Construction And Optimization Of Cleaner Production Models In Zhejiang Sea Water Pond

Pond culture system as a typical artificial feeding system, has a simple ecological structure and food chain led to its extremely low eco-efficiency, because of its energy flow and material cycles obstruction. With rapid development of aquaculture in recent years, the pollution load from aquaculture put into the culture system had greatly increased, which caused an imbalance of the system, then induced serious threat to the sustainable marine aquaculture industry and its healthy development. Based on ecological principles, we added seaweed (Gracilaria lichevoides) and benthos (Phasolosma aibuhitensis) into single fish culture system to build up a multi-culture system. This multi-culture system could regulate species niches, kept material flow be smooth, reduced energy loss, and finially achieved a cleaner production.1. Simulated a major pollution load in culture system, the release concentration and rate of nitrogen (N) and phosphorus (P) of trash and commercial feed were studied under different temperature. The result showed, temperature variation could make a remarkable effect on feeds'nutrients release rate and ratio. The release rate of N and P could be speed under high temperature, so as the release ratio. Finially, each treatment had almost 30%～35%release ratio.2. Four different mariculture models in this study, included 3 species organisms, seaweed (Gracilaria lichevoides), benthos (Phasolosma aibuhitensis) and fish (Pseudosciaena crocea), in 16 land-based enclosures to investigate the effect of seaweed and benthos on removing N and P in different culture systems and analyzing the optimum density of benthos for building up an integrated mariculture system (IMCS). The results showed, the seaweed, G. lichevoides with the density of 1.5 kg·m- 2 could make a obvious effect to remove pollution in water column and had a effective increase the harvested fish yield. Meanwhile, the benthos made remarkably effect to reduce POM in sediments. Compared to the models, single-culture fish (F), t FP (fish + P. aibuhitensis) and FGP(fish + G. lichenoides + P. aibuhitensis), N and P of sediment decreased by 9.59%～10.47%, 7.11%～8.18%. Furthermore, the density of benthos has a significant impact on the removal of POM in sediment and the culture benefit. The model with the density of 22.5 kg·ha- 1 and 30 kg·ha- 1 have better environment and resources benefits than the one with 15 kg·ha- 1 of benthos. And there are no remarkable difference between the one with 22.5 kg·ha- 1 and 30 kg·ha- 1. Considering this two treatments'remediation effects and culture benefits, 22.5 kg·ha- 1 of benthos'density can promote the culture benefit and improve the sediment environment.3. Analyzed culture benefits and discussed recovery efficiency of nitrogen (N) and phosphorus (P) in these four system showed that the seaweed, G. lichenoides had a high recovery efficiency of nitrogen and phosphorus, especially, phosphorus came to 33.82%～34.00%. While the benthos P. aibuhitensis was 7.45%～7.79%, and compare to F, total nutrient,total phosphorus,Inorganic phosphorus in FP and FGP reduced by 8.90%～9.19%,6.10%～6.33% and 8.02%～8.11%. The model FGP (fish + seaweed + benthos) had the highest culture benefits and optimal resource efficiency, compare to F, the recovery efficiency of nitrogen (N) and phosphorus (P) promoted to 148.9% and 901.4%, and the yield of the main culture animal was 1.72 times as that in F.