Effects of feeding time and organic loading in an anaerobic sequencing batch biofilm reactor (ASBBR) treating diluted whey

An investigation was carried out on the performance of an anaerobic sequencing batch biofilm reactor (ASBBR) treating diluted cheese whey when submitted to different feed strategies and volumetric organic loads (VOL). Polyurethane foam cubes were used as support for biomass immobilization and stirring was provided by helix impellers. The reactor with a working volume of 3 L treated 2 L of wastewater in 8-h cycles at 500 rpm and 30 degrees C. The organic loads applied were 2, 4, 8 and 12 g COD L(-1) d(-1), obtained by increasing the feed concentration. Alkalinity was supplemented at a ratio of 50% NaHCO(3)/COD. For each organic load applied three feed strategies were tested: (a) batch operation with 8-h cycle; (b) 2-h fed-batch operation followed by 6-h batch; and (c) 4-h fed-batch followed by 4-h batch. The 2-h fed-batch operation followed by 6-h batch presented the best results for the organic loads of 2 and 4 g COD L(-1) d(-1), whereas the 4-h fed-batch operation followed by 4-h batch presented results slightly inferior for the same organic loads and the best results at organic loads of 8 and 12 g COD L(-1) d(-1). The concentration of total volatile acids varied with fill time. For the higher fill times maximum concentrations were obtained at the end of the cycle. Moreover, no significant difference was detected in the maximum concentration of total volatile acids for any of the investigated conditions. However, the maximum values of propionic acid tended to decrease with increasing fill time considering the same organic load. Microbiological analyses revealed the presence of Methanosaeta-like structures and methanogenic hydrogenotrophic-like fluorescent bacilli. No Methanosarcina-like structures were observed in the samples.     

Phosphorus Loadings Associated with a Park Tourist Attraction: Limnological Consequences of Feeding the Fish

The Linesville spillway of Pymatuning State Park is one of the most visited tourist attractions in Pennsylvania, USA, averaging more than 450,000 visitors · year⁻¹. Carp (Cyprinus carpio Linnaeus) and waterfowl congregate at the spillway where they are fed bread and other foods by park visitors. We hypothesized that the “breadthrowers” constitute a significant nutrient vector to the upper portion of Pymatuning Reservoir. In the summer of 2002, we estimated phosphorus loadings attributable to breadthrowers, and compared these values to background loadings from Linesville Creek, a major tributary to the upper reservoir. Items fed to fish included bread, donuts, bagels, canned corn, popcorn, corn chips, hot dogs, birthday cakes, and dog food. Phosphorus loading associated with park visitors feeding fish was estimated to be 3233 g day⁻¹, and estimated P export from the Linesville Creek watershed was 2235 g·day⁻¹. P loading attributable to breadthrowers exceeded that of the entire Linesville Creek watershed on 33 of the 35 days of study, with only a heavy rainfall event triggering watershed exports that exceeded spillway contributions. Averaged across 5 weeks, breadthrowers contributed 1.45-fold more P to Pymatuning Reservoir than the Linesville Creek watershed. If Linesville Creek P exports are extrapolated to the entire Sanctuary Lake watershed, spillway contributions of P added 48% to the non-point source watershed P entering the lake. Park visitors feeding fish at the Linesville Spillway are a significant source of nutrients entering Sanctuary Lake.     

EUTROPHICATION MEASURES FOR SMALL LAKE WATER QUALITY MANAGEMENT1

ABSTRACT: Continuous measures of water quality responsiveness to changes in nutrient loadings are developed for use by environmental regulators attempting to achieve the greatest degree of water quality improvement consistent with competing uses of scarce resources. Recent contributions to the literature, based upon the nutrient loading concept, provide statistical relationships applicable to broad categories of lakes. In order to meet the requirements of water quality regulators, equations based upon USEPA survey data are developed in terms of the functional forms formulated and tested in the literature. Since recent authors have observed that much existing survey data are inappropriate for the formulation and testing of nutrient loading relationships, we have utilized results from the literature that work best with the existing data base, on grounds that such data are most inexpensively available to water quality managers. The nature of existing data limitations is discussed, and approaches to the revision of current results in light of improvements in the data base are indicated.     

生物炭负载氮还田对水稻生长、根系形态及氮素利用的影响

建立连接富营养化水体养分与农田养分的枢纽是减少农田养分投入、缓解水体富营养化的难点.为探明生物炭材料负载氮还田的可行性,开展了基于溶液氮及生物炭负载氮两种氮源添加方式的水稻根箱试验.结果表明,生物炭负载氮添加方式分别较溶液氮添加方式降低了水稻地上部分生物量及氮累积16%及14%,提高了生物量根冠比25%～27%,降低了氮利用效率.不定根的根长及体积是两种氮源添加方式在水稻地下部分差异的体现,地下部分生物量及氮累积与土壤铵态氮含量呈正相关关系,而地上部分氮累积与根尖数呈负相关关系.生物炭负载氮完全替代化学肥料施用农田会影响水稻生物量及氮素利用.但生物炭负载氮与普通化学肥料共同施用,水稻并不会显现利用偏好.生物炭负载氮对水稻氮素利用无不良影响,且能有效提高土壤矿质态氮固持量.因此,生物炭可以作为载体实现水体到农田土壤的氮素迁移,鉴于化肥氮替代比例对作物生长的影响,适宜替代比例还需进一步研究确定.     

中国农田畜禽粪尿氮负荷量及其还田潜力

为准确掌握中国各省区畜禽粪尿及氮负荷量,以及还田利用潜力,本研究基于统计数据和已有资料,利用猪粪当量(N)估算了1978年以来中国畜禽粪尿量的变化规律,以及各类畜禽粪尿的构成比例,分析和评价了2016各省份畜禽粪尿、纯氮负荷量的空间分布和污染风险,并估算了各省份畜禽粪尿的还田潜力.结果表明,中国畜禽粪尿猪粪当量(N)及其N养分量总体上呈"快速增加(1978~2005年)-保持稳定(2006~2016年)"的变化态势,到2016年,分别达到366 822.01×10~4t和2 024.10×10~4t,均增长了105.78%,94.03%~98.34%的粪尿量来源于家禽、羊、猪和牛.畜禽粪尿猪粪当量(N)及其N养分量最大的区域是华北地区,其中河南省为最,分别占全国的22.25%和8.81%.其次是四川,占8.14%.按耕地、作物播种面积和农用地面积分别计算单位面积上的畜禽粪尿猪粪当量(N)及其N养分量,并进行r值分级和环境风险评价.如果承载场所为耕地,负荷量较大的是西南和东南地区,污染风险较严重的是华北地区,为Ⅳ级;若按农作物种植面积,西北和西南地区负荷量较大,西北和华北地区为Ⅲ级有污染风险;若按农用地计算,华北和东南地区负荷量较大,华北地区Ⅲ级有污染风险,湖南负荷量最大,北京、山东和河南为Ⅳ级较严重污染风险.全国畜禽粪尿猪粪当量(N)及其N养分还田量分别为113 480.75×10~4t和626.15×10~4t,按单位农用地面积分别相当于3.07 t·hm~(-2)和16.92 kg·hm~(-2),华北地区最大,为8.27t·hm~(-2)和45.62 kg·hm~(-2).若按50%的粪尿N养分环境容量(85 kg·hm~(-2))计算,全国可增加粪尿N养分还田量为2 520.21×10~4t,粮食主产区黑龙江还田潜力最大,其次是四川.     

H2O2预氧化对负载铁制备污泥炭基催化剂效能的影响

以城市污水厂二沉池污泥为原料,考察了不同H_2O_2投加量下污泥预氧化对铁负载污泥形成前驱体及其热解后制得炭基催化剂性能的影响,研究了污泥预氧化对强化铁负载制备均一分散型污泥炭基催化剂的机理.结果表明,污泥预氧化促进了污泥细胞破解,降低了絮体颗粒粒径和表面Zeta电位,使铁负载量增加、铁活性位点在污泥载体上的分散性明显增强,形成炭基催化剂保持着高催化活性,其稳定性显著增加.对模拟含铬黑T染料废水的多相芬顿降解试验说明,当污泥预氧化H_2O_2投加量为2.25%时制备的炭基催化剂,其反应120 min后铬黑T的降解率为91%,略低于未预氧化时污泥炭基催化剂的降解效率(96%);但未预氧化炭基催化剂其反应后溶液中铁离子的溶出量(18.9%)远高于预氧化后形成的催化剂(2.5%),且后者循环3次对铬黑T的降解率仍可达到86%,表现出较强的稳定性.     

多级土壤渗漏系统处理农村生活污水

构建了多级土壤渗漏系统（MSL）以处理农村生活污水,主要研究了MSL的挂膜启动特征,进水水力负荷对MSL处理生活污水性能的影响,以及MSL运行过程中生物膜的特征.实验结果表明,采用连续进水的方式挂膜28d后,挂膜成功,MSL对生活污水中COD,氨氮,TN,TP的去除率分别达到84.5%,74.7%,66.7%,76.4%.MSL运行过程中,表现出对进水水力负荷变化较强的适应性,水力负荷为400L/（m²·d）时,生活污水中COD,氨氮,TN,TP的平均去除率分别达到93.4%,94.9%,80.4%,94.7%,系统出水水质能够满足城镇污水处理厂污染物排放标准（GB18918-2002）一级A标准.MSL对有机物和氮磷的去除途径结果表明,微生物降解和转化作用对污水中COD,氨氮,TN的去除贡献率最大,Fe³⁺与PO₄^3-的化学沉淀作用则是TP去除的主要途径.实时荧光定量PCR技术检测结果显示,生物膜中硝化功能菌占总菌群的35.5%.     

qPCR揭示丙酸降解菌群随OLR提高的演替规律

为探讨有机负荷率（OLR）对升流式厌氧污泥床（UASB）反应器运行效能的影响及互营丙酸降解菌群的响应,以稀释的制糖废水为底物,考察了OLR升高对UASB处理效能的影响,并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群随OLR提高的演替规律.结果表明,在OLR为6.0~54.0kgCOD/（m³·d）的范围内,UASB处理制糖废水取得了良好的效果,其COD去除率为92.0%以上.qPCR检测结果表明,至少有3种已鉴定的丙酸氧化菌（Pelotomaculum schinkii,P.propionicum和Syntrophobacter sulfatireducens）存在于UASB反应器中.其中,S.sulfatireducens是主要的丙酸氧化菌,其数量为126~1.2×10³ 16S rRNA基因拷贝数/ng DNA,约占检测到丙酸氧化菌总数的47.9%~58.6%.OLR从6.0提高至54.0kgCOD/（m³·d）导致所有丙酸氧化菌数量显著减少.Methanospirillum hungatei和Methanosaeta concilii是该UASB系统中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌.与丙酸氧化菌的变化趋势相反,这两种产甲烷菌的数量均随OLR的提高而显著增加,并在OLR54.0kgCOD/（m³·d）条件下达到最大值.     

Removal of veterinary antibiotics from anaerobically digested swine wastewater using an intermittently aerated sequencing batch reactor

A lab-scale intermittently aerated sequencing batch reactor(IASBR)was applied to treat anaerobically digested swine wastewater(ADSW)to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand(COD)volumetric loadings,solid retention times(SRT)and ratios of COD to total nitrogen(TN)or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand(COD)volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.     

上海市水体富营养化及洗涤剂中磷的影响研究

针对上海市水体污染状况进行调查研究,结果表明,上海市主要水体苏州河和黄浦江有机污染日益严重,其中苏州河TP 0.6mg/L、TN 10.06mg/L,黄浦江TP 0.23mg/L、TN 4.03mg/L,超标较严重,存在发生富营养化的条件,根据国内外经验和上海的相关资料估算,洗涤剂中的磷占总磷负荷的6.82％。