High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations

Abstract

This research was carried out on a full-scale pure oxygen thermophilic plant, operated and monitored throughout a period of 11 years. The plant treats 60,000 t y⁻¹ (year 2013) of high-strength industrial wastewaters deriving mainly from pharmaceuticals and detergents production and landfill leachate. Three different plant configurations were consecutively adopted: (1) biological reactor + final clarifier and sludge recirculation (2002-2005); (2) biological reactor + ultrafiltration: membrane biological reactor (MBR) (2006); and (3) MBR + nanofiltration (since 2007). Progressive plant upgrading yielded a performance improvement chemical oxygen demand (COD) removal efficiency was enhanced by 17% and 12% after the first and second plant modification, respectively. Moreover, COD abatement efficiency exhibited a greater stability, notwithstanding high variability of the influent load. In addition, the following relevant outcomes appeared from the plant monitoring (present configuration): up to 96% removal of nitrate and nitrite, due to denitrification; low-specific biomass production (0.092 kgVSS kgCODremoved⁻¹), and biological treatability of residual COD under mesophilic conditions (BOD5/COD ratio = 0.25-0.50), thus showing the complementarity of the two biological processes.

Rheology and Microbiology of Sludge from a Thermophilic Aerobic Membrane Reactor

“…The facility is located in Northern Italy and treats 60,000 t/y of solid and liquid highstrength COD wastes (except mutagens and carcinogens); since fifteen years ago, this technology has been investigated in detail by [80]. Figure 1 depicts the scheme of the unit fed with liquid wastes: the main phase consists in the TAMR (see [80] for a complete description).…”

“…Figure 1 depicts the scheme of the unit fed with liquid wastes: the main phase consists in the TAMR (see [80] for a complete description).…”

“…Furthermore, other valuable advantages consist in faster chemical reaction rates, increased organics solubility, high process stability, that is, the prompt activity recovery after operational changes, capability of degrading high salinity and biorecalcitrant wastewater, and possibility of integrating the thermophilic stage, as a pretreatment into a combined scheme, thus improving the removal extent of organic substances [76,78,79]. Nevertheless, despite the aforementioned advantages, thermophilic processes are still rarely adopted at the real scale [80,81].…”

H2O2 Based Oxidation Processes for the Treatment of Real High Strength Aqueous Wastes

“…The concentrations of COD, N-NH 4 + , N-NO 2 − , N-NO 3 − , total nitrogen (TN), total phosphorus (TP), anionic surfactants (MBAS), and non-ionic surfactants (TAS) were measured according to standard methods for water and wastewater [30]. BOD 5 was determined at 20 • C by inoculation of activated sludge from a municipal wastewater treatment plant.…”

“…This poses a challenge for their treatment, there being three alternatives: (a) advanced biological processes, which may be able to treat high organic loads with a typical operational stability [1-3] and a very low sludge production [1,4]; (b) advanced chemical processes [5][6][7][8][9]; (c) or a combination of both [4,10,11]. In the past, chemical oxidation has been used for reducing the concentrations of residual organics, removing ammonia, controlling odors, and for disinfection purposes.…”