Ground Water Pollution around the Northern Part of Yokkaichi City

Water pollution in the ground water has been widely found in the northern part of Yokkaichi city. The biggest illegal disposal site of industrial waste in central Japan was found in this area. In order to identify the source of this pollution, the authors have investigated the ground water pollution around this illegal landfill site. Investigation of well and the seepage water was carried out at 26 observation sites, and the concentrations of the following parameters such as pH, EC, COD, T-N, T-P, D-Fe, D-Mn, arsenic and 1, 4-dioxane were analyzed. Pollution of COD, T-P, T-N, D-Fe, D-Mn, arsenic and 1, 4-dioxane was found. However, relation between these pollutants and the illegal disposal is not apparent, and needs further investigation.

Phosphorus Recovery from Incinerated Ash of Sewage Sludge by Heat Treatment

The phosphorus recovery from incinerated ash of sewage sludge by a heat treatment method was investigated.The incinerated ash of sewage sludge was mixed with sodium hydroxide or sodium carbonate,and treated at 750 ℃ to 900 ℃ in aerobic conditions.The phosphorus was successfully recovered as an alkali metal phosphate from the treated ash through water extraction.The recovery rate of the phosphorus reached about 74% to 78%.The optimal condition of the phosphorus recovery and composition of the recovered phosphorus was investigated.

Phosphorus Transfer in the Ash through Acid or AlkaliExtraction Processes

In order to find the best method of the phosphorus recovery, some kinds of the phosphorus recovery methods were applied using the same raw material. The acid treatment shows the highest recovery performance, on the contrary, the alkali treatment indicates the lowest recovery rate. The recovery rate was improved by the application of the heat treatment or hydrothermal method. In the acid treatment, the recovered phosphorus is mainly composed of aluminum phosphate, conversely, in alkali treatment, recovered phosphorus was mainly composed of sodium phosphate containing a small amount of aluminum. But the aluminum content in the phosphorus decreased by introduction of the heat treatment or hydrothermal method.

Phosphorus Recovery from the Ash of Sewage Sludge Using NaOH by Heat Treatment-II—Reuse of the Alkali Water Generated by Phosphorus Recovery

The phosphorus recovery from the incinerated ash using NaOH by the heat treatment,was investigated.In this method,non-reacted NaOH containing alkali water was generated with the phosphorus recovery.In order to find out the best method for reuse of the alkali water,the alkali water was mixed with new reagent of NaOH,and the phosphorus recovery was carried out.The phosphorus was recovered as a sodium phosphate,and the recovery rate was almost the same even with the reuse of the alkali water.

The Development of a Fluorine Removal Agent Using Incinerated Ash

Calcium-based compounds are used as fluorine removal treatment materials in water.However,due to the water solubility of calcium fluoride,there is a problem with low fluorine removal performance.For this reason,various removing agents including phosphorus have been developed.We have found that a combination of aluminum phosphate recovered from incinerated ash of the sewage sludge and refuse incineration ash has a high fluorine removal performance.At the highest removal performance,F ion concentration of the treated water reached 0.1 mg/L,so an optimal formulation method was investigated.

The Development of a Fluorine Removal Agent UsingIncinerated Ash (Ⅱ)

The compounds of aluminum phosphate are used to remove the fluorine compounds from wastewater. The fluorine removal agent using the ash of sewage sludge and the municipal waste in addition to sulfuric acid were investigated. The removal agent showed high removal performance, and the fluorine concentration of the treated water reached below 0.1 mg/L, and the noticeable elution of the harmful metals from the ashes were not found in this experiment.

Experiment of Removing Traces of Phosphorus in Water Using Bottom Sludge of Ise-Bay

Large amounts of sludge has accumulated in the Inner Bay,which is one factor of environmental deterioration.We found that this sludge has an effect of absorbing low concentrations of phosphorus in water.For the purpose of development of water treatment agents and effective utilization of the sludge,phosphorus removal performance was investigated using wet sludge collected in Ise-Bay.A small amount of sludge was added to the test water having a phosphorus concentration of about 1~2 mg/L,and the phosphorus concentration of the filtrate after stirring and filtration was measured.Depending on the sludge conditions,it showed 30% to 80% of phosphorus removal performance.We investigated the relationship between the physical properties of the sludge and the removal performance.

Phosphorus Recovery from Dehydrated Water Sludge by Incineration Using Alkali Metal Compounds

In order to recover the phosphorus from the waste water sludge,the dehydrated sludge was mixed with the reagent of NaOH,KOH or Na2CO3,and incinerated at 750℃ or 900℃.Phosphorus in the incinerated ash of the sludge was dissolved by the addition of water,and recovered by the evaporation of the phosphorus resolved water.The recovered phosphorus was confirmed to be an alkali metal phosphate,and the recovery rate reached about 75%regardless any combination of the reagents(NaOH,KOH or Na2CO3).