8.2.4 Operation and Maintenance Costs

Categories: 8.2 Project Implementation Costs
Time of issue: 2022-04-28 10:55:22
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Operation and maintenance cost items for a rural wastewater project include:

Labor for routine operation and maintenance,
Sludge treatment and disposal,
Electrical power,
Equipment repair and/or replacement,
O&M of sewer collection system,
Expendable materials (such as disposal gloves, cleaning products),
Routine water quality and groundwater quality (if required) testing,
Administration and reporting, and
Follow up and training.

Labor Costs. All sanitary systems require some level of routine maintenance to properly operate. The skill level required of operating and maintenance personnel depends on the type and complexity of the waste management system. Decentralized sanitary systems generally require a lower level of maintenance. Household or on-site wastewater systems are typically maintained by household members. A neighborhood or clustered system requires a higher level of maintenance and may be maintained by a designated and trained community member or a private operator. A centralized wastewater system requires more maintenance than a smaller decentralized system. Daily operation can usually be performed by a previously unskilled community member trained for the task with weekly or monthly supervision by a skilled professional operator from a commissioned third party.

Sludge Treatment and Disposal. The costs associated with the handling and disposal of sludge from the village sanitation systems depends on the type of sanitation system and the method of sludge treatment, disposal or reuse. For example, the use of on-site composting toilets requires household members to clean the toilet, remove the sludge, transport the stabilized sludge to the final land application site, and spread and turn sludge into the soil. These activities are usually conducted by the household members voluntarily and do not have monetary costs associated with them.

According to the Guideline for Construction and Investment of Rural Domestic Wastewater Treatment Project (2013), the O&M cost is 0.5-2.0 RMB/ton of sludge for sludge dewatering, 0.5-2.0 RMB/tons of sludge for sludge drying, 2.0-8.0 RMB/ton of sludge for sludge digestion, and 80-120 RMB/ton of dewatered sludge for sludge composting.

Sludge management involves removing the sludge from the treatment units and either directing it to sludge drying beds or a small composting system within the facility or hauling it offsite to a regional treatment facility. Sludge management costs depend on which of these methods pertains. The labor cost required to remove the sludge from the treatment units is the same in each case but the cost of subsequent handling varies. The cost of the sludge drying bed operation is very low. It requires one to two days of unskilled labor every three to four months.

Operating a composting system is more involved and therefore more expensive than operating a sludge drying bed. However, the quality of the product is expected to be higher than simple dried sludge, and the compost can be sold as an agricultural product to recover the management and production costs.

Haulage of septage waste from the village wastewater treatment system will incur fees for pumping, transport and disposal. The pumping costs are dependent on the size of the facility and time required to remove the septage. The transport costs will depend on the distance between the village and the septage treatment facility and the treatment/disposal fees are set by the company operating the regional treatment facility.

Electricity Costs. Sanitation systems using electromechanical equipment, such as pumps, aerators, blowers or motors, will consume electricity, which is billed directly to the community by the electric utility. The electrical demand will vary depending on the size and energy requirements of the equipment employed.

Equipment Repair and Material Replacement. Periodic cost will be incurred by the village to repair or replace damaged equipment or to purchase parts. An additional cost will be to purchase basic supplies for cleaning and maintenance, including safety gloves and coveralls, hoses, cleaning supplies (bleach, soaps, and detergents), and other expendable goods. It is important that these relatively inexpensive items are maintained on site to encourage the operators and unskilled labor to use good health and safety procedures at the wastewater facility to protect their own and the public’s health.

O&M of Sewer Collection System. The O&M costs for sewer pipes are approximately 20 to 30 CNY per km per year. The maintenance cost and sewer pipe replacement cost account for 1.5%-2% of the total capital cost, respectively.

Water Quality Testing. If a village installs a clustered or central wastewater treatment and disposal system, routine water quality testing will be required by the county level ecology and environment bureau (EEB). The monitoring program will consist of testing of the performance of the wastewater treatment system and groundwater monitoring up and down gradient of the community land disposal system. The costs for wastewater and ground water testing will include the labor required to collect and transport water samples to an approved testing laboratory plus the fees of the laboratory. The laboratory fees will depend on the type and frequency of tests performed.

Administration and Reporting. The operation and maintenance of a wastewater facility requires administrative support to manage the tariffs or fees collected, to manage the system in order to pay the system operator and laborers, to pay for electricity and the other expenses discussed above. A system administrator may also be responsible for scheduling water testing and the preparation of monthly or quarterly reports that will be required by the EEB. A system administration position is typically a part time position; however, the amount of time required to administer the system will depend on the size of the village and the overall responsibility of the administrator. For example, in some villages the administrator may be responsible for visiting each household to collect the monthly tariff, which can be a time consuming activity. Alternatively, the administrator may require the villagers to make the payment on a specific day each month and bring the money to the administrator at a specified location.

Follow-up and Training. The village committee may bear costs related to training and technical assistance activities. At a minimum, anyone filling a technical role in the operation of the system, even a part-time role, should periodically attend technical workshops relevant to refreshing or upgrading his/her skills.