Executive Summary
What was this pilot project about?
At this pilot project, a solar-driven, semi-automatic disinfection process was showcased in a rural water supply scheme in Lavale Village, Maharashtra, India. The system provides a low-cost alternative to conventional disinfection processes that rely on regular chemical input and skilled manpower for operation.
The installed disinfection station produces the chlorine and doses the required amount automatically on-demand (see Fig 1). The process, termed Onsite Chlorination Generation (OCG) uses Electro-Chlorination reactors and an online-operation system to simplify and limit the required manual operation tasks to a minimum, i.e. regular adding of NaCl (Salt) into a salt storage tank.
Figure 1. Training imparted to village council and view on on-site disinfection unit. Source: Own illustration (n.d.a)
The station is directly connected to the pumping system that transports well water in the water supply’s storage tank (see Fig. 2). Whenever the pumps are operated, the required dosage of disinfectant is added into the water storage tank. This way, drinking water quality is safeguarded when distributed to the households. The disinfection station is continuously producing small batches of chlorine stock solution, which is intermittently stored inside the stock solution storage tank (SSST). Whenever the well pumps are running the chlorine is dosed. Even at very high flow rates of the pumped water, the system can supply sufficient chlorine from the SSST. The production of chlorine is decoupled from the pumping of water.
Figure 2. Training imparted to village council and view on water storage tank of existing water supply system. Source: Own illustration (n.d.b)
General project profile
Population served: 6.000 inhabitants
System capacity: 300 m3/day
Hand-over from PAVITR to long-term owner: 01/2024
Piloted technological system
Input: Bank-filtrated river water and ground water
Output: Disinfected drinking water
Flow scheme: Solar-driven Electro-Chlorination with an Onsite Chlorine Generation reactor (OCG) connected to the storage tank of an existing water supply system
(Existing water supply system: Groundwater/bank filtration well – Pumping station – Storage Tank – Distribution network – about 600 household and yard tabs)
| Use of outputs/products: | Disinfected drinking water |
Location and conditions
The pilot is located in Lavale village, an agglomeration with around 6000 inhabitants about 14 km away from the Symbiosis International University (SIU) Campus Pune, Maharashtra, India. The climatic conditions of Lavale are tropical in nature. During the winter season, precipitation levels are significantly lower compared to those experienced in summer. The mean yearly temperature recorded in Lavale is 23.7 °C | 74.6 °F, as per the available data. The annual rainfall is 1200 mm | 47.2 inch. Because Lavale is located near the equator, the summers are not easy to define. The total geographical area of village is 1960 hectares. Lavale has a total population of 6,732 peoples, out of which male population is 3,621 while female population is 3,111.The ground water level is fairly good.
The pilot station was an addition to an already existing village water supply system, where raw water is primarily supplied through a well installed into the bank of Mula river. In case this well is flooded, a second well located along a small creek near the village, serves as raw water source. The water is pumped to a centrally located 300 m3 storage tank from which it is transported through gravity in two main pipes throughout the village. Most plots of the village are supplied with yard connections (through pipes passing the respective properties). Larger buildings are directly connected to the pipeline network and store water in overhead tanks connected to in-house supply pipes.
Prior to the pilot project, bleaching powder was added by villagers directly into the well to disinfect the water, at a rather arbitrary rate. The water from the storage tank was then distributed without any further treatment or disinfection. Water consumption was not metered or controlled at all, leading to unaccounted water losses. Multiple reasons lead to this insufficient safety measures and inefficient use of water, which can also be observed in many other rural water supplies throughout India. Lacking funds to assure appropriate operation and maintenance of the water supply infrastructure (there is no tariff-based cost-recovery), leading to irregular supply with chemicals but also use of low-quality components that break quickly; lacking competences and protocols to assure accurate operation and maintenance of the treatment units, and i.e. handling of the chemicals and correct dosing was observed prior installation.
Project milestones
These were the main steps we took in order to set up the project:
- Site and location selection: 1. Reconnaissance survey: to identify potentially interesting sites 2. Preliminary survey at Lavale Village:
- Meeting with community members (villagers) and Gram Panchayat to explain the project objectives and the piloted technology.
- Technical baseline survey: feasibility check of available water source and infrastructure at the proposed site.
- Geographical survey.
- Sampling and water characterization-for site selection.
- Site visit of technology provider and system designer (AUTARCON) and implementing partner (SIU).
- Planning and design of pilot system complemented with meetings and group discussions to define internal setting of the container it was installed in, required components to be purchased in India but also sensitize community members regarding the system and its benefits to the society etc.
- Construction / Installation: Construction of concrete base for installation of pilot set-up. Transport and installation of container; system installation of OCG reactor + Solar energy supply + Plumbing.
- Start-up phase: continuous remote monitoring, sampling and water characterization and adaptation of system configuration to face operational challenges and calibration of the system and sensors for different operational conditions.
- Regular sensitization activities with community members with Gram Panchayat: awareness raising on water losses/wastages.
- Training was imparted to the pump operator and 3-4 Lavale gram panchayat members for regular operation of disinfection unit and basic trouble-shooting and cleaning activities (to rotate for the O&M).
- Steady-state operational phase: on-going monitoring of functionality of the disinfection system and extent of disinfection. Regular remote meetings of SIU with technology provider and site visits to organise and prepare transition for hand-over to Lavale village Gram Panchayat.
The following stakeholders were involved in these respective roles/capacities:
- SIU project team: technical and administrative project implementation on-site; contact point for community members; on-site system monitoring and trouble-shooting
- AUTARCON technical experts: system design, installation, and start-up configuration; remote system monitoring and trouble-shooting
- (NOC) Gram Panchayat Lavale village: support to site selection, community mobilisation; 3-4 members of Gram Panchayat trained to carry out O&M (rotating modus)
- Community members: system beneficiaries and support to day-to-day operation (1 village inhabitant/volunteer was trained)
What could be observed quite clearly at this pilot site, was the required effort but also value accompanying stakeholder engagement has for the success of such type of project. Whereas the technical design and construction/installation of the station were quite straight-forward tasks that were completed in a few weeks’ time, on-boarding, and involvement of the village council (Gram Panchayat) and community members was an iterative, time-consuming process starting in the early project stages and accompanying the whole implementation process. It proved to be key for assuring the acceptance of the system by the community members and to build required capacities within the community to prepare the hand-over of the system for the time after project closure. Also, the recurring sensitization efforts and other measures had a positive effect on the general water management practices in the village.
Set-up of operation and maintenance phase
For the duration of PAVITR, day-to-day operation was carried out by one skilled operator who needs to be present on-site on a daily basis. The operator was trained by the AUTARCON and SIU. The O&M training was held in local language and involved the operator but also village council staff. In addition to the training, O&M guidelines including the day-to-day schedule were prepared and communicated in local language. Drawing and analysing water quality samples, supervision and ad-hoc trouble-shooting was covered by SIU research staff. In case of operational challenges that could not be tackled on-site, technical experts of AUTARCON were consulted remotely.
For regular maintenance a local plumber was engaged for leakages or small issues, and an electrician to solve popping up issues of electrical work. The CRT Tank and strainer cleaning required fortnightly, as well as overhead water tank cleaning, which is required once in six months, or the regular cleaning of the solar panels was covered by additional locally hired labourers.
Operational experience and performance
In the first months of operation, adjustment of the softener was required due to changing hardness levels of the raw water. Also, water consumption was exceeding the design capacity which resulted in difficulties to achieve the targeted disinfection performance. This mismatch of water demand and disinfection capacity was caused by a considerable amount of water spillage and leakage, which was not observed during the primary survey. For that reason, together with Gram Panchayat, it was agreed to organise awareness programs, reduce pumping hours, improve valve control management, and cover the wells with mesh. These improvement measures were successful and allowed to maintain a water demand below 300 m3/day. Except for the refilling of salt, the OCG system itself did not require any manual operational steps. The system continuously produces chlorine and remains idle only when the Chlorine Stock Solution Storage tank is completely filled.
The average residual chlorine could be maintained at 0.1mg/l at the farthest tap if the water consumption is less than 300 cubic metres per day. Tests for pathogen indicators revealed that the water was safe during distribution and storage at this low chlorine concentration.