Septic tanks are treatment equipment that utilizes sedimentation and anaerobic fermentation principles to remove suspended organic matter from domestic wastewater. The corrugated fiberglass septic tank is internally equipped with baffles, where the holes are positioned unevenly from top to bottom, preventing short-circuiting and dividing the entire tank into three sections: primary anaerobic chamber, secondary anaerobic chamber, and clarification section.
The room features a first and second-grade anaerobic chamber with a common bottom, internally equipped with "MDS Special Type Filler." This separation minimizes the contact time between wastewater and sludge, allowing the acidic fermentation and alkaline fermentation processes to be unobtrusive to each other. At the same time, the presence of the filler increases the contact surface area between wastewater and sludge, significantly...
Enhanced response efficiency.
The actual test data for the effluent quality of septic tanks, the removal rate of impurities, and the treatment effectiveness are not as comprehensive as those for water and wastewater treatment facilities. It is necessary to select representative types of buildings in various regions, and conduct tests on the water quality in and out of septic tanks at different times of the day across seasons. Regular testing should also be performed based on changes in the composition of domestic wastewater to enrich and perfect the design data, and guide engineering design.
Cleaning Cycle
The cleaning cycle of septic tanks is related to the temperature of fecal wastewater, ambient temperature, nature of the building, and the quality and volume of drainage water. If the designed cleaning cycle is too short, the concentration of the septic tank sludge will be excessively high, significantly differing from the actual cleaning cycle, which can affect normal fermentation and wastewater treatment effectiveness, and even lead to sludge overflow, impacting the environment.
Sanitation. If the cleaning cycle of the design is too long, the septic tank volume will be too large, increasing the construction cost. The "Code for Design of Water Supply and Drainage of Buildings" (GBJ15-88) (hereinafter referred to as the "Code") requires a cleaning cycle of 3 to 12 months, with most actual designs opting for 3 to 9 months, and the acid fermentation period in the acidic fermentation stage is 3 months.
In the month, the acidic reduction period is about 5 months. Practical experience shows that the determination of the cleaning cycle should take into account three factors: the wastewater treatment effect, construction cost, and management. Generally, the cleaning cycle should not be less than 12 months. The Shangyuamen Waterworks dormitory area has a common septic tank for a cluster of bungalows, serving 200 people, with standard domestic wastewater.
Each person requires 30L/day, sludge output per person is 0.4L/day, fresh sludge moisture content in the septic tank is set at 95%, and the moisture content of the sludge after fermentation is 90%. The design cleaning cycle is chosen as 12 months, and the calculated septic tank volume is 21m³.
Dwell time
The detention time in a septic tank is a critical indicator related to the effectiveness of wastewater treatment and the volume and cost of the septic tank. A short detention time results in poor wastewater treatment; an extended detention time increases the volume and cost of the septic tank, as well as complicates its layout. The determination of detention time should balance the effectiveness of wastewater treatment with construction costs.
Price considerations should take into account the impact of fermentation-generated bubbles on the laminar flow state required for sedimentation, the negative effects of numerous turns in the septic tank on sedimentation, and the significant instantaneous changes in domestic wastewater discharge on the uniformity of incoming flow rate. Adequate leeway should be left for the retention time in the septic tank. "The Standard" requires: During retention time,
Retrieval interval: 12 to 24 hours. Practical evidence shows that the retention time should not be less than 12 hours to ensure effective wastewater treatment. The septic tank in the dormitory area of the Shangyuanmen Waterworks has a retention time of 24 hours.
Wastewater sludge disposal issue
Based on the technical standards for septic tanks, the sludge removal time for septic tanks typically ranges from 90 days, 180 days, to 360 days. [3] The sludge removed can be used as organic fertilizer or disposed of in a non-hazardous manner. However, with the widespread use of chemical fertilizers and societal development, the use of fecal fertilizers has decreased accordingly.
At the same time, our country's sludge disposal industry is significantly lagging behind, with insufficient harmless treatment of fecal sludge. With a population of 1.36 billion, China generates over 100 million tons of fecal sludge annually. According to statistics, only 8.014 million tons of fecal sludge were treated harmlessly in 2012. The large-scale removal and transfer of fecal sludge have led to secondary...
Pollution. Therefore, if the problem of non-hazardous disposal of septic tank sludge cannot be resolved, the sludge will become a source of water pollution. The septic tank issue is an environmental problem related to the effectiveness of water pollution control. [2] [3]
Septic tank blockage issue
Sewage treatment tank sedimentation sludge consists of bottom sediment, surface floating sludge, and suspended sludge and wastewater in between. The tank is divided into two or three compartments by partition walls, with overflow openings located in the middle of the partition walls. If the tank is not emptied in a timely manner, the sediment may...
Excess sludge accumulation exceeds the height of the overflow opening, causing the sludge to block the opening and leading to a septic tank blockage. Septic tank blockages severely disrupt normal user life and are urgent application issues for septic tanks that need to be addressed.
Trends in Development Editor's Report
Wastewater pollution in daily life is increasingly serious. This product, based on the summary of foreign imported domestic wastewater treatment technologies, combined with scientific research achievements and engineering practice, utilizes high polymer composite materials for factory production. It is an energy-saving, lightweight, and cost-effective domestic wastewater treatment equipment. It has successfully replaced...
Traditional brick-and-mortar septic tanks and concrete ones have polluted underground water quality and endangered the safety of surrounding buildings due to leakage and poor operating conditions. This product utilizes the gravitational flow of water, requiring no external power or operation costs, thus saving energy and making management convenient. It offers excellent social, environmental, and economic benefits.
Benefit.
