Treatment of anthraquinone dye wastewater by hydrolytic acidification-aerobic process

Experiment on microbial degradation with two kinds of biological process, hydrolytic acidification-aerobic process and aerobic process was conducted to treat the anthraquinone dye wastewater with CODc, concentration of 400 mg/L and chroma 800. The experimental result demonstrated that the hydrolytic-aerobic process could raise the biodegradability of anthraquinone dye wastewater effectively. The effluent CODc, can reach 120-170 mg/L and chroma 150 which is superior to that from simple aerobic process.     

Enhancement of anaerobic biodegradability of flower stem wastes with vegetable wastes by co-hydrolysis

The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments were carried out in batches. When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13, the overall hydrolysis rate increased by 8%, 12%, and 2% according to the carbon, nitrogen, and total solid （TS） conversion rate, respectively. While the dry weight ratio was designed as 1 to 3, there was a respective rise of 5%, 15%, and 4% in the conversion rate of carbon, nitrogen, and TS. The enhancement of anaerobic hydrolysis from the mixed vegetable wastes and flower stems can be attributed to the formation of volatile fatty acids （VFA） and nutrient supplement like nitrogen content. The maximum VFA concentration can achieve 1.7 g/L owing to the rapid acidification of vegetable wastes, loosing the structure of lignocellulose materials. The statistic bivariate analysis revealed that the hydrolysis performance was significantly related to the physical and biochemical compositions of the feeding substrate. Especially, the soluble carbon concentration in the liquid was significantly positively correlated to the concentration of nitrogen and hemicellulose, and negatively correlated to the concentration of carbon and lignocellulose in the feeding substrate, suggesting that the regulation and control of feedstock can have an important influence on the anaerobic hydrolysis of organic wastes.     

Coupling catalytic hydrolysis and oxidation for CS2 removal

CS2 removal was Obtained by coupling catalytic hyidation on bi-functional catalyst.On the hydrolysis active sites,CS2 is hydrolyzed to H2S,while on the oxidation active sites,H2S is oxidized to elemental S or sulfuric acid deposited on the porous support.The above process can be expressed as followsCS2→H2O COS →H2O H2S→O2 S/SO2- 4.H2S oxidation eliminates its prohibition on CS2 hydrolysis so that the rate of coupling removal CS2 is 5 times higher than that of CS2 hydrolysis.The same active energy of hydrolysis and coupling reaction also indicates that H2S oxidation does not change the reaction mechanism of CS2 hydrolysis.Temperature has obvious effect on the process while the mole ratio of O2 concentration to CS2 concentration (O/S) does not,especially in excess of 2.5.The formation of sulfuric acid on the catalyst surface poisons hydrolysis active sites and causes the decrease of left OH-1 concentration on the catalysts surface.Lower temperature is suggested for this bi-functional catalyst owing to the low yield ratio of S/SO4 2-.     

Effects of cyclodextrins on hydrolysis of malathion

Cyclodextrins （CDs）, with hydrophobic interior cavity and hydrophilic external surface, are capable of accelerating or inhibiting chemical degradation of organophosphorus pesticides through forming inclusion complexes between CDs and pesticides. This work evaluated the effects of CDs on hydrolysis of malathion in an attempt to assess their potential application in environmental approach. β-CD and its two derivatives, randomly methylated β-CD （RAMEB） and hydroxypropyl β-CD （HP-β-CD）, were tested. It was found that RAMEB could inhibit the hydrolysis of malathion, and this was the function of pH and temperature, the inhibitory effects increase with increasing concentration of RAMEB and elevating temperature between 15 and 35℃. On the other hand, β-CD and HP-β-CD have little or no stabilizing effects on malathion at all pH and temperature studied, except that the large concentration of β-CD and HP- β-CD can mildly reduce hydrolysis of malathion. Both 2 mol/L and 5 mol/L urea increase the inhibitory effects of RAMEB on hydrolysis of malathion at 25℃, oH 9.0.     

Effect of proteins, polysaccharides, and particle sizes on sludge dewaterability

Four batch experiments of hydrolysis and acidification were carried out to investigate the distributions of proteins (PN) and polysaccharides (PS) in the sludge, the PN/PS ratio, the particle sizes, and their relationship with sludge dewaterability (as determined by capillary suction time, CST). The sludge flocs were stratified through centrifugation- and ultrasound-based method into four fractions: (1) slime, (2) loosely bound extracellular polymeric substances (LB-EPS), (3) tightly bound EPS (TB-EPS), and (4) pellet. The results showed that PN was mainly partitioned in the pellet (80.7%) and TB-EPS (9.6%) fractions, while PS distributed evenly in the four fractions. During hydrolysis and acidification, PN was transferred from the pellet and TB-EPS fractions to the slime fraction, but PS had no significant transfer trends. The mean particle sizes of the sludge flocs decreased with hydrolysis and acidification. The pH had a more significant influence on the dewaterability of sludge flocs than temperature. Sludge dewaterability during hydrolysis and acidification processes greatly deteriorated from 9.7 s at raw sludge to 340–450 s under alkaline conditions. However, it was just slightly increased under acidic conditions. Further investigation suggested that CST was a ected by soluble PN, soluble PN/PS, and particle sizes of sludge flocs, but was a ected slightly by total PN, PS, or PN/PS in the whole sludge flocs and other fractions (except slime).     

絮凝预处理对微囊藻机械过滤的影响

蓝藻水华是水体富营养化破坏性灾变的表现之一,其治理一直是国内外的研究热点。受限于水华蓝藻广泛的尺寸分布,机械过滤作为水中悬浮颗粒的去除手段尚未在水华治理中推广。微囊藻是水华蓝藻中常见的优势种,絮凝可使其形成较大尺寸的絮体,有利于机械过滤设备将其去除。通过比较不同尺寸絮体的叶绿素a浓度,可以考察聚合硫酸铝、聚合硫酸铁、聚合氯化铝、聚合氯化铝铁对微囊藻机械截留效果的影响。结果表明,絮凝效果PFSPASPACPAFC,200 mg/L PFS的絮体有92.26%可被250μm滤网截留,97.55%可被100μm滤网截留。pH值为7～10时絮体截留效果较好;搅拌转速250 r/min时PFS絮体粒径最大,滤网截留效果最好。通过PFS絮凝预处理,64μm滤网对微囊藻的截留效果由14.6%提高到95.1%,并大幅度削减藻水的营养物质。     

Partial least square modeling of hydrolysis: analyzing the impacts of pH and acetate

Introduction Environm ental and econom ic advantages highlight anaerobic digestion as a sustainable technology for solid w aste treatm ent (Edelm ann etal., 2000). A naerobic digestion could be described as four sequential steps: hydrolysis, acidogenesis, aceto- genesis and m ethanogenesis, am ong w hich the hydrolysis is recognized as the rate-lim iting step for particulate organic w aste (Jain et al., 1992; M ata-A lvarez, 2000). H ydrolysis occurs com m only together w ith the acidogenesi…