Ozonation of persistent DOC in municipal WWTP effluent for groundwater recharge

Abstract

Groundwater recharge is becoming common in areas where the withdrawal of groundwater exceeds its natural recharge. Wastewater treatment plant (WWTP) effluent can be used for this purpose, but persistent organic compounds can only be partly removed during soil passage. This point was confirmed in degradation tests using soil columns in which the DOC of a membrane bioreactor (MBR) permeate could only be reduced by 15% and adsorbable organic iodine (AOI) by 2%. However, ozonation was found to improve biodegradation and at the maximum formation of biodegradable DOC at 2.5 mg O3/mg DOC0, the DOC values of MBR permeate (11-13 mg/L) could be reduced in aerobic degradation batch tests to the DOC of Berlin drinking water (3-5 mg/L). A combination of ozonation at 1.9 g O3/g DOC0 with soil passage could adjust DOC, UVA254, colour (436 nm) and the molecular DOC size distribution to drinking water ranges, but AOI was only reduced from 143 microg/L to 92 microg/L and remained high compared to tap water (2.2 microg/L). The extremely persistent X-ray contrast compound iopromide, which represents part of AOI, was spiked into MBR permeate at a low concentration. Iopromide was reduced by 88% during ozonation, but AOI only decreased by 23% indicating that a transformation, but not a mineralization, of iodinated organic compounds occurs.

A hybrid process of biofiltration of secondary effluent followed by ozonation and short soil aquifer treatment for water reuse

“…Results from this study confirmed that the combination of ozonation and SAT provides a good way to benefit from this effect. A significant reduction in DOC following a treatment combining ozonation and sand columns was also demonstrated by Schumacher et al (2004).…”

“…Ozonation followed by soil columns to simulate the SAT process (Schumacher et al, 2004;Tiwari et al, 2014), quick biological sand filtration (Hollender et al, 2009) or biological activated carbon (BAC) treatment (Gerrity et al, 2011;Reungoat et al, 2012) demonstrated improved biodegradation of DOC and elimination of ozonation byproducts and TrOCs.…”

Optimized removal of dissolved organic carbon and trace organic contaminants during combined ozonation and artificial groundwater recharge

“…Siddiqui et al, 1997;Trequer et al, 2010;Yavich et al, 2004). Experiments with permeate from a membrane bioreactor and sand columns to simulate artificial groundwater recharge showed an improvement of DOC reduction from 15% to 61% by applying 1.9 mg O 3 /mg DOC (Schumacher et al, 2004). Thus, a combination of oxidation technologies using ozone with the natural degradation capacity of a subsurface passage could help to ensure the drinking water production under changing climate and hydraulic conditions.…”

The formation and influence of hydrogen peroxide during ozonation of para-chlorophenol

“…Ozonation has a good effect on the oxidation of refractory contaminants, due to its higher oxidation potential and the formed secondary oxidant, hydroxyl radicals (OH • ) [4]. Most of the studies concerning the ozonation of CPs are focused on the degradation levels or the identification of some reaction by-products [5][6][7].…”