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EP-4741351-A2 - REMOVAL OF MICROPOLLUTANTS FROM WATER AND INSTALLATION FOR USE THEREIN

EP4741351A2EP 4741351 A2EP4741351 A2EP 4741351A2EP-4741351-A2

Abstract

The invention pertains to a process for the removal of micropollutants and/or other pollutants from water, comprising subjecting the water to a consecutive combination of biological adsorbent filtration (BAF) followed by oxidation treatment (OT), preferably ozone treatment. In a preferred embodiment, an adjustable amount of the OT effluent, preferably an adjustable amount ranging between 10 - 100%, more preferably 20 - 90%, more preferably 20 - 80%, most preferably 20 - 50% of the OT effluent, is recirculated to the BAF. The process may involve monitoring the formation of oxidation products at the end of the OT, and/or for measuring TOC, DOC, SUVA, ammonium and/or specifically targeted pollutants in or at the end of the BAF, and controlling the amount of BAF-OT treated water which is recirculated to the consecutive steps of BAF and OT based on the output of the monitoring step.

Inventors

  • DE WILT, Henrik Arnoud
  • VAN GIJN, Koen
  • LANGENHOFF, ALETTE ANNA MARIA
  • RIJNAARTS, HUBERTUS HENRICUS MARTINUS

Assignees

  • HaskoningDHV Nederland B.V.
  • Wageningen Universiteit

Dates

Publication Date
20260513
Application Date
20221031

Claims (15)

  1. A process for the removal of organic micropollutants from water, comprising subjecting the water to a combination of biological adsorbent filtration (BAF) treatment only then followed by oxidation treatment (OT), preferably ozone treatment, wherein in the BAF treatment micropollutants, organic matter and ammonia are partially removed by the combination of adsorptive and biological processes, and in the OT micropollutants are further removed by oxidation.
  2. A process for the removal of organic micropollutants from water, comprising subjecting the water to a combination of biological adsorbent filtration (BAF) treatment and oxidation treatment (OT), performing the BAF treatment using an adsorbent before the OT treatment, preferably ozone treatment, wherein an adjustable amount of the OT effluent, preferably an adjustable amount preferably ranging between 10 - 100%, more preferably 20 - 90%, more preferably 20 - 80%, most preferably 20 - 50% of the OT effluent, is recirculated to the BAF.
  3. The process according to claim 1 or 2, comprising monitoring the formation of oxidation products at the end of the OT and/or monitoring total organic carbon (TOC), dissolved organic carbon (DOC), specific UV absorbance (SUVA), bromide, ammonium, and/or other quality parameters and/or specifically targeted micropollutants in or at the end of the BAF, and controlling the amount of BAF-OT treated water which is recirculated to BAF and OT based on the output of the monitoring step.
  4. The process according to any of the preceding claims, wherein the oxidant in the OT is Cl 2 , CIO, ClO 2 , ClO 3 , H 2 O 2 , Fenton, ferrate, ozone, or combinations thereof, OT more preferably involves or is ozone treatment, and wherein the oxygen-rich off-gas of the OT is preferably provided to the BAF.
  5. The process according to any one of the preceding claims, wherein the BAF comprises a granular activated carbon (GAC), any type of other absorbent, any other type of adsorptive material such as charcoal, woodchips or activated biomass, or any type of carrier material for microorganisms, or combinations thereof, provided the carrier material can both adsorb micropollutants and provide a surface for microorganisms to grow, preferably in an amount of 10 to 100 %, preferably between 50 and 100%, such as 80-100% of the total reactor volume of the BAF allowing the feed water to flow through the adsorbent in the BAF.
  6. The process according to any of the preceding claims, wherein the oxygen concentration in the feed of the BAF is in the range of 3 - 25 g/m3, and is preferably in the range of 5 - 22 g/m3, such as is in the range of 7 - 20 g/m3, and wherein the oxygen is provided by any suitable means to the feed of the BAF and/or in the BAF.
  7. The process according to any of the preceding claims, wherein the hydraulic retention time of the water flow in the BAF is between 5 and 180 minutes, preferably between 10 and 120 minutes, such as between 30 and 60 minutes; and/or wherein the hydraulic retention time and superficial flow velocity in the BAF are adjustable by means of changing the inlet water flow of the BAF by a buffer prior to the BAF.
  8. The process according to any of the preceding claims, wherein the superficial flow velocity of the water in the BAF, measured at the inlet of BAF, is between 0.1 and 40 m/h, preferably between 0.5 and 20 m/h, such as between 1 and 10 m/h.
  9. The process according to any of the preceding claims, wherein OT involves or is ozone treatment, wherein the applied specific ozone dose is between 0.05 and 2.0 g O3/g DOC, preferably between 0.1 and 1.5 g O3/g DOC, such as between 0.2 and 1.0 g O3/g DOC, and/or between 0.05 and 2 g O3/g TOC, preferably between 0.1 and 1.5 g O3/g TOC, such as between 0.2 and 1 g O3/g TOC.
  10. The process according to any of the preceding claims wherein the biological adsorbent filtration (BAF) treatment and oxidation treatment (OT) are preceded by a water or wastewater purification process comprising processes like a treatment with activated sludge, aerobic granular sludge, moving bed bioreactor (MBBR), IFAS (integrated fixed film activate sludge) and/or chemical/physical treatment like clarification, flocculation, filtration, precipitation.
  11. The process according to any of the preceding claims wherein the biological adsorbent filtration (BAF) treatment and oxidation treatment (OT) are used to treat brines and/or concentrate streams as are being produced in the purification of water and wastewater, such as streams which are a waste product of treatment processes like membrane filtration, sand filtration, disk filtration, ion exchange, and adsorption.
  12. An installation suitable for the process according to any one of the preceding claims, comprising one or more BAF reactors (5) in parallel and/or in series, and one or more OT reactors (11) in parallel and/or in series, and wherein the last BAF reactor or last set of parallel BAF reactors has a fluid connection with the first OT reactor or first set of parallel OT reactors, wherein the BAF reactor(s) is(are) provided with a water inlet and an inlet for oxygen, the BAF reactor(s) comprising an adsorbent or mixture of adsorbents, and a water (overflow) outlet to the OT or to the next BAF reactor in series, and optionally connections for a washing unit 15a, and wherein the OT reactor(s) is(are) provided with a water inlet from the BAF reactor(s) outlet, a water (overflow) outlet, and an inlet for the oxidant and an outlet for the off-gas.
  13. The installation according to claim 12, wherein the OT reactor(s) is(are) provided with an outlet which is in fluid connection with the BAF(s) reactor(s) and equipped controlling means for adjusting the amount of the OT effluent 14 that is recirculated to the BAF reactor(s), and wherein the installation is preferably equipped with one or more sensoring devices, such as sensors for flow, oxygen, TOC, DOC, SUVA, pressure and/or ammonium, bromide and/or specifically targeted pollutants at the water inlet and/or outlet of the BAF and/or can be equipped with level transmitters in the BAF.
  14. The installation according to claim 12 or 13, wherein OT involves ozone treatment, and wherein the OT reactor(s) is(are) provided with an inlet for a gaseous ozone mixture, and wherein the outlet of the off-gas is in fluid connection to the inlet of oxygen into the BAF reactor(s).
  15. The installation according to any one of claims 12 - 14, wherein the inlet of the one or more BAF reactors is connected to a wastewater treatment plant.

Description

FIELD OF THE INVENTION The invention is in the field of the removal of micropollutants from water, such as the treatment of waste water treatment plant effluent for micropollutant removal or production of water for consumption or industrial use. The invention also relates to an installation for use therein. BACKGROUND OF THE INVENTION Water, such as waste water treatment plant effluent, surface water, industrial waste streams, and the like, commonly contain organic substances from anthropogenic origin (micropollutants), such as pharmaceuticals, pharmaceutically active compounds, pesticides, herbicides, corrosion inhibitors and other organic compounds. These micropollutants jeopardize the aquatic environment, drinking water sources and public health. Several technologies have been developed for the removal of micropollutants as post-treatment to conventional treatment processes in water purification, such as activated sludge processes. Typically, these technologies comprise the use of an oxidant such as ozone as described in US6824695B2, an adsorbent such as activated carbon as described in EP2147711B1, or biological treatment. Although a selection of micropollutants can be removed by those technologies, these technologies also have major disadvantages as reported by de Wilt et al. Water Research 138 (2018) 97-105: Drawbacks of the use of oxidants such as ozone for micropollutant removal are multiple; there is the issue that ozone gets scavenged also by organic compounds other than the target compounds, which thus requires higher ozone dosages and associated high-energy consumption, commonly between 0.05 to 0.2 kWh/m3, and thereby leaving a high CO2-footprint. Furthermore, bromate is formed, which is an undesired, potentially carcinogenic compound, and even at levels above surface quality standards or drinking-water quality standards. Also, there is only a limited selection of micropollutants that is abated by ozone treatment. Drawbacks of the use of an adsorbent such as activated carbon for micropollutant removal are also multiple; firstly, there is the high consumption of activated carbon, resulting in high costs and COz-footprint, and secondly, there is again a limited selection of micropollutants that is abated by activated carbon treatment. Drawbacks of the use of biological treatment for micropollutant removal are also multiple; these typically come with low micropollutant removal efficiencies, and high biomass retention times are required to acquire a microbial population capable of micropollutant biodegradation. Furthermore, high hydraulic retention times, meaning costly reactors with large volumes and surface footprints, are required to provide sufficient time for the microorganisms to take up the micropollutants from the water. Attempts to overcome the drawbacks of the use of oxidants such as ozone, adsorbents such as activated carbon, or biological treatment for micropollutant removal mainly focus on the combination of technologies. The following combinations are reported as post-treatment to conventional treatment processes in water purification; ozone followed by activated carbon,ozone followed by biological treatment,activated carbon and biological treatment in a single step such as described in EP0812806B1,and biological treatment followed by ozone (Knopp et al. Water Research 100 (2016) 580-592, STOWA 2009-34 and de Wilt et al. Water Research 138 (2018) 97-105). While such arrangements indeed can result in higher removal efficiencies, the costs, energy consumption and CO2-footprint are usually also higher. In addition, the amount of ozone and reaction time required in these multistep techniques available in the art lead to the formation of bromates in hazardous concentrations. In the art there is thus a need to improve the removal of micropollutants from water. SUMMARY OF THE INVENTION It was surprisingly found that a broad spectrum of (organic) micropollutants can be removed by the combination of adsorption and biological treatment and subsequent oxidation by carrying out the combination as a biological adsorbent filtration (BAF) only then followed by oxidation treatment (OT), preferably ozone treatment. The present invention therefore relates to a surprising combination of biological, adsorptive and oxidation technologies for the removal of micropollutants from water, which overcomes one or more of the above disadvantages at equal or lower costs, energy consumption and CO2-footprint. In the BAF - OT order a lower oxidant dose in OT can be accomplished due to the removal of micropollutants and organic matter in the BAF. The efficiency of removal of micropollutants is synergistically increased by performing the BAF treatment using an adsorbent before the OT treatment. In the present order, the BAF is the first step in which micropollutant as well as organic matter are removed. LIST OF PREFERRED EMBODIMENTS 1. A process for the removal of organic micropollutants from water, comprising subjecti