Physico-chemical process for removal of nitrogen species from recirculated aquaculture systems

Patent metadata

Field	Value
Publication number	US-2017029299-A1
Application number	US-201615292863-A
Country	US
Kind code	A1
Filing date	Oct 13, 2016
Priority date	Nov 17, 2010
Publication date	Feb 2, 2017
Grant date	—

Abstract

Processes for removing nitrogen species from fresh water or high salinity water recirculated aquaculture systems. The processes are based on physico-chemical treatments which are performed at ambient temperatures and at low pH values thus keeping the total ammonia nitrogen concentrations below a value which is considered detrimental for the growth or survival rate of cultured fish/shrimp.

First claim

1 . A process for removing ammonia from a saline water recirculated aquaculture system (RAS) while maintaining a total ammonia nitrogen (TAN) concentration in the water in said system between 15 and 50 mgN/L, the process comprising the steps of:
a. maintaining the pH of the water in the RAS below 7.5 by adding an acid; b. extracting a portion of the water from the RAS; c. oxidizing the ammonia in the portion of the water to nitrogen gas by electrochemical treatment or by breakpoint chlorination in the presence of a solution comprising Cl 2 at concentrations required for attaining breakpoint chlorination;

2 . The process of claim 1 , further comprising the step of recycling at least some of the portion of the water obtained after step (c) back to the RAS.

3 . The process of claim 1 , wherein steps (b) and (c) are performed continuously.

4 . The process of claim 1 , wherein step (b) is performed continuously and step (c) is performed during low cost electricity hours.

5 . The process of claim 1 , wherein the solution comprising Cl 2 is generated in situ by electrooxidation of seawater.

6 . The process of claim 1 , wherein the acid is H 2 SO 4 .

7 . The process of claim 1 , further comprising adding a base during the electrolysis step.

8 . The process of claim 7 , wherein the base is selected from Ca(OH) 2 , CaO, NaOH and KOH.

9 . The process of claim 1 , further comprising stripping of CO 2 wherein stripping of CO 2 comprises the addition of pure oxygen or aeration.

10 . The process of claim 1 , wherein the recirculated aquaculture system (RAS) has a total ammonia nitrogen (TAN) concentration at about 40 mgN/L.

11 . The process of claim 1 , further comprising, repeating steps (a) to (c) in a continuous manner as needed.

Assignees

• Technion Res & Dev Foundation

Inventors

• Lahav Ori
• Gendel Youri
• Mozes Noam
• Benet Perlberg Ayana
• Hanin Yuri

Classifications

• A01K63/04 Primary

  Arrangements for treating water specially adapted to receptacles for live fish · CPC title

• B01J49/50

  characterised by the regeneration reagents · CPC title

• Y02A40/81

  Aquaculture, e.g. of fish · CPC title

• B01J49/53

  for cationic exchangers · CPC title

• C02F1/42

  by ion-exchange (ion-exchange in general B01J) · CPC title