| About3-4million tons of printing and dyeing wastewater is discharged everydayin our country, it is one of large pollution source among various industries. Printingand dyeing wastewater are mainly composed of desizing, scouring, bleaching,mercerizing, dyeing and printing wastewater. It generally characterizes as highconcentrations of pollutants, variety, high toxicity and chromaticity. The studiedwastewater was sourced from a printing and dyeing factory in Hubei province, itcontains dyes, coloring agents, dyeing auxiliaries, surfactants and other toxic andharmful pollutants. The direct discharge without any treatment of this wastewater willresult in great damage to the environment, ecological system and human health.Different technologies including physic-chemical, biological or their combinationtechnologies, especially for economical biological technology, have been developedand raised great attention for the disposal of printing and dyeing wastewater.The research of the FCR processing printing and dyeing wastewater’scommissioning and operation is a cooperative project with Wuhan SentaiEnvironmental Protection Engineering Co., LTD. Currently, the technology ofefficient anaerobic reactors is confidential. The experiences of design, construction,operation, start-up, and management are limited. Few researches have reported thedisposal of organic wastewater with low concentration, especially for printing anddyeing wastewater with low concentration. A concept and design philosoopy ofhome-designed forced circulation anaerobic reactors (FCR) were firstly proposed andthe reactor was developed for the treatment of printing and dyeing wastewater withlow to medium concentration in this work. The main contents studied in the presentstudy included the study of water quality and degradability of printing and dyeingwastewater, acclimation and cultivation of sludge. The first and second start-upprocess of the forced circulation anaerobic reactor was evaluated. The operationcharacteristics of this system and corresponding process parameters were alsoinvestigated.Sludge culture was begun on March24th2011and ended on May5th2011. It wasfound that FCR could run smoothly at low loading amount when sludge was culturedin a simulated flour wastewater. However, FCR could not run smoothly, theacidification circumstance would occur when the loading amount of wastewater washigh, this resulted in poor disposal efficiency. Sludge with fine particles were alsofound in the reacter after53days’ cultivation of sludge. The first operation for the home-designed FCR was begun on May16th2011andended on June15th2011, lasting for31days. It was found that the removal rate ofdyestuff was high up to61.4%, and the measured final S-COD was less than700mg/L after the acidification phenomenon was resolved by introducing water into thereactor. The study of MLVSS/MLSS indicated that it decreased from65%to30%after continual pumping water into this system.The second operation of the home-made FCR was begun on July30th2011andended on September11th2011, lasting for45days. Although COD, pH, SS andtemperature fluctuateed greatly, the highest removal rate of the reactor was found tobe up to62.5%after the operation was terminated. The removal rate of T-COD,S-COD for the final effluent reached up to53.6%and58.0%, respectively, when theoptimal external circulation flow (1m3/h) and hydraulic retention time (7h) was used.Ferric chloride was added into the reaction system to remove the salinity for the finaleffluent after FCR reaction. The removal of sulfate, sulfide and conductivity aresignificant in the final effluent. The possible degradation mechanism in this systemwas primarily investigated by the combination of violet-visible absorptionspectroscopy, infrared spectroscopy and gas chromatography-mass spectrometryanalytical techniques. The appropriate resolutions for the possible problems that mayoccur during practical operation processes have been supplied based on ourexperience.Forced circulation anaerobic reactor (FCR) is characterized as small landoccupancy and good running stability. The process was firstly applied to engineeringpractice in printing and dyeing industry. Satisfied disposal efficiency has beenachievd. The application of the present technology improved the treatment efficiencyfor anaerobic disposal technique, alleviated the subsequent aerobic treatment burden.Simultaneously, it shows as an environmentally friendly and economical technique insaving infrastructure investment and energy consumption.. |
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