Average Removal Rate Of Turbidity Research Articles

Effects of pre-ozonation and chemical coagulation on the removal of turbidity, color, TOC, and chlorophyll a from drinking water

Background: Ozone can be used as a single technology or in combination with other processes to improve the coagulation- flocculation or biodegradability in order to remove pollutants in natural water treatment. Methods: In this study, the effects of pre-ozonation with coagulant substances on the quality parameters of drinking water were investigated using humic acid, kaolin, clay, and green algae in a pilot scale. This study was conducted under laboratory conditions (at both acidic and alkaline pH in different dosages of ozone and coagulant at ozone contact time with simulated water sample (5-20 minutes) in different scenarios). Results: The highest removal efficiency of parameters in the state of pre-ozonation alone and preozonation with a coagulant was observed at contact time of 20 minutes, ozone dosage of 5 g/h, coagulant dosage of 25 mg/L, at alkaline pH along with a decrease in temperature. So that, the average removal rate of turbidity, total organic carbon (TOC), color, and chlorophyll a in contact time of 20 minutes was 76.9%, 52.8%, 66.6%, and 85%, respectively. However, compared to ozonation under similar conditions, the reduction in turbidity, TOC, color, and chlorophyll a was 36.13%, 24.4%, 32.13%, and 79.6%, respectively. Also, it was revealed that pre-ozonation with coagulant could effectively improve the removal of parameters. Conclusion: However, since pre-ozonation can be effectively used to improve the coagulation efficacy in the drinking water treatment, the pre-ozonation combined with coagulation is proposed as an alternative to conventional coagulation to improve the process of drinking water treatment plant.

Decontamination Features and Mechanism Research of Copolymerization Dissolved Air Flotation Process

In the traditional dissolved air flotation (DAF), micro bubbles generally cannot mesh and adhere to particles efficiently, and the adhesion between microbubbles and particles is not stable, either. In this paper, a self-developed copolymerization dissolved air flotation (Co-DAF) system was proposed to strengthen the copolymerization of condensation reaction during the adhesion of bubbles and flocs, by grading the refluxed dissolved air water, which could significantly enhance the adhesion efficiency and the stability of the bubble-flocs. On this basis, raw water of low turbidity, high algae and high organic contents from the Yellow River reservoir was used as the water supply to verify the effectiveness of the proposed system. The results showed that the average removal rate of turbidity was 95.2%, among, which 93.6% of the particles larger than 2 μm were removed effectively. Meanwhile, the removal rates of CODMn, UV254, DOC, SUVA and ammonia nitrogen were 43.2%, 48.5%, 38.2%, 20.5 and 77.3%, respectively, and those of organics with molecular weight between 3000–10000 Da and more than 3000 Da were 30.6% and 85%, respectively. However, for those organics with molecular weight less than 1000 Da, only a removal rate of 10% was achieved. During the test, DBPFP could be well controlled by the Co-DAF process, and the removal rates of CHCl 3, CHClBr2, CHCl 2Br and CHBr3 were 22.9%, 21.9%, 16.0% and 18.2%, respectively. It was deduced that the mechanisms of removing pollutants by the Co-DAF process mainly included the collision and adhesion effects between micro bubbles-floc particles, the copolymerization between microbubble-flocs and particles, and the adsorption bridging effects among bubble-flocs, microbubbles and particles.

Laboratory Experiments of Roofwater Treatment by Sand Column in Jinan

To satisfy the requirements of high speed, large volume and high water quality for fracture-karst aquifer recharge by roofwater, sand filtration column was designed. Lab experiment of roof rainwater treatment by sand column was conducted to study the effect of roof rainwater purification in Jinan as pretreatment for fracture-karst aquifer recharge. The results show that the sand filtration column is effective in removing pollutants in roof rainwater. The average removal rate of turbidity reaches 87%, and the average removal rate of suspended solids is above 70%; the sand column is also effective in removing chroma, volatile phenol, Pb and Zn to a certain degree. However, it has a poor effect in removing ammonia nitrogen and nitrite nitrogen. In addition, the removal of most pollutants such as turbidity, chroma and suspended solids mainly take palce in the upper layer, which needs to be replaced regularly.

Coagulation/Ultrafiltration Process for Treatment of Da Huofang Reservoir Water in Low Temperature and Low Turbidity Period

The treatment efficiency of Da Huofang Reservoir water in low temperature and low turbidity period by Coagulation/Ultrafiltration process was investigated in pilot study, and the water quality treated by the process was compared with that by the traditional treatment process. When coagulant dosage is 30 mg/L, the average removal rates of turbidity, CODMn and UV254 were 89.2%, 47.3% and 52.8% respectively in the coagulation/ultrafiltration process, and the treatment efficiency was obviously superior to the traditional process. In the study of operation parameters optimization for Coagulation/Ultrafiltration process, the optimum membrane flux was determined that was 50 L/m2h. The cleaning membrane water was treated by coagulation sedimentation process, and the quality of effluent was good which was mixed with raw water for reuse, and the experiment indicated that this method did not affect the stable operation of Coagulation/Ultrafiltration process, eventually the water recycling rate was improved from 89% to 96.5%.

Pilot Study of Yangtze River Water Treatment in the Winter by Sludge Return

Abstract. In order to optimize the dosage and improve the coagulation effect when Yangtze river with low temperature and low turbidity was treated by conventional treatment in the winter, pilot study of enhanced conventional treatment was conducted by dosing two coagulant respectively and returning sludge in sedimentation tank to flocculant tank, so the optimal ratio of sludge return and the impacts of sludge return on effluent turbidity in sedimentation tank and the remove effect of CODMnwas discussed. The results indicates that the optimal sludge return ratio for Yangtze river in winter is 8%. Under 8% sludge return ratio ,the dosage is reduced from 12mg/L (under no sludge return) to 3mg/L~6 mg/L, and dosage is saved 50%~75%. When dosing respectively 3mg/L~6 mg/L composite coagulant and 3mg/L~6 mg/L polymeric aluminum chloride, it can make average effluent turbidity in sedimentation tank decrease to 3.7NTU~2.4 NTU ,8.1NTU~4..4 NTU respectively and the average removal rate of turbidity and CODMncan reach up to 94.3%~96.3%, 89.9%~94.5%,30.8%~39%,32.5%~38.6% respectively, so the requirement of effluent turbidity in sediment tank is met. Comparing to the treatment effect under no sludge return condition, sludge return can not only improve the treatment effect but also reduce the dosage greatly.

Study on Treatment Efficiency of Livestock Waste Water with Biogas Slurry by Subsurface Constructed Wetland

The main objective of this study is to investigate the feasibility of treatment of livestock waste water with biogas slurry by the constructed wetland and provide the operation parameters for a full scale constructed wetland to improve the quality of waste water. The results showed that when the influent flux was 1.5m3/d, the average removal rates of Turbidity, COD, TN, NH4+-N and TP in the horizontal subsurface flow constructed wetland system were 89.57%, 59.21%, 55.09% 55.57% and 53.80% respectively. The wetland system has high treatment effect and run stably in the pretreatment process of livestock waste water with biogas slurry.

Biochemical Characteristics of UBAF in Different Influent NH<sub>4</sub><sup>+</sup>-N Concentration under Yellow River Condition

The upflow biological aerated filter(UBAF) filled with grain slag was applied in Yellow River treatment. The aim is to study the reactor’s ability withstanding ammonia nitrogen volumetric loading in Yellow River water treatment. As influent NH4+-N concentration increases from 0.2mg/L to 3.0mg/L, the average removal rate of turbidity, CODMn and NH4+-N were 82%, 27% and 97% respectively, and removal of NH4+-N occurs mainly in the filter layer depth changing from 150cm to 210cm. The nitrification performance improves when PO43- -P concentration in water reach 60μg/L, and the removal of NH4+-N occurs mainly in the filter media layer depth shortened from 210cm to 90cm.

Advanced Treatment of Municipal Wastewater Effluent by Coagulation/Sedimentation and Chlorine Dioxide Disinfection

Due to increasing water scarcity, reclamation and reuse of the secondary effluent of wastewater treatment plant are widely concerned in many countries. Before reuse, the residual contaminant in the secondary effluent should be further removed to guarantee safe reuse. Coagulation/sedimentation and subsequent chlorine dioxide(ClO2) disinfection was adopted for tertiary treatment of secondary effluent. Selection of coagulant and optimization of tertiary treatment parameters were performed in this study. The results showed that coagulation could remove turbidity and total phosphours(TP) effectively. Polyaluminium chloride(PAC) was the most suitable coagulant. The optimal coagulation condition was as follows: PAC dosage of 10mg/L(measured as Al3+), reaction time of 20 min, settling time of 40 min, in this case, the average removal rate of turbidity, color, UV254, TP and TOC could reach to 58.2%, 22.8%, 18.2%, 60.6% and 22.2%, respectively. ClO2could inactive bacteria andE. colieffectively. ClO2could further remove UV254, color and TOC. In case of ClO2dosage of 5mg/L, the sterilization efficiency could reach 100%, and the removal rate of UV254, color and TOC was higher than 25%, 70% and 25%, respectively. In the optimal condition, the removal efficiency of residual contaminant by the combination process was as follows: UV254of 45.9%, color of 76.5%, TOC of 66.7%, turbidity of 61.9% and TP of 96.3%.

Effect of Ozone Enhanced Flocculation on the Treatment of Secondary Effluent

Abstract Due to poor removal efficiency of refractory organic compounds, color and total phosphorous (TP) residual in the secondary effluent by the conventional advanced treatment technology, effect of ozone (O 3 ) enhanced coagulation on the treatment of the secondary effluent was investigated in this research. The results showed that ozone could improve the pollutant removal efficiency. After ozonation, the pollutant removal rate by the coagulation and filtration process increased. O 3 pre-treatment could extend the operation cycle of the variable void deep filter. In case of O 3 dosage of 1.5 mg/L, PAC dosage of 4 mg/L, flocculation time of 15 min and the filter operation cycle of 16 h, the average removal rate of turbidity, COD, UV 254 , TP and color by the combination of O 3 enhanced microflocculation and variable void deep filtration process (combination technology) was 79.0%, 46.5%, 56.6%, 30.8% and 69.2%, respectively, higher than that by the traditional combination of microflocculation and filtration process (traditional technology). In summary, the combination technology is an effective treatment technology in the tertiary treatment of the secondary effluent.

Constructed Wetland Series Process for Pretreatment Raw Water of Drinking Water Treatment Plant

In order to investigate the feasibility of pre-treatment of drinking water treatment plant by the constructed wetland and provide the operation parameters for a full scale constructed wetland to improve the quality of raw water. The constructed wetland series process was used to pre-treat influent water of drinking water treatment plant based on raw water of the Song hua jiang River. The results showed that when the influent flux was 1m3/d, the average removal rates of Turbidity, COD, TN and NH4+-N in the constructed wetland system were 94.27%, 56.77%, 2.37% and 55.65% , respectively. The wetland system has high treatment effect and run stably in the pretreatment process of the raw water. This system could lighten the load of the conventional water treatment processes effectively.