| Summary: | 碩士 === 國立交通大學 === 工學院產業安全與防災學程 === 102 === This study investigates the wastewater treatment of backside grinder (BG) and the assessment of wastewater recycling using ultrafiltration (UF) hollow fiber membrane filter pilot system to deal with BG wastewater from the case factory. While the water production rate process was promoted, the wastewater pollutant concentration in the BG of the pilot system was also raised. To understand the changes in water quality while the wastewater pollutant concentration was increased in the BG, the water quality of BG wastewater in the UF system and that after filtering through UF hollow fiber membrane were analyzed.
Analytical results indicated , the average total solid content of BG wastewater in the case factory was 1,000mg/L, which mainly contains silicon particles; 90% of these particles had a diameter less than 1µm a small amount of calcium, magnesium, iron, etc. were also found.
After using the GE UF hollow fiber membrane (40nm) to filter BG wastewater, the removal efficiency of suspended solids (SS) was above 99% and the average removal efficiency of solids such as silicon, calcium, magnesium, and iron was above 90%. Thus, UF hollow fiber membrane demonstrated a good performance at removing the silicon particles. However, when the total solid in pilot system increased to 15,000mg/L, the silicon amount of wastewater after filtering through UF exceeded 50mg/L. This is no good for the case factory to reuse. In the BG wastewater treatment process, without adding any chemicals, when the pilot system operates under the membrane flux of 27LMH backwash for 30 sec every 10 min with Air blow 15 L/min, stable permeate water production could reach 570L/day, and UF membrane can have a long term operation without clogging.
BG wastewater has great water quality after filtering through UF hollow fiber membrane, which is better than secondary living water and tap water. Therefore, the filtered water can be used as the supply for cooling water tower and as the secondary living water without any additional treatments. However, considering the water quality and risk of water production, it is recommended to use reverse osmosis membrane treatment to filter the water before importing into the pure water system to supply the production line.
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