SU854891A1 - Method of biological purification of rain water - Google Patents

Description

The invention relates to sewage systems, more specifically to the biological purification of rainwater discharged from the territory of cities and industrial enterprises. There is a known method in which upstream dp (evicus waters, discharged together with household and (or) industrial wastewater ivOi. In the systems of combined and semi-separate sewage systems, are subjected to biological treatment with active sludge in aerotanks l j. At the same time, the aerotank capacity is determined by outcome from the total inflow into the rain, significantly exceeds the capacity needed in dry weather, when only household and / or industrial wastewater is received. The closest in technical essence to the proposed is the way in which additional The wastewater flow rate in the combined sewage system that enters the rain period is treated in a separate aeration facility using aerobic-stabilized excess sludge from aeration tanks, in which the wastewater is treated in a dry WEATHER J2. The disadvantage of this method is low oxidative capacity of stabilized sludge while a significant decrease in its mass as a result of self-oxidation during prolonged (up to 20 days. aeration in the absence of exogenous nutrition. As a result, the cleaning efficiency in aerotanks operating on stabilized excess sludge is low, especially at high flow rates of wastewater during the period of rain. The goal of the invention is to increase the degree of purification. This goal is achieved by the fact that according to the method of biological purification of rainwater in the aeration tank using excess active sludge formed during aeration of household and (or) industrial wastewater, an aerobic-conditioned mixture of excess activated sludge and primary sludge is introduced into the aeration tank. the aerobic-conditioned mixture is pre-compacted by settling for 1-2 hours, and the mixture of excess activated sludge and raw sewage sludge is aerobically conditioned to resistivity (10-15 ). The supply of an aerobic-conditioned mixture of excess sludge and sediment of primary sedimentation tanks into the aeration tank allows it to maintain a high concentration of active biomass while the flow of wastewater to the treatment plant increases during the period of rainfall, and thus maintain the optimum load on the sludge, which ensures high quality of treated water. waste liquid. Biological treatment facilities include a primary settling tank, an aeration tank with or without a regenerator, a secondary settling tank, an aerobic conditioner, which is an aerocycle of the aerotank type, a mechanical dewatering unit for a conditioned mixture of excess sludge and sediment of the primary settling tank on filter presses or vacuum filters dry weather. With semi-separate and all-sewage systems with the accumulation of a part of the inflowing water into the rain, for which the storage tank serves, a separating chamber is placed on the supply collector. With a full separate sewage system, when the rainwater is supplied to the sewage treatment plant separately from household (or) industrial wastewater, the separation chamber is not arranged. One silt paddler is designed to compact excess sludge, the other to compact a conditioned mixture of excess sludge and primary sediment from a stant. The flow of domestic and (or) industrial wastewater flowing in dry weather passes through the separation chamber, from which the wastewater enters the septic tank, from where the clarified wastewater is fed into the aeration tank. The aerated fluid enters the secondary settling tank, where sludge is separated. The purified wastewater after chlorination is removed outside the treatment plant with 8–14 orelu1E1Y, and the circulating melt is discharged into the regenerator, from which it is circulated. –– the active sludge is transferred into the nitrogen pool. When the aerotank is operating without separate regeneration, the circulating activated sludge from the secondary clarifier is fed directly into the aerotank. Excess silt removed from the secondary clarifier goes directly into the aerobic conditioner, which also receives the sediment of the primary clarifier, or passes through the ilofilter beforehand, from which the aerobic conditioner serves compacted excess sludge. In an air conditioner, a mixture of excess sludge and sediment of the primary clarifier is aerated. An indicator of sufficient duration of conditioning can be the sedimentation characteristic of biomass, the value of the volume index of 25–40 cm per 1 g of dry matter after settling for 1-2 hours at a humidity of 97.5–99Z or the specific resistance of the biomass is not more than 50 cm / g. An unconditioned conditional mixture of excess sludge and sediment of the primary clarifier are fed either directly to the mechanical dewatering unit or to the compactor, from where the unit receives the compacted conditioned mixture. The dehydrated conditioned mixture is sent for drying. Yapovy water from the sealant and the liquid phase from the mechanical dewatering plant are sent for treatment together with clarified wastewater. The liquid phase from the compactor is similar in its parameters to the treated wastewater and can be discharged together with them outside the treatment plant. During the period of rain, the semi-separate and all-sewage sewage systems without accumulating part of the structure's drain work as in dry weather, however, the unconsolidated conditioned mixture of excess sludge and sediment of the primary clarifier or compacted conditioned mixture does not go to the mechanical dewatering plant, but is fed to the aeration tank. If there is an accumulation tank, the inflow stream, which is a mixture of rainwater with household and (or) industrial wastewater, is divided into two parts in the separation chamber, part of the stream passes through the sump, the aeration tank and the rythrik 5 sump. A portion of the flow from the separation chamber enters the battery (pyvjiMV) tank, which is gradually triggered in dry weather. The settled wastewater from the tank is sent for treatment together with clarified domestic and / or industrial wastewater while simultaneously supplying unconditioned conditioned mixture or compacted conditioned mixture to the aeration tank. With a completely separate sewage system, the damnable water flows directly into the accumulating tank from which accumulated the runoff is directed to the aeration tank with simultaneous feeding of unconsolidated conditioned of a mixture of excess sludge and sediment of the primary waste a toy or an unconsolidated codified mixture. During aeration of rainwater with or without household wastewater and / or poultrywater, in a separate aerotank, the facilities include a primary sedimentation tank, aerostatic tank, secondary sedimentation tank, aerobic air conditioning, mechanical dehydration installation, 1 conditioned mixture, storage tank, separation chamber, and a separator, separator chamber, and a separator, installation of mechanical decontamination of the first 1 conditioned mixture, storage tank, separation chamber, and a separator, separator chamber, and a separator, installation of mechanical decontamination 1 seals excess sludge and sealer for air-conditioned, mixture compaction. Aerotank and secondary sedimentation tank, designed for incoming during the period of rain water consumption in excess of the flow of domestic and (or) industrial wastewater in dry weather. Flowing in dry weather, the wastewater stream transits through the separation chamber, from which the wastewater enters the septic tank, from which clarified wastewater enters the aeration tank. The aerated liquid enters the secondary settling tank, from where the treated wastewater is removed outside the treatment plant, and the circulating sludge is fed to the regenerator. From the regenerator, circulating activated sludge is directed to the aeration tank. When the aerotank is operating without separate regeneration, the circulating activated sludge from the secondary settling tank is fed directly into the aero tank. Excess sludge from the secondary settling tank is fed directly into the aerobic conditioner, where the sediment of the primary settling tank is also fed, or is pre-passed through a sludge compactor, from which condensed excess sludge is fed into the aerobic 1 conditioner. The unconditioned conditioned mixture is fed either directly to the mechanical dehydration plant or to the compactor, from where the condensed conditioned mixture enters the unit. The dehydrated conditioned mixture is sent for drying. The sludge water from the sludge thickeners and the liquid phase from the mechanical dewatering plant are sent for treatment together with the clarified wastewater. The liquid phase from the compactor is diverted outside the treatment plant together with the treated wastewater. During the period of rain in the systems of combined and semi-separate sewage the flowing stream of sewage is divided into two parts in the separation chamber. Part of the stream is treated similarly to household and / or industrial HbJM wastewater in dry weather, and part of the stream is sent directly to the aeration tank or to the storage tank, from which the accumulated discharge is fed to the aeration tank. At the same time, a compacted conditioned mixture of excess sludge and sediment of the primary sediment, or a compacted conditioned mixture, is supplied to the aerotank. Pro-aeroi fluid from the aerotank is sent to a secondary settling tank, from which purified cTO4ffi) i.e. water is diverted outside the treatment plant, and the separated biomass is fed to the air conditioner. In the full sewage system, domestic and / or industrial wastewater is treated similarly to wastewater flowing in dry weather with combined and semi-separate sewage, and rainwater is directed either to the aeration tank while simultaneously supplying an unconditioned conditioned mixture or a compacted conditioned mixture, or in the storage tank, from which the accumulated water is fed into the aeration tank. An example. Municipal wastewater, which is found in household and industrial CTO4iaix waters, is mixed with rainwater in a 2: 1 ratio. The resulting mixture is aerated in the following variants: with active sludge when an aerobic-conditional mixture of excess sludge is added and the primary settling tank is drained. The duration of conditioning is 2 days, the ratio of excess sludge and sediment of the primary settling tank by volume is 4: 1, dry matter is 4: 4, with active sludge when adding aerobic stabilized excess sludge. Duration of stabilization 10 days; with an aerobic-conditioned mixture of excess sludge and sediment of the percipital clarifier after conditioning under the conditions specified in the first variant with aerobically stabilized excess sludge after stabilization under the conditions specified in the second variant. The results are summarized in table. 1 and 2. As can be seen from the table. 1 and 2 degree of wastewater treatment by BOD. and suspended solids in the case of using the proposed method transforms the one for this method, both in case of aeration of excess (during the rain) consumption in a separate structure, and; in aeration of increased flow flowing in rain in the same aeration tank in which the wastewater is treated to dry the weather. By supplying an aerobic-conditioned mixture of excess sludge and sediment of primary sedimentation tanks to the aerotank, it is possible to increase the cleaning efficiency in the systems of combined, semi-partitioned and full separate sewage systems or, with the same cleaning efficiency, reducing the duration of aeration and, correspondingly, the aeration tanks required for cleaning the above-charge costs during the rainy season. In addition, aerobic-conditioned mixture of excess sludge and sediment of primary clarifiers has better drainage compared with raw sediment of primary clarifiers and aerobic-stabilized excess silt, which ensures high performance of the apparatus during mechanical dewatering of the solid phase of wastewater. At the same time, aerobic conditioning is less prolonged than aerobic stabilization, which also ensures the reduction of capacities in the complex of sewage treatment plants. Table 1

Dose injected into waste liquid - g / l

stabilized excess sludge

aerobic-conditioned mixture of excess sludge and sediment of primary sedimentation tanks

BODC treated wastewater, after aeration - with stabilizing excess sludge

with aerobic-conditioned mixture of excess sludge and sediment of primary settling tanks

BOD reduction,%

after aeration with stabilized excess sludge

with aerobic-conditioned mixture of excess sludge and sediment of primary clarifiers

4.52

3.74

39.0

21, 2

76.6

86.9

Suspended solids rf concentration of treated wastewater

M if iT X

after aeration with stabilized excess sludge

with aerobic-conditioned mixture of excess sludge and sediment of primary settling tanks

The decrease in the concentration of suspended substances,%

after aeration with stabilized excess sludge

with aerobic-conditioned mixture of excess sludge and sediment of primary clarifiers

Indicators

Dose of injected eastern liquid, g / l. active la

stabilized excess sludge aerobic-conditioned mixture

excess sludge and sediment of primary sedimentation tanks

BnjCj- the best effluent, MG02 / L after aeration with activated sludge upon administration

stabilized excess sludge

aerobnock (. of the diluted mixture of excess; exact I.11.Ch n the sludge of primary clarifiers

36.1

24.3

80.7

87.0

Table 2

Way

Proposed

Famous

2.04

2.04 2.26

1.87

18,8

11.4 V The ratio of the volume of a mixture of domestic and industrial wastewater to rainwater is 2: 1, i.e. Excess consumption during rain by 50% compared with rainless period. The duration of aerobic stabilization of excess sludge is 10 days. -f -, -, ..... l .n - 1 cturwiJi, o ruwmitTMrnjlW HJict I L / Cyt Duration of aerobic conditioning of the mixture of excessive force and sediment of primary sedimentation tanks for 2 days. BOD of the original waste fluid (filter test) 162. -X Concentration of suspended substances in the initial waste liquid 18 / mg / l.

Claims (3)

Claim 1. A method of biological treatment of rainwater in an aeration tank using excess activated sludge generated by aeration of household and ⁴⁰ (or) industrial wastewater, characterized in that, in order to increase the degree of purification, an aerobic-conditioned mixture of excess activated sludge is introduced into the aeration tank and sediment of ⁴⁵ primary sedimentation tanks. 2. The method according to π. 1, due to the fact that the air-conditioned mixture is pre-compacted by settling for 1-2 hours. ⁵⁰ 3. The method according to p. 1 and 2, characterized in that the mixture of excess activated sludge and crude sewage sludge is aerobically conditioned to a specific resistance of (10-50) x 10 10 ^O cm / g.