Study on the Enzyme Activity Change during the Aerobic Composting Process of Sewage Sludge

2014 ◽  
Vol 955-959 ◽  
pp. 706-710
Author(s):  
Jun Ling Niu ◽  
Jun Hui He
Keyword(s):  
Enzyme Activity ◽  
High Temperature ◽  
Sewage Sludge ◽  
Moisture Content ◽  
Cellulase Activity ◽  
Moisture Loss ◽  
Intensity Change ◽  
Composting Process ◽  
Activity Intensity ◽  
Sludge Disposal

Compost is widely used for treating urban garbage and sewage sludge. The enzyme activity is one of the important parameters of microbial quantity and its activity intensity change in the composting process, and all of the biochemical reactions during the composting process are carried out with the enzymes involving. The composting progress and the material change are directly reflected by the enzyme activity. In Zhengzhou Bagang sludge disposal plant, sludge was mixed with straw to compost together and with the technology of high temperature solid state aerobic slot for sludge treatment. This study was done to research the tendency of peroxide enzyme activity, cellulose enzyme activity, pH, conductivity, moisture content in the process of compost. The result showed that at the beginning of the compost, cellulase activity increased first and then decreased gradually and tended to be stable. The catalase activity was higher at the beginning of the compost and at the period of temperature raising it was stable basically, then decreases quickly and after that it maintain on the lower level. The moisture content declined gradually during the composting process, and in the period of high temperature there are more moisture loss. PH increased at first, and with the temperature raised to high the pH decreased gradually and tended to be stable. Conductivity increased first, then decreased gradually to steady.

Effect of Turning on Moisture Content in Sewage Sludge Composting

2013 ◽  
Vol 777 ◽  
pp. 457-460 ◽  
Author(s):  
Nian Hong ◽  
Jun Chen ◽  
Xue Hong Zhang ◽  
Tong Bin Chen
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Water Removal ◽  
Water Reduction ◽  
Composting Process ◽  
Cooling Phase ◽  
Sludge Composting

Turning can supply oxygen and increase dewatering efficiency during the composting process. This study was conducted to investigate the influence of turning on water removal. In this study, different turning modes were used in different fermentation phases. Results showed that turning in thermophilic phase improve the efficiency of water removal; in cooling phase, higher turning frequency resulted in lower water removal; turning in temperature-increasing phase had no significant effect on water removal. Unturning in the temperature-increasing phase, turning once in the thermophilic phase, and turning every 4 days in the cooling phase achieved the best effects of water removal, the water reduction was 0.566 tonston-1 matrix.

Sewage Sludge Composting Process by Static Pile Method

1991 ◽  
Vol 23 (10-12) ◽  
pp. 1979-1989 ◽  
Author(s):  
H. Ishii ◽  
K. Tanaka ◽  
M. Aoki ◽  
T. Murakami ◽  
M. Yamada
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Natural Ventilation ◽  
Water Evaporation ◽  
Bulking Agents ◽  
Intermittent Aeration ◽  
Feed Mixture ◽  
Composting Process ◽  
Average Temperature ◽  
Sludge Composting

This paper reports the results of experiments on the static pile composting process undertaken in different conditions. The experiments have revealed the following:–In order to compost dewatered sludge with polymer without any bulking agents, we used recycled compost to adjust the moisture content of dewatered sludge.When the moisture content of feed mixture, which was dewatered sludges and recycled composts, was lowered to approximately 50%, the raw sludge could be composted by either natural ventilation or intermittent aeration.–When the BOD of feed mixture was lower than 50 g/kg-DS, the fermentation temperature did not reach 60°C and the moisture content of the mixture was not lowered during composting period.–The required composting time was approximately 50 days for natural ventilation (at an average temperature of 10°C or 24°C) and approximately 35 days for intermittent aeration (at an average temperature of 10°C to 24°C), when the moisture content and the BOD of finished compost was 40% or less and 30 g/kg-DS or less, respectively.–There was a highly positive correlation between the amount of water evaporated and the amount of BOD removed. This result suggested that the amount of water evaporation could be deduced from the amount of BOD removed.

scholarly journals Co-composting of meat packing wastewater sludge and organic fraction of municipal solid waste

2013 ◽  
Vol 15 (4) ◽  
pp. 513-521 ◽  
Keyword(s):  
Organic Matter ◽  
High Temperature ◽  
Sewage Sludge ◽  
Ambient Air ◽  
Wastewater Sludge ◽  
Maximum Temperature ◽  
Bulking Agents ◽  
Organic Fraction ◽  
Composting Process ◽  
Helminth Eggs

<p>The use of organic manures as amendments to improve soil organic matter level and long term soil fertility and productivity is gaining importance. The disposal of the great quantity of organic wastes produced by the municipal, agricultural and agroindustrial activities, is causing energetic, economic and environmental problems. Sludge composting and using them in agriculture should be a priority for their disposal. Sludge should be treated not as a waste but as a valuable non-farm sources of organic matter to soil. The composting process is a useful method of producing a stabilized material that can be used as a source of nutrients and soil conditioner in fields. The objective of this study was estimation of optimal dose of sewage sludge in composting mixture to obtain of mature and stable compost. The mixture was prepared from sewage sludge (10-40%), organic fraction of MSW(30%), grass (20-50%), sawdust as a bulking agents. Maximum temperature in the bioreactor reached 68.9&deg;C between 1st and 3rd day of composting, and the mean temperature during this period fluctuated from 36 to 46&deg;C. Later, the temperature gradually decreased and after 30 days of composting it approached ambient air temperature which means the end of process. There was significant impact of the high temperature on the rate of the process and of the extent of the hygienisation. The results show that all initial samples are infected with helminth eggs but there is a large variation in the degree of infection for the different sludge samples (102 to 256 eggs kg-1 d.m.). The inactivation of the helminth eggs in the compost can be accomplished, if the temperature inside of the reactor is sufficient as in the case M III and M IV. The final compost M III and M IV was well sanitized as a result of the high temperature achieved due to higher grass addition in those mixtures. Composts M I and M II can not be used in agriculture because of bad microbiological characteristic, however MII can be used for recultivation after hygienisation. The composted material assumed the appearance and structure similar to the so-called horticultural soil. As an exothermic process, composting caused very high loss of water in composted material. All the composts were granular, dark grey in color without foul odor and attained an ambient temperature after 30 days of composting, indicating the stable nature of composts. Additional researches are required in order to optimize the better organic and nitrogen compounds degradation during co-composting process.</p>

Small Scale Pilot Plant Thermal Dryer for Sewage Sludge Dewatering System – A Preliminary Study

2014 ◽  
Vol 695 ◽  
pp. 336-339
Author(s):  
Mohd Safuan Zakaria ◽  
Suhaimi Hassan ◽  
M. Faizairi
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Solid Fuel ◽  
Continuous Production ◽  
Small Scale ◽  
Sludge Dewatering ◽  
System A ◽  
Sludge Disposal ◽  
The Common ◽  
Treatment And Disposal

Malaysia expected to face serious problem in sewage sludge disposal in the next few years if this problem is not properly manage and well treated. The common way of sludge disposal in Malaysia is to dispose it on the land, by landfill disposal. However, most of the landfill has been closed since reaching it capacity. This product required innovation and advance solution for treatment and disposal since the production of sewage sludge rapidly increasing and the available solution for their disposal is out dated .One of the ideal solution to dispose the sludge is by converting it into useful energy in the form of solid fuel such as pallet and briquette and burn it as a solid fuel to generate power. However, the main problem faced is it contains high moisture content which is more than 90% of moisture content. In order to convert it into useful energy, the moisture content of the sludge need to be reduced into acceptable level which is below 20% . One of the effective methods to remove the moisture content is by using a thermal dryer. The preliminary results from this study found that the thermal dryer produced 63.32kg/h of dried sewage sludge with moisture content less than 20% . The production rate of this dryer shows positive result and with continuous production, this dryer cable to dry tons of wet sewage sludge.

Estimation of Energy Saving for Melting Process on Sewage Sludge

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2011-2018 ◽  
Author(s):  
T. Murakami ◽  
K. Sasabe ◽  
K. Sasaki ◽  
T. Kawashima
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Saving ◽  
Fuel Consumption ◽  
Melting Process ◽  
System Operation ◽  
Operational Conditions ◽  
Volatile Solids ◽  
Cake Moisture ◽  
Very High

The possible volume reduction and stabilization of the sewage sludge associated with the melting process are expected to be greater than with the incineration process. In addition, melted slag can be utilized. However, since the melting process requires a very high temperature to melt inorganics (ash) in the sludge, the technologies to minimize energy consumption, to establish system operation and to prolong durability of facilities should be developed. This paper discusses the auxiliary fuel consumption as follows.(1)Preparation of a model that provides the auxiliary fuel consumption of the melting system on the basis of the mass and heat balances.(2)Evaluation of the auxiliary fuel consumption in the above model using the cake moisture content, the volatile solids of the cake, the dried cake moisture content and the melting temperature as parameters.(3)Examination of the operational conditions for an energy saving melting system based on the results of (1) and (2) above.

scholarly journals Assessment of content and chemical forms of arsenic, copper, lead, and chromium in sewage sludge compost as affected by various bulking agents

2020 ◽  
Vol 43 (1) ◽  
pp. 56-66
Author(s):  
Mahboub Saffari ◽  
Vahid Reza Saffari ◽  
Hojatollah Khabazzadeh ◽  
Hormazd Naghavi
Keyword(s):  
Sewage Sludge ◽  
Total Concentration ◽  
Bulking Agents ◽  
Chemical Forms ◽  
Organic Fraction ◽  
Specific Kind ◽  
Composting Process ◽  
Mobility Factor ◽  
Arsenic Copper ◽  
Different Levels

AbstractIn current study, the effect of various organic substances as bulking agents (BAs) including wheat straw, pistachio hull wastes, and tree leaves at different levels (10, 25, 45% v/v) were investigated on total concentration and chemical forms of Cu, Pb, Cr, and As in sewage sludge (SS) compost prepared by windrow method. According to the results, the composting process (with/without BAs), due to losses of SS mass and volume, increased the total concentration of heavy metals (HMs) compared to the un-composted SS sample (RSS). Evaluation of HMs chemical forms in prepared compost sample without BAs application (CSS) showed that the composting process reduced the mobility factor of As (from 28% to 20%), Pb (from 11.6% to 9.3%), and Cr (from 14.5% to 9.2%) compared to the RSS. Application of three BAs considerably decreased the mobility factor of As (17.5-18.8%), Pb (4.8-7.9%), and Cr (1.4-6.8%) compared to CSS and RSS. Changes of Cu mobility in prepared compost samples showed an unclear trend, however in some treatments, due to transferred organic fraction into exchangeable and carbonate fractions, increasing of this factor was obvious. Generally, the composting appeared to reduce As, Pb, and Cr availability by stabilizing the three metals and making them more stable and less mobile. In addition, the BAs application effect on HMs behavior of SS compost samples were so different and no specific kind of BAs can be recommended as a superior BAs in SS composting process.

Influence of Enzyme Activity of Bacteria and Leucocytes in Raw Milk on Age Gelation after UHT Processing

1984 ◽  
Vol 47 (2) ◽  
pp. 105-107 ◽  
Author(s):  
BARBARA P. KEOGH ◽  
G. PETTINGILL
Keyword(s):  
Enzyme Activity ◽  
High Temperature ◽  
Inhibitory Action ◽  
Raw Milk ◽  
Bacterial Counts ◽  
High Temperature Processing ◽  
The Relationship ◽  
Ultra High Temperature

An investigation was undertaken into the relationship between the enzyme activity of cells harvested from raw milk and time taken for age gelation (TAG) to occur in the milk after ultra-high-temperature processing. It was shown that there was no relationship between the TAG and the bacterial counts on milk agar at 30°C or 7°C nor was there a relationship between the counts and the level of enzyme activity of the harvested cells. There was, however, a significant correlation between the level of enzyme activity of the harvested cells and the TAG. When extra bovine leucocytes were added to raw milk before processing, the TAG was increased. This suggested that there was an inhibitory action of leucocytes in development of age gelation.

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