Water Conservation – sea water flushing

For more than 50 years seawater has been used for toilet and urinal flushing in Hong Kong, saving significantly quantity of fresh water. If you are near the coast, the process is straightforward, sea water is filtered, treated and then pumped to purpose built service reservoirs ready for use in residual and commercial buildings. Eighty percent of Hong Kong buildings are served by the sea water infrastructure.  In the year 2011, the potable water savings were 740 tonnes per day,  or more than 270,000 tonnes per year.

All new buildings by regulation mustbe provided with two separate water systems, potable and flushing water. The flushing water infrastructure must be designed to handle sea water.  in buildings uPVC is the material of choice for pipework serving all sanitary appliances.  WC cisterns are designed without any metal components exposed to the corrosive seawater.

WSD Distribution Diagram

Underground the pipework distribution utilises cement lined piping for sea water to the service reservoirs and buildings as shown in the above diagram (courtesy of Hong Kong Water Supplies Dept. http://www.wsd.gov.hk).

Having separate potable and sea water infrastructure has another advantage, in the event that one water service is shut-down for maintenance, that doesn’t stop all the water services. Furthermore, since the sea water provides part of the buildings water demand, the potable infrastructure is smaller and lower cost.

One of the major objections against using sea water is a concern that potable water and seawater piping could be cross-connected, in reality that’s an unlikely occurrence because the materials are different, its physically difficult to connect a cement lined pipe to PE piping.

China is starting to embrace sea water as a resource too.

Its obvious really, in coastal areas, why flush our precious potable fresh water down the toilet? The use of sea water is a low-tech solution to lower and conserve potable water usage, and very cost effective.

Update: John Herbert was appointed to the Hong Kong Green Building Council Faculty June 2012 and chairs the Water Aspects technical group.

Malaysia’s Rainwater Harvesting Code

water conservation

It has always been difficult to predict how and when the purely voluntary green building rating systems will become part of the building code requirements, not so for Malaysia, where the local newspaper reports today that all new buildings (new bungalows, semi-detached homes, government buildings) must have rainwater harvesting systems to gain building approval.

In case that over complicated link is broken, here is the report from the The Star (http://thestar.com.my):

Published: Monday June 13, 2011 MYT 4:42:00 PM

New bungalows, semi-detached homes, govt buildings must have rain water systems

By NG CHENG YEE

KUALA LUMPUR: Developers must include rain-harvesting systems in new bungalows, semi-detached homes and government buildings to get their plans approved.

This new regulation would soon be incorporated into the Uniform Building By-Laws to make the green feature mandatory, said Housing and Local Government Minister Datuk Chor Chee Heung.

The National Council for Local Government, chaired by the Deputy Prime Minister, had approved the new by-law on May 23, he said.

“Such a feature will allow owners of these premises to conserve rain water and use it to water plants, wash cars and for other purposes,” he told a press conference on Green Solution for Property Development Conference 2011: Greener Cities here on Monday.

He said developers who failed to include the feature in these buildings would not be able to get approval for their building plans.

On existing buildings, Chor said owners were encouraged to install such feature on a voluntary basis.

“We hope that when more houses are equipped with such feature, house owners will be able to see the benefit of it and follow suit,” he said.

Water conservation is a serious and often overlooked issue, countries across the region are only just beginning to consider and the fact Malaysia has acted can only be a positive indication.  As I have said before water is the new carbon.  Under the Hong Kong green building rating system BEAM fresh water conservation is encouraged with rainwater harvesting being one of many solutions. One would hope the Malaysian building code will address the issue of load (usage) reduction first and foremost, and no rely on rainwater harvesting to support unsustainable practices.

Precious water

Buildings demand a significant use of our finite resources including fuel for energy usage, water consumption, and cause atmospheric and environmental impacts from waste. Our pace of consumption cannot be maintained if some natural resources are to be spared, we need to build smarter, its crucial for our sustainability if tomorrow’s child is to be left with some usable resources.

The Green Building concept aims to reduce the environmental impact of new and existing buildings, yet environmental impact of buildings is often underestimated, a recent survey show people though buildings had little or no impact on the environment! whereas the scary fact is that 63% of Hong Kong’s Carbon footprint results from its buildings.

Some green labelling systems such as BEAM address part of the problem, but its only voluntary system. However building labelling and sustainability requires more science, including the entire life cycle impacts being assessed.

Sadly, the availability of fresh water is a critical, life threatening issue for many regions, yet developed countries, including Hong Kong frequently waste water. The photograph above shows a typical Hong Kong “Irrigation system”, a diesel fuel water tanker truck and manual hose, water efficiency is clearly not important. In this system most the water is lost in the spray, evaporation to atmosphere, or wetting the adjacent paving. Hong Kong is not alone in this regard, it occurs elsewhere, but that is not an excuse. Its a practice that needs to be stopped to avert water security and shortfall nightmares.

Water efficient alternatives exist, sub-soil irrigation avoids the short-comings delivering water into the root systems without evapouration losses, and excess.

— John Herbert, consultant, Kelcroft E&M Limited

Water charge increase threatened – China

China is once again suffering with problems in the Water sector, although plentiful in some areas, other areas suffer drought conditions.  Here in Hong Kong it’s relativity cold now, barely 10 deg C outside, as our thoughts turn to hot humid summers, the cost of operating cooling towers and providing domestic water services could escalate if the threatened 24% increase becomes fact.

John Herbert leading green building consultant Hong Kong

John Herbert BEAM Faculty, a leading green building consultant Hong Kong

The above (extracts from the unlink-able South China Morning Post on 17-12-2009) gives an indication that the authorities will try to stave off water shortages, not by small changes, but dramatically increasing the cost of water.

Energy Efficiency
Energy Efficiency project managers will certainly need to be aware, and weigh the possible risk of increased water charges into the financial model and assessment for future projects.  Also operators of systems with Process or Comfort cooling Air conditioning systems that use cooling towers would be advised to look closely at the system design and operation for opportunities to reduce water, and energy consumption before the new charging regime is implemented.

Replacing blocked and damaged fill in cooling tower John Herbert BEAM Faculty, a leading green building consultant Hong Kong

Replacing blocked and damaged fill in cooling tower

In many jurisdictions a separate charge is levied for discharge of sewerage/waste, and it can be expense. Therefore while we are considering projects that provide water conservation benefits, let’s not forget to include the avoided sewerage charge in our financial model.

Hot Water Systems
It could be an appropriate time to review to the hot water system, to identify any existing energy losses or water wastage. How many tonnes of tepid water are discharge directly into to drain everyday while we wait for the hot water to actually reach the tap or process? too many I’d argue. Reducing the waiting time lowers bother energy and water consumption.

Industrial Process
Many industrial facilities often need to heat one product line, and at the same time cool another, this is particular common in the food and beverage industry. Many of these systems uses a different water system, often oversized for heating and one for cooling. However, if we consider the problem from a greening perspective, we could easily combine these systems, adding very little complexity, using heat transfer to drive all or part of the process, and replacing one thou water systems for cooling. Therefore, a smart green design would reduce water, sewerage and energy charges.

More than just energy saving
One key point that is often undersold in the rush for energy saving projects are those extra additional benefits, some might argue intangible benefit. But they are real and often overlooked. Many businesses are recovering from the financial crisis, with capital scarce for facilities upgrades. Energy efficiency projects not only save energy, minimising the use of a resource creates opportunities for generating spare capacity without upfront investment.

For example after an energy efficiency project, a switchboard that was fully loaded now has spare capacity. That newly created spare capacity could be used for any number of purposes, perhaps expansion, new machinery, etc. without investing in a new power supply.

Right-sized, and regularly maintained equipment that is not forced to strain unnecessarily all day long has extended operating life span, and avoids the inconvenience, and capital expense of early replacement.

– John Herbert, consultant, Kelcroft E&M Limited
lowering the cost of doing business in Asia

Energy and water conservation pilot test?

water and energy conservation?

Here is a photograph I took yesterday in Jardin House (Central, Hong Kong) this hand basin tap was obviously intended to save energy and water, in reality does neither. You will note that this particular model has the flat faced user sensor located very near the base of the stem, and that its downfall.

When using this tap water droplets adhere to the sensor plate. Therefore after you have finished, the sensor still detects “a user” and the tap continues to discharge water long after the user has left the room. Just because it says energy saving on the box doesn’t make it so.

– John Herbert, Consultant, Kelcroft E&M Limited
helping lower the cost and impact of doing business in Asia