https://commons.ru.ac.za/vital/access/manager/Index en-us 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:4195 Wed 12 May 2021 23:59:16 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4389 Wed 12 May 2021 23:17:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4394 Wed 12 May 2021 23:07:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4071 Wed 12 May 2021 22:26:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4526 Wed 12 May 2021 22:26:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2210 Wed 12 May 2021 22:20:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3746 Wed 12 May 2021 19:48:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3992 Wed 12 May 2021 19:32:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3443 Wed 12 May 2021 19:09:43 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2199 Wed 12 May 2021 19:04:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5802 Wed 12 May 2021 18:57:17 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1583 Wed 12 May 2021 18:22:44 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4076 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.]]> Wed 12 May 2021 18:01:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:2780 Wed 12 May 2021 17:54:35 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4588 Wed 12 May 2021 17:37:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1196 Wed 12 May 2021 17:28:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3932 Wed 12 May 2021 17:27:51 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1320 Wed 12 May 2021 17:15:03 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5771 Wed 12 May 2021 17:13:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3796 Wed 12 May 2021 16:50:45 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5487 Wed 12 May 2021 16:48:40 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4354 Wed 12 May 2021 16:47:09 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3924 Wed 12 May 2021 16:20:08 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1953 Thu 13 May 2021 12:10:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5833 Thu 13 May 2021 07:22:04 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5668 Thu 13 May 2021 07:07:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4225 Thu 13 May 2021 06:35:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4448 Thu 13 May 2021 06:32:05 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4386 Thu 13 May 2021 06:22:18 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3944 Thu 13 May 2021 06:01:30 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5489 Thu 13 May 2021 05:54:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3958 Thu 13 May 2021 05:51:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1446 Thu 13 May 2021 05:38:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5750 Thu 13 May 2021 05:15:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1145 Thu 13 May 2021 05:09:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4408 Thu 13 May 2021 05:07:50 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4414 Thu 13 May 2021 04:19:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:1174 Thu 13 May 2021 04:05:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3996 Thu 13 May 2021 03:32:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5683 Thu 13 May 2021 03:30:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5678 Thu 13 May 2021 02:40:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3930 Thu 13 May 2021 01:44:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4765 Thu 13 May 2021 00:31:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:972 Thu 06 Jul 2023 16:10:51 SAST ]]>