DE19648646A1 - Waste water treated by fermentive coagulation and bio-reactor system - Google Patents

Abstract

Waste water treatment process comprises treating the water by a combination of: (a) fermentive coagulation, (b) high-performance bio-reactor systems, and (c) "BioAqua-LEMNA-Technik" (RTM); In (a) a fermentive coagulation process subjects the water to the action of a mixed culture of anaerobic microbes with selected chemical additives to form low-molecular wt. acids, the mixed anaerobic microbes culture is derived from silage waste water by self-immobilisation on a standard substrate material. The second stage is an intermittent high-performance bio-reactor activated sludge system with a submerged jet fermenter and in (c) the waste water is subjected to general removal of the nutrients, and the flow rate stabilised by a buffer arrangement while minimising odour emissions.

Description

State of the art today

According to the current state of the art, it is common practice to use highly contaminated wastewater in one treat multi-stage process.

This process essentially consists of a pre-treatment and a biological one Treatment.

One of the most common methods of pretreating highly contaminated wastewater is the use of Chemicals and additives. Lime and iron sulfate are often used, which result in a reduction of the BOD5 in the wastewater.

On the other hand, it is known that waste water with a high content of dissolved and undissolved organic ingredients, e.g. B. wastewater from the food industry, anaerobic in Biogas plants can be pretreated.

This involves hydrolysis and pre-acidification at a pH of 5.0. The biological treatment of the pretreated wastewater is then carried out by different Method. There are single or multi-stage trickling filter systems, single or multi-stage conventional aeration systems and deep-flow ventilation systems (deep-shaft) for Commitment.

Other disposal methods for wastewater, some of which is unpurified, find their way through Irrigation / raining of the untreated wastewater takes place due to the already existing and future legal restrictions will no longer be permitted. It has to be there However, it should be mentioned that, especially in drained areas, a negative influence on the Receiving water (e.g. fungus formation) cannot be excluded. You must also continue on possible damage to the plant is pointed out. In addition, those who perform also play Odor emissions play a crucial role in the elaboration of the disposal concept.

The well-known SBR process is also without appropriate pretreatment highly contaminated wastewater is not easy to assess in general.

The system is unable to remove the dissolved and undissolved organic matter to clean according to the legal regulations.

In addition, this system does not provide adequate nutrient reduction and hydraulic Freight equalization reached, which leads to an unreasonable burden on the receiving water.

Disadvantages of the method are high energy costs for aerobic treatment or high Disposal costs for sludges with undefined chemicals and Auxiliary materials. With many of these methods, direct discharger values cannot be achieved.  

According to the invention the problem is solved in that the highly polluted waste water by a combined process, the BioAqua-Combination Technology® will.

The BioAqua combination technology® consists of the following three components ( Fig. 1):

• 1. Fermentative coagulation
• 2. High performance bio-reactor system
• 3. BioAqua®-LEMNA-Technik®

Description of the BioAqua combination technology® Fermentative coagulation

According to the invention, highly polluted wastewater can be treated in such a way that in one multi-stage process, the Suspensa separated in succession, the remaining high cargo significantly reduced in a suitable aerobic high-performance level and the remaining freight, especially the remaining nitrogen compounds and other plant nutrients an intensive plant growth, such as B. the BioAqua®-LEMNA-Technik® the Case is to be cleaned. There is also the possibility of different types to a high degree to combine contaminated wastewater.

The first stage is designed according to the invention so that a partial hydrolysis of the microbial Ingredients are made by lowering the pH and by partially structural Conversions is marked. The lowering of the pH takes place primarily through the Formation of low molecular acids.

Even protein loads are either reduced by hydrolytic processes in one upstream stage so broken down into low molecular weight fragments that already at the beginning of the aerobic stage only ammonium ions and lower fatty acids exist or will the particulate proteins together with other particulate wastewater ingredients treated and separated.

According to the invention, use is made of the fact that in the anaerobic hydrolysis of the macromolecular Substances can specifically form lactic acid, which causes a particularly sharp drop in pH it does. The use of mixed cultures producing lactic acid in the wastewater sector is not usual because the autochthonous anaerobic flora is usually allowed to develop. That has However, the disadvantage that all the steam-volatile fatty acids in the  following aerobic stage can be used poorly. It is known that lactate in certain concentration ranges a better substrate than the anions of the others Fatty acid is (HANEL).

The necessary hydraulic dwell time for the effect of the lactic acid generator is in the Depending on the usable carbohydrates at 8 hours to 3.5 days. Here there is a risk of the lactic acid generators being discharged. This is according to the invention counteracted by settling the lactic acid generators on a carrier material. Commercial plastic carriers with a density of less than one are preferred have, loaded with the microorganisms swim on the surface and so the Separation process does not counteract.

High-performance bio-reactor system

The invention further relates to a high-performance bio-reactor system for cleaning highly contaminated waste water. It is a batch process.

The high-performance bio-reactor system consists of the following components:

• - buffer pool
• - one or more high-performance bio-reactors
• - in special cases, a separate sedimentation tank
• - Optional sludge stacking container and / or sludge dewatering

In the buffer pool, a defined pre-treated is buffered Waste water volume.

The biological degradation of the wastewater constituents takes place in the high-performance bio-reactor. Everyone High-performance bio-reactor works as an independent reactor.

The following parameters can be recorded and controlled in each of these reactors:

• - Inlet quantity per defined time unit
• - Oxygen content and / or pH value and / or redox potential and / or temperature and / or nitrate and ammonium nitrogen
• - level  
• - Dry matter concentration and / or turbidity.

The various are controlled as a function of these determined values Wastewater inlets, mixing, ventilation, wastewater outlets, Excess sludge removal from the high-performance bio-reactor and the one to be submitted Inoculation mass on activated sludge.

Another object of the invention is a high-performance bio-reactor system, which in is able to approximate the various highly contaminated wastewater to each required limit values to be cleaned.

It is a batch process. The procedural feature is periodic operation by dissolving the process into individual treatment sections (Batches). Depending on the cleaning goal, different controls can be used Operating states are run one after the other or alternately. This will do the same Sequence and periodicity of reaction conditions created, like in a tubular reactor or in a cascade system, but fixed in time.

This wastewater treatment process is a time-oriented one, of the specific ones Process with decoupled conditions with a cyclical sequence of treatment phases: filling, stirring, aerating, settling, clear water drainage, excess sludge removal and waiting, whereby filling, stirring and aerating can take place simultaneously. A major advantage of this method is that fluctuations in the inflow loads occur a simple adjustment of the response time can be intercepted. The sewage lingers thereby in the reactor until it is the one required in this combination sequence Meets cleaning requirements.

The reactor is sometimes used as an aeration room and sometimes as a sediment. This means that the biological reactions and the separation of the activated sludge of the purified wastewater take place in one and the same reactor. Because vaccine sludge for those Treatment needed can only be a certain percentage of the total reactor volume be used for wastewater treatment. This volume is called the total exchange volume designated.

After decanting the cleaned wastewater, the sedimented biomass remains in the Reactor. This volume is called the sludge volume.

According to the invention, the separation of the activated sludge from the cleaned wastewater in one separate sedimentation tanks take place.

For biodegradation, the ratio of wastewater ingredients to oxygen is from special meaning.  

This makes the high-performance bio-reactor a submersible jet fermenter. To do this the ratio of diameter to height should be at least 1 to 2. The ventilation and Turbulence is generated by a gassing device that automatically draws in air and introduces a liquid-air mixture free jet into the fermenter from above.

The fermenter contents are circulated by a special centrifugal pump. The speed of the Centrifugal pump is infinitely adjustable, which also increases the rate of oxygen entry can be regulated continuously.

Vertical forced circulation, pulse energy and air content of the free jet ensure very effectively:

• - Air dispersion and mixing of the fermenter content
• - high specific mass transfer performance with low energy consumption
• - best growth conditions for microorganisms.

At defined times, a defined share of the total exchange volume or a Defined dirt load from the buffer tank into the respective high-performance bio-reactor initiated.

This interval loading makes a process-specific change between the phases Substrate supply and substrate shortage created.

After biological cleaning and reaching the required limit values, everyone will be The units are switched off and the sludge sediments in the high-performance bio-reactor. The clear water is then drawn off via a floating drain device. in the The excess sludge produced is then removed, which in one appropriate sludge stacking container is stored until the time of disposal and may have been mechanically drained beforehand.

According to the invention, the operation of the system can be carried out with different, highly contaminated wastewater be modified.

A defined waste water volume is exchanged at defined time intervals. This each volume exchanged is fed to a separate sedimentation tank and there with one or more additives to improve sedimentation behavior.

The clear water is withdrawn from this sedimentation tank. The mud is considered either Excess sludge removed from the system or, if necessary, the respective high-performance Bio-reactor fed again.

BioAqua®-LEMNA-Technik®

The BioAqua®-LEMNA-Technik® is the third step of the two according to the invention stages described to carry out a tertiary cleaning. Doing so  in particular the still existing nutrient concentration is reduced and thus a Achieved water quality that directly according to legal regulations or the water cycle can be directed to a receiving water, rained or seeped away.

The BioAqua®-LEMNA-Technik® process consists of:

• - one or more technically ventilated waste water ponds and / or
• - one or more naturally ventilated waste water ponds and
• - if necessary, one or more nitrification zones and
• - one or more LEMNA ponds and
• - If necessary, one or more sand filters and
• - if one or more disinfection stations are required.

The use of technically or naturally ventilated wastewater ponds enables through Creation and promotion of aerobic conditions an extensive biological nutrient and Pollution reduction.

By switching nitrification zones a biological conversion of the Ammonium content by providing sufficient growth area for nitrifying Microorganisms reached. This facility is very heavily loaded with nitrogen Waste water to insert according to the invention.

A channel belongs to the nitrification zone for use in a wastewater treatment pond system a supply line and an outflow for the flow of the waste water from the inflow to the discharge line guarantee.

Surface fabrics within a channel provide sufficient space for the Bacterial growth. The surface materials are isolated from the rest of the pond in order to Rinse and prevent thinning effects as well as a trouble-free Ensure nitrification process.

Adequate oxygenation, e.g. B. an aerator drives air and water in one sufficient speed and concentration past the growing areas an effective bacterial conversion of ammonium nitrogen via nitrite to nitrate.

A detailed description can be found in Patent No. WO 94/06720.

The LEMNA pond is used within the BioAqua®-LEMNA-Technik® for further Wastewater treatment through bacterial, chemical and physical Processes and treatment with the help of floating aquatic plants. The floating Aquatic plants take nutrients, carbon compounds, metal traces, etc. from the Wastewater and form biomass from it or store it in it. By periodic  Removing parts of the plant biomass will remove these substances from the Wastewater treatment system withdrawn.

The LEMNA pond is not a technically ventilated pond, which is buoyant due to the Shore-anchored grid structure is characterized according to Patent No. WO 90/11255. Due to the grid forming a barrier system on the water surface, the floating aquatic plants a wave-calm and wind-protected habitat created, which is populated by them nationwide and optimal living conditions offers.

The pond volume can be divided into individual reaction rooms by separations, which results in more effective cleaning.

So that the floating aquatic plants can be enclosed and harvested, keep the grid structure contributes to buoyancy. However, it is flexible enough to fit under the Being able to push water surface when a harvester is over the Water surface moves to remove the floating aquatic plants as well to adapt to fluctuating water levels, which means that treatment can also be discontinuous inflow, as is possible from the second stage of the invention.

By treating the wastewater in a downstream sand filter any remaining suspended solids, dyes, algae or the like that are no longer removable. remove. In addition, by passing the sand and soil filter with the grown microorganism flora and the changing reaction conditions in the Pore volume of the sand filter a further reduction in the remaining nutrients and Carbon compounds reached.

With the BioAqua®-LEMNA-Technik®, in addition to the achieved tertiary cleaning Compensation of the hydraulic cargo achieved that the water cycle or An even inflow of purified wastewater is ensured. It means that Impact loads with regard to nutrient load and water quantity can be avoided. This would otherwise have a negative impact on the ecological balance of the receiving water.

example

With a mixture of fruit, production and wash water one food processing factory, for example, the invention as in the drawing represented.  

Fig. 1 shows the overall schematic structure. The successive stages of the process are clearly shown.

Fig. 2 shows the schematic structure of the 1st stage. There is a separate treatment of the very highly contaminated amniotic fluid and the highly contaminated production water with wash water. Anaerobic acidification takes place in the reactor ( 1 ) for both treatment lines. The anaerobic conditions and the circulation in the reactor are realized by an agitator ( 2 ). After leaving the reactor, one or more additives are added to the wastewater to improve the sedimentation behavior, which enables rapid sedimentation ( 3 ).

The sedimentation residue is separated via decanter ( 4 ), while the liquid phase is introduced into the 2nd stage.

Fig. 3 shows the schematic structure of the 2nd stage. The liquid phase from the 1st stage enters a bioreactor ( 1 ), which serves as a buffer in front of the high-performance bio-reactor ( 2 ).

Due to the amount of wastewater generated, several high-performance bio-reactors ( 2 ) are available, which can be fed optionally.

A defined wastewater volume is exchanged from this high-performance bio-reactor and fed to a separate settling tank ( 3 ). There the sedimentation behavior is improved with one or more additives. The clear water reaches the 3rd stage. The sludge is either removed from the system as excess sludge ( 4 ) or returned to the respective high-performance bio-reactor ( 2 ) if required.

Fig. 4 The clear water from the 2nd stage, see Fig. 3, reaches in the 3rd stage in a technically ventilated wastewater pond ( 1 ), in which biological nutrients and pollutants are largely reduced.

By switching nitrification zones ( 2 ) in the first pond, an increased biological conversion of the high ammonium content in the course of the second stage is achieved by providing sufficient growth areas for nitrifying microorganisms.

The LEMNA pond ( 3 ), as a subsequent anaerobic part, is used within the BioAqua®-LEMNA-Technik® for further treatment of the wastewater through bacterial reactions, chemical and physical processes as well as treatment with the help of floating aquatic plants. In this case, species from the Lemnaceae family serve as plants for cleaning. By harvesting the grown biomass 2-3 times, the nutrients are removed from the system.

This is followed by aeration of the cleaned wastewater.  

The BioAqua®-EMNA-Technik® in the overall system compensates for the discontinuous mode of operation of the 2nd stage resulting fluctuations in the hydraulic Freight reached, so that an even inflow for the recycling of the treated wastewater is secured.

Claims (13)

1. Combined process for the purification of highly contaminated waste water, in particular with particulate ingredients, high organic pollution and high nitrogen pollution, such as liquid manure, silage waste water and waste water from the food industry, characterized in that a combination technique is used for the treatment, which consists of three stages of fermentative coagulation, high-performance Bio-Reaktor-System and BioAqua®-LEMNA-Technik® exists. 2. The method according to claim 1, characterized in that the first stage is a represents fermentative coagulation, in which, due to the staggered action of anaerobic microbial mixed cultures and the respective wastewater chemical additives low molecular acids are formed. 3. The method according to claim 2, characterized in that the microbial mixing Culture from silage wastewater through self-immobilization on common Carrier bodies is obtained. 4. The method according to claim 1, characterized in that the second stage High-performance bio-reactor system. 5. The method according to claim 4, characterized in that for biological Cleaning with activated sludge intermittently a defined waste water volume is introduced into the reactor and there until the required Reini is reached result lingers. The wastewater treatment process is decoupled from the specific inlet conditions by installing a wastewater buffer. 6. The method according to claim 5, characterized in that the high-performance bio-re actuator is designed as a submerged jet fermenter. 7. The method according to claim 5, characterized in that the waste water cleaning process in its entirety through constant recording and evaluation parameters of the feed quantity / unit of time, oxygen and / or pH value and / or Redox potential and / or nitrate and ammonium nitrogen, level, dry substance concentration and / or turbidity is regulated.   8. The method according to claim 5, characterized in that the sedimentation and the biological purification take place in one and the same reactor. 9. The method according to claim 5, characterized in that the sedimentation in a separate sedimentation basin takes place. 10. The method according to claim 9, characterized in that the process of sediments tation is improved by adding one or more additives. 11. The method according to claim 1, characterized in that the third stage of Treatment is carried out by the BioAqua®-LEMNA-Technik®. 12. The method according to claim 11, characterized in that the waste water in the BioAqua®-LEMNA-Technik® an extensive cleaning regarding the Nutrient content is subjected and the daily inflow to the receiving water is balanced and thus adapted to the respective requirements. 13. The method according to claim 11, characterized in that the delivery of odor-intensive substances in the atmosphere as far as possible.