An example of alcohol wastewater treatment engineering

Project overview

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

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

Two-process process

Design wastewater quality

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

2 treatment process

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

Engineering adopted Ι level + Ⅱ full hybrid high temperature anaerobic fermentation temperature in UASB + SBR aerobic anaerobic fermentation process.

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

CSTR is suitable for the treatment of high concentration and high suspension of dry liquor, with the removal rate of over 82%, 90% of BOD removal rate and 80% of SS removal rate. The waste liquid treated by CSTR contains a large number of SS, which is separated by high depositing of mud water and the upper cleaning fluid enters the digestive liquid storage pool. The dilute sludge is dehydrated into dry sludge, which can be used for high quality organic fertilizer or mixed coal. Continue to clear liquid from the digestive liquid storage pool will continuous pumping Ⅱ UASB, UASB with temperature is 33 ~ 35 ℃ anaerobic fermentation. After anaerobic fermentation, the digestion liquid enters the air float device. COD can be removed over 66 %, and SS removal of over 66 %.

The solution of the secondary anaerobic air - floating treatment was added to the water tank, and the waste cooling water (or water) was added, and the COD was controlled 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. The waste water is in the SBR pool, in order to carry out water, aeration, precipitation, decanting discharge, and discharge to meet the emission standard.

By class Ⅱ UASB and air floating device discharge sent to anaerobic sludge dehydration processing, high quality organic fertilizer. Return acidification aerobic sludge discharged from the SBR pool, and then enter the Ⅰ anaerobic fermentation tank level processing, also can increase the methane production.

Main design parameters

Main technological 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 load 8 ~ 10 kgcod/(m after · d).

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

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

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

Three operation conditions

1. Main technical and economic indicators

The project has saved 20% of the engineering investment by using the secondary anaerobic aerobic treatment of alcohol waste, compared with the conventional first-level anaerobic aerobic process. The energy saving is 30%, and the running cost is reduced by 50%.

2 engineering benefits

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

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

Five project analysis

The project draws on the experience and engineering practice of the light industrial environmental protection research institute for over 20 years to control the waste of alcohol (cassava dry raw materials), and the secondary anaerobic fermentation is used to complement each other. Will Ⅰ and Ⅱ series, may obtain the desired effect of the anaerobic microbe treatment, overcome the adoption of the disadvantage of anaerobic treatment is difficult to meet.

Ⅰ CSTR anaerobic fermentation tank level using large injection pump mixing and sludge reflux device, suitable for high concentration and high suspended solids alcohol waste liquid, the equipment and technology in 1988 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 adopts the silicon rubber film microporous aerator imported from Germany.

The project has been paid to small and medium-sized enterprises in the United Nations. The United Nations development program (UNDP) deployment, officials said the practice of the alcohol plant, realize win-win situation of the environmental protection and economic development, small and medium enterprises in the world, especially for small and medium-sized enterprises in developing countries has general guide meaning.

濟寧天通是一家水處理設備生產和銷售集一體的公司，公司擁有高尖端的技術人才，擁有高素質的工作團隊，可以及時地為客戶提供完善的售后服務。我公司主要產品：水處理設備，污水處理設備、廢水處理設備、工業污水設備、農業廢水設備、雨水凈水設備、醫院污水設備、鋼廠廢水設備、屠宰場廢水設備、食品廠廢水處理設備等多種設備，可根據要求專業定制水處理設備。

Jining tiantong is a company of water treatment equipment production and sales integration. The company has high quality technical personnel and high-quality work team

Timely provide customers with perfect after-sales service. Our main products: water treatment equipment, sewage treatment equipment, waste water treatment equipment, industrial sewage equipment

Agricultural waste water equipment, rainwater purification equipment, hospital sewage equipment, plant waste water equipment, slaughterhouse waste water equipment, food factory waste water treatment equipment and other facilities

Prepare water treatment equipment according to requirements.

酒精廢水處理工程實例

一 工程概況

山東某酒精有限公司是采用木薯干原料生產酒精的專業工廠，年產酒精5萬噸、無水乙醇1萬噸，每天排放酒精廢液1600t。廢水處理工程設計規模1600m3/d。

該廢水處理工程2010年被列為原國家經貿委示范工程。采用了輕工業環保所研制的二級厭氧—好氧工藝路線。厭氧工段于1999年建成投入運轉，好氧工段于2002年建成，并通過驗收，達標運行。

二  處理工藝

1 設計廢水水質

該廠每天排放1600m3（木）薯干酒精廢液（每年生產330d），廢液COD為55000~60000mg/L，BOD為24000 mg/L，SS為22700mg/L，pH值為4.2。處理后的出水要求達到國家《污水綜合排放標準》（GB8978—1996）中的二級標準，COD≤300mg/L，BOD≤100mg/L，SS≤150mg/L，pH值為6~9。

2 處理工藝

薯干酒精廢液（原糟液），其COD:BOD=2:1，屬于高溫、高濃度、高SS、可生化性良好的的有機廢液。采用厭氧-好氧法處理（木）薯干酒糟廢液能回收大量沼氣能源，并能將廢液處理達標，是技術和經濟均為最佳的處理方

工程采用了Ι級全混合高溫厭氧發酵+Ⅱ級中溫UASB厭氧發酵+SBR好氧處理工藝。

由酒精蒸餾塔排出的薯干酒糟廢液經廢熱回收后，進入沉砂池，在沉砂池中盡量將原料夾帶的砂石去除。然后進入貯存池水解，再將廢液用泵打入Ⅰ級全混合厭氧發酵罐（CSTR）進行高溫厭氧發酵，發酵溫度52~54℃，pH值控制在7.厭氧發酵罐內裝有大型水力噴射泵和厭氧污泥回流裝置。噴射泵用于罐內全混合攪拌，并可用于加熱、破碎浮渣。厭氧發酵產生的沼氣（每立方米COD為55000mg/L的廢液可產30m3沼氣，熱值相當于30KG原煤）經氣水分離，水封后進入沼氣貯柜，用作鍋爐燃料。

CSTR適用于高濃度、高懸浮物的薯干酒糟廢液處理，COD去除率82%以上，BOD去除率90%、SS去除率80%。CSTR處理后的廢液尚含大量SS，經高位沉淀槽泥水分離，上清液進入消化液貯池。稀污泥經臥螺離心機脫水成干污泥，可作優質有機肥料或拌煤后送入鍋爐燒掉。繼續從消化液貯池中將上清液連續泵入Ⅱ級UASB，UASB采用中溫33~35℃厭氧發酵。厭氧發酵后消化液進入氣浮裝置處理。出水COD可去除66%以上，SS去除66%以上。

經上述二級厭氧-氣浮處理的消化液進入集水配水池，同時加入廢冷卻水（或達標水），控制廢水COD在1000~1500mg/L之間，并底部予以曝氣混合。然后泵入SBR好氧裝置繼續處理。廢水在SBR池中，按順序進行進水、曝氣、沉淀、潷水排放，出水達到排放標準。

由Ⅱ級UASB和氣浮裝置排出的厭氧污泥送去脫水處理，作優質有機肥料。由SBR排出的好氧污泥返回酸化池，再進入Ⅰ級厭氧發酵罐處理，還可增加沼氣產量。

3 主要設計參數

 主要工藝裝置包括：沉砂池、貯存池、Ⅰ級厭氧發酵罐、Ⅱ級UASB反應器、給水配水池、SBR池、汽水分離器、沼氣貯柜。

Ⅰ級CSTR厭氧發酵罐：鋼制，6座，單罐有效容積2000m3，發酵時間7.5d，容積負荷8~10kgCOD/(m3·d)。

  Ⅱ級UASB反應器：鋼筋混凝土結構，2座，單池有效容積1100m3，水力停留時間1.3d，容積負荷3.3 kgCOD/(m3·d)。

   SBR池：鋼制，2座，單池有效容積1060m3，交替進行。

沼氣貯柜：濕式貯氣柜，容積25000m3，氣壓350mmH₂O。

三 運行情況

1         主要技術經濟指標

該工程由于采用了二級厭氧-好氧處理酒精廢液，比常規的一級厭氧-好氧工藝節省了工程投資20%。節省能耗30%，降低了運行成本50%。

2         工程效益

該工程節能效果明顯，每年可節煤1.65萬噸，減排38.7萬噸CO₂，同時廢水達標，環境污染得到治理。

工程總投資2500萬元，年運行成本400萬元。年獲效益：（1）若按原煤熱值500元/t計算，年回收425萬元；（2）若按天然氣熱值計算，1m3沼氣可獲益1元，年回收1250萬元。尚未計算肥料收益和免交的排污費收益。

五  工程評析

工程借鑒了輕工業環境保護研究所20多年來治理酒精（木薯干原料）廢液的經驗和工程實踐，采用二級厭氧發酵，互為補充。將Ⅰ級和Ⅱ級串聯，可獲得厭氧微生物處理的最佳效果，克服了僅采用一級厭氧處理難以達標的缺點。

   Ⅰ級CSTR厭氧發酵罐采用大型噴射泵攪拌和污泥回流裝置，適用高濃度、高懸浮物酒精廢液，該裝置和工藝曾于1988年獲我國國家科技進步獎。Ⅱ級UASB裝置引進消化了2000年德國的“組合式雙層三相分離器”先進設計。SBR裝置采用了德國進口的硅橡膠膜微孔曝氣管。

該工程已被收入了聯合國中小型企業案例。聯合國開發計劃部署（UNDP）官員表示，該酒精廠的做法，實現了環境保護和經濟發展的雙贏，對全世界的中小型企業，尤其對發展中國家的中小企業具有普遍指導意義。