This research aimed to study the causes of changes in water quality and compare the water quality in Khlong Bang Khen Mai when the seasons and sampling points are different. These factors may cause a change in water quality. A total 50 of water samples were collected from 5 sampling points each point approximately 300 meters apart for a total distance of 1.5 kilometers. They cover three seasons such as winter (October 2020 to February 2021) summer (March to May 2021) and rainy (June and July 2021). Three parameters of this research which consist of both the chemical and physical quality parameters are pH Dissolved Oxygen (DO) and Electrical Conductivity (EC). The result shows that the average pH has ranged from 7.10 - 7.74 the dissolved oxygen (DO) was in 1.80 - 2.84 mg/L and the electrical conductivity (EC) was in the range of 327 - 517 μs/cm. A two-way analysis of variance is a statistical method used to compare the water quality in Khlong Bang Khen Mai. The results indicate that the test differences between seasons affected the change in water quality in all parameters with a statistically significant level of 0.05. Afterward the comparison of multiple comparisons by Scheffes method showed that the pH and dissolved oxygen (DO) in the rainy season were significantly different from winter and summer at the level of 0.05. For the electrical conductivity (EC) there was significant differences between summer and winter at the 0.05 level.

The objectives of this study were to investigate communities confidence in their local leaders the locals awareness and factors affecting peoples participation in the water quality management. Data were collected from interviewing 400 households and analyzed with a Logit model. Results showed that the samples were well aware of water quality problems. The communities confidence in their local leaders was in a middle level and the communities’ participation in common activities was low. Factors that affected communities participation in water quality management were confidence in local leaders membership of the conservation groups education level and awareness of water source problem respectively.

The objective of this study was to investigate water quality and river utility among people settling along the Li River Lumphun Province. The study was designed by mixed methods. The number of sample size was 364 households in the communities. The research data were collected by questionnaires and analyzed by using descriptive statistics (SPSS for Windows version 19 ).The results showed that total water quality including DO BOD TCB FCB and NH3-N in the summer was at the moderate level (WQI 58 - 68). The Li River utility was at the moderate level (Mean = 2.73 S.D. = 0.57). The relationship between the water quality and the river utility for agriculture had a statistically significant correlation at 0.05 (p –value 0.04).

In Klong Rangsit Pathumthani province where the water entering was filtered by a prototype quality water machine and autonomously controlled by pumps and sensors this research tested improvements to water quality. It employs a total dissolved solid and temperature sensor as part of the consideration of the water quality criterion in accordance with the water quality requirements of the Pollution Control Department and is 99% successful in treating contaminants in water. According to the Pollution Control Departments water quality criteria which are divided into four main categories: very good water quality good water quality degraded water quality and very degraded water quality it is used in the analysis of the division of the four categories of water quality. Machines for producing good quality water to maintain water sanitation during COVID-19 and anticipated flooding across the nation. This is simple to use. Since the made quality water machine prototype has a battery to back up the power for the pump and UV lamp control by filtering water through various stages of a quality water producer prototype it is simple can generate clean water for usage and can be carried. No energy is used and there is no residue filtration effluent. It eliminates 99 percent of water pollutants and has no color.

The study of Hydrilla (Hydrilla verticillata) effectiveness in water treatment was investigated using completely randomized designs with 4 Hydrilla densities: 0 (control) 30 50 and 70 plants. Each plot was experimented in round cement tanks added with sandy clay on the bottom. Fifty liters of canal water was then filled in. Along 6 weeks of the experiment each tank was aerated with no water exchanged. Results showed that there were no significant differences in values of temperature pH dissolved oxygen conductivity alkalinity hardness nitrite ammonia phosphate and biochemical oxygen demand in every treatment (p > 0.05). However the experimental plot with 50 hydrilla plants showed the best tendency in eradication of phosphate and improvement of biochemical oxygen demand at 86.00 and 45.73 percent respectively. On the other hand the experimental plot with 70 hydrilla plants showed the best tendency in eradication of ammonia and nitrite at 65.00 and 66.66 percent respectively.