Comparison of several brewery wastewater treatment processes

Pay more attention to official account: water purification for environmental protection (hbscl01) Comparison of several brewery wastewater treatment processes


Acidification - SBR method for brewery wastewater treatment

The main technological equipment of this method is acidification column and SBR reactor. When treating beer wastewater in anaerobic reaction, this method abandons methane fermentation stage with long reaction time and high control conditions, and controls reaction in acidification stage, which has following advantages compared to anaerobic reaction in whole process: < /p>

(1) Since reaction is controlled in hydrolysis and acidification steps, reaction is fast, so volume of hydrolysis tank is small;

(2) no need to collect resulting biogas, which simplifies structure, reduces cost, easy to maintain and easy to expand;

(3) The sludge degradation function is exactly same as that of digester, and amount of excess sludge generated is small. At same time, after hydrolysis reaction, proportion of soluble COD increases significantly, which favorably affects absorption of substrate by microorganisms and reduces an important link in metabolic process of microorganisms, which will accelerate decomposition of organic substances. substances and create more favorable conditions for subsequent biological treatment of state.

(4) Acidification - The SBR method is ideal for treatment of highly concentrated beer wastewater with a removal rate of 94% to 99%.

In order for this method to achieve ideal results in treatment of wastewater from beer, working environment must meet following requirements:

(1) Acidification - The SBR method is very important for treating medium and high strength beer wastewater. It has two functions. One is to change organic components of wastewater to improve biodegradability of wastewater; second is that it has significant effect on removal of easily degradable contaminants in organic matter. The quality of acidification effect directly affects treatment effect in SBR reactor, and removal of organic matter is mainly concentrated in SBR reactor.

(2) Acidification - SBR treatment of beer effluent depends on alkalinity of feed stream and reaction temperature. The optimum temperature is 24°C and optimum alkalinity range is 500-750 mg/L. Depending on quality of source water, if alkalinity is insufficient, alkalinity pre-adjustment method is used for this process, if temperature difference is small, there is no need to adjust operating parameters, if temperature difference is large, it depends on specific situation.


UASB - Aerobic Contact Oxidation Process for Brewery Wastewater

The main treatment equipment in this treatment process is upflow anaerobic sludge bed and aerobic contact oxidation tank. The main treatment process: sewage passes through drum filter, and SS removal rate ism filter is more than 10%, with removal of organic matter from wheat husks, concentration of organic matter in wastewater also decreased. The regulating tank not only has function of regulating quality and quantity of water, but also has function of settling and anaerobic fermentation due to long residence time of waste water in tank. Thanks to addition of an anaerobic treatment unit, process works very well. The upflow anaerobic sludge bed has low power consumption, stable operation and good wastewater quality, which effectively reduces treatment load and operating energy consumption of aerobic biochemical plant (because power consumption of aerobic treatment plant is directly proportional to treatment load). ).

Aerobic treatment (including aerobic biological contact oxidizing tank and sloping plate settling tank) provides a high rate of SS and COD removal in wastewater, since wastewater still contains many easily biodegradable substances after anaerobic treatment with organic substances. The process has good curative effect, simple operation and high stability. The beer wastewater treatment process with successive upflow anaerobic sludge bed and aerobic contact oxidation tank is characterized by high treatment efficiency, stable operation, low power consumption, easy commissioning and easy annual restart. By adding anaerobic sludge strains that make up 1/3 of volume of anaerobic tank, stable growth of sludge strains can be guaranteed. After 3 months of debugging, UASB can reach full load. The COD removal rate of whole process reaches 96.6%, and suspended solids removal rate reaches 97.3%-98%. This process is very suitable for popularization and application in beer wastewater treatment.


Wastewater treatment of a brewery by new contact oxidation method

The purification process by this method is as follows: wastewater first removes most of suspended solids through a microfilter, wastewater enters a control tank, and then is pumped by a medium-pressure pump into VTBR reactor for biochemical treatment, and wastewater contacts filler through a forced fan air supply to maintain oxygen demand of biochemical reaction, VTBR reactor effluent enters precipitator, removes part of biofilm falling off to reduce process load of air flotation equipment, and then air flotation equipment of flow removes remaining biofilm, and sludge and foam are sent to sludge tank , which is concentrated and then dehydrated.

The treatment process has following main features:

①The VTBR is converted from waste alcohol tanks, which saves investment. Compared with reinforced concrete structure, it features low uniformtemporary investment, stable performance and good curative effect.

②In winter operation, a layer of insulating material is added outside HTBR reactor to maintain a constant high temperature in tank and improve biological activity.

③Because height of VTBR reactor is about 10m and water depth is large, a high-pressure fan with a wind pressure of 98kPa and N=75kW is selected, which consumes a lot of power.


Treatment of brewery wastewater by biological contact oxidation

This process uses hydrolytic acidification as a biological contact oxidation pretreatment. Hydrolytic acidifying bacteria hydrolyze solids in water into solubles through metabolism and decompose macromolecular organics into low molecular weight organics. Hydrolytic acidification not only removes some organic contaminants, but also improves biodegradability of wastewater, which is beneficial for subsequent aerobic biological contact oxidative treatment. This process is relatively reasonable in terms of purification method, process combination and parameter selection, while taking full advantage of advantages of each process to convert and remove contaminants. However, if design of some structures will affect operational effect, leading to unsatisfactory wastewater quality, COD of wastewater from biological contact oxidation tank (clarified liquid settled for 30 minutes) is 500-600 mg/l. , after coagulation. After air flotation treatment, wastewater COD is still 300 mg/l, which is well above emission requirements (150 mg/l).

However, this processing method has following problems in design and operation:

(1) The main problem in hydrolytic acidification tank is that sedimentary sludge cannot be removed in time. Due to high concentration of suspended solids in wastewater, sludge generation in tank is very high, but original process only had a sludge bucket at front of hydrolytic acidification tank, so back of tank was soon full. sludge. In addition, with an increase in microbial mass, a silt mass was formed in middle of soft biological filler, which reduced area of ​​mass transfer. In view of accumulation of sludge in front of hydrolytic acidification tank, first stage of coagulation air flotation can be added to remove suspended solids in water. After this improvement, hydrolysis acidification tank can work stably and efficiently for a long time, and wastewater COD also ranges from 1100 to 1200 mg/l was reduced to 900-1000 mg/l and good results were obtained. However, addition of coagulation airear flotation increases operating costs, and O2 dissolved in air flotation process can also adversely affect hydrolysis and acidification. Therefore, when designing and implementing hydrolytic acidification for treatment of wastewater with a high concentration of suspended solids, number of sludge bins can be increased for timely removal of settled sludge. In addition, to prevent formation of sludge accumulations on surface of filler, semi-soft fillers with a large specific surface area and without sludge accumulations should be used.

(2) If concentration of pollutants in wastewater is high or pretreatment effect is not ideal, organic matter load in front of biological contact oxidation tank is high, making oxygen supply relatively insufficient. anoxic state of pond, while mature aerobic biofilm at end of pool is amber yellow. At same time, concentration of biologically active inhibitory substances in water is also high, which also has a certain inhibitory effect on microorganisms. These factors lead to fact that pond of biological contact oxidation does not play its due role, and curative effect is not ideal. In this regard, once measures for staged aeration are in place, water can enter at several points, and wastewater can enter biological contact oxidation tank at several points along length of tank, in order to evenly distribute load and eliminate adverse effects of frontal anoxia. and high concentrations of inhibitory substances. After switching to multi-point water intake and after a period of stable operation, COD of effluent (30 min of clarified liquid) of biological contact oxidation tank is 200-300 mg/l. After coagulation and air flotation processes, COD of final waste water is less than 150 mg/l (typically 130 mg/l), which meets emission requirements.

(3) In process of commissioning and operation, biofilm in biological contact oxidation tank is removed, bubble diameter becomes larger (the aeration method is microporous aeration), sewage is turbid, cleaning effect is deteriorated from time to time. After research, analysis and verification, it was found that this was caused by insufficient dissolved oxygen caused by load fluctuations or improper operation. The lack of dissolved oxygen leads to transition of biofilm from an aerobic to anaerobic state, its adhesion decreases. When air bubbles are agitated, a large number of biofilms fall off, which leads to an increase in water viscosity, an increase in diameter of bubbles, a decrease in efficiency of oxygen transfer, cause hypoxia and thus form a vicious circle , worsening therapeutic effect.

(4) In initial stage of commissioning and operation, when this phenomenon occurs, air supply is usually increased to improve abilityo oxygen supply to eliminate lack of oxygen. As a result, due to increased agitation intensity of air bubbles, removal of a wider range of biofilms, more viscous water and lower oxygen transfer efficiency instead of improving oxygen supply capacity worsened situation. The correct treatment measure should be to reduce aeration rate and then gradually increase aeration rate after fused biofilm has flowed out with water flow to restore dissolved oxygen concentration to its original level. If water temperature is appropriate, biofilm will recover in 2- 3 days is ok.

Therefore, when using this process to treat brewery wastewater, following requirements must be met: ① When using hydrolytic acidification as a pretreatment process, measures to remove suspended solids should be taken into account. ② When using a plug-flow biocontact oxidation tank, multiple water inlets can be used to avoid excessive inlet organic loading. ③ Dissolved oxygen concentration must be strictly controlled. Insufficient oxygen supply will cause biofilm to fall off over a large area, resulting in malfunction.


Beer wastewater treatment in UASB internal circulation reactor + oxidation channel process

This process uses a sequential anaerobic and aerobic method. Anaerobic uses UASB internal circulation technology. There is a long and narrow pond in aerobic processing area. In order to reduce construction costs and adapt measures to local conditions, process of oxidizing ditch is adopted. The key equipment of this purification process is UASB reactor. The reactor uses anaerobic microorganisms to decompose organic matter in wastewater. Its main body is divided into four parts: water distribution system, reaction zone, gas-liquid-solid three-phase separation system, and biogas collection system. Anaerobic micro-organisms do not have as broad water quality requirements as aerobic micro-organisms. The optimum pH is 6.5-7.8 and optimum temperature is 35°C-40°C, but water quality of beer wastewater in this project exceeds this range. This requires that acidity and temperature be adjusted before effluent enters UASB reactor. It practically enlarges electrical appliances. Investment in equipment and complexity of designing a professional tool. UASB internal circulation technology is to add a set of internal circulation system based on conventional UASB technology, which includes a return pool and a return pump. The quality of water leaving UASB reactor is generally relatively stable and is returned to water distribution system under action of irrigation system.I. In this way, adaptability of UASB reactor to water temperature, pH value and COD concentration can be improved, and it is only necessary to make a coarse adjustment of pH and temperature before UASB reactor enters water. The UASB reactor uses annular perforated pipes for water distribution, and water is discharged through a three-phase separator, and a side-flow flocculation reaction sump is added above three-phase separator. .

This processing process mainly has following characteristics:

① Practice has shown that it is possible to use UASB internal circulation reactor + oxidation channel process to treat brewery wastewater, and operation results show that overall COD removal rate reaches 95%.

②Because series combination of internal circulation UASB reactor and oxidation ditch process is used, combination of operation of UASB reactor or oxidation treatment can be adjusted according to seasonality of beer production, water quality and water quantity to further reduce operation cost.


UASB+SBR method for treating beer wastewater

This purification process mainly includes an EGSB reactor and a CASS reactor. Combining two treatment plants EGSB and CASS, formed treatment process highlights advantages of each treatment plant, simplifies treatment process and reduces operating costs, and uses EGSB as a pre-treatment plant for all wastewater discharge in accordance with standard, reducing wastewater concentration resulting biogas can be processed as energy. At same time, since amount of organic matter entering aerobic treatment stage is greatly reduced, aeration energy consumption and formation of residual sludge in aerobic treatment stage are reduced, which greatly reduces cost of entire wastewater treatment process.

Compared to hydrolytic acidification+SBR treatment, EGSB+CASS treatment has following advantages:

(1) "EGSB+CASS" has reasonable technology and high practicability. The core of this process is aerobic pool. The whole process goes through anoxic and aerobic processes, which can effectively control growth of filamentous bacteria, prevent sludge from swelling, and effectively remove ammonium nitrogen due to high concentration of organic matter in water before and during reaction, microorganisms are in growth amount, fast processing speed, high oxygen utilization rate, thereby reducing energy consumption; At same time, flexible process adjustment, water intake, aeration, settling, drainage time can be adjusted according to actual situation and easy to operate. Suitable for breweries of all sizes.

(2) The processing process is simple, and installation, operation and maintenance are very convenient. After collection of wasted, to be treated, they are pumped into EGSB reactor. The flow rate and water intake are regulated in accordance with specified technological parameters. The waste water does not need to be mixed, after which waste water naturally rises into CASS. reservoir, and discharged after intermittent aeration and settling. The process is simple. The settling tank and CASS tank in EGSB design reactor are semi-underground reinforced concrete structures. The aeration device (except aeration head) can be manufactured on site. Easy installation and manufacture, flexible operation control, and it can be controlled automatically or manually. Very convenient.

(3) Low investment costs, 60% lower than price of similar foreign equipment.

(4) Large processing performance and good processing effect. Due to accumulation of a large amount of anaerobic granular sludge in reaction zone of EGSB reactor, wastewater can fully contact with it, and reaction rate is high, which can decompose more than 80% of COD in water. A three-phase separator is installed at top of reactor, which can separate solid, liquid and gaseous substances generated during processing in a timely manner to speed up reaction process. The CASS tank integrates water intake, aeration, sedimentation and drainage, which expands functions of reaction tank, not only improves processing speed, but also has obvious curative effects. The pool can decompose more than 90% COD and BOD.

(5) The process is mature and stable, impact resistant, fluctuations in water quality and quantity have little effect on wastewater, process is highly automated, operation control and maintenance are convenient, and labor quota is small.

Practice has shown that anaerobic-aerobic sequential process has advantages in processing of beer, and this is direction of acceptance or correction of beer wastewater treatment process in my country. At same time, turbidity separation is used for beer wastewater, and high concentration wastewater is pre-treated by an anaerobic process (such as UASB), and then mixed with low concentration wastewater in an aerobic treatment system, which makes it easy to achieve unity. environmental and economic benefits.

When conditions permit, make most of advanced wastewater treatment technologies. Factors such as technology, equipment, capital, site, personnel quality, geographical environment and climatic conditions must be fully taken into account, and technical methods must be flexibly selected to suit characteristics of in-house manufacturers.

Beer companies should not only pay attention to wastewater treatment technology itself, but also pay sufficient attention to operation and management of wastewater treatment plants. Advanced Scientific Management can also be used as a technology to influence process itself so that it can playplay right role.

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