Anexample of alcohol wastewater treatment engineering

Projectoverview

Shandongprovince alcohol co., LTD. Is a professional factory that USES cassava driedraw materials to produce alcohol, with annual production of 50,000 tons ofalcohol, 10,000 tons of anhydrous ethanol, and 1600t of alcohol waste per day.Wastewater treatment engineering design scale 1600m cubed/d.

Thewaste water treatment project was listed as a demonstration project of theformer national economic and trade commission in 2010. The secondary anaerobic- aerobic process route developed by light industrial environmental protectionis adopted. The anaerobic section was put into operation in 1999. The aerobicsection was completed in 2002 and passed the acceptance inspection.

Two-processprocess

Designwastewater quality

Theplant emits 1600m cubed (wood) of dry alcohol waste (330d per year), the wasteliquid COD is 55000~ 60000mg/L, BOD is 24000 mg/L, SS is 22700mg/L, and the pHvalue is 4.2. After treatment, the water discharge requirement reaches thesecondary standard of the national sewage comprehensive discharge standard(gb8978-1996), COD is less than 300mg/L, BOD is less than 100mg/L, SS is lessthan 150mg/L, and the pH value is 6~ 9.

2treatment process

Dryalcohol waste liquor (original bad liquor), its COD:BOD= 2:1, belongs to hightemperature, high concentration, high SS, and good biodegradable organic wasteliquid. Using anaerobic - aerobic treatment (wood), the waste liquid canrecover a large amount of biogas energy, and can handle the waste solution tothe standard, which is the best treatment for the technology and economy

Engineeringadopted Ι level + Ⅱ full hybrid hightemperature anaerobic fermentation temperature in UASB + SBR aerobic anaerobicfermentation process.

Afterthe waste heat recovery, the waste liquid of the dry dry liquor discharged fromthe alcohol distillation column enters the sink pool, and the sand stone of theraw material is removed as far as possible in the sedimentation tank. And theninto the storage pool water solution, the waste liquid pump into Ⅰ level full hybrid anaerobic fermentation tank (CSTR) for hightemperature anaerobic fermentation, 52 ~ 54 ℃ fermentationtemperature, pH value control in 7. In the anaerobic fermentation tank isequipped with large hydraulic jet pump and anaerobic sludge reflux device. Thespray pump is used for mixing and mixing in the tank, and can be used forheating and crushing scum. The biogas produced by anaerobic fermentation (thewaste liquid of 55000mg/L per cubic meter per cubic meter can produce 30m cubicmethane, which is equivalent to 30KG of raw coal), separated from the gas andwater, and then into the biogas storage tank after the water seal is used asthe boiler fuel.

CSTRis suitable for the treatment of high concentration and high suspension of dryliquor, with the removal rate of over 82%, 90% of BOD removal rate and 80% ofSS removal rate. The waste liquid treated by CSTR contains a large number ofSS, which is separated by high depositing of mud water and the upper cleaningfluid enters the digestive liquid storage pool. The dilute sludge is dehydratedinto dry sludge, which can be used for high quality organic fertilizer or mixedcoal. Continue to clear liquid from the digestive liquid storage pool willcontinuous pumping Ⅱ UASB, UASB withtemperature is 33 ~ 35 ℃ anaerobicfermentation. After anaerobic fermentation, the digestion liquid enters the airfloat device. COD can be removed over 66 %, and SS removal of over 66 %.

Thesolution of the secondary anaerobic air - floating treatment was added to thewater tank, and the waste cooling water (or water) was added, and the COD wascontrolled in the water with a mixture of aeration at the bottom of 1000~1500mg/L. Then pump into the SBR aerobic device to continue processing. Thewaste water is in the SBR pool, in order to carry out water, aeration,precipitation, decanting discharge, and discharge to meet the emissionstandard.

Byclass Ⅱ UASB and air floatingdevice discharge sent to anaerobic sludge dehydration processing, high qualityorganic fertilizer. Return acidification aerobic sludge discharged from the SBRpool, and then enter the Ⅰ anaerobicfermentation tank level processing, also can increase the methane production.

Maindesign parameters

Maintechnological devices include: grit chamber, storage pool, Ⅰ anaerobic fermentation tank, Ⅱ UASB reactor,SBR water pool, pool, steam separator, biogas storage cabinet.

Ⅰ level CSTR anaerobic fermentation tank:steel, 6, 2000 m after single tank volume, fermentation time 7.5 d, volume load8 ~ 10 kgcod/(m after · d).

Ⅱ level UASB reactor: reinforced concretestructure, 2, 1100 m after ChanChi volume, hydraulic retention time of 1.3 d, volumeload 3.3 kgCOD/(m after · d).

SBRpool: steel, 2 seats, single pool effective volume 1060m cubed, alternating.

Biogasstorage tank: wet storage tank, volume 25000m cubed, pressure 350mmH2O.

Threeoperation conditions

1.Main technical and economic indicators

Theproject has saved 20% of the engineering investment by using the secondaryanaerobic aerobic treatment of alcohol waste, compared with the conventionalfirst-level anaerobic aerobic process. The energy saving is 30%, and therunning cost is reduced by 50%.

2engineering benefits

Theenergy saving effect of this project is obvious, it can be 1.65 million tons ofcoal per year, the emission reduction of 38.70 million tons of CO2, and thewaste water standard, the environmental pollution is managed.

Thetotal investment of the project is 25 million yuan, and the annual operatingcost is 4 million yuan. Annual benefit: (1) if the original coal value is 500yuan/t, the annual recovery is 4.25 million yuan; (2) if the gas calorificvalue is calculated, 1m cubic biogas can benefit 1 yuan, and the annualrecovery of 12.5 million yuan. The income from fertilizer and the freedischarge fee has not been calculated.

Fiveproject analysis

Theproject draws on the experience and engineering practice of the lightindustrial environmental protection research institute for over 20 years tocontrol the waste of alcohol (cassava dry raw materials), and the secondaryanaerobic fermentation is used to complement each other. Will Ⅰ and Ⅱ series, may obtain the desiredeffect of the anaerobic microbe treatment, overcome the adoption of thedisadvantage of anaerobic treatment is difficult to meet.

Ⅰ CSTR anaerobic fermentation tank level usinglarge injection pump mixing and sludge reflux device, suitable for high concentrationand high suspended solids alcohol waste liquid, the equipment and technology in1988 won the national progress prize in science and technology in our country. Ⅱ level UASB device introduced digested the 2000 German advanced"combined" double three-phase separator design. The SBR device adoptsthe silicon rubber film microporous aerator imported from Germany.

Theproject has been paid to small and medium-sized enterprises in the UnitedNations. The United Nations development program (UNDP) deployment, officialssaid the practice of the alcohol plant, realize win-win situation of theenvironmental protection and economic development, small and medium enterprisesin the world, especially for small and medium-sized enterprises in developingcountries has general guide meaning.

济宁天通是一家水处理设备生产和销售集一体的公司，公司拥有高的技术人才，拥有高素质的工作团队，可以及时地为客户提供完善的售后服务。我公司主要产品：水处理设备，污水处理设备、废水处理设备、工业污水设备、农业废水设备、雨水净水设备、医院污水设备、钢厂废水设备、屠宰场废水设备、食品厂废水处理设备等多种设备，可根据要求专业定制水处理设备。

Jiningtiantong is a company of water treatment equipment production and salesintegration. The company has high quality technical personnel and high-qualitywork team

Timelyprovide customers with perfect after-sales service. Our main products: watertreatment equipment, sewage treatment equipment, waste water treatmentequipment, industrial sewage equipment

Agriculturalwaste water equipment, rainwater purification equipment, hospital sewageequipment, plant waste water equipment, slaughterhouse waste water equipment,food factory waste water treatment equipment and other facilities

Preparewater treatment equipment according to requirements.

酒精废水处理工程实例

一 工程概况

山东某酒精有限公司是采用木薯干原料生产酒精的专业工厂，年产酒精5万吨、无水乙醇1万吨，每天排放酒精废液1600t。废水处理工程设计规模1600m3/d。

该废水处理工程2010年被列为原国家经贸委示范工程。采用了轻工业环保所研制的二级厌氧—好氧工艺路线。厌氧工段于1999年建成投入运转，好氧工段于2002年建成，并通过验收，达标运行。

二  处理工艺

1 设计废水水质

该厂每天排放1600m3（木）薯干酒精废液（每年生产330d），废液COD为55000~60000mg/L，BOD为24000mg/L，SS为22700mg/L，pH值为4.2。处理后的出水要求达到国家《污水综合排放标准》（GB8978—1996）中的二级标准，COD≤300mg/L，BOD≤100mg/L，SS≤150mg/L，pH值为6~9。

2 处理工艺

薯干酒精废液（原糟液），其COD:BOD=2:1，属于高温、高浓度、高SS、可生化性良好的的有机废液。采用厌氧-好氧法处理（木）薯干酒糟废液能回收大量沼气能源，并能将废液处理达标，是技术和经济均为的处理方

工程采用了Ι级全混合高温厌氧发酵+Ⅱ级中温UASB厌氧发酵+SBR好氧处理工艺。

由酒精蒸馏塔排出的薯干酒糟废液经废热回收后，进入沉砂池，在沉砂池中尽量将原料夹带的砂石去除。然后进入贮存池水解，再将废液用泵打入Ⅰ级全混合厌氧发酵罐（CSTR）进行高温厌氧发酵，发酵温度52~54℃，pH值控制在7.厌氧发酵罐内装有大型水力喷射泵和厌氧污泥回流装置。喷射泵用于罐内全混合搅拌，并可用于加热、破碎浮渣。厌氧发酵产生的沼气（每立方米COD为55000mg/L的废液可产30m3沼气，热值相当于30KG原煤）经气水分离，水封后进入沼气贮柜，用作锅炉燃料。

CSTR适用于高浓度、高悬浮物的薯干酒糟废液处理，COD去除率82%以上，BOD去除率90%、SS去除率80%。CSTR处理后的废液尚含大量SS，经高位沉淀槽泥水分离，上清液进入消化液贮池。稀污泥经卧螺离心机脱水成干污泥，可作优质有机肥料或拌煤后送入锅炉烧掉。继续从消化液贮池中将上清液连续泵入Ⅱ级UASB，UASB采用中温33~35℃厌氧发酵。厌氧发酵后消化液进入气浮装置处理。出水COD可去除66%以上，SS去除66%以上。

经上述二级厌氧-气浮处理的消化液进入集水配水池，同时加入废冷却水（或达标水），控制废水COD在1000~1500mg/L之间，并底部予以曝气混合。然后泵入SBR好氧装置继续处理。废水在SBR池中，按顺序进行进水、曝气、沉淀、滗水排放，出水达到排放标准。

由Ⅱ级UASB和气浮装置排出的厌氧污泥送去脱水处理，作优质有机肥料。由SBR排出的好氧污泥返回酸化池，再进入Ⅰ级厌氧发酵罐处理，还可增加沼气产量。

3 主要设计参数

主要工艺装置包括：沉砂池、贮存池、Ⅰ级厌氧发酵罐、Ⅱ级UASB反应器、给水配水池、SBR池、汽水分离器、沼气贮柜。

Ⅰ级CSTR厌氧发酵罐：钢制，6座，单罐有效容积2000m3，发酵时间7.5d，容积负荷8~10kgCOD/(m3·d)。

 Ⅱ级UASB反应器：钢筋混凝土结构，2座，单池有效容积1100m3，水力停留时间1.3d，容积负荷3.3 kgCOD/(m3·d)。

  SBR池：钢制，2座，单池有效容积1060m3，交替进行。

沼气贮柜：湿式贮气柜，容积25000m3，气压350mmH₂O。

三 运行情况

1         主要技术经济指标

该工程由于采用了二级厌氧-好氧处理酒精废液，比常规的一级厌氧-好氧工艺节省了工程投资20%。节省能耗30%，降低了运行成本50%。

2         工程效益

该工程节能效果明显，每年可节煤1.65万吨，减排38.7万吨CO₂，同时废水达标，环境污染得到治理。

工程总投资2500万元，年运行成本400万元。年获效益：（1）若按原煤热值500元/t计算，年回收425万元；（2）若按天然气热值计算，1m3沼气可获益1元，年回收1250万元。尚未计算肥料收益和免交的排污费收益。

五  工程评析

工程借鉴了轻工业环境保护研究所20多年来治理酒精（木薯干原料）废液的经验和工程实践，采用二级厌氧发酵，互为补充。将Ⅰ级和Ⅱ级串联，可获得厌氧微生物处理的效果，克服了仅采用一级厌氧处理难以达标的缺点。

  Ⅰ级CSTR厌氧发酵罐采用大型喷射泵搅拌和污泥回流装置，适用高浓度、高悬浮物酒精废液，该装置和工艺曾于1988年获我国国家科技进步奖。Ⅱ级UASB装置引进消化了2000年德国的“组合式双层三相分离器”先进设计。SBR装置采用了德国进口的硅橡胶膜微孔曝气管。

该工程已被收入了联合国中小型企业案例。联合国开发计划部署（UNDP）官员表示，该酒精厂的做法，实现了环境保护和经济发展的双赢，对全世界的中小型企业，尤其对发展中国家的中小企业具有普遍指导意义。