Performance of a constructed wetland in treating brackish wastewater from commercial recirculating and super-intensive shrimp growout systems

► We integrated constructed wetlands into the recirculating shrimp growout systems. ► The IVF–IHF wetland satisfactorily performed as brackish water treatment filters. ► Various water quality parameters were deemed suitable for shrimp culture. ► The estimated optimal ratio of wetland area to culture tank area was approximately 1. A recirculating aquaculture system was developed for treating Pacific white shrimp (Litopenaeus vannamei) production wastewater using an integrated vertical-flow (IVF) and five connected integrated horizontal flow (IHF) constructed wetlands as water treatment filters for mesohaline conditions (8.25‰–8.26‰ salinity). The constructed wetlands demonstrated the ability to reduce total nitrogen, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorous, chemical oxygen demand, and total suspended solids to levels significantly lower than those in effluents from culture tanks. Various water quality parameters in the culture tanks were deemed suitable for shrimp culture. The actual ratio of wetland area (Aw) to culture tank area (At) was 1.1439, and the estimated optimal ratio Aw/At was approximately 1. The IVF–IHF wetlands showed flexibility and reliability in consistently removing the main pollutants from commercial recirculating and super-intensive shrimp growout systems throughout the culture period.