Performance evaluation of on-site treatment facilities for wastewater from Households, Hotels and Restaurants

1999 ◽  
Vol 39 (8) ◽  
pp. 85-92 ◽  
Author(s):  
Jun Nakajima ◽  
Yoko Fujimura ◽  
Yuhei Inamori
Keyword(s):  
Nitrogen Removal ◽  
Treated Wastewater ◽  
Small Scale ◽  
Environment Protection ◽  
Intermittent Aeration ◽  
Household Wastewater ◽  
Hexane Extracts ◽  
Individual Household ◽  
Treatment Facilities ◽  
Low Performance

In order to evaluate performance of on-site treatment facilities which can be provided for environment protection in coastal areas, effluent qualities and removal efficiencies were surveyed in actual treatment facilities for wastewater from households, hotels and restaurants. On-site treatment facilities in Japan are fundamentally built according to the structural standards. They have a pretreatment process (sedimentation separation tank, anaerobic filter or equalization tank with screens) followed by an aerobic process (contact aeration, activated sludge, etc.). Small-scale facilities for individual household wastewater showed good performance of BOD removal with their effluent BOD below 20mg 1−1. They also exhibited nitrogen removal efficiency when they were operated in mixed liquor recycle mode. The facilities applied to wastewater from hotels, restaurants and stores showed good performance when the influent oil (hexane extracts) concentration had been decreased below 30mg 1−1 by using pretreatment. Nitrogen removal performance was high in the facilities which treated wastewater from a residential area or a condominium when they were operated in intermittent aeration mode. But resort condominiums of which influent BOD load was extremely low showed low performance of nitrogen removal even though they were operated in intermittent aeration mode because of the low BOD/N ratio in the influent. An equation was proposed to estimate the amount of methanol to be added in facilities in which the influent BOD/N ratio is low.

Effect of dissolved oxygen conditions on nitrogen removal in continuously fed intermittent-aeration process with two tanks

2002 ◽  
Vol 45 (12) ◽  
pp. 181-188 ◽  
Author(s):  
T. Hidaka ◽  
H. Yamada ◽  
M. Kawamura ◽  
H. Tsuno
Keyword(s):  
Nitrogen Removal ◽  
Rural Areas ◽  
Aerobic Condition ◽  
Small Scale ◽  
Intermittent Aeration ◽  
Solids Retention ◽  
Oxygen Conditions ◽  
Control Set ◽  
Aeration Process ◽  
Biological Nitrogen

In this study, an intermittent aeration type activated sludge process that is fed continuously is evaluated for nitrogen and organic carbon for facilities in rural areas, which are characterized by small scale, low loading rate and automatic operation. Anoxic and aerobic conditions can be regulated alternatively by intermittent aeration for biological nitrogen removal. It is proved that an intermittent aeration cycle of 90 min, with aeration/anoxic mixing periods of 25~30 min/65~60 min in Tank 1, and 30~45 min/60~45 min in Tank 2, and a DO control set at 0.6~1 mg/L during the aeration period are required for satisfactory treatment performance. Under these conditions, a stable effluent water quality with BOD ≤ 5 mg/L, CODMn ≤ 8 mg/L, Nitrogen ≤ 3 mgN/L, SS ≤ 5 mg/L and transparency ≥ 80 cm can be achieved. The solids retention time in aerobic condition was 10~25 d, which is sufficient for nitrification.

Feasibility of contact aeration method for small-scale domestic wastewater treatment system in rural China

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
T. Kuyama ◽  
M. Mizuochi ◽  
H. Koyanagi ◽  
T. Wako
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Wastewater Treatment Plants ◽  
Rural China ◽  
Domestic Wastewater ◽  
Treated Wastewater ◽  
Small Scale ◽  
Billing System ◽  
Domestic Wastewater Treatment ◽  
Treatment Facilities

This study examines the feasibility of the contact aeration method for utilisation in small-scale domestic wastewater treatment facilities in various rural areas of China, where the national government starts to address the water pollution issue. Three pilot facilities using the contact aeration method with different capacities were constructed, operated and monitored in Chongqing city and Jiangsu province. In order to evaluate the feasibility of the constructed facilities, the quality of treated wastewater and the operational cost were monitored. Results obtained from the monitoring showed that BOD and COD effluent concentrations achieved quality targets in all facilities. As for the other pollutants, quality targets were met for most of the period. Operational costs of facilities bettered those set for the facility in the town of Baiyang and new village of Zhaojia, but exceeded them for the facility in the village of Dongbei. The main reasons for the differences were the electricity billing system and operational system for each facility. In order to promote small-scale aeration-based domestic wastewater treatment plants in rural China in the future, the issue of what constitutes efficient facility maintenance first needs to be addressed.

Practical Performance of Nitrogen Removal in Small-Scale Sewage Treatment Plants Operated in Intermittent Aeration Mode

1991 ◽  
Vol 23 (4-6) ◽  
pp. 709-718 ◽  
Author(s):  
Jun Nakajima ◽  
Mitsumi Kaneko
Keyword(s):  
Nitrogen Removal ◽  
High Performance ◽  
Nitrogen Concentration ◽  
Sewage Treatment ◽  
Small Scale ◽  
Aeration Tank ◽  
Intermittent Aeration ◽  
Sewage Treatment Plants ◽  
Chiba Prefecture ◽  
Practical Performance

Research was carried out to clarify the number and the scale of small-scale sewage treatment plants operated in intermittent aeration mode by asking questions to maintenance workers in Chiba Prefecture, Japan. The percentage of the number of plants operated in intermittent aeration mode was 26.5%. This percentage was high in the plants larger than 200 population equivalent (p.e.). The practical performance of nitrogen removal was evaluated in nine existing plants operated in intermittent aeration mode. A high performance of nitrogen removal was noticed in the plants us ing extended aeration process. The performances of nitrogen removal in two plants operated in intermittent aeration mode were compared with those operated in continuous aeration mode. The characteristics of denitrification taking place in the aeration tank in a plant operated in intermittent mode were investigated by measuring the change in nitrogen concentration in the tank during the intermittent period. The seasonal performanee of denitrification was studied by a long term practical experiment for 16 months. By operating the length of intermittent time according to the change of the water temperature in the aeration tank, a high performance of nitrogen removal was obtained throughout the year.

Cultivation of rice for animal feed with circulated irrigation of treated municipal wastewater for enhanced nitrogen removal: comparison of cultivation systems feeding irrigation water upward and downward

2015 ◽  
Vol 72 (4) ◽  
pp. 579-584 ◽  
Author(s):  
A. Muramatsu ◽  
H. Ito ◽  
A. Sasaki ◽  
A. Kajihara ◽  
T. Watanabe
Keyword(s):  
Nitrogen Removal ◽  
Irrigation Water ◽  
Rice Plant ◽  
Municipal Wastewater ◽  
Animal Feed ◽  
Paddy Fields ◽  
Treated Wastewater ◽  
Human Consumption ◽  
Cultivation System ◽  
Treated Municipal Wastewater

To achieve enhanced nitrogen removal, we modified a cultivation system with circulated irrigation of treated municipal wastewater by using rice for animal feed instead of human consumption. The performance of this modified system was evaluated through a bench-scale experiment by comparing the direction of circulated irrigation (i.e. passing through paddy soil upward and downward). The modified system achieved more than three times higher nitrogen removal (3.2 g) than the system in which rice for human consumption was cultivated. The removal efficiency was higher than 99.5%, regardless of the direction of circulated irrigation. Nitrogen in the treated municipal wastewater was adsorbed by the rice plant in this cultivation system as effectively as chemical fertilizer used in normal paddy fields. Circulated irrigation increased the nitrogen released to the atmosphere, probably due to enhanced denitrification. Neither the circulation of irrigation water nor its direction affected the growth of the rice plant and the yield and quality of harvested rice. The yield of rice harvested in this system did not reach the target value in normal paddy fields. To increase this yield, a larger amount of treated wastewater should be applied to the system, considering the significant amount of nitrogen released to the atmosphere.

Reflections on Ecological and Environmental Construction of New Rural Program in Underdeveloped Areas

2011 ◽  
Vol 368-373 ◽  
pp. 3602-3606
Author(s):  
Ze Xin Li ◽  
Min Chen
Keyword(s):  
Rural Areas ◽  
Rural Economy ◽  
Living Environment ◽  
Ecological Environment ◽  
Small Scale ◽  
Environment Protection ◽  
Underdeveloped Areas ◽  
Rural Program ◽  
Rural Construction ◽  
New Rural Construction

Underdeveloped rural areas have good but very vulnerable ecological environment, so the environment protection should be given priority in new rural construction. Based on the problems that rural areas have faced in ecological environment, some thoughts are given in this paper on ecological and environmental: ①To solve the conflicts between the development of rural economy and ecological environment protection, the development of eco-industry can be a key solution. ② For the point that people of underdeveloped areas live in scattered and small scale groups, which leads to difficulty in facility arrangements, some proposals are put forward on the construction of living environment in underdeveloped new rural areas.

Coronavirus SARS-CoV-2 in wastewater

2021 ◽  
pp. 45-55
Author(s):  
В.Я. Кофман
Keyword(s):  
Rna Virus ◽  
Health Hazard ◽  
The United States ◽  
Treated Wastewater ◽  
The European Union ◽  
Sewer Systems ◽  
Long Time ◽  
Treatment Facilities ◽  
Coronavirus Infection ◽  
Low Prevalence

Пандемия СOVID-19, объявленная ВОЗ чрезвычайной ситуацией в области здравоохранения, вызвана новым коронавирусом SARS-CoV-2. По сообщениям из Евросоюза, США и Австралии, потенциальная выживаемость коронавируса SARS-CoV-2 в фекалиях и сточных водах в течение достаточно длительного времени создает реальную возможность его поступления с канализационными стоками на очистные сооружения или непосредственно в поверхностные воды при сбросе неочищенных стоков. Это свидетельствует о существовании потенциальной возможности передачи SARS-CoV-2 через воду. В этой связи особую актуальность приобретает разработка эффективных способов удаления и инактивации вирусов на очистных сооружениях. Наличие коронавирусной инфекции в сточных водах может представлять серьезную опасность для здоровья контактирующих с ними людей. К ним относится персонал очистных сооружений, а также население в целом, которое может подвергаться непосредственному воздействию необработанных или недостаточно обработанных сточных вод через неисправные водопроводные или канализационные коммуникации. Во многих странах для получения своевременной достоверной информации о распространении коронавирусной инфекции используют методы эпидемиологии сточных вод. Возможность выявления РНК вируса в сточных водах даже при низкой распространенности СOVID-19 и корреляция между концентрацией РНК SARS-CoV-2 в сточных водах и официальной информацией указывают на то, что наблюдение за сточными водами может стать чувствительным инструментом мониторинга циркуляции вируса в популяции. The COVID-19 pandemic, declared by WHO as a health emergency, is caused by a novel SARS-CoV-2 coronavirus. According to reports from the European Union, the United States and Australia, the potential survival of the SARS-CoV-2 coronavirus in feces and wastewater for a sufficiently long time creates a real threat of its entry with wastewater into treatment facilities or directly into surface water while raw wastewater is discharged. This indicates the potential for the transfer of SARS-CoV-2 by water. In this regard, the development of effective methods for the removal and inactivation of viruses at the treatment facilities is of special actuality. The presence of coronavirus infection in wastewater can pose a serious health hazard to people in contact with it. These include the personnel at the wastewater treatment facilities, as well as the general population, who may be directly exposed to raw or inadequately treated wastewater through defective water or sewer systems. In many countries wastewater epidemiology methods are used to obtain timely reliable information on the spread of coronavirus infection. Possible detection of RNA virus in wastewater even with a low prevalence rate of COVID-19 and the correlation between the concentration of SARS-CoV-2 RNA in wastewater and official information indicate that monitoring wastewater can become a sensitive tool for monitoring the circulation of the virus in the population.

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