Ozonation Of Secondary Effluent Research Articles

The Role of Soil Aquifer Treatment (SAT) for Effective Removal of Organic Matter, Trace Organic Compounds and Microorganisms from Secondary Effluents Pre-Treated by Ozone

ABSTRACTSoil aquifer treatment (SAT) is an effective natural and economically feasible tertiary treatment for wastewater reuse. An innovative hybrid process based on biofiltration, ozonation and short SAT (sSAT, with ~22 days retention time) was demonstrated in a 6 m3/hr pilot system to remove emerging trace organic compounds (TrOCs), organic matter and control Mn2+ dissolution in reclaimed water. The biofiltration stage was proposed for nitrification of ammonia as well as removal of dissolved and particulate organic matter (DOM and POM), to enable efficient ozonation of secondary effluents. The pilot system was operated in two modes, where samples were periodically taken from all pilot stages to observe changes in product water quality. At first (Mode 1), biofiltered effluents were infiltrated through sSAT (i.e., no ozonation prior infiltration). During this operation, ammonia, nitrite and phosphate were completely removed, and pathogens were highly reduced. In addition, all measured TrOCs were effectively removed after sSAT, besides the persistent TrOCs Carbamazepine (CBZ) and Iodine-organic contrast media Iopamidol (IPDL). In Mode 2, biofiltered and ozonated (1.0–1.2 mg ozone/mg DOC) effluents were infiltrated through sSAT. In the final reclaimed product, values of DOC, UVA and Mn2+ were reduced to 0.8 mg/L, 2.2 L/m, and 29–35 µg/L, respectively. Furthermore, ammonia and nitrite were not detected in the product, and good bacterial quality was obtained. Following 56–75 days of operation at Mode 2, all TrOCs were reduced down to <100 ng/L. The delay in the effect of the pretreatment stages on TrOCs removal by sSAT (>56 days instead of ~22 days) could be explained by their displacement retardation in the upper soil layers of the pilot SAT (0–25 cm). In-depth sampling in the observation well after 111 days at Mode 2 showed homogeneity along the overall perforated section of the well (from −14 to −26 m) with 0.7–0.9 mg/L DOC, 2.1–2.2 1/m UVA and <10 ng/L CBZ. This result proved that the ozonated water completely covered the area around the observation well and positively affected the quality of the reclaimed water.

No silver bullet for wastewater treatment.

Antibiotic Resistance The spread of antibiotic resistance is a major public health concern. Czekalski et al. investigate whether ozonation of wastewater can help to combat this spread by eliminating resistant bacteria. In laboratory experiments, ozone doses that can be used in full-scale applications disrupted intracellular resistance genes. However, ozonation of secondary effluent at a wastewater treatment plant did not affect the abundance of intracellular resistance genes, and multiresistant bacteria partly regrew after ozonation. The results have important implications for wastewater treatment plants that are planning to implement ozonation. Environ. Sci. Technol. 10.1021/acs.est.6b02640 (2016).

Fate of bulk organic carbon and bromate during indirect water reuse involving ozone and subsequent aquifer recharge

Long-term column studies with ozonated secondary effluent were conducted to evaluate the removal of dissolved organic carbon (DOC) and to assess formation and stability of the oxidation by-product bromate in combined ozonation and managed aquifer recharge (MAR) systems. DOC removal during simulated MAR was continuously increased from approximately 20 to 40% by pretreatment with ozone indicating the high potential of this combination to remove disinfection by-product (DBP) precursors. This improvement in DOC removal was likely caused by transforming DOC into fractions that are more amenable to biodegradation, as well as the supply of dissolved oxygen favouring aerobic degradation processes. Bromate formation during ozonation of secondary effluent from the Berlin-Ruhleben WWTP exceeded the limit of the EU Drinking Water Directive at a specific ozone consumption of &amp;gt;0.9–1.0 mg O3/mg DOC0. During oxic infiltration, no significant removal of bromate could be observed. Under anoxic conditions, bromate concentration was efficiently reduced. Additional biodegradation tests in small-scale columns indicated a simultaneous consumption of nitrate and bromate as electron acceptors.

Fish larval deformity caused by aldehydes and unknown byproducts in ozonated effluents from municipal wastewater treatment systems

Ozonated secondary effluents (SEs) from municipal wastewater treatment plants (MWTPs) have been found to cause developmental retardation of fish embryos. This study explored the potential cause of the embryo toxicity formed in ozonated SEs by exposing Japanese medaka (Oryzias latipes) (d-rR) embryos to ozonated SE from a MWTP in Tianjin, China. The increase of ozone dose from 0.26 to 0.96 mg O3/mg DOC0 (consumed ozone per initial DOC), which produced total aldehyde (mixture of formaldehyde, acetaldehyde, propionaldehyde, and glyoxal) from 41.5 to 114.7 μg/L, resulted in an increase in the percentage of deformed larvae from 2.2% to 24.1%. Increases in larval deformity and embryo mortality were also observed in ozonated SEs from other MWTPs. The exposure experiment using the mixture aldehyde solution showed that the production of aldehydes could explain approximately 13.6% of larval deformity caused by ozonation of SEs. Pilot experimental results in Tianjin and Beijing, China showed that biofiltration as a post-treatment technology was effective in removing the aldehydes as well as reducing embryo toxicity caused by ozonation.

Options and limitations of hydrogen peroxide addition to enhance radical formation during ozonation of secondary effluents

The oxidation of secondary effluent with ozone and O3/H2O2 (peroxone) was evaluated in batch experiments as pre-treatment for soil aquifer treatment for non-potable reuse purposes. The addition of hydrogen peroxide improved the reduction of ozone-resistant compounds with an optimized radical formation at 0.5 mol H2O2/mol O3. However, the improvement of radical formation was shown to be limited to approximately 30–40% independent from ozone dosage. Also a preozonation step did not accelerate efficiency of subsequent peroxone treatment. Thus, other treatment options, such as an increase of ozone dosages, need to be considered for more efficient removal of ozone-resistant compounds. However, the peroxone process might still be a promising option for oxidation of bromide containing effluents, since a reduction of bromate formation can allow the application of higher ozone dosages.

Effect of ozone on secondary effluent treatment for reuse in agriculture

The results of secondary effluents ozonation from domestic sewages treatment plants in Havana, Cuba are presented. The ozone effect on some physico-chemical parameters was determined. The ozone gas concentration is the parameter, which exerts the greatest influence on the ozone transferred. The results indicated that ozonation of secondary effluents is a safe disinfection alternative for wastewaters reuse in agriculture or safe disposal, whose effectiveness depends on an adequate application. Therefore, effluents ozonisation can contribute to the environment protection and sustainable development. A preliminary economic comparison is performed between ozonation and chlorination treatments. An ozonation reactor design is proposed.

The removal of estrogenic activity and control of brominated by-products during ozonation of secondary effluents

The purposes of this study were to investigate the behavior of brominated by-products, such as bromate ion and total organic bromide, formed during ozonation for the removal of estrogenic activity in sewage effluents and to propose operation parameters for the ozonation process. It is necessary to reduce the E 2 equivalent concentration of estrogenic activity in secondary effluent treated by 90% of the initial one. To do so, ozonation until dissolved ozone concentration increased to 0.1 mg/L (which corresponds to approximately 1 mg O 3/mg DOC 0 [consumed ozone per initial DOC] of consumed ozone for the effluent in this study) is proposed as an operation parameter for ozonation without the formation of brominated by-products.

Ozonation parameter for removal of oestrogenicity from secondary effluent without by-products

The purposes of this study are to investigate ozonation characteristics, to evaluate oestrogenicity and to confirm behaviours of by-products during ozonation of secondary effluent. For the ozonation of secondary effluent, TOC was decreased only 10% when 4 (mgO3/mgC) of ozone consumption per initial TOC. However, UV254 and SUVA was decreased approximately 65% until ozone consumption of 2 (mgO3/mgC). Ozonation was also shown to be very effective for decrease of oestrogenicity in secondary effluent. Bromate ion started to form obviously when the ozone consumption per initial TOC exceeded 2 (mgO3/mgC) and increased while the time of ozonation became longer. From these results, ozone consumption per initial TOC was shown to be an appropriate operation parameter to reduce SUVA effectively and E2 equivalent concentration to less than 0.1 nM without significant formation of bromate ion, and its value was determined to be 2 (mgO3/mgC) in ozonation of secondary effluent.

Identification Of Products Resulting From Ozonation Of Organtic Compounds In Water

Abstract Determination of ozonation by–products using five organic compounds and secondary effluents was carried out. Formaldehyde, acetaldehyde, propionaldehyde, furfural, methlyglyoxal, glyoxylic acid, and pyruvic acid were detected by gas chromatography of their 2,4–dinitrophenyl–hydrazones. Acetic acid, formic acid, and propionic acid were also detected. One–sixth to one–fifth of the total COD was accounted for by the TOD summations of formaldehyde, methylglyoxal, pyruvic acid and acetic acid produced by the ozonation of secondary effluents.

二次処理水のオゾン処理による反応生成物の同定と定量

Some batch ozonation experiments on the secondary effluents. The identification of intermediates and end products resulting from the ozonation was studied, setting the reaction time and the ozone concentrations applied as reaction parameters. The feed gas to the reactor had ozone concentration of 9.6-59.5 mg/l. Trace amounts of formaldehyde, acetaldehyde, proponic aldehyde, methyglyoxal, glyoxylic acid and pyruvic acid were detected by gas chromatography and colorimetry for 2, 4-dinitrophenylhydrazones. Formaldehyde was a common product resulting from the ozonation of many organic compounds in the early reaction time. But, this was finally oxidized to carbon dioxide by the prolonged reaction time at a faster rate. Methylglyoxal and pyruvic acid were also oxidized to pyruvic acid and acetic acid, respectively. But, the decomposition rate of pyruvic acid is not so fast as formaldehyde's. Acetic acid, formic acid and propionic acid were also detected by gas chromatography for their benzyl esters. The latter two were present in trace amounts. The quantity of acetic acid increased with the reaction time increment. During the course of the reaction, 1/6-1/5 of total COD can be accounted for by the summations of each TOD on formaldehyde, methylglyoxal, pyruvic acid and acetic acid produced by the ozonation of secondary effluents.