Removal of lead from wastewater using an anaerobic sulfate reduction process | |
| Author | Paphungkorn Teekayuttasakul |
| Call Number | AIT Diss. no.EV-08-12 |
| Subject(s) | Sewage--Purification--Heavy metals removal--Thailand Lead--Toxicology--Thailand |
| Note | A dissertation submitted in partial fulfillme of the requirements for the degree of Doctor of Philosophy in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. EV-08-12 |
| Abstract | Presently, there are 4-5 factories producing car battery in Thailand. The factories use large quantities of lead and sulfuric acid in its manufacturing process, which in turn produce large quantities of highly polluted wastewater which contains sulfate and lead as major pollutants. This investigation was focused on one of the factories presently operating in Thailand. The wastewater discharged from a selected factory has a flow rate of approximately 200 m3/d. From chemical analysis, the results revealed that sulfate and lead were found in the range of 15,000- 20,000 mg/L and 20-50 mg/L, respectively. Moreover, pH was in the range of 1.0-2.0. At present, lead is removed as lead hydroxide (Pb(OH)2) by conventional precipitation process using lime (Ca(OH)2), whereas sulfate is partially precipitated as lead sulfate (PbS04). It is obvious that the current treatment process generates bulky sludge requiring dewatering and is unstable due to pH change. This research aimed to investigate the feasibility of mesophilic (35. C) sulfate reduction process for lead and sulfate removal from wastewater discharged from a battery producing factory. The study aimed to maximize sulfide production from the sulfate reduction process using hydrogen as an electron donor as well as to optimize both sulfate and lead removal. Furthermore, the toxicity of wastewater in terms of whole effluent toxicity (WET) before and after treatment were analyzed by using Microtox analyzer. The experiments were divided into three stages as follows: Stage I, startup and operation of sulfidogenic process fed with synthetic wastewater in a gas-lift reactor, whereas stage II, operation of sulfidogenic process fed with real wastewater in the same reactor. In stage I, the volumetric sulfate loading rate was gradually increased from 3.0 until no improvement of sulfide production efficiency at 7.73 kg S04/m3.d and maximum sulfide concentration was 340 mg/L. In stage II, the results showed that the lab scale reactor could treat real wastewater without inhibition or any remarkable problem. The produced sulfide, 250 mg/L, was a little less in comparison with feeding with synthetic wastewater. It could be due to the higher concentration of total dissolved solid (TDS). However, the sulfate concentration was still reduced by approximately 30 %. The WET test by Microtox showed that toxicity was reduced more than 13 times. In precipitation process, the effluent from the reactor containing sulfide in the range of 250 mg/L and lead-containing solution of 20 mg/L were fed with sulfide to lead ratio 3 moles: 1 mole into the precipitation chamber in which the optimum pH for lead sulfide precipitation of 8.0 was maintained. It was found that lead removal of 99 % was attained |
| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. EV-08-12 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Ajit Annachhatre |
| Examination Committee(s) | Preeda Parkpian ;Norwarat Coowanitwong |
| Scholarship Donor(s) | Royal Thai Government Fellowship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2008 |