本文選題：化學沉淀　切入點：氣浮　出處：《遼寧科技大學》2015年碩士論文　論文類型：學位論文

【摘要】：鋼繩在現(xiàn)代工業(yè)中應用非常廣泛,但鋼繩在生產(chǎn)過程中會產(chǎn)生大量污水。鋼繩生產(chǎn)污水是鋼繩在生產(chǎn)過程中經(jīng)酸洗、磷化、沖洗、電鍍等過程形成的,其中含有氨氮、油類、鋅離子、鐵離子、鉛離子、磷酸鹽、硫酸鹽等多種污染物,污水成分復雜,污染物濃度高、毒性大,對環(huán)境污染嚴重。本文采用化學沉淀-混凝氣浮工藝對某鋼繩廠的生產(chǎn)污水進行了實驗研究及實際工程應用研究,并對氣浮過程進行了理論探討。本文首先采用化學沉淀法初步去除鋼繩生產(chǎn)污水中的磷酸鹽離子和重金屬離子,然后采用混凝氣浮法進一步去除污水中殘余的重金屬離子和其他污染物。選擇多種無機混凝劑進行混凝實驗,結(jié)果表明不同混凝劑單獨使用時對污水的處理效果不同,PAFC單獨使用時處理效果優(yōu)于其他無機混凝劑。通過比較PAFC單獨使用及與有機混凝劑聯(lián)合使用的處理效果可知,無機與有機混凝劑聯(lián)合使用的處理效果優(yōu)于單一混凝劑,適當?shù)呐浔扔欣谔岣咛幚硇屎徒档退幒�。實驗確定化學沉淀法去除鋼繩生產(chǎn)污水的主要污染物的最佳pH為9,磷與鈣的投加摩爾比為1.0:1.3,反應時間為30min,反應后沉淀靜置時間為30min,在最佳沉淀條件下在對污水中磷酸鹽的去除率為99.6%,Pb2+的去除率為95.3%,Zn2+的去除率為99.0%。利用樣機進行混凝氣浮實驗確定,最佳混凝氣浮條件為:PAFC用量為20mg/L、PAM用量為3mg/L、pH值為7.5、氣浮壓力為0.6Mpa,在最佳條件下混凝氣浮系統(tǒng)對污水中磷酸鹽、Pb2+、Zn2+、COD的去除率分別達到了85.2%、85.1%、83.3%、77.0%。將本研究的工藝流程和最佳運行參數(shù)應用于某鋼繩生產(chǎn)污水的實際處理工程上,連續(xù)運行的結(jié)果表明本工藝流程處理鋼繩生產(chǎn)污水效果良好。其設計流量為40m3/d,進水磷酸鹽濃度為228mg/L,Pb2+濃度為40mg/L,Zn2+濃度為285mg/L,COD為230mg/L,HRT為8h。經(jīng)過連續(xù)穩(wěn)定的運行,經(jīng)本工藝處理后出水中各污染物的平均濃度如下:磷酸鹽濃度為0.4mg/L,Pb2+濃度為0.6mg/L,Zn2+濃度為0.5mg/L,COD為25mg/L。其中磷酸鹽濃度、COD濃度均能達到《遼寧省污水綜合排放標準》(DB 21/1627-2008)中的直接排放要求;《遼寧省污水綜合排放標準》中未要求的Pb2+、Zn2+也能達到《污水綜合排放標準》(GB 8978-1996)中一級排放的要求,每噸污水的處理成本約為2.49元。理論探討認為,氣浮壓力與回流比對氣浮池的溶氣效率有較大影響。在回流比為30%,氣浮壓力為0.6MPa時,氣浮池內(nèi)空氣濃度為22.20L/m3,單位體積的污水中微氣泡數(shù)量為9.89×1014個/m3。在工程允許的情況下應盡量提高回流比,增加氣浮池的溶氣效率。在溫度為20℃時,最佳氣浮條件下氣泡的上升速度為0.68mm/s。
[Abstract]:Steel rope is widely used in modern industry, but it will produce a lot of sewage in the process of production. The sewage of steel rope production is formed by acid pickling, phosphating, washing, electroplating and so on, which contains ammonia nitrogen, oil, etc. Zinc ion, iron ion, lead ion, phosphate, sulfate and so on many kinds of pollutants, the sewage composition is complex, the pollutant concentration is high, the toxicity is big, The environmental pollution is serious. In this paper, the chemical precipitation-coagulation air flotation process is used to study the production sewage of a steel rope plant and its practical engineering application. In this paper, the chemical precipitation method is used to remove phosphate ions and heavy metal ions from steel rope wastewater. Then the residual heavy metal ions and other pollutants were removed by coagulation flotation method. A variety of inorganic coagulants were selected for coagulation experiments. The results show that the treatment effect of different coagulants on wastewater is different. The treatment effect of PAFC alone is better than that of other inorganic coagulants. By comparing the treatment effect of PAFC alone with organic coagulant, it can be seen that the effect of PAFC is better than that of other inorganic coagulants. The treatment effect of inorganic and organic coagulant is better than that of single coagulant. The optimum pH value, molar ratio of phosphorus to calcium is 1.0: 1.3, the reaction time is 30 min and the sedimentation time is 30 min. The optimum pH of chemical precipitation method for removing the main pollutants from steel rope production sewage is 9, the molar ratio of phosphorus to calcium is 1.0: 1.3, and the reaction time is 30 min. The precipitation time is 30 min, the removal rate of phosphate in wastewater is 99.6% under the optimum precipitation conditions, the removal rate of 95.3% Zn2 is 99.0%. The optimum coagulation air flotation conditions are as follows: the dosage of 20 mg / L PAFC is 20 mg / L PAM, pH value is 7.5 mg / L ~ (-1), and the air flotation pressure is 0.6 Mpa. under the optimum conditions, the removal rate of COD of phosphate Pb2 ~ (2 +) ~ (2 +) Zn ~ (2 +) ~ (2 +) in sewage by coagulation air flotation system reaches 85.21,83.33.37.00.The technological process of this study and the most important one are obtained. The best operation parameters are applied to the practical treatment project of the sewage produced by a steel rope. The results of continuous operation show that the process has a good effect on the treatment of steel rope wastewater, the design flow rate is 40 m3 / d, the influent phosphate concentration is 228 mg / L Pb2, 40 mg / L Pb2 concentration is 285 mg / L ~ (2) COD is 230 mg / L ~ (-1) H ~ (-1) HRT, and the HRT is 8 h. The average concentrations of pollutants in the effluent treated by this process are as follows: phosphate concentration 0.4 mg / L Pb2 0.6 mg / L Zn _ 2 0.5 mg / L ~ (2) COD 25 mg 路L ~ (-1). The phosphate concentration and COD concentration can reach the level of DB21 / 1627-2008. The discharge requirements of Pb2 Zn-2, which are not required in Liaoning Comprehensive sewage discharge Standard, can also meet the requirements of the first class discharge in the Integrated sewage discharge Standard (GB8978-1996). The treatment cost per ton of sewage is about 2.49 yuan. The theoretical discussion shows that the ratio of air flotation pressure to reflux ratio has a great effect on the gas dissolution efficiency of the air floatation tank. When the reflux ratio is 30 and the floating pressure is 0.6 MPA, The air concentration in the air floatation tank is 22.20L / m ~ (3), and the number of microbubbles in the wastewater per unit volume is 9.89 脳 1014 / m ~ (3). The reflux ratio should be increased as much as possible, and the gas dissolution efficiency of the air flotation tank should be increased when the temperature is 20 鈩，

本文編號：1604437