A sustainable increase in wastewater reuse is necessary to solve problems related to the operation and maintenance of WWTPs, in order to effectively and continuously maintain effluent quality. The problems encountered in both collection and treatment systems, summarized based on the survey and evaluation reports of municipal WWTPs at the provincial level from 2013 to 2017 (Office of the Environment Region 1-16 2016; Pollution Control Department 2017b; Office of Strategy and Evaluation 2020), are presented in Table 5. Common problems in wastewater treatment systems include blockages and breakdowns of the sewage collection pipe system. As a result, the amount of wastewater entering the treatment system may be lower than the designed value. Some WWTPs had less than 20% of the intended water intake (see Table 4), leading to effluent quality that was not suitable for reuse.
Table 5
Common problems when operating municipal WWTPs in Thailand
Households  | Collection pipe system  | Municipal WWTPs  | Distribution systems for wastewater reclamation |
|---|---|---|---|
| -Some communities have not installed preliminary wastewater treatment devices, leading to large amounts of O&G in the influents to WWTPs. | -Collecting pipelines do not cover all community areas yet. -Expanding the construction of collecting pipe systems in dense communities and alley areas is difficult, as there is almost no space for pipe laying. -Garbage often blocks the grates at the sewage pumping station, causing damage to the pump. -The sewage pipe is clogged by sand sediment. -Sewage pipes under roads are often broken and damaged, causing wastewater to be collected below the designed volume. -Insufficient water collection pipes in the rainy season cause flooding, and the collection pipe system is damaged. -In community areas near the sea, there are often problems with seawater flowing into the sewage pipe system (e.g., flap gates), causing damage to machinery and equipment. -Lack of budget for system monitoring and maintenance. | -Wastewater input is significantly less than the designed capacity. -Due to the depletion of the wastewater level during the dry season, the pond edge collapses. -During the dry season, some parameters cannot meet the water quality standard due to the lower flow rate, the long retention time, algae blooming on the surface causing less DO, higher SS and a bad smell in the effluents. -A large amount of bottom sediment accumulates in the ponds, causing the treatment efficiency to decrease. -Total coliform bacteria and fecal coliform bacteria are detected in the effluents from the last pond with relatively high values, causing water reuse problems. -Sedimentation in the polishing ponds is ineffective due to people trespassing into the ponds in order to fish. -During the dry season, wastewater is illegally pumped from WWTPs for agricultural watering. -Lack of nearby laboratories for wastewater quality analysis. -Lack of specialized personnel for operations and maintenance. -Lack of statistical data on the flow rate of wastewater entering WWTPs, causing operations to become ineffective. -Lack of budget for system maintenance. |
| Households | Collection pipe system | Municipal WWTPs | Distribution systems for wastewater reclamation |
|---|---|---|---|
| -Some communities have not installed preliminary wastewater treatment devices, leading to large amounts of O&G in the influents to WWTPs. | -Collecting pipelines do not cover all community areas yet. -Expanding the construction of collecting pipe systems in dense communities and alley areas is difficult, as there is almost no space for pipe laying. -Garbage often blocks the grates at the sewage pumping station, causing damage to the pump. -The sewage pipe is clogged by sand sediment. -Sewage pipes under roads are often broken and damaged, causing wastewater to be collected below the designed volume. -Insufficient water collection pipes in the rainy season cause flooding, and the collection pipe system is damaged. -In community areas near the sea, there are often problems with seawater flowing into the sewage pipe system (e.g., flap gates), causing damage to machinery and equipment. -Lack of budget for system monitoring and maintenance. | -Wastewater input is significantly less than the designed capacity. -Due to the depletion of the wastewater level during the dry season, the pond edge collapses. -During the dry season, some parameters cannot meet the water quality standard due to the lower flow rate, the long retention time, algae blooming on the surface causing less DO, higher SS and a bad smell in the effluents. -A large amount of bottom sediment accumulates in the ponds, causing the treatment efficiency to decrease. -Total coliform bacteria and fecal coliform bacteria are detected in the effluents from the last pond with relatively high values, causing water reuse problems. -Sedimentation in the polishing ponds is ineffective due to people trespassing into the ponds in order to fish. -During the dry season, wastewater is illegally pumped from WWTPs for agricultural watering. -Lack of nearby laboratories for wastewater quality analysis. -Lack of specialized personnel for operations and maintenance. -Lack of statistical data on the flow rate of wastewater entering WWTPs, causing operations to become ineffective. -Lack of budget for system maintenance. |