MIAO Ying-xia WANG Shu-xun WANG Jing ZHANG Yu-shan

(Institute of Seawater Desalination and Multipurpose Utilization,SOA,Tianjin 300192,China)

0 Introduction

The domestic seawater technology which is the technology of applying treated sea water as domestic water(mainly for flushing)is one of the effective means of addressing coastal cities from fresh water resource scarcity[1].The present utilization of this technology is subject to limited regulations which far from enough for sound water resource allocations.Under this context,looking for a reliable and efficient method to mitigate this contradiction becomes particularly important.

1 Review of legislation on utilization of domestic seawater

1.1 Hong Kong legislation on domestic sea water for flushing

Hong Kong is serious water scarcity city however holding rich sea water resources.From the late 50’s of the last century,Hong Kong has started using the new system with sear water purification,application of anti-corrosion water supply pipes to popularize domestic sea water for flushing[2].After decades of promoting,about 80%people are now using sea water for flushing.The widespread use of sea water in return has reduced the need for freshwater,which large fresh water saving to Hong Kong[3].Since fresh water is so important to Hong Kong and seawater flushing has been largely popularized,it is natural for the Government to take measures to prohibit the waste behavior of using fresh water for flushing thanks to Hong Kong’s comprehensive legislation system.

1.2 Current state of mainland China domestic seawater utilization legislation

2 The necessity of legislation on domestic seawater

2.1 The maturity of industry development calls for legislation

Today,the domestic seawater technology is well understood and mastered industrial wise.More and more coastal cities,such as Shenzhen,Weihai,Dalian,Qingdao,Xiamen,have drafted domestic seawater system construction planning as the result of urgent need for domestic seawater.

Facing the fast-growing need from industrial development,it is crucial important to put in place a comprehensive legislation system which would clarify the rights and responsibilities on domestic sea water utilization for government,enterprises and citizens.

2.2 The function of residential community demos and its scale limitation

Domestic seawater for flushing is scale-effective technology,i.e.with the increase of construction scale,the unit fixed investment and operational costs are reduced dramatically.Calculations show that when the water supply is relatively low,the seawater utilization facility construction cost is higher than that of treated surface water and greywater with the same operational costs.However at large water supply,the operational cost of unit domestic seawater is dramatically reduced and the investment on capacity-related facility is reduced proportionally.Therefore,even the residential community demos have proven the technical feasibility of domestic seawater technology,the industrialization of domestic seawater technology is able to demonstrate is economic advantages only when popularized in large scale.

2.3 Hong Kong legislation process and result

Hong Kong has issued “Water system infrastructure regulations” and“Hong Kong water system specification” to be served as law and specification for water system management.It is specified that all buildings must have one drinking water supply system and one flushing supply system even for the area temporally without seawater supply.Where seawater supply is available,it is obligatory to use seawater for flushing however forbidden for other application.It is regarded as a commitment of an offence if utilize fresh water for flushing or seawater for other utilization than flushing.Meanwhile,a multilevel water charging system is implemented by encouraging the citizens and enterprises to utilized free charge seawater for flushing.

Restrict legislation has been effective in promoting the implementation of seawater for flushing.Today,about 80%of population in Hong Kong utilizes seawater for flushing which result in an annual saving of 300 million tons of fresh water.

3 The feasibility of legislation on domestic seawater and legislation conception

From technical point of view,the domestic seawater technology is mature enough to set up comprehensive technical specifications.The responsibility in the sectors of manufacture,sales,application and treatment of domestic seawater has been clearly defined,which paved the way for legislation feasibility.

3.1 Policy research on utilization of domestic seawater

Implement the promotion of domestic seawater utilization into coastal cities government strategic planning,clarify the objectives and responsibilities of government in promoting domestic seawater and define feasible promoting price,finance and taxation policy of domestic sea water.

The construction of seawater utilization infrastructure and the utilization of seawater will increase infrastructure investment and daily management cost.For real estate developers,the implementation of domestic seawater systemmeanstheincrease of investment（on certain pipeworks.

Sea water utilization is a project with environmental and social benefits.Promote seawater utilization to smooth freshwater scarcity is governmental act and should be sponsored by the whole society than to be borne entirely by the consumer.Hence,considerations should be carefully taken with various interests,it is necessary to promote the application of seawater with demonstration of fairness.In addition to constrictive regulations,preferential policies for infrastructure construction and water price is also necessary.

3.2 Principles on domestic seawater

Principles on domestic seawater legislation:

Respect national and local current law and regulations.

Fairness reflected in politics and economic policies,especially for consumers which are subject to obligatory utilization.

Operational feasibility compatible with local specific situation.

Market operation principle.Integrated planningwith utilization greywater and other recycled water.Encourage research and application of advance process,equipment and material.

Legislation on utilization of domestic seawater needs firstly to clarify the production and treatment utilities’qualification.Domestic seawater treatment utility should have sea water contained water treatment capacities,which are either municipal sewage water treatment plant or qualified residential community property management utility.Seawater supply and sewage seawater treatment enterprises must be qualified by related municipal administration department before carry out domestic sea water operational activities.

It is highly recommended to reference Hong Kong’s experience on legislation process to set up domestic seawater infrastructure construction and operational specifications with domestic seawater environmental impact assessment and post assessment system.For the sales and utilization of domestic seawater,the application scope should be clearly documented with strict monitoring system for sales qualification,subcontract conditions and regulations to be able to encourage reasonable and rational use of domestic seawater.

4 Conclusion

Presently,the industrial technical specification system framework of utilization of domestic sea water has been formed,the key players and legal responsibilities have been clarified which paved the way for necessity and feasibility for legislation.Legislation can be practiced in certain scope to promote the healthy and rapid development in this field.S

［1］Kang Liu.Utilization prospect of seawater toilet-flushing[J].Ocean Exploitation，2003，20(6):17-19.

［2］Total Water Management in Hong Kong[M].Hong Kong Water supplies Department，2010.

［3］Microsoft PowerPoint—seawater[PPT].Hong Kong Water supplies Department，2010.?