Abstract:
The objective of this research is to study the use of spent alkaline from black oxide coating industry for lead precipitation process of wastewater from storage battery recycling industry compare with 2 type of precipitant, NaOH and Na[subscript 2]CO[subscript 3]. The source and generation rate of wastewater from storage battery recycling industry that shown the storage battery recycling industry have wastewater 40 cu.m./day. The ratio of wastewater and product in process is 1.9 litre/ 1 kg. ingot of lead. The spent alkaline from black oxide coating is 42 litre/day, ratio of spent alkaline and black coating iron product is 0.06 litre/ 1 kg. of product. The lead removal from chemical precipitation process that use NaOH to precipitate substance is appropriate pH at 8.5 - 10.5, and using anionic polymer to increase precipitation capacity shown it best concentration is 2 mg/l, it can remove lead solution and total lead 100 and 99.57%, respectively., and there are 24% of lead in dry solid sludge. The budget for treatment is 197 baht/1 cu.m. of wastewater. To use spent alkaline, that shown the appropriate pH at 8.5- 10.5, and use anionic polymer to increase precipitation capacity shown it best concentration is 1.8 mg/l, it can remove lead solution and total lead 100 and 99.22%, respectively., and there are 21% of lead in dry solid sludge. The budget for treatment is about 0.28 9.05 baht/1 cu.m. of wastewater. To use Na[subscript 2]CO[subscript 3], that shown the appropriate pH at 8.5- 10.0, and using anionic polymer concentration is 0.6 mg/l it not increase the precipitation efficiency but it can reduce the turbidity, it can remove lead solution and total lead 88.81 and 98.77%, respectively., and there are 14% of lead in dry solid sludge. The budget for treatment is about 168.75 168.85 baht/1 cu.m. of wastewater. From the experimental, spent alkaline from black oxide coating industry is possible to use to precipitate dissolve lead and total lead and reduce turbidity. So, it possible to use spent alkaline for removal the lead contaminated in wastewater from storage battery recycling industry. In the case of waste exchange between two industry. It can reduce the cost for spent alkaline disposal to 0 - 929 baht/cu.m.(from 4,679 baht/cu.m.) and reduce the cost of wastewater precipitation process from stotage battery recycling industry to 0.28 9.05 baht /cu.m. (from 197 baht/cu.m.).