Operating strategies for acid phase digestion: an industrial case study

Abstract

Acid phase digestion was investigated for enhanced operation in an industrial wastewater treatment plant. In particular, sludge retention time (SRT), temperature and pH were assessed for determining optimal conditions under operating constraints. Volatile fatty acid (VFA) production and soluble chemical oxygen demand (SCOD) were the key process parameters used to assess system performance. Increase in SRT from 0.8 to 1.4 days (at 22°C) had moderate effect on VFA production (approximately 15% increase), achieving a maximum VFA production of 3600 mg/L. High VFA production rate (0.101 ± 0.035 mg/mgVS.d) was obtained at the highest operating retention time during summer (27°C). The degree of solubilisation of particulate organic matter increased with temperature and retention time. Despite an increase in SCOD (6472 ± 873 mg/L max.), a corresponding increase in VFA was not observed. SCOD showed a linear correlation with decrease in pH, while acidogenesis (SCOD conversion to VFA) was found to be favourable at a pH of 4.5.

Engineering photo cross-linked porous network for efficient and selective removal of toxicants from wastewater

“…Purification was carried out by column chromatography in ethyl acetate/hexane. The product formation was confirmed by 1H NMR, 13 CNMR and by Mass spectrometry (Suppplimentary Figures 5-10). For the preparation of the gel, Cross-linker, photoinitiator and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) were dissolved in dry DCM and kept under UV light.…”

“…The newly formed C-S bond in the gel was confirmed by Raman spectra (Suppplimentary Figure 8). To recognise the connectivity in the gel, cross-polarisation (CP), 13 C MAS spectrum was also recorded (Suppplimentary Figure 9), where the decrease of olefin signal at 136.8ppm confirmed successful thiol-ene click reaction.…”

“…[5][6][7] Contamination of water by toxic dyes is a major threat to both aquatic lives and mankind as it is associated with several risk factors.8,9 Thus, it is absolutely necessary to remove the toxicants from contaminated water for sustainability of life on earth. [10][11][12][13][14][15] The limitations of several physical, chemical and biological approaches that are traditionally followed to remove dyes from wastewater arise from their exorbitant price, harsh route of synthesis and lack of flexibility. 16,17 Additionally, the adsorbent that finds application in wastewater treatment must be non-toxic, preferentially biocompatible, in order to eliminate any secondary pollution.…”

“…Furan 8.32g (122.4 mmol) was added to the filtrate and left for stirring for 48hours. A white coloured precipitate was formed which was then filtered and washed using cold toluene to obtain the product (yield 82%).1H NMR (400MHz, DMSO-d 6 ) δ 3.2 (s, 2H), 5.42 (s, 2H), 6.54 (s, 2H);13 C NMR (100 MHz, DMSO-d 6 ) δ 49.2, 81.52, 137.40, 171.48.…”