• Korean Journal of Environmental Agriculture
• /
• v.21 no.2
• /
• pp.117-121
• /
• 2002

This study was conducted to find out the effect of municipal sewage sludge on the growth and heavy metal content of rose and soil chemical properties. Municipal sewage sludge was applied to soil at rate of 0, 3, 5, 10 and 15 ton/10a, the plant height, flower number and stem size of rose were found to be increase in the treatments of sewage sludge. Contents of mineral nutrients in rose stem were determined to be higher at municipal sewage sludge application plots than those of no application. But, there were not any significant increases of heavy metal contents in soil and rose stem with the sludge applications. from the results of this study, it is apparent that the application of municipal sewage sludge would not increase available heavy metals in soil.

• Journal of Environmental Health Sciences
• /
• v.35 no.1
• /
• pp.58-63
• /
• 2009

This study investigated improvement to sludge dewaterability and coagulation for sewage treatment plant sludge by using sodium hypochlorite solution (NaOCl), ferric sulfate [$Fe_2(SO_4)_3$] and zeolite. The specific resistance to filtration(SRF), chloride, pH and turbidity were used to evaluate the sludge dewatering behaviors. The results of study were as follows: By varying the amount of NaOCl added the optimum result in terms of enhancement for pretreatment occurred when 34 mg/l of NaOCl was injected. When the total solids concentration of the sludge was 10,000 mg/l, the optimum ferric sulfate dosage for the sludge dewaterability was 150 mg/l and the corresponding SRF was $1.7{\times}10^7sec^2/g$. It was observed that injecting zeolite into sludge was effective in improving the dewaterability of sludge.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.4
• /
• pp.25-34
• /
• 2003

This paper is focused on an experimental study in order to investigate the utilization of sewage sludge ash as the cover and liner materials for the waste disposal landfill or as construction materials. A series of tests were performed to evaluate the basic properties, compaction, compressive strength, consolidation, permeability, and CBR of sewage ash. Specially, clay bricks were made as increasing replacement ratio of sewage ash (such as 5, 10, 15, 20, 25, 30%). And tests were fulfilled for its quality. Bentonite and lime were used as the additives to improve permeability properties of sewage sludge ash. As a result of tests, it was shown that the permeability coefficient decreases as increasing bentonite content and the percentage of bentonite was roughly needed 20% to keep the permeability coefficient below $1{\times}10^{-7}cm/sec$. The results of unconfined compression tests show that sewage ash meets the criteria of the unconfined compression strength for cover material. It was shown that the compressive strength decreases as increasing the replacement ratio of sewage sludge ash and the maximum replacement ratio of sewage sludge ash to satisfy the quality standards of the third degree bricks was about 15%.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.4
• /
• pp.508-514
• /
• 2004

Industrial and municipal wastewater treatment plants produce large amounts of sludge cakes for final disposal. This problem is an inevitable drawback inherent to the activated sludge process. Both the reduction of the amount of sludge produced and improvement of its dewaterability are presently very important issue also in Korea. So many pre-treatment processes have been developed in order to improve sludge dewatering efficiency. In this study the effects of hydrogen peroxide and paper sludge mixing processes were considered as reasonable alternatives to enhance sludge dewaterability. The CST of sludge was significantly decreased, and dewaterability improved by hydrogen peroxide oxidation treatment. The optimum dosage of hydrogen peroxide was proved to be 10mg/g-TS (when TS of sludge was 2%) with the conditions of pH 4 and only 1~2 minutes of reaction time. The mixing of paper sludge with sewage sludge was turned out to be very effective in reduction of sludge cake; 30% of sludge cake reduction was accomplished. Optimum mixing ratio of paper sludge was about 30%(v/v). This process also could save 25% of polymer to be required. These two alternatives are somewhat realistic, but it was concluded that paper sludge mixing process will be the best choice.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.3
• /
• pp.299-304
• /
• 2014

The need of reusing sewage sludge is highly increasing as the amount of domestic sewage sludge is growing and sewage management strategies were reinforced. Accordingly, in this research, we studied the composting possibility of sludge in sewage treatment plant J, using dryer facility with indirect system by conducting component analysis of dried sludge and experiment on cultivating crops. It was observed from the component analysis, that the dried sludge is appropriate for both decomposed manure standard of Ministry of Environment and fertilizer standard of Rural Development Administration. Besides, in the experiment on cultivating lettuce, the experimental group(soil + dried sludge) was superior to the control group(soil + bed soil) in apparent condition of leaves tensity and damage by disease and pest. In case of cultivating tomato, the experimental group showed stronger durability of fruits dangling on stems compared to the control group after 9 weeks. Consequently, the excess sludge dried by indirect heating system in the sewage treatment plant J is appropriate for the standard of both Ministry of Environment and Rural Development Administration and show good result in experiment on cultivating crops therefore it can be reused for composting.

• Journal of Korean Society on Water Environment
• /
• v.36 no.4
• /
• pp.322-331
• /
• 2020

By introducing chemically enhanced primary treatment (CEPT) in the first stage of sewage treatment, organic matter in sewage can be effectively recovered. Because CEPT sludge contains a high biodegradable organic matter in volatile solids (VS), it is feasible to convert the collected CEPT sludge into energy through anaerobic digestion. This study examined the properties and biochemical methane potential (BMP) of the CEPT sludge obtained from a sewage treatment plant located in an ocean area. The CEPT sludge contains a VS content of 37,597 mg/L, which is higher than that of excessive sludge (ES), i.e., 33,352 mg-VS/L. In the methane generation reaction, the lag period was as short as 1 to 2 days. The BMP for the CEPT sludge was 0.57 ㎥-CH₄/kg-VS_removed which is better than that of ES, i.e., 0.36 ㎥-CH₄/kg-VS_removed. Unfortunately, the CEPT sludge showed a high salinity as 0.56~0.75% probably due to the saline sewage. Due to the salinity, repeated BMP testing in a sequencing batch reactor showed significantly low methane production rates and BMPs. Also, the ES showed a strongly reduced BMP when the salinity was adjusted from 0.20 to 0.70% by NaCl. The ES mixture with higher CEPT content showed a better BMP, which is suitable for co-digestion. Besides, anaerobic digestion for 100% CEPT sludge can be a considerable option instead of co-digestion.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.3
• /
• pp.31-38
• /
• 1999

The purpose of this study were to determine the optimum mixing ratio of sewage sludge and papermill sludge as carbon source required to SRB in treating abandoned mine drainage with natural purification wetland. If mixing sewage sludge/papermill sludge 2.0 SO42- reduced 46.2%, and then 30% in mixing ratio 0.5.Because sewage sludge was faster biodegradability than papermill sludge, effluent SCOD was 40mg/L in mixing ratio 0.5, and after that was all but regular. pH and ORP were almost neutral and -160mV, but after that was all but regular and it indicated that SRB activity was suitable. Fe removal rate was 60% in mixing ratio 2.0, and 54% in mixing ratio 0.5. In point of carbon source supply, It indicated that mixing ration 0.5 was considered as the most appropriate, because degradability of swewage sludge under short time was higher than that of papermill sludge.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.6
• /
• pp.800-808
• /
• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• The Korean Journal of Ecology
• /
• v.19 no.3
• /
• pp.271-282
• /
• 1996

This study was aimed to observe the effects of municipal sewage sludge as a organic fertilizer on the growth and KDICical omposition of Altari radish (Raphanus sativus). The accumulation rate of heavy metals of the sludge in the radish was also observed. Municipal sewage sludge of Taejon City was applied to the soil of Pai-Chai University Farm to make 6 gradients of sludge contents in the soil. Root weight of Altari radish was affected significantly by N and P contents in the soil. The longest leaves and roots were produced in the control group, in which urea was applied as nitrogen source to the soil. Even though any other sludge-applied groups produced shorter leaves and roots than the control group, the length of the leaves and roots and the weight of the whole plant of the radish tended to increase with the increase of the sludge application. Contents of N, K, Ca and Mg in the radish were not significantly different among those in 6 experimental groups, but P contents in leaves varied among the 6 groups. Zn content of spring Altari radish treated with 200% sludge was 57.6 mg/kg. It is the highest contents among 6 experimental groups. Contents of Zn, Mn and Cd were higher in leaves than in roots, but less than those in market vegetables. From the above results, it is concluded that municipal sewage sludge can be applied as organic fertilizer to the growth of Altari radish. But this sludge could not be applied under our current regulations, which must be reviewed at intra-governmental leavels.

• Applied Chemistry for Engineering
• /
• v.25 no.5
• /
• pp.510-514
• /
• 2014

In this work, the effect of torrefaction on the basic characteristic of sewage sludge was studied to evaluate the energy potential as a solid fuel. Torrefaction experiments were performed at temperatures of $150{\sim}600^{\circ}C$. The torrefied sewage sludge was characterized by the energy yield, ash content, volatile fraction and high heating value (HHV). The gaseous products from torrefaction of the sewage sludge were also analyzed. Thermogravimetric analysis was carried out for the kinetic analysis of sewage sludge torrefaction. From this work, it was found that the ash content increased with an increase of the torrefaction temperature while the energy yield, HHV and volatile fraction decreased. It was also found that the emission of carbon monoxide and hydrocarbon gases started at $300^{\circ}C$ by the thermal degradation of volatile components in the sewage sludge.