污泥好氧堆肥中反硝化作用与腐植酸组分稳定化关系研究

1研究亮点 *反硝化作用的增强降低了好氧污泥堆肥中腐植酸组分含量; *反硝化作用的增强刺激了反硝化功能基因丰度; *反硝化芳香族化合物降解微生物是反硝化功能基因的宿主微生物,是影响腐植酸组分的主要因素. 2背景 腐植酸是堆肥过程中微生物降解有机物转化形成的一种高分子量芳香族化合物,其形成数量、芳构化程度与堆肥稳定性、腐...     

城市污泥反应器堆肥实验

采用强制通风好氧静态方式对城市污泥进行堆肥实验,结果表明:通过调节城市污泥水分和C/N,经过好氧反应器堆肥处理,污泥有机质发生降解,TN、TP和TK含量都呈上升趋势,VS和有机碳分别达到60%和30%的稳定状态,种子发芽指数达到100%左右,有效杀灭病原菌,实现城市污泥无害化、稳定化和减量化的要求.腐熟的污泥堆肥成为高价值的农用产品.     

污泥中温厌氧消化的实验研究

通过实验室装置对活性污泥中温 (35℃) 厌氧消化过程中的沼气产生量和气体成分进行了监测,并对消化前后污泥的含水率、vS、成分等进行对比分析.结果表明:该污泥可以采用中温厌氧消化的方法进行处理,沼气的收集可以实现能量的回收,但由于消化后污泥中Cu、Ni的重金属含量超过GB 4284-1984 农用污泥中污染物控制标准,...     

厨余垃圾厌氧沼渣处理案例探析

我国厨余垃圾处理工程大多采用厌氧工艺,末端产生大量沼渣,堆肥资源化是其利用的重要手段,但目前缺乏沼渣特性和处理效果的研究.针对典型城市厨余垃圾厌氧发酵工程产生的沼渣和堆肥进行了取样调研,研究了沼渣和堆肥的物理组成、生物稳定性、植物毒性、溶解性物质特性,分析了厨余垃圾厌氧沼渣好氧堆肥的必要性.结果表明:一级沼渣(即螺旋挤...     

造纸污泥交替好氧厌氧堆肥中氮素的形态转变研究

通过交替式好氧厌氧堆肥处理造纸污泥试验,研究氮素的变化规律.结果表明:堆肥初始的中高温期,主要是堆体中的有机氮转化为氨氮;之后的降温期和腐熟期是硝态氮形成的主要阶段;总氮在整个堆肥阶段呈上升趋势.无机氮(NH3-N,NO-3-N)可以直接被作物吸收,是污泥堆肥中的主要氮素形态,因此减少堆肥初期氨氮的挥发,增加腐熟阶段NO-3-N的形成,以及降低滤液中无机氮的流失是提高造纸污泥堆肥肥效的关键.     

有机负荷对餐厨单相厌氧消化产甲烷的影响

采用消化污泥接种,在中温条件下（37℃左右）以连续式单项厌氧消化技术对餐厨单独厌氧消化进行研究.实验中以产气量、产气中甲烷含量、消化液中氨氮及总氮浓度、体系中pH以及有机质降解率为指标,研究高含固率条件下（含固率12％）有机负荷对餐厨垃圾厌氧消化产甲烷的影响.结果表明：当有机负荷为2.5～3.0 kg/（m^3·d）时,厌氧消化总体效果较好,体系中各项指标均维持在较好水平.继续提高有机负荷,体系中pH下降,氨氮浓度上升,产气率及有机质降解率明显下降,不利于厌氧消化的进行.     

餐厨垃圾处理技术研究进展

介绍了餐厨垃圾的特点及存在的污染问题,探讨了目前常用的餐厨垃圾处理技术如焚烧、卫生填埋、生态饲料、厌氧消化、好氧堆肥和蚯蚓堆肥等的现状和存在问题,分析了餐厨垃圾厌氧消化资源化技术的发展趋势。     

药品和个人护理用品（PPCPs）影响剩余污泥厌氧消化研究进展

目前市政污水处理厂多关注水质排放标准中规定参数的阈值而忽略药品和个人护理用品（PPCPs）等新型微污染物。厌氧消化是污水处理厂实现碳中和与剩余污泥资源化利用的关键技术,而剩余污泥中积累的PPCPs会限制厌氧消化及其残余物资源化技术的推广。本研究分析了市政污水处理厂PPCPs来源与行为,以频繁检出的典型PPCPs为研究对象,解析了实验室环境下中高浓度的PPCPs对厌氧消化性能潜在影响;综述了典型PPCPs对消化过程中关键参数如甲烷产率、挥发酸分布和微生物群落结构的影响;同时评价了PPCPs对剩余污泥厌氧消化的后风险。结果表明：典型PPCPs能够促进污泥溶解,为微生物提供更多的营养物质,而水解酸化细菌因PPCPs胁迫而过度活跃导致挥发酸过度积累;与氢营养型产甲烷菌相比,乙酸型产甲烷菌更易受到PPCPs抑制,从而降低甲烷产率;厌氧消化沼渣和沼液资源化利用的同时PPCPs也会带来潜在的生态风险。未来研究应从细胞水平加深理解PPCPs暴露对细菌和古菌的影响,开发既可满足污水水质排放标准、又能缓解PPCPs对厌氧消化的潜在抑制的新工艺,加速污水处理厂碳中和进程,降低PPCPs生态风险。     

厌氧消化技术在生活垃圾堆肥处理中的应用

介绍了国内外厌氧消化技术在城市生活垃圾堆肥处理上的应用,指出运用厌氧发酵技术处理有机垃圾是实现固体废弃物资源化、减量化j无害化的新趋势。     

用排水管污泥混合堆肥或做建筑材料的可行性研究

对利用城市排水管污泥进行堆肥和做建材进行探讨，通过采用高温好氧混合静态堆肥进行实验，可知排水管污泥经堆肥处理后，可达到我国的无害化处理要求。将排水管污泥与粘土混合烧制成砖和陶粒。测试表明用排水管污泥烧制砖或陶粒具有可行性。     

Phytotoxicity of municipal sewage sludge composts related to physico-chemical properties, PAHs and heavy metals

The aim of the study was to determine the influence of the composting on the phytotoxicity of sewage sludge in relation to their physical-chemical properties, heavy metals and polycyclic aromatic hydrocarbons content. Four municipal sewage sludges were composted for 76 days. A Phytotoxkit Test and pot experiment with Lepidium sativum were used for bioassay. The total PAH content in sludges ranged from 3674.1 to 11236.3 microg kg(-1). Heavy metals content was in the range Cd (1.9-76 mg kg(-1)), Cr (27.6-120 mg kg(-1)), Cu (156-335 mg kg(-1)), Pb (37.5-59.5 mg kg(-1)), Ni (21.7-155 mg kg(-1)) and Zn (1015-1385 mg kg(-1)). The results showed a varied toxicity of sewage sludge in relation to the plant tested. In the case of two sludges a 100% inhibition of seed germination were noted. Sludge composting limited their negative influence on most of the phytotoxicity parameters. Only chlorophyll concentration was often lower than in the plant bred on compost obtained from sludge.     

Modification of progesterone and testosterone by a food-borne thermophile Geobacillus kaustophilus

Abstract

The present work was carried out to study structural modification of steroids by Geobacillus kaustophilus, a bacterial thermophile present in milk and the environment. Incubation of progesterone and testosterone with G. kaustophilus at 65°C resulted in oxygenated steroid nuclei. The oxygenation of the steroid molecule was stereo specific. Seven metabolites of progesterone─6β/6α-hydroxytestosterone, 20-hydroxyprogesterone, 6β-/6α-20-dihydroxyprogesterone, 5α-pregnane-3,6,20-trione, and 3β-hydroxy-5α-pregnane-6,20-dione─were identified. Four compounds─namely, 66-/6--hydroxytestosterone and 6β/6α-hydroxyandrostenedione─and androst-4-en-3,17-dione were identified as testosterone metabolites. This shows that G. kaustophilus is capable of modifying steroid nuclei at elevated temperatures. G. kaustophilus is a stable thermophile first isolated from milk. Our results show that endogenous steroids present in milk can be modified by G. kaustophilus, causing detrimental effect on human health.     

引风式好氧堆肥装置设计及通风效果研究

运用“烟囱效应”研制成一种新型引风式好氧堆肥装置,研究其对通风供氧的影响效果.通过对园林垃圾与餐厨垃圾混合堆肥试验表明:本装置能有效地改善静态堆肥过程的通风供氧效果,保证好氧堆肥的顺利进行,一次发酵周期内堆体平均氧浓度由9.7％提高至16.3％,最低氧浓度提高至12.6％,一次发酵周期由12 d缩短至10d.     

Fecal steroids and colorectal cancer

The fecal steroid profiles of healthy subjects were compared with those of colorectal cancer (CRC) patients. The multicomponent profiles did not differ qualitatively in that CRC patients, like control subjects, had similar fecal steroids. The major bile acids detected in fecal extracts were lithocholic acid (LCA) and deoxycholic acid (DCA). The major sterol of animal origin was cholesterol and its bacterial metabolite coprostanol, whereas the major plant sterols were beta-sitosterol, stigmasterol, campesterol, and their corresponding bacterial metabolites. CRC patients excreted higher amounts of total major bile acids (LCA and DCA) than did the control group, but this difference was not significant. However, the LCA-to-DCA ratio was much higher in the CRC group [(1.43, p less than 0.01) compared with the control group (0.72)]. The control group excreted significantly higher amounts of total neutral sterols (p less than 0.001), sterols of animal origin (p less than 0.001), and plant sterols (p less than 0.001) compared with the CRC group; the plant sterols represented a much lower proportion of excreted total neutral sterols in the CRC group (p greater than 0.001) compared with the control group. We propose the following hypotheses. The LCA-to-DCA ratio may be an important discriminant market for CRC susceptibility. The fecal LCA-to-DCA ratio may depend on the differential hepatic synthesis of their respective precursors chenodeoxycholic acid (CDCA) and cholic acid. Hepatic synthesis of CDCA may be increased by more efficient conservation of dietary cholesterol because it has been shown that cholesterol of exogenous origin is the main precursor of this bile acid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feasibility of some treatments for improving the composting of municipal solid waste

During composting limited degradation of organic matter occurs due to the influence of various factors such as presence of lignin, resistant nature of cellulose, high temperature, etc. During windrow composting, temperature within the waste mass rises and limitation in degradability of organic matter, studies on composting in temperature range of 45-60 degrees C were carried out. With a view to observe the effect of pretreatment for improving composting, Municipal Solid Waste (MSW) was subjected to alkali treatment using lime, and ammonia gas circulation in the waste mass. In practice aerobic condition within the windrow is ensured by turning/mixing the waste 5-6 times during the composting period. In the present study to find out the extent of aerobic condition, the waste mass was composted in the masony brick tank which was provided with honeycomb opening from all the sides. Similarly composting was also carried out on perforated false bottom. Various parameters such as fermentable organic substance (FOS), carbon to nitrogen (C/N) ratio and temperature were monitored for the waste mass undergoing composting. The study reveals that experiments with aeration from bottom as well as surface followed by alkaline treatment give better composting performance.     

Fecal steroids and colorectal cancer

The fecal steroid profiles of healthy subjects were compared with those of colorectal cancer (CRC) patients. The multicomponent profiles did not differ qualitatively in that CRC patients, like control subjects, had similar fecal steroids. The major bile acids detected in fecal extracts were lithocholic acid (LCA) and deoxycholic acid (DCA). The major sterol of animal origin was cholesterol and its bacterial metabolite coprostanol, whereas the major plant sterols were ß‐sitosterol, stigmasterol, campesterol, and their corresponding bacterial metabolites. CRC patients excreted higher amounts of total major bile acids (LCA and DCA) than did the control group, but this difference was not significant. However, the LCA‐to‐DCA ratio was much higher in the CRC group [(1.43, p < 0.01) compared with the control group (0.72)]. The control group excreted significantly higher amounts of total neutral sterols (p < 0.001), sterols of animal origin (p < 0.001), and plant sterols (p < 0.001) compared with the CRC group; the plant sterols represented a much lower proportion of excreted total neutral sterols in the CRC group (p > 0.001) compared with the control group.

We propose the following hypotheses. 1) The LCA‐to‐DCA ratio may be an important discriminant market for CRC susceptibility. 2) The fecal LCA‐to‐DCA ratio may depend on the differential hepatic synthesis of their respective precursors chenodeoxycholic acid (CDCA) and cholic acid. 3) Hepatic synthesis of CDC A may be increased by more efficient conservation of dietary cholesterol because it has been shown that cholesterol of exogenous origin is the main precursor of this bile acid. 4) Cholesterol absorption may be augmented in CRC patients because of the low intake of plant sterols, which are known to suppress cholesterol absorption.     

Comparison of effects of dietary unesterified and esterified plant sterols on cholesterol absorption in rats

Effects of dietary unesterified plant sterols and plant sterol oleates and stearates on absorption and metabolism of cholesterol were compared in rats fed a cholesterol-supplemented diet. Fecal excretion of neutral steroids (cholesterol plus coprostanol) in rats fed unesterified plant sterols or plant sterol oleates was significantly higher than in those fed the control diet or plant sterol stearates. Deposition of cholesterol in the liver was significantly lower in rats fed unesterified plant sterols or plant sterol oleates than in those fed the control diet or plant sterol stearates. No significant difference was observed in fecal excretion of cholesterol plus coprostanol and hepatic cholesterol concentration between unesterified plant sterols and plant sterol oleates. Unesterified plant sterols were significantly more effective to reduce lymphatic recovery of radiolabeled cholesterol given to the stomach than plant sterol oleates. Although our observations suggest a possibility that unesterified plant sterols are potentially more effective to inhibit cholesterol absorption than plant sterol oleates in rats, difference in the activity is substantially small between these two forms of plant sterols.     

我国城市生活垃圾堆肥技术的工程应用

介绍了高温好氧静态仓式堆肥的前处理和粗堆肥及利用粗堆肥生产复合肥的生产工艺和设备.     

Binding of the anti-progestin RU-486 to rat ovary steroid receptors

RU-486 is a recently synthesized steroid with anti-progesterone and anti-glucocorticoid properties. Its direct anti-progesterone action on the uterus is believed to be the basis for its ability to induce menstruation and early abortion. RU-486 likely antagonizes progesterone action on the uterus progesterone receptor. We have studied the binding of RU-486 to rat ovary steroid receptors in order to learn whether this interesting synthetic compound binds to ovary steroid receptors and thus learn if this antagonist can be used to better define the mechanism(s) of steroid actions on the ovary. Ovaries from estrogen stimulated hypophysectomized immature female rats were homogenized in buffer. The 100,000 x g supernatant was incubated with tritiated steroid agonists (R5020, dexamethasone, or testosterone) alone or with unlabeled steroids including RU-486. Receptor bound, and free steroid, were separated by Sephadex G-200 columns. The relative abilities of the various tested steroids to bind to the rat ovary progesterone receptor were: RU-486 greater than or equal to R5020 greater than progesterone. RU-486 bound to the ovary glucocorticoid receptor with an affinity equal to that of dexamethasone. The affinity of RU-486 for the rat ovary androgen receptor was only about 9% that of testosterone. Thus, RU-486 binds with very high affinity to the rat ovary progesterone and glucocorticoid receptors. This steroid receptor antagonist offers a new tool by which the mechanism(s) of action of these steroids on the ovary can be tested.     

Fecal steroids of the coprolite of a Greenland Eskimo mummy, AD 1475: a clue to dietary sterol intake.

BACKGROUND: Sterols in feces reflect sterols in the diet. In previous analyses of the fecal steroids in 1000-2000-y-old Native American coprolites found in the dry caves of Nevada, we showed that the sterol nucleus was stable. The coprolites provided useful dietary information. OBJECTIVE: In the present study, we analyzed the fecal steroids of an Eskimo mummy buried and frozen >500 y ago in Greenland. We compared these analyses with our findings in the coprolites from Nevada and in present-day stool samples from Tarahumara Indians of Mexico and Americans consuming low- and high-cholesterol diets. DESIGN: The fecal material from the Eskimo mummy was subjected to saponification, extraction, and digitonin precipitation. The sterols and bile acids were further analyzed by thin-layer chromatography and gas-liquid chromatography. RESULTS: The fecal steroids of the Greenland Eskimo mummy were remarkably similar to those of present-day stool samples. However, unlike in the stool of modern humans, a portion of the neutral steroids in the coprolite had been converted to sterol epimers. Instead of deoxycholic acid, 3alpha,6beta,12alpha-trihydroxycholanic acid was one of the major fecal bile acids. The plant sterol output in the coprolite was only 0.4% of the output of Americans consuming 250-400 mg plant sterols/d. The ratio of bile acid to cholesterol in the coprolite was similar to that in stool from Tarahumara Indians consuming a low-cholesterol diet. CONCLUSION: The sterol nucleus is stable when frozen. The analysis of coprolite showed that the young Eskimo woman had consumed a diet very low in plant sterols and moderate to low in cholesterol content.