Purification of wastewaters from oil refining plant with membrane technology
Smolyaninov, Vladimir (2019)
Diplomityö
Smolyaninov, Vladimir
2019
School of Engineering Science, Kemiantekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2019123149499
https://urn.fi/URN:NBN:fi-fe2019123149499
Tiivistelmä
The aim of this master’s thesis was to improve wastewater treatment quality at the oil refinery by developing an effective membrane treatment procedure which would reduce biological and chemical oxygen demand (BOD and COD) and concentrations of pollutants in the wastewater to meet the effluent quality requirements.
In the literature part of the thesis, oily wastewater sources, amounts, and composition along with different treatment techniques focusing on membrane processes were discussed. Additionally, main sources of oily wastewater and existing wastewater treatment process at the refinery were reviewed.
The experimental part of the thesis focused on the evaluation of the treatment efficiency of different membrane processes. The wastewater contained high BOD, COD, and total organic carbon (TOC). Ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes were used for wastewater treatment. The effect of operating conditions on membrane retention and flux was studied using the Taguchi method. Two combinations of multistage membrane processes were tested and compared to achieve the required wastewater treatment quality. The effect of recovery rate on membrane retention was studied to estimate how much the feed solution could be concentrated to reduce the amount of produced concentrates. Different pretreatment methods were tested to enhance membrane process performance.
Both tested multistage membrane processes demonstrated high treatment performance, reduced COD of the wastewater by 83% and 87% and achieved 73% and 74% water recovery, respectively. COD of the effluent was reduced below the target value. There was a potential to increase water recovery. The main limiting factor was fouling and concentration polarization in UF. Combination of powdered activated carbon (PAC) and UF treatment mitigated the effect of fouling.
In the literature part of the thesis, oily wastewater sources, amounts, and composition along with different treatment techniques focusing on membrane processes were discussed. Additionally, main sources of oily wastewater and existing wastewater treatment process at the refinery were reviewed.
The experimental part of the thesis focused on the evaluation of the treatment efficiency of different membrane processes. The wastewater contained high BOD, COD, and total organic carbon (TOC). Ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes were used for wastewater treatment. The effect of operating conditions on membrane retention and flux was studied using the Taguchi method. Two combinations of multistage membrane processes were tested and compared to achieve the required wastewater treatment quality. The effect of recovery rate on membrane retention was studied to estimate how much the feed solution could be concentrated to reduce the amount of produced concentrates. Different pretreatment methods were tested to enhance membrane process performance.
Both tested multistage membrane processes demonstrated high treatment performance, reduced COD of the wastewater by 83% and 87% and achieved 73% and 74% water recovery, respectively. COD of the effluent was reduced below the target value. There was a potential to increase water recovery. The main limiting factor was fouling and concentration polarization in UF. Combination of powdered activated carbon (PAC) and UF treatment mitigated the effect of fouling.