發(fā)布時間：2018-04-10 03:01

  本文選題：大型水生植物　切入點：厭氧發(fā)酵　出處：《南京大學(xué)》2017年碩士論文

【摘要】：大型水生植物對污染水體有良好的凈化效果,被廣泛應(yīng)用于水體富營養(yǎng)化治理和人工濕地污水處理中,其資源化利用問題得到廣泛關(guān)注。利用硫酸鹽還原菌處理重金屬廢水成本低、無二次污染,難點在于尋找合適且廉價的碳源。本論文探索了大型水生植物厭氧發(fā)酵產(chǎn)酸的資源化利用方式,將大型水生植物發(fā)酵液作為硫酸鹽還原菌的碳源處理重金屬廢水,并進一步將大型水生植物發(fā)酵液用作生物濾池的碳源強化重金屬去除能力。主要研究結(jié)論如下:(1)以挺水植物圓幣草、蘆葦和再力花作為發(fā)酵原料,圓幣草厭氧發(fā)酵產(chǎn)酸效果最好,圓幣草發(fā)酵液中的揮發(fā)性脂肪酸總量分別是蘆葦和再力花的5.1和8.7倍。不同植物種類對揮發(fā)性脂肪酸種類影響不大,乙酸均為主要發(fā)酵產(chǎn)物。粉碎預(yù)處理和提高溫度都可有效提高厭氧發(fā)酵產(chǎn)酸速率,縮短發(fā)酵周期。堿性條件可以促進圓幣草厭氧發(fā)酵產(chǎn)酸,pH9時VFAs產(chǎn)量分別是pH5和7時的1.74和1.56倍。圓幣草、蘆葦和再力花厭氧發(fā)酵過程中氮釋放率分別為68%、79%和43%,磷釋放率分別為47%、43%和48%。堿性條件下發(fā)酵的發(fā)酵液可形成羥基磷酸鈣,可作為磷回收的一種方式。厭氧發(fā)酵產(chǎn)酸最優(yōu)條件為:以圓幣草為原料,發(fā)酵溫度37℃、經(jīng)粉碎處理在堿性條件下發(fā)酵。(2)圓幣草發(fā)酵液是一種良好的硫酸鹽還原菌碳源,效果優(yōu)于葡萄糖和蔗糖,劣于乙醇和乳酸鈉。但圓幣草發(fā)酵液作為大型水生植物資源化的產(chǎn)物,具有價格低廉的優(yōu)點。在批次試驗反應(yīng)器中,水生植物發(fā)酵液作為硫酸鹽還原菌碳源,COD/SO42-為1.2、5、7時硫酸鹽最大還原率分別為24.4%、43.6%和60%。(3)批次試驗中,硫酸鹽還原菌可利用圓幣草發(fā)酵液,有效去除低濃度的Cd2+、Cu2+、Pb2+和Ni2+4種重金屬離子,去除率分別可達到95.2%、98.7%、93.0%和89.6%。同時,硫酸鹽還原菌利用圓幣草發(fā)酵液作為碳源,對10mg/L的Ni2+、Cu2+、Cd2+和Pb2+4種重金屬廢水仍有良好的處理效果,重金屬去除率均超過90%,且硫酸鹽還原菌的活性沒有受到抑制。(4)為提高生物濾池的重金屬去除能力,添加圓幣草發(fā)酵液作為外加碳源,促進硫酸鹽還原菌的生物還原作用。穩(wěn)定運行后,生物濾池系統(tǒng)對低濃度重金屬廢水的去除效果良好,Ni2+、Pb2+、Cd2+和Cu2+4種重金屬離子均得到有效去除,去除率分別達到90%、75%、92%和87%。同時圓幣草發(fā)酵液中揮發(fā)性脂肪酸等有機物質(zhì)得到有效利用,進水初始COD為300 mg/L時,去除效率可達84%-98%。COD/SO42-為3和8時硫酸鹽最大還原率分別為 18.8%和 42.8%。因此,圓幣草等水生植物發(fā)酵液是一種有效的碳源,可以被硫酸鹽還原菌利用還原硫酸鹽去除重金屬離子,也可以用于在人工濕地前端設(shè)置生物濾池去除重金屬離子。
[Abstract]:Macrophytes have good purifying effect on polluted water body and have been widely used in eutrophication treatment and sewage treatment of constructed wetland.The treatment of heavy metal wastewater by sulfate reducing bacteria has low cost and no secondary pollution. The difficulty lies in finding suitable and cheap carbon source.In this paper, the resource utilization of anaerobic fermentation of macroaquatic plants to produce acid was explored. The fermentation broth of large aquatic plants was used as a carbon source of sulfate reducing bacteria to treat heavy metal wastewater.Furthermore, the fermentation broth of large aquatic plants was used as a carbon source in biofilter to enhance the removal capacity of heavy metals.The main results were as follows: (1) the total volatile fatty acids in the fermentation broth were 5.1 and 8.7 times higher than those of Reed and reclaimed flower, respectively.Different plant species had little effect on volatile fatty acids, acetic acid was the main fermentation product.The acid production rate of anaerobic fermentation can be increased effectively and the fermentation period can be shortened by grinding pretreatment and raising temperature.Alkaline conditions could promote the production of VFAs by 1.74 and 1.56 times of pH5 and 7, respectively, at pH 9 of anaerobic fermentation.During anaerobic fermentation, the nitrogen release rates were 68% and 43%, respectively, and the phosphorus release rates were 47% and 48%, respectively.The fermentation broth under alkaline conditions can form calcium hydroxyl phosphate, which can be used as a way of phosphorus recovery.The optimum conditions for acid production by anaerobic fermentation are as follows: the fermentation temperature is 37 鈩，

本文編號：1729347