eg heavy metals, do not usually exceed the limits set for heavy metals in soils according to the Federal Standards. They are homogeneous against the sands used. The ash according to the analysis of samples from the Prunéřov deposit contains 93% of particles with a diameter smaller than 0.5 mm with the following granulometry:

particles below mm % 0.50 93 0.25 85.6 0.20 81.6 0.16 76.2 0.10 61.6 0,063 37.8

Power and heating fly ash have a lower price than sands. Their use does not require the occupation of agricultural land such as sand mining, but on the contrary, the removal of fly ash from power plant and heating plant depots will prolong the life of existing depots and reduce the barriers of land for the construction of new depots. CSSR with an annual production of 20 million tons is one of the largest papillus producers in the world. Soil filters, if they have a higher specific surface area than fly ash, have a higher efficiency but a lower flow rate of purified water (for fly ash replaced efficiency by multi-stage cleaning). Filtration of liquid biological waste and liquid sludge after the production of biogas and waste water treatment plants through power and heating fly ashes yields a non-flowing substrate with a mixture of fly ash, organic matter and biogenic salts, which can be handled by conventional loading and conveying techniques. The produced substrate is suitable for the production of industrial compost or it can be added to field manure to the manure or used for direct fertilization of agricultural and other soils (forest land, parks, public greenery). The application of the substrate to heavy clay soils will simultaneously lighten and biologically revitalize them while increasing the fertility of these soils. The practical benefit is the utilization of two wastes that burden the environment, ie liquid bio-waste and liquid sewage sludge and power and heating fly ash, and ensure the recycling of materials, nutrients, energy and their return to the soil. Purified water by fly ash filtration complies with CSN for surface water (after one or more stages of purification).

The attached drawings show tanks for the treatment of liquid bio-waste and liquid sewage sludge by a layer of power or heating ash. Fig. 1 is a plan view; Fig. 2 shows a section A-A; Fig. 3 shows a section Β-B with a one-stage cleaning container. Fig. 4 is a plan view, Fig. 5 is a section A-A, Fig. 6 is a section Β-B of a single stage cartridge battery. Fig. 7 is a plan view, Fig. 8 is a section A-A, Fig. 9 is a section Β-B of a cleaning station with mobile cartridges for multi-stage cleaning. Fig. 10 is a plan view, Fig. 11 is a section A — A, Fig. 12 is a section Β — B of a cleaning station with built-in aboveground tanks for multi-stage cleaning. Fig. 13 is a plan view, Fig. 14 is a section A-A, Fig. 15 is a section Β-B, Fig. 16 is a section C-C of a groundwater treatment station.

For the filtration of liquid biological waste and sewage sludge we prepare tanks of power or heating fly ash so that filtered water can flow out of them. For example, the mobile containers (containers) can be adjusted by perforating part or all of the bottom 13. The filtered water outlet is ensured by perforating the bottom Figs. 2-6, 11, or by inserting a perforated lead Fig. 8, 9, 11, 14. . To reduce the penetration of the finest fractions of fly ash into the filtered water, cover the perforated bottom and water ducts as closely as possible with a textile filter 14 Figs. 3, 5, 6, 8, 11, 14. For example, use a perforated flexible pipe to drain water. In the case of above-ground tanks 8, we build a drainage system that is secured against excessive fly ash penetration. Above-ground storage tanks 8 Figs., 10-12 secure leaky joints of moving parts (container opening faces, hinged bottom of the above-ground storage tank) by sealing with waterproof mastic etc. · against leakage of untreated biological waste and sewage sludge. The treatment layers are governed by the quality of fly ash (granulometry), the requirements for the quality of water purification, the number of stages of treatment and the composition of bio-waste and sewage sludge, in particular the dry matter content. For high-quality cleaning, it is usually sufficient to filter the ash layer 1 with a thickness of 0.5 m Fig. 2, 3, 5, 6, 8, 9, 11, 14. Depending on the treatment used for water outflow from mobile tanks Fig. 1-9 1 to 3 or to the sloped station of the container 26 or in the incline to the inserted lead 13 of Fig. 8, 9. Let the liquid fly-waste or sewage sludge 2 flow through the fly ash layer either directly from the source 4 of Fig. 2 or from the buffer Tank 3 Fig. 4—16. Liquid biowaste or sewage sludge is pumped and distributed by the handling system 6 to the mobile containers 7 of Figs. 4-9, or to the built-in aboveground containers 8 of Figs. 13-16, with control of the 9th maximum sludge level of Figs. 5, 11, 12, 14. If the automatic level control fails, the sludge is discharged through the emergency drain 12 of FIGS. 11, 12 or discharged from the treatment station surface 26 through the waste 16 of FIGS. 7-12 to the bio-waste storage tank 3. Purified water 10 is discharged through a fly ash tank 22 into a rainwater sewer 25 or drain 23 from the last cleaning stage of Figs. 1-3, or to other cleaning stages 18 through an accumulation tank 15 of Figs. 7-15. These tanks are pumped through the Purified Water Distribution System 17 for further purification. In the above-ground tanks it is captured by the collecting device 19 Fig. 11 and led into the accumulation of the tank 15. From the accumulation tanks Fig. 7–16 the purified water is pumped to further cleaning stages by the manipulation system 17 into the reservoirs 7 Fig. 7–16 As the fly ash is saturated with the dry matter of bio-waste or sewage sludge, it gradually loses its absorption capacity. The saturation stops. When using mobile containers, the obtained substrate 5 of Fig. 12 is weighed. 10 to 12, the saturated substrate is discharged by tilting bottom 20 of FIG. 11 into the prepared conveying means 21. The removed mobile container is replaced by a new prepared container with a fly ash filter layer. For aboveground tanks, a new fresh pop260625 lek is placed in the empty tank. For ground tanks, the fly ash layer saturated with bio-waste or sewage sludge during vegetation may be sown by plants to form a vegetation cover. After the vegetation cover has been formed, it is further saturated with bio-waste if soaked. At the end of the growing season, a layer saturated with the dry matter of bio-waste or sewage sludge enriched with the biomass of the vegetation cover plants is removed by conventional earth moving machinery and topped up with a fresh fly ash layer. In simple treatment stations not equipped with automatic handling of bio-waste and sewage sludge and purified water, we change the order of mobile containers. For example, in three stages of cleaning, the first container (as soon as the fly ash loses its absorbency) is drained and placed in its place a container that stood in the second order and through which water was filtered in the second stage of purification. This container will be newly saturated with bio-waste. In place of the second container is placed the third, in which the water was filtered in the last stage of purification. Instead of the third one, a new container with fresh ash is placed, which will serve again as the last third stage of cleaning.

The invention can be used in the field of wastewater treatment where it can solve the waste-free treatment of liquid sewage sludge by increasing its dry matter content. They facilitate handling and the resulting substrate is easily processed by composting. Pre-treatment of biological waste can be advantageously used in waste water treatment plants, provided that chemical treatment of the filtered water follows. Both the filtration of liquid bio-waste and sewage sludge creates a substrate of a mixture of fly ash for captured organic substances and biogenic salts, which can be used for the production of industrial compost, direct fertilization of agricultural and non-agricultural soils for establishing green areas. With the broadening and utilization of the invention, the need for power and heating ashes would translate into lower requirements for power plants and heating plants producing ashes to reduce the occupation of agricultural land to build up dumps.

Claims (2)

Method for cleaning and concentrating liquid biological waste and sewage sludge, characterized in that wastes and sludges with a dry matter content of 0.2% to 20 ° / o are allowed to flow once or repeatedly through power or heating ash, and the resulting substrate is preferably used as organic fertilizer. 2. A method according to claim 1, characterized in that the liquid biological waste or liquid sewage sludge is allowed to flow through power or heating fly ash placed in the plant-seeded soil tanks to form a vegetation cover and the resulting biomass enriched plant is used as organic fertilizer. 18 sheets of drawings