High Rate Anaerobic Digestion of Wool Scouring Wastewater in a Digester Combined with Membrane Filter

Abstract

The performance and sludge diminution property in wool scouring wastewater treatment of an anaerobic process in combination with an ultrafiltration membrane (UFM) was evaluated. With regard to TOD removal, both mesophilic (37°C) and thermophilic (53°C) digestion, without UFM, showed the same trend of decreasing sharply from about 90 % to 30 % in proportion to the increasing TOD loading rate from 3 to 45 kg/m3· d. When a digester was provided at the effluent line of a reactor with UFM separator, about two times higher concentration of biomass was retained and the quality of the effluent improved remarkably due to better filtration. TOD and grease removal improved remarkably from 45 to 90 % and 37 to 99 % respectively, at a TOD loading rate of 15 kg/m3 · d in both fermentative temperatures. Further, the effective recirculation system of rejected liquid from UFM was studied to diminish the quantity of sludge generated. The study revealed that 33 % of the incoming SS was biodegraded under the recirculation system for rejected liquid from UFM to reactor, while 17 % was achieved in one pass through the system at the same TOD loading rate. Deterioration in the flux rate of UFM was observed for the first 40 days of operation from 37 to 23 l/m2 · h which then gradually decreased to 17 l/m2 · h after 210 days of service.

A pilot study of anaerobic membrane digesters for concurrent thickening and digestion of waste activated sludge (WAS)

“…In general the flux obtained during this experiment was within the range of typical design fluxes in AnMBR that have been previously reported (Hogetsu et al 1992) To further characterize the major foulants, the neutral and negatively charged membranes were cleaned sequentially using mechanical means (hot water and sponge balls), and chemically with NaOH and citric acid solutions. For the neutral membrane, the clean water flux of the fouled membrane was initially 25% of the virgin membrane and after the sequential cleaning process it recovered to 93% of the virgin value.…”

Wastewater treatment with combined upflow anaerobic fixed-bed and suspended aerobic reactor equipped with a membrane unit

“…These COD removal rates were 98.39, 98.35, 97.88 and 94.00% for 5.58, 7.20, 9.00 and 16.56 kg COD m −3 per day organic removal rates, respectively. High removal rates at high OLR values achieved with membrane bioreactors were also reported by many researchers [21][22][23].…”

Anaerobic fluidized membrane bioreactor polishing of baffled reactor effluent during treatment of dilute wastewater

“…The fouling extent varies with wastewater characteristics and reactor operating conditions. At higher temperatures fouling is reduced as a result of the higher hydrolysis rate of particulate organics and by the reduced permeate viscosity . Accumulation of biological agents such as soluble microbial products (SMP), either through the growth process or subsequent cell decay and lysis, has been widely associated with membrane fouling …”