Rainwater appears to cut groundwater need of factories in Bangladesh

By SM Najmus Sakib

DHAKA, Bangladesh (AA) - Harvested rainwater could halve the dependency of textile and garment factories on groundwater in a context of falling underground water level and pollution of surface water in Bangladesh.

Factory demand for groundwater rose to 70% while the groundwater level is falling, and it will lead to major water scarcity, according to a new study.

According to Dhaka Water and Sewerage Authority, Dhaka’s daily water demand of 2.45 billion liters and 78% was met by extracting groundwater. Meanwhile, a huge quantity of water is needed for the country’s largest industry that contributes over 80% to Bangladesh’s total exports.

WaterAid Bangladesh and RAiN Forum with support from Bangladesh Garment Manufacturers and Exporters Association (BGMA) recently conducted the feasibility study on 65 industrial infrastructures in Dhaka and surrounding areas to know the water demand for production.

In Dhaka, the average annual rainfall is over 2,000 mm (more than 78 inches), and annually 50-60% of total rainwater could be used for various purposes, the study said.

- Rainwater can cut pressure on groundwater

The study showed harvested rainwater can meet up to 60% demand for non-potable water with even 100% of those not having the dyeing and washing units.

Speaking to the Anadolu Agency, architect Md Ashraful Alum (Ratan), the secretary of the RAiN Forum, said Bangladesh had built much more dyeing and washing factories than other countries because of the availability of water here.

“But, apart from polluting water sources, the cost of washing and dyeing in factories manifold due to water extraction cost. Groundwater level got down extremely in the last 10 years due to the emissive use. So, we won’t have other alternatives in the future than to move for the harvested rainwater.”

Ratan, also the principal architect of the Idyllic Design, said factories have vast rooftops or catchments which can be used to collect rainwater, and they can reserve rainwater in underground reservoirs.

“Fresh investment of installing facilities for collecting and preserving rainwater would pay back (return of investment) between 12 to 20 years.”

Harvested rainwater can cover the demand of non-potable water between 15% to 60% in 39 factories, 15% in six factories, 60% in 20 factories, read the study.

Some 12 factories have 2,000 square meters of rainwater catchment area, while 40 factories have 2,000-8,000 square meters (21,528-86,111 square feet) and 13 have 8,000 square meters, it said.

We want to share the practical know-how of using rainwater with the BGMEA member factories and can provide technical support with the least cost to cut the pressure on groundwater, he noted.

It will establish them as green factories and get a good green mark for global branding, he also said.

“We are now mining groundwater which permanently dries or destroys the underground water level for any future use. Meanwhile, the groundwater in many areas contains dangerous levels of arsenic and iron contamination.”

- Rainwater a safe method for industry use

Speaking to Anadolu Agency, Hasin Jahan, the WaterAid Bangladesh country director, said: "Harvested rainwater carries low PH level and can directly be used to wash garments in factories while we have to purify groundwater to cut the PH level before factory use."

The government provides subsidies to supply groundwater while the use of rainwater can cut financial pressure on the government. Jahan added: "Before that, we have to focus on training people and building capacity. So, investment in some cases is essential for long-term return."

“We can install such facilities in other factories too and on the purpose of drinking water,” she suggested, saying “the use of rainwater remains ineffective and wasted due to lack of open ground which also can recharge groundwater.”

Md Ziaul Haque, the director of the Department of Environment of the Dhaka district, told Anadolu Agency that there is a provision to have the facility for harvested rainwater in issuing environmental clearance for major physical infrastructure.

“We have similar provisions for major industrial parks or industrial cities but we still don't have any legal provision for factories. This is a quite good proposal of installing a rainwater harvesting facility on the catchment of factories to reduce the pressure on failing groundwater,” he added.

People in cities like Dhaka are reluctant to use rainwater due to a shortage of facilities. But rainwater during the monsoon could be a major source of non-potable water in Dhaka, he observed.