Dairy Manure Treatment,Digestion and Nutrient Recovery as a Phosphate Fertilizer

A combined approach of biological treatment, solids digestion and nutrient recovery was tested on dairy manure. A sequencing batch reactor (SBR) was operated in three modes, in order to optimize nutrient (nitrogen and phosphorus) removals. The highest average removal efficiencies of 91% for NH₄-N, 59% for PO₄-P and 80% for total chemical oxygen demand (COD) were achieved. Staining experiments suggested the coexistence of glycogen and phosphorus accumulating organisms. Anaerobic digestion of wasted bio-solids was able to produce a PO₄-P concentration of 70 mgL^?1 in the supernatant. A pilot-scale experiment, designed to recover phosphorus in the supernatant as struvite (magnesium ammonium phosphate), was able to remove 82% of soluble PO₄-P.     

Characterizing food waste substrates for co-digestion through biochemical methane potential (BMP) experiments

Co-digestion of food waste with dairy manure is increasingly utilized to increase energy production and make anaerobic digestion more affordable; however, there is a lack of information on appropriate co-digestion substrates. In this study, biochemical methane potential (BMP) tests were conducted to determine the suitability of four food waste substrates (meatball, chicken, cranberry and ice cream processing wastes) for co-digestion with flushed dairy manure at a ratio of 3.2% food waste and 96.8% manure (by volume), which equated to 14.7% (ice-cream) to 80.7% (chicken) of the VS being attributed to the food waste. All treatments led to increases in methane production, ranging from a 67.0% increase (ice cream waste) to a 2940% increase (chicken processing waste) compared to digesting manure alone, demonstrating the large potential methane production of food waste additions compared to relatively low methane production potential of the flushed dairy manure, even if the overall quantity of food waste added was minimal.     

Improved biogas production from rice straw by co-digestion with kitchen waste and pig manure

In order to investigate the effect of feedstock ratios in biogas production, anaerobic co-digestions of rice straw with kitchen waste and pig manure were carried out. A series of single-stage batch mesophilic (37 ± 1 °C) anaerobic digestions were performed at a substrate concentration of 54 g/L based on volatile solids (VS). The results showed that the optimal ratio of kitchen waste, pig manure, and rice straw was 0.4:1.6:1, for which the C/N ratio was 21.7. The methane content was 45.9–70.0% and rate of VS reduction was 55.8%. The biogas yield of 674.4 L/kg VS was higher than that of the digestion of rice straw or pig manure alone by 71.67% and 10.41%, respectively. Inhibition of biogas production by volatile fatty acids (VFA) occurred when the addition of kitchen waste was greater than 26%. The VFA analysis showed that, in the reactors that successfully produced biogas, the dominant intermediate metabolites were propionate and acetate, while they were lactic acid, acetate, and propionate in the others.     

Polymer and invert emulsifying oil effects upon droplet size spectra of sprays

Abstract

A series of wind tunnel atomization studies were carried out to investigate the effects of polymer and invert suspension oil “drift control adjuvants” upon the droplet size distribution spectra produced by nozzles typically used in aerial and ground based spraying of pesticides. A D8–46 disc and core was used as a typical aerial application nozzle, and an 8003 fan nozzle was used for the ground based sprayers simulation. The droplet size spectra were evaluated in a wind tunnel using a Malvern 2600 laser particle size analyzer immediately upon mixing and at 15 minutes after re‐circulation through a pumping system. The addition of the polymer‐based adjuvants significantly increased the droplet size spectra parameters of the spray cloud, but all the polymer products showed signs of breakdown of their molecular arrangements in the liquid medium, as a result of agitation. The invert suspension oil adjuvant did not change the droplet size spectra markedly, nor did it show signs of breakdown of the internal liquid structure after re‐circulation.     

猪粪堆肥中一株溶磷菌的筛选鉴定及溶磷能力初步测定

从猪粪堆肥中分离纯化得到一株具有较强溶磷能力的菌株PSM-1,进行了形态学和分子生物学鉴定,研究了其溶磷能力和遗传稳定性.结果表明:通过菌落形态和ITS基因序列分析鉴定,菌株PSM-1为产黄青霉(Penicillium chrysogenum);在3种不同无机磷源液体培养基中其溶磷量依次为Ca3(PO4)2(138.36 mg·L-1)Fe PO4(117.38 mg·L-1)Al PO4(113.76 mg·L-1),且PSM-1的溶磷量均与培养液p H值呈现出显著负相关性;以葡萄糖为碳源、硝酸铵为氮源时,菌株PSM-1的溶磷量最高可达195.67 mg·L-1,比初始有效磷高141.42%;该菌株对碳源和氮源的利用效率分别依次为:葡糖糖蔗糖麦芽糖淀粉,硝酸铵硝酸钾硫酸铵草酸铵;经过20次传代培养后PSM-1的溶磷量保持在(124.54±3.50)mg·L-1,说明其溶磷遗传稳定性良好.研究表明:PSM-1菌株具有良好的溶解无机磷的能力,在土壤微生态改良方面具有重要的应用潜力.     

Numerical simulation of evaporation of volatile liquids

The paper presents the results of the validation of the developed pool evaporation model using literature and our own experimental data. The proposed model was used to examine the effect of wind velocity and pool sizes on the evaporation rate of volatile liquid (hexane). Contrary to the semi-empirical evaporation model widely used in hazard assessment, stronger dependence of evaporation rate on pool size at low wind speeds is obtained.     

Optimization and evaluation of an air-recirculated stripping for ammonia removal from the anaerobic digestate of pig manure

An air-recirculated stripping involved two processes and did not require any pretreatment. First, stripping CO₂ decreased the buffer capacity of the anaerobic digestate, thereby reducing the amount of lime used to achieve a high pH. Second, lime was added to increase pH and remove ammonia from the anaerobic digestate of pig manure. pH increased from 8.03 to 8.86 by stripping CO₂ in the first process (gas-to-liquid ratio = 180) and further reached 12.38 in the second process (gas-to-liquid ratio = 300). During process optimization, the maximum ammonia removal efficiency reached 96.78% with a lime dose of 22.13 g. The value was close to 98.25%, which was the optimal result predicted by response surface methodology using the software Design-Expert 8.05b. All these results indicated that air-recirculated stripping coupled with absorption was a promising technology for the removal and recovery of nitrogen in the anaerobic digestate of pig manure.     

Fire accident investigation of an explosion caused by static electricity in a propylene plant

This study investigated a 2010 fire and explosion that occurred at a polypropylene (PP) and copper-clad laminate high-tech plant in Taiwan. Liquid acetone leakage caused the fire and explosion. One person was killed and five were injured; property damage was estimated at US$20 million. In contrast to conventional plants, high-tech plants have sophisticated instrumentation, highly complex pipelines, and confined spaces. In addition, the floor area in a high-tech plant is large and frequently contains a channel through the ground floor to the second or third floor. This channel design enables the fire compartment to be destroyed. Therefore, the system cannot confine the fire to a specific area, thus hindering fire-relief operations. In this study, the original fire outbreak occurred in the PP processing area on the ground floor. The acetone storage tank was located on the third floor. The investigation conducted at the fire site of the situations of the burning (bursting) loss determined that the acetone liquid leaked and dripped from floor cracks and tunnel oven to the PP processing area. Because the PP manufacturing process rapidly generates static electricity, the flammable liquids made contact with the source of ignition, which caused the explosion and fire. Various procedures, such as those involving the operating environment of production, packaging, and processing in a high-tech plant, are likely to produce static electricity in a workplace. Improved electrostatic management can prevent the loss of property and lives, liquid acetone leakage, and loss of equipment caused by static electricity fire.     

液/液界面电化学及在环境监测分析中的应用

介绍了液/液界面电化学四种基本结构和主要实验方法,综述了液/液界面电化学分析方法在环境监测分析中的应用。作为一种新方法测定离子载体及能与其形成络合物的金属离子组分的浓度,它具有简便、快捷、经济实用等特点。     

Evaluating peats for their capacities to remove odorous compounds from liquid swine manure using headspace “solid‐phase microextraction”

Abstract

This paper reports on research designed to investigate the capacities of different highly characterized peats to remove odorous compounds from liquid swine manure (LSM). Peat types representing a wide range of properties were tested in order to establish which chemical and physical properties might be most indicative of their capacities to remediate odors produced by LSM. Eight percent slurries (of peat/LSM) were measured for odor changes after 24 hours using odor panel and GC/MS‐Solid‐phase microextraction (GC/MS‐SPME) analysis.

The GC/MS‐SPME and odor panel results indicated that, although all peats tested in this study were found to be effective at removing odor‐causing compounds found in LSM, some peats tended to work better than others. Overall, the peats that were the most effective at removing odor‐causing compounds tended to have lower bulk densities, ash contents, fulvic acids contents, and guaiacyl lignins contents,and higher water holding capacities, hydraulic conductivities, “total other lignins”; contents, hydrogen contents, carbon contents, and total cellulose contents.

GC/MS‐SPME analysis was found to be a reasonably inexpensive and efficient way of conducting this type of research. It allows one to identify a large number of the odor‐causing compounds found in LSM, and more importantly, to detect with some precision specific differences in the amounts of these compounds between peat types.