Experimental Study On Improved Integrative Biofilm Reactor For Grey Water Treatment And Reuse

In this article, a new model of submerged modified biofilm reactor has been designed to treat and reuse grey water which is low-contaminated and of large water quantity basing on the traditional biological treatment process of grey water. The new model can treat grey water to a level which can satisfy the reuse water quality criterion, avoiding the disadvantages of the old model which are energy-consuming, ecological/land-consuming and hydraulic retention time-consuming. And the new model can be great in the practical using.Start-up capability of the reactor, impact factors of treat process in the test have been investigated, including the impact of hydraulic retention time, the adding ratio of suspended filler, the quantity of dissolved oxygen, correlation temperatures parameters, acid hydrolysis effect to the biodegradability of LAS and stability of system operation.The results indicated that at 25 to 33℃, the system showed great stability and impact resistance ability to organic compounds fluctuation in influent water, the optimal hydraulic retention time was 3.5h and the average removal rate of CODcr, LAS were 91.1%,81.3%. While the DO was 4.6mg/L in biological contact oxidation pond, the removal rate of organic compounds could reach 85%. Lower temperatures could not affect the removal of CODcr and LAS so much but could lower the removal rate of TN severely. After pretreatment by acid hydrolysis, the B/C ratio of grey water increased from 0.36 to 0.48, and the concentration of LAS has decreased severely which proved that acid hydrolysis pretreatment could accelerate the degradation of LAS. When the adding ration in the first suspension clarifiers pond and the biological contact oxidation pond were 55% and 75%, respectively, the average CODcr value of the effluent was 29.8mg/L, and the removal rate was up to 80%; the average value of ammonia was 3.4mg/L, and 81% has been removed, which meet a higher requirements for reuse.The experiment has provided necessary function parameters and control conditions to grey water treatment for family and residential district use. The quality of effluent water can reach criterion of reclaimed water in the city. The new model which was high in efficiency, low in energy consumption and low in investment was practical in future use.