Showing papers by "Deli Wu published in 2010"

Effects of electrolytes on the reduction of 2,4-dinitrotoluene by zero-valent iron

Abstract: BACKGROUND: Dinitrotoluenes (DNTs) are environmentally persistent, making the remediation of contaminated streams and groundwater difficult. Zero-valent iron (Fe 0 ) can be used as an electron source for the reduction of recalcitrant DNTs in waste-water and thus enhance their biodegradability. However, little is known about the qualitative effects of major anions and cations present in waste-water on the reduction of DNTs by Fe 0 . RESULTS: The presence of Na 2 SO 4 and NaCl at levels between 0.25 and 2 mmol L -1 was observed to enhance the reactivity of Fe 0 towards 2,4-DNT. The positive effect of K 2 SO 4 is stronger than that of Na 2 SO 4 at the same level (1 mmol L -1 ). Varying (NH 4 ) 2 SO 4 from 0.1 to 1.0 mmol L -1 improved the efficiency of 2,4-DNT degradation by Fe 0 . The effects of varying NaNO 3 and NaNO 2 from 0 mmol L -1 to 4.7 mmol L -1 and 0 mmol L -1 to 5.8 mmol L -1 , respectively, were also investigated. Both NaNO 3 and NaNO 2 at low concentration improved the efficiency of 2,4-DNT degradation by Fe 0 , however, at high concentration, inhibiting effects appeared. CONCLUSION: SO 4 2- , Cl - , Na + , K + and NH 4 + notably enhanced 2,4-DNT reduction by Fe 0 at the tested concentrations. The positive effect of K + , Cl - was relatively stronger than that of Na + and sulfate (SO 4 2- ). However, the effect of NH 4 + was relatively weaker at concentrations greater than 1.0 mmol L -1 . The presence of low concentrations of NO 3 - and NO 2 - promoted 2,4-DNT reduction by Fe 0 and inhibited the reaction. The results suggest that 2,4-DNT reduction by Fe 0 can be controlled by the ions composition of the waste-water.

Integral processing method for industrial waste water by catalyzed iron internal electrolysis and suspended carrier bio-film

Abstract: The invention provides an integral treatment method for industrial waste water by catalyzed iron internal electrolysis and suspended carrier bio-film for hard dissolved industrial waste water treatment. The method comprises the following steps: firstly, preparing catalyzed iron internal electrolysis filter materials; secondly, arranging a conventional biological reaction tank, filling suspended carriers into the biological reaction tank; thirdly, placing the catalyzed iron internal electrolysis filter materials on a proper position above an aeration system in the biological reaction tank, andputting a catalyzed iron internal electrolysis filter material device in a water stream vertical direction; fourthly, treating sewage in the biological reaction tank which is filled with the catalyzediron internal electrolysis filter materials and the suspended carriers; and fifthly, separating slurry and water for mixed fluid from the biological reaction tank in a secondary sedimentation tank, and discharging the slurry and the water respectively. The method can carry out organic coupling treatment on the hard biodegraded industrial waste water by the catalyzed iron internal electrolysis technology and the biological method, can reduce toxic actions of toxic pollutant to microorganisms, improve the biological property of the waste water, and reinforce the effect of biochemical treatment.

Method for cooperated industrial wastewater pretreatment by catalytic ion reduction and anaerobic hydrolytic acidification

Abstract: The invention belongs to a wastewater treatment technology, relating to a method for coordinated pretreatment of nondegradable industrial wastewater by means of catalyzed iron reduction and anaerobic hydrolysis acidification. The method comprises the following steps: step 1, a catalytic iron filter material is prepared and pressed into a unitized catalytic iron filter material; step 2, a common anaerobic hydrolysis-acidification reaction tank is arranged; step 3, the catalytic iron filter material is put in the anaerobic hydrolysis-acidification reaction tank; and step 4, sewage is fed into the anaerobic hydrolysis-acidification reaction tank, flows through the catalytic iron filter material and is discharged, and the hydraulic residence time is between 3 and 8 hours for anaerobic hydrolysis-acidification reaction. The method not only removes poisonous functional group of poisonous contaminant so as to reduce the toxic action on anaerobe generated by the poisonous contaminant, but also hydrolyzes nonbiodegradable contaminant into easily biodegradable small molecular substance; therefore, the method improves the comprehensive biodegradability of wastewater, and has the advantages of high treatment efficiency and excellent treatment effect.

Method for pre-treating difficultly-degradable wastewater by catalyzed iron inner electrolysis fluidized bed

Abstract: The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for pre-treating hard-degradable wastewater by a catalyzed iron inner electrolysis fluidized bed, which comprises the following specific steps that: a suspended catalyzed iron inner electrolysis spherical vector is put into a fluidized bed body, wherein the addition amount of the suspended catalyzed iron inner electrolysis spherical vector is 10 to 60 percent of the active volume of the fluidized bed body; wastewater to be treated is introduced through a water inlet, and a valve on a reflux pipe or an inlet pipe is opened and regulated; a hydraulic fluidized bed is used as an oxygen-deficiency device or a hydrolysis device, and a reflux amount is determined according to the amount of the treated water, the cross sectional area of the bed body and the bulk specific weight of catalyzed iron fillers; a pneumatic fluidized bed is used as an aerobic treatment device, and the compressed air amount of the pneumatic fluidized bed meets the requirements of filler fluidization on the premise that the dissolved oxygen of the wastewater in the device is between 0.5 and 2.5 mg/L; air supply is 6 to 20 times of the amount of the treated water; when the pneumatic fluidized bed is used as a hydrolysis system, the concentration of the dissolved oxygen is less than 0.5 mg/L; the fillers in the fluidized bed body form circulation under the action of an internal guide cylinder and are discharged from a water outlet pipe through solid-liquid separation in a settling region; and a sludge discharge pipe is used for discharging residual sludge. The method is simple, simple in device structure and strong in operability, and can be adapted to the treating scales of different water yields.

Method for back washing electrolysis filler in catalytic iron by air and water

Abstract: The invention relates to a maintaining method of a sewage treatment device, in particular to a method for back washing electrolysis filler in catalytic iron by air and water. The method comprises thefollowing steps: inserting back washing air pipes connected with a compressed air pipeline and back washing water pipes connected with a high-pressure water supply pipeline into electrolysis filler incatalytic iron in a catalytic iron reactor; setting distributed planes of the back washing water pipes to be parallel to the bottom plane of the filler and have a distance of 30-50 mm with the bottomplane of the filler, wherein the spraying directions of back washing water outlet holes on the back washing water pipes is downward; setting the distributed planes of the back washing air pipes to beparallel to the outer plane of the filler facing water flows and have a distance of 30-50 mm with the outer plane, wherein the spraying direction of back washing air holes on the back washing air pipes is opposite to the directions of the water flows; and after the catalytic iron reactor is operated for a period of time, back washing the filler by the back washing air pipes and the back washing water pipes. The invention can conveniently and efficiently clear the electrolysis filler in the catalytic iron so as to improve the sewage treatment effect.

Split-type hydrolysis acidification and catalyzed iron coupling device

Abstract: The utility model relates to a sewage treatment device, particularly to a split-type hydrolysis acidification and catalyzed iron coupling device. The device comprises a hydrolysis acidification reactor and a catalyzed iron reactor which are connected in series in a water-treatment channel. In the first technical scheme, the water inlet pipe of the entire device is connected with the water distribution pipe of the hydrolysis acidification reactor, the water outlet pipe of the hydrolysis acidification reactor is connected with the water distribution pipe of the catalyzed iron reactor, and the water outlet pipe of the catalyzed iron reactor is connected with the water outlet pipe of the entire device. The water outlet pipe of the catalyzed iron reactor is also connected with a branch pipe, and the branch pipe is connected with the water inlet pipe of the entire device through a reflux pump Q1. The split-type hydrolysis acidification and catalyzed iron coupling device can improve the biodegradability of toxic and harmful hardly-degradable wastewater and adjust the treatment procedures according to the water quality condition, and has stable treatment effect and wide wastewater applicability range.